Dynamometer Results & Comparisons - Truck Coils MYTH PROVEN INSIDE

Well we dynoed a H/C stalled auto car with truck coils and did multi pulls so we whould not have any fluke pulls and the results speak for them self. The plugs were gaped at .050 ngktr55 if the trck coils were beter they whould deff show on the .050 gap

TRUCK COILS 374.41
STOCK COILS 375.20
http://i27.photobucket.com/albums/c182/dalejr38/scan0001.jpg

I'm a little lost to what the results were...

374hp vs 375hp with the truck coils, i dont know about the torque tho

I'm a little lost to what the results were...

0.79rwhp aka slight dyno variance from humidity change? haha

started to rain

Dont ruin this for everyone!!! Im waiting to see "Truck coil swap" in peoples sigs...:shiner:

LOL I was sold on this that's why I tested it

So these were the D585 coils with the heat sink?

I don't doubt your results but I am still on the fence about this. Why would sponors, who don't sell these, post up inflated #'s?

Hmm, and now it gets interesting...

cars that gain could have a weak coils. swap them with another set and i pet it will show the same gain

Coils don't get "weak"..either they're good or they're not... This is one test result vs. how many??? How many times have we seen guys go from an LS6 mani to Fast 90 and posted a loss and other's have picked up 14+/- hp&tq.

IMHO..the numbers listed are pretty low for a H/C stalled auto car anyway...may have other problems

i never knew truck coils would really show improvement on a low HP car like this anyways? i always hear they were only beneficial in the high HP applications.

Would also like to know. Doing research on COP for 1000rwhp

Why would sponors, who don't sell these, post up inflated #'s?


Please tell me you kidding!

this seems like an accurate result-i really can't see changing coils adding power unless there is another ignition problem.If the coil is lighting the plug and firing the cylinder there is no more power to be had through ignition.

Please tell me you kidding!

I dont think he is kidding at all. Im the one that started the last thread showing a gain from swapping coils.

Please tell me what I have to gain by that? Do you think I have a shed full of used coils Im trying to sell?

I simply posted the results we saw from one test. Thats all. Do with it what you will.

The numbers don't lie guys... Some people have no idea about stalled autos and dynos

The numbers don't lie guys... Some people have no idea about stalled autos and dynos

Lock the converter :D

FWIW, Jeff @ Spectacle was merely posting some results he found in his shop. There's nothing to gain from posting HP gains from a truck coil, unless you're a GM parts dealer. So there's absolutely no reason to make direct or indirect comments about anyone making false claims, or claims for personal gain. They simply posted feedback on it.

Carry on.

PS- For the record, I've never thought it was worth the swap either.

FWIW, we tested my car back to back getting it ready for the last rental... In hopes of making the most possible power, I ended up gaining like 10 average hp under 5,000 rpm, but lost over 5,000 rpm by ~10 hp I think... So, back to stock coils for me, as my car really never see's sub 5,000 rpm at the track.... We did the baseline, swap to trucks, then swap back and the only time it lost was with the trucks. We did 6 pulls.

Hey Damian we'll put it to test when I come see you for everything else...i have a set of the coils completely assembled that I haven't mounted yet

its better this way, so I wont feel bad staying with my stock coils :P

Nice!!!!!! Coil swap gain BUSTED!

I dont think he is kidding at all. Im the one that started the last thread showing a gain from swapping coils.

Please tell me what I have to gain by that? Do you think I have a shed full of used coils Im trying to sell?

I simply posted the results we saw from one test. Thats all. Do with it what you will.


Sorry, I wasn't meaning you. You did a test and posted results, nothing wrong with that.

Over the years, I have seen a few sponsors and companies post results of something that the buying public could not reproduce with the same identical parts! I'm not talking 2-4 RWHP, more like 15-20 RWHP difference! :eek2:

If you have the time, do 3 pulls back to back with the stock coils, then do 3 pulls back to back with the truck coils then put the stock LS1 coils back on and do 3 more pulls back to back.

Then repeat on a totally different car to see if the results are the same. If they are, then I'm sold!

we did 4 pulls with the truck coils and 3 pulls with the stock coils...... dynos dont lie

Sorry, I wasn't meaning you. You did a test and posted results, nothing wrong with that.

Over the years, I have seen a few sponsors and companies post results of something that the buying public could not reproduce with the same identical parts! I'm not talking 2-4 RWHP, more like 15-20 RWHP difference! :eek2:

If you have the time, do 3 pulls back to back with the stock coils, then do 3 pulls back to back with the truck coils then put the stock LS1 coils back on and do 3 more pulls back to back.

Then repeat on a totally different car to see if the results are the same. If they are, then I'm sold!

I agree, SS should do this as well

this seems like an accurate result-i really can't see changing coils adding power unless there is another ignition problem.If the coil is lighting the plug and firing the cylinder there is no more power to be had through ignition.You're F'ING CRAZY! That's insane-o talk right there! Lies!


:jest:

Dyno results are dyno results.Sometimes parts just don't pan out.I've switched LS6 manifolds to FAST 90's and gain nothing.Is it the manifold? No,the combination dictated it by a Cam properly matched for a LS6.

So,do I buy changing coils does nothing? No,not yet.I agree with Shawn on the spark is spark theory but for my own sake I will fully test them on my own 427ci with full tuning of stock coils compared to a truck coil.Keep the temps exact and make sure the converter is locked.I figure a car running 12-1 comp. and 500+rwhp should make it easier to see a differencce if there is any.

.Please tell me what I have to gain by that? Do you think I have a shed full of used coils Im trying to sell? .

wish i did these sum-bitches are selling like hotcakes..:jest:

its all good man. no problem.

I dont know if the car we did the swap on will be back in the shop anytime soon, but like I said, we will probably try this swap on our 98 vette in the near future so I will give it a shot there and see what happens.

whether we show gains or not, I will definately post it up. we would have never tried this swap at all if a customer hadnt come to us and asked us to do it for him.

its not something we have ever advertised or tried to push as some sort of money making scheme.

Sorry, I wasn't meaning you. You did a test and posted results, nothing wrong with that.

Over the years, I have seen a few sponsors and companies post results of something that the buying public could not reproduce with the same identical parts! I'm not talking 2-4 RWHP, more like 15-20 RWHP difference! :eek2:

If you have the time, do 3 pulls back to back with the stock coils, then do 3 pulls back to back with the truck coils then put the stock LS1 coils back on and do 3 more pulls back to back.

Then repeat on a totally different car to see if the results are the same. If they are, then I'm sold!

I ran a test on my own truck engine using a engine dyno. With charge time at 7ms the truck coils picked up 15hp if memory serves. When just testing the coils the truck coil had 8 amps the car coil 5 amps. I just got the report on that test, I did not run it.

Kurt

I tested the coil theory years ago when I had my 383 on the engine dyno....swapped to the MSD coils ($600!) and picked up squat (they were sent by MSD to the test facilty where I happened to be dyno testing in hopes the shop (Westech) would try to pimp them a bit....the dyno test operator jumped at the chance to try them on my engine hoping something with 50% more output than stock might see a gain).

The first pull went from a best of 610-611 to 614 and we were both surprised a little thinking an eight coil system wouldn't really show much.....the next 4 pulls after that were back to 610-611.

Sorry....we have some nice parting gifts though :gruffy:

(They certainly looked a bunch better....maybe even a $100 worth but certainly not $600!)

Bottom line with an individual coil per cylinder its really hard to improve on the system unless you need some ridiculous amperage to fire the mixture where a significantly higher output coil can help. Its different with a single coil system because the coil has so much less time to regenerate its spark energy (its unloading eight times to every one time in an individual coil set-up).

Good post....probably helps many others not waste their time and money.

-Tony

did both sets of coils have the same amount of miles? where differant wires used? did the afr change?

Make sure your using the truck coils with the alum heat sink on the top...

and then those coils can use a different dwell time, and in our results(on my 418 bracket motor) we gained 15 to 20 everywhere... and I gained around 8 to 12 on the L92 head 6.0L

we did 4 pulls with the truck coils and 3 pulls with the stock coils...... dynos dont lie

So were these the D585's with the heat sink?

this seems like an accurate result-i really can't see changing coils adding power unless there is another ignition problem.If the coil is lighting the plug and firing the cylinder there is no more power to be had through ignition.

If you buy this, then it must be worthless to install different plugs or wires, huh?



Maybe I missed it but did the OP change the dwell?

Get a grip - One dyno test doesn't prove or disprove anything, guys. We'll see over time how this really pans out. The guys that see gains may have something in common in their combos/scenarios...or the guys that show no gain may be missing something.

Keep in mind, these coils were designed to benefit under heavy loads - which isn't exactly the same as WOT on a dyno. If someone's tune doesn't need any more spark, I see no reason why it would benefit. In most cases though, I think you would benefit, even in small ways: smoother idle, a MPG or 2, etc.

Seriously though, this is common sense - you can feel a stronger spark, especially when the difference is a factor of 3. To say that makes no difference intuitively seems silly. I guess since spark makes no difference, fuel and air must not either...
It is perfectly reasonable that one could/would pick up 2-3% power/efficiency (not a huge amount) by multiplying the spark energy, even with an ignition system as good as ours is.

Why is this such a tough concept for some people to wrap their heads around?

IMHO..the numbers listed are pretty low for a H/C stalled auto car anyway...may have other problems

Yea, you are right... Most stalled A4 H/C cars are at LEAST 425rwhp on average...................................

I have another measly 375Rwhp stalled a4.. Sucks to be me...

Why is this such a tough concept for some people to wrap their heads around?Because people are dying to put "truck coil swap" in thier sig next to thier Optima Battery, K&N filter, and aftermarket plug wires. and say "I made 4xxhp, before my coils swap"

Does anyone have a stock tune of a vehicle that surely has these coil? We could at least look at the dwell time vs standard coils.

The only way I could possibly see a gain from a coil swap is when you take a tired out 120+k mile coil setup off and replace them with new coils whether it is Stock replacements or the truck coils.

Either way I dont think the gain is big enough, or will ever be big enough to have this huge debate about it. Whats a few hp honestly?? nothing at all. However in Charles case, their was no gain seen. Sure someone could do the same thing and their might show a gain, but how do you know its not just a change in Temperature/weather etc. that actually shows a gain???

In the end IMO coils are coils and coils. They all do the same and the Benefit (even if any) is so minimal it doesnt really make a difference at all.

Yea, you are right... Most stalled A4 H/C cars are at LEAST 425rwhp on average...................................

I have another measly 375Rwhp stalled a4.. Sucks to be me...

Wasn't ragging on his ride..just thought the numbers seemed a little low for the mods listed...dyno's are tuning and measuring tools....a H/C stalled auto may not produce good dyno numbers but can run it's ass off at the track and I was merely stating my opinion (last I checked you were free to speak your mind) as far as the comment goes about it "sucking" to be you only you or the guy/guys you blew would know that:gay: ...anyways back to the subject there is good info out there about these coils vs. regular LS coils and feel free to check the thread that has detailed info..I'l try to dig it up for those to lazy to use the search

If you buy this, then it must be worthless to install different plugs or wires, huh?



Maybe I missed it but did the OP change the dwell?

Get a grip - One dyno test doesn't prove or disprove anything, guys. We'll see over time how this really pans out. The guys that see gains may have something in common in their combos/scenarios...or the guys that show no gain may be missing something.

Keep in mind, these coils were designed to benefit under heavy loads - which isn't exactly the same as WOT on a dyno. If someone's tune doesn't need any more spark, I see no reason why it would benefit. In most cases though, I think you would benefit, even in small ways: smoother idle, a MPG or 2, etc.

Seriously though, this is common sense - you can feel a stronger spark, especially when the difference is a factor of 3. To say that makes no difference intuitively seems silly. I guess since spark makes no difference, fuel and air must not either...
It is perfectly reasonable that one could/would pick up 2-3% power/efficiency (not a huge amount) by multiplying the spark energy, even with an ignition system as good as ours is.

Why is this such a tough concept for some people to wrap their heads around?

Really,please explain to me how a stronger spark is going to help if there is no misfires to start with?

comparing amount of spark to air and fuel is foolish.

last question-how do you feel a stronger spark?

I was actually told the other day that my car was no longer stock because I had changed the wires and plugs...... wires aren't even MSD wires, and the plugs are NGKtr55 cause we all know that alone adds 30 hp.....((this guy plays an online game with me and in the game if you change the plugs and wires you gain 30hp))

I told him he plays too many video games...lol.

I was actually told the other day that my car was no longer stock because I had changed the wires and plugs...... wires aren't even MSD wires, and the plugs are NGKtr55 cause we all know that alone adds 30 hp.....((this guy plays an online game with me and in the game if you change the plugs and wires you gain 30hp))

I told him he plays too many video games...lol.

I thought the dwell time needed to be changed at least?

Wasn't ragging on his ride..just thought the numbers seemed a little low for the mods listed...dyno's are tuning and measuring tools....a H/C stalled auto may not produce good dyno numbers but can run it's ass off at the track and I was merely stating my opinion (last I checked you were free to speak your mind) as far as the comment goes about it "sucking" to be you only you or the guy/guys you blew would know that:gay: ...anyways back to the subject there is good info out there about these coils vs. regular LS coils and feel free to check the thread that has detailed info..I'l try to dig it up for those to lazy to use the search

Heres a little info for you to consider....

I have a MS3 camaro SS. Charles (the OP) did the install and dyno tune. Yesterday I went back to his dyno and first pull it put down 367rwhp...now, before he even tuned anything, my car in that exact form on a dyno dynamics put down 412rwhp. What Im saying is, Dont judge a car by measily dyno numbers.

BTW, after tuning I left with 396.xxrwhp on his dyno...so if I went back to the dyno dynamics at the other shop, it would be 420+rwhp. Pretty much just bragging rights.

I fail to see how one is going to pick up power on a H/C bolt on car when the coils are good in the first place.

Reminds me of the thread a few day ago....picked up a second and 9mph going from tr6's to tr55's hahaha. Yeah that will happen when you have a bad plug lolz.

So were these the D585's with the heat sink?

Yes they were

I WIll be testing these on MY 440LSX in the next month.... i will post results

Heres a little info for you to consider....

I have a MS3 camaro SS. Charles (the OP) did the install and dyno tune. Yesterday I went back to his dyno and first pull it put down 367rwhp...now, before he even tuned anything, my car in that exact form on a dyno dynamics put down 412rwhp. What Im saying is, Dont judge a car by measily dyno numbers.

BTW, after tuning I left with 396.xxrwhp on his dyno...so if I went back to the dyno dynamics at the other shop, it would be 420+rwhp. Pretty much just bragging rights.



Good Job...your car is a M6 according to your sig and the guy whom this was directed to and the OP have auto's...for some reason M6's dyno higher

Good Job...your car is a M6 according to your sig and the guy whom this was directed to and the OP have auto's...for some reason M6's dyno higher

no shit. You completely over looked my point that my car was on two different dynos and put down very different numbers which in the end the Dyno is nothing but a Tuning Device.

On an engine making very high cylinder pressures thats having trouble lighting off the plug...the D585's can be beneficial because they will keep you from having to tighten your plug gap down to almost nothing in order to make a spark...which is a good thing.

I'm running D585's on my Camaro because I got them for free (bought an LQ4 to use the block for a buildup and it had coils on it), but I didn't see any gain at all because my stock coils were fine and I don't make nearly enough cylinder pressure for the stock coils to have any problems making a spark at stock plug gap.

I never tested the MSD coils, but I had them bench tested for output and they fell behind the truck coils.
I wonder if you need an engine that is struggling to see the gain. My truck engine had no audible misfire with the f car coils, seemed fine on the dyno. The truck coils picked it up starting just a bit before peak torque (3900rpm 900+ft lbs) all the way out to peak power (5200rpm-900hp) and slightly beyond power peak. My engine now is 100,000 miles and sounds like a diesel! One coil did go bad at about 80,000 miles, but they have generally been good.

Kurt

I tested the coil theory years ago when I had my 383 on the engine dyno....swapped to the MSD coils ($600!) and picked up squat (they were sent by MSD to the test facilty where I happened to be dyno testing in hopes the shop (Westech) would try to pimp them a bit....the dyno test operator jumped at the chance to try them on my engine hoping something with 50% more output than stock might see a gain).

The first pull went from a best of 610-611 to 614 and we were both surprised a little thinking an eight coil system wouldn't really show much.....the next 4 pulls after that were back to 610-611.

Sorry....we have some nice parting gifts though :gruffy:

(They certainly looked a bunch better....maybe even a $100 worth but certainly not $600!)

Bottom line with an individual coil per cylinder its really hard to improve on the system unless you need some ridiculous amperage to fire the mixture where a significantly higher output coil can help. Its different with a single coil system because the coil has so much less time to regenerate its spark energy (its unloading eight times to every one time in an individual coil set-up).

Good post....probably helps many others not waste their time and money.

-Tony

ng my opinion (last I checked you were free to speak your mind) as far as the comment

Wrong. :judge:

no shit. You completely over looked my point that my car was on two different dynos and put down very different numbers which in the end the Dyno is nothing but a Tuning Device.

Thanks again GENIUS......exactly what I said before which is why you shouldn't take the OP's results and expect the same outcome ...we should all know by now that there are many variables to consider when reading dyno results and dynos can be manipulated to read higher or lower...not trying to get into a pissing match not argue with stupidity ....back to the subject at hand please

Wrong. :judge:

And who is going to stop me....this forum is full of peoples opinions....let's not get into this

I had was always under the impression the truck coils were better suited for forced induction/ high compression engines. Maybe even benificial in NO2 engines because you can run a larger gap on the plugs.

I am going to give them a try. This will be on my 11.7:1 416. It will also be with the t56, which should paint a better picture of any gains or losses than an auto on the dyno.

Really,please explain to me how a stronger spark is going to help if there is no misfires to start with?

comparing amount of spark to air and fuel is foolish.

last question-how do you feel a stronger spark?


Good comments, Shawn, let me address in reverse order.

I don't FEEL a stronger spark, I KNOW it because it was measured comparatively here:
http://www.megamanual.com/seq/coils.htm
I took the time to research this a bit because it's interesting. Given your profession and reputation, perhaps it's worth your time to do so also.

Perhaps there is a point of diminishing returns with spark vs. air and fuel that continue to see benefit as they are increased but to say it's foolish is ignorant and narrow minded. To say that spark is spark is plain silly and not at all consistent with your reputation. If that were the case, we'd all use the same plugs, wires, etc. If that were the case, why did we go from points to electronic distributors? From those to shared coils? From those to coil on/near plug designs? Stronger spark is better, period. If you have proof otherwise, you could make a mint selling downgrades to every single manufacturer's ignition systems.

Want more? Worn out plugs or wires will often not cause misfires. Does that mean there is no benefit to changing them? Guess what, when you do, the engine runs markedly better - smoother, stronger, etc. I've seen this literally hundreds of times...as has anyone that has dealt with tune and driveability issues for a living. So no misfires but adding a stronger spark means more power and efficiency. I'm surprised you've never seen such a thing.

Given that GM Powertrain has been a consistent bright spot, do you think they'd make a change like this to so many vehicles that see high loads for no reason? That's too stupid even for GM.

So the question behind the question is key and it is two fold:
1. Was there an existing weak spot in the system that the hotter coil compensated for?
2. Can the system benefit from or use the additional spark energy?

Those questions require MUCH more attention to detail and troubleshooting, and can't be answered by a handful of dynos. In the end, each car and application will be somewhat different, so we have to see lots of results over time to get a consistent finding on if a few HP is worthwhile or not.

Finally, many people here spend a lot more money for a lot less HP so for folks to say a few HP is not worth is just silly given the HP hungry population here. :)

Given all of that specific detail, I'd say it's up to you to tell ME how a stronger spark CAN'T help...

Good comments, Shawn, let me address in reverse order.

I don't FEEL a stronger spark, I KNOW it because it was measured comparatively here:
http://www.megamanual.com/seq/coils.htm
I took the time to research this a bit because it's interesting. Given your profession and reputation, perhaps it's worth your time to do so also.

Perhaps there is a point of diminishing returns with spark vs. air and fuel that continue to see benefit as they are increased but to say it's foolish is ignorant and narrow minded. To say that spark is spark is plain silly and not at all consistent with your reputation. If that were the case, we'd all use the same plugs, wires, etc. If that were the case, why did we go from points to electronic distributors? From those to shared coils? From those to coil on/near plug designs? Stronger spark is better, period. If you have proof otherwise, you could make a mint selling downgrades to every single manufacturer's ignition systems.

Want more? Worn out plugs or wires will often not cause misfires. Does that mean there is no benefit to changing them? Guess what, when you do, the engine runs markedly better - smoother, stronger, etc. I've seen this literally hundreds of times...as has anyone that has dealt with tune and driveability issues for a living. So no misfires but adding a stronger spark means more power and efficiency. I'm surprised you've never seen such a thing.

Given that GM Powertrain has been a consistent bright spot, do you think they'd make a change like this to so many vehicles that see high loads for no reason? That's too stupid even for GM.

So the question behind the question is key and it is two fold:
1. Was there an existing weak spot in the system that the hotter coil compensated for?
2. Can the system benefit from or use the additional spark energy?

Those questions require MUCH more attention to detail and troubleshooting, and can't be answered by a handful of dynos. In the end, each car and application will be somewhat different, so we have to see lots of results over time to get a consistent finding on if a few HP is worthwhile or not.

Finally, many people here spend a lot more money for a lot less HP so for folks to say a few HP is not worth is just silly given the HP hungry population here. :)

Given all of that specific detail, I'd say it's up to you to tell ME how a stronger spark CAN'T help...


I like how you sidestep the question.in other words you can't tell me how more spark is going to make more power if your ignition system is working properly with no misfires.
you're the one who said you can feel more spark,just trying to figure that out.Maybe you should read what you typed.
plugs and wires aren't going ot make more power-unless they are bad.if they have more resistance than the coil can overcome you will start having misfires.The main reason for aftermarket plug wires is to prevent spark leakage.If an engine is running rough that is a misfire.the main reason for having different spark plugs is to have different heat ranges and electrode designs to reduce detonation.
The only way possible for more ignition to help is that if you can widen the plig gap and have a better flame kernal.and that is pretty iffy.

You need to quit reading what these companys say to sell their products.This is what i do for a living-i have tested all of this stuff-where do you get you info from-the internet,if you havn't done it personally it's just hear say from another person.

Good comments, Shawn, let me address in reverse order.

I don't FEEL a stronger spark, I KNOW it because it was measured comparatively here:
http://www.megamanual.com/seq/coils.htm
I took the time to research this a bit because it's interesting. Given your profession and reputation, perhaps it's worth your time to do so also.

Perhaps there is a point of diminishing returns with spark vs. air and fuel that continue to see benefit as they are increased but to say it's foolish is ignorant and narrow minded. To say that spark is spark is plain silly and not at all consistent with your reputation. If that were the case, we'd all use the same plugs, wires, etc. If that were the case, why did we go from points to electronic distributors? From those to shared coils? From those to coil on/near plug designs? Stronger spark is better, period. If you have proof otherwise, you could make a mint selling downgrades to every single manufacturer's ignition systems.

Want more? Worn out plugs or wires will often not cause misfires. Does that mean there is no benefit to changing them? Guess what, when you do, the engine runs markedly better - smoother, stronger, etc. I've seen this literally hundreds of times...as has anyone that has dealt with tune and driveability issues for a living. So no misfires but adding a stronger spark means more power and efficiency. I'm surprised you've never seen such a thing.

Given that GM Powertrain has been a consistent bright spot, do you think they'd make a change like this to so many vehicles that see high loads for no reason? That's too stupid even for GM.

So the question behind the question is key and it is two fold:
1. Was there an existing weak spot in the system that the hotter coil compensated for?
2. Can the system benefit from or use the additional spark energy?

Those questions require MUCH more attention to detail and troubleshooting, and can't be answered by a handful of dynos. In the end, each car and application will be somewhat different, so we have to see lots of results over time to get a consistent finding on if a few HP is worthwhile or not.

Finally, many people here spend a lot more money for a lot less HP so for folks to say a few HP is not worth is just silly given the HP hungry population here. :)

Given all of that specific detail, I'd say it's up to you to tell ME how a stronger spark CAN'T help...

:cheers:MY POINT EXACTLY and thank you for taking time to point this out. Most people on here (or just most people in general) would rather take what someone else posted in regards to their results and use that as if it were written in stone. However , people who take the time out to look further at all the little details and variables involved in dyno results know to take the posted results with a grain a salt ( most dyno results posted {not necessarily refering to these} are not even corrected thus yielding higher results) there are alot of different tuning tables in tuning software that some "tuners" don't even fool around with because they don't know enough about them, now depending on all the details of a particular setup there can be an advantage to using the truck coils, now if someone is taking a stock, untuned car with a lid, catback, etc.... and thinking that just bolting these on is going to give them 10+/- HP/TQ without addressing other issues should look into "modding" alot further in detail......just saying you shouldn't say that "I put "these" coils on "this" car with "those" mods and didn't get results like "that" guy....I'm sure we know people thathave picked up and lost HP/TQ by changing manifolds yet people still buy them and people still continue to produce results because it take time to get the "most" out of any particular setup

Shawn, without a doubt you have more experience with dealing with the issue than most people on this board. With that said would ou agree that given the right combo of parts and tuning that there would be some benefit to running these coils????

Shawn, without a doubt you have more experience with dealing with the issue than most people on this board. With that said would ou agree that given the right combo of parts and tuning that there would be some benefit to running these coils????

yes indeed,there comes a time when more ignition is demanded.Very high compression engines,n2o engines and forced induction engines can cause spark blow out which causes misfires.When this is the case,more ignition is clearly needed.

I never tested the MSD coils, but I had them bench tested for output and they fell behind the truck coils.
I wonder if you need an engine that is struggling to see the gain. My truck engine had no audible misfire with the f car coils, seemed fine on the dyno. The truck coils picked it up starting just a bit before peak torque (3900rpm 900+ft lbs) all the way out to peak power (5200rpm-900hp) and slightly beyond power peak. My engine now is 100,000 miles and sounds like a diesel! One coil did go bad at about 80,000 miles, but they have generally been good.

Kurt

Kurt, Isn't your truck turbocharged? I bet the spark was weak...not completely out...but weak under boost, with the stock coils, and was therefore not misfiring, but was having trouble initiating combustion.

If anything, I'd bet specifically in a setup like that, you'd be able to get away with less spark advance under boost once you went to the stronger coils and still make the same, if not more power...could probably get away with a little more plug gap too, and possibly pickup more power and necessitate LESS advance.

If you can light off the mixture really well...you don't need to light it off so early to get max cylinder pressure at the optimal time...if you're having trouble getting it lit off well, you need to ignite it earlier so that your max cylinder pressure happens at the right time...and that max pressure is probably ever so slightly lower (as evidenced by your increase in torque when going to the D585's).

I'd bet you saw little to no difference before the turbo spooled, and then as it spooled, if you had enough resolution in the dyno, you probably saw it gain proportionally to the total torque (torque is an excellent indiactor of how much total charge there really is in the chamber) until peak boost was achieved, and then as torque started to drop off (if it did) you probably saw the gain begin to diminish as well.

Shawn, wouldn't you agree that your last post seems to agree with this?

Anyone else care to debate (rather than just make angry BS posts)? It's the best way for us all to learn.

3. To say that makes no difference intuitively seems silly. I guess since spark makes no difference, fuel and air must not either...


this guy gets the concept.

fuel air and spark makes fast cars go vroom vroom, so i should get a bad ass intake badass fuel injectors, and leave spark alone?



In the end IMO coils are coils and coils.

and a cam is a cam? fuck it i'm going back to stock...

Thanks again GENIUS......exactly what I said before which is why you shouldn't take the OP's results and expect the same outcome ...we should all know by now that there are many variables to consider when reading dyno results and dynos can be manipulated to read higher or lower...not trying to get into a pissing match not argue with stupidity ....back to the subject at hand please

I'm not sure what your getting at with the comment that dynos can be manipulated to read higher or lower comment but I can tell you that I was there and helped swap out the coils and there was nothing done to manipulate the dyno. Just so you know.... we were hoping to see some gains.

dynos lie! et's dont! to the people who say they pick up xxhp and xxlbs with there truck coils did your times change?

I'm not sure what your getting at with the comment that dynos can be manipulated to read higher or lower comment but I can tell you that I was there and helped swap out the coils and there was nothing done to manipulate the dyno. Just so you know.... we were hoping to see some gains.

Simply pointing out that some dynos (different types of dynos, different areas {DA,weather,temps,altitude,etc..}) read higher or lower than others because there are a few "tricks" that people do to get their dyno to read higher so customers will be super pleased with their combo (not getting into that) Not saying that this dyno was or wasn't manipulated because I wasn't there and don't know all the details (nor does anyone else except for those who were there), the only info we have is what the OP posted...Thank you Shawn for chiming in and answering the question directly:cheers: And the truck coil "MYTH" has not been proven as there has not been enough r/d to say what works and what doesn't...simply put if you have an application such as Shawn mentioned and are still running stock coils it may benefit you to give it a try, for you bolt-on guys it may be best to wait and make sure the rest of your system (plugs, wire, etc..) are in optimal condition before you add these expecting some sort of tremendous gain

Simply pointing out that some dynos (different types of dynos, different areas {DA,weather,temps,altitude,etc..}) read higher or lower than others because there are a few "tricks" that people do to get their dyno to read higher so customers will be super pleased with their combo (not getting into that) Not saying that this dyno was or wasn't manipulated because I wasn't there and don't know all the details (nor does anyone else except for those who were there), the only info we have is what the OP posted...Thank you Shawn for chiming in and answering the question directly:cheers: And the truck coil "MYTH" has not been proven as there has not been enough r/d to say what works and what doesn't...simply put if you have an application such as Shawn mentioned and are still running stock coils it may benefit you to give it a try, for you bolt-on guys it may be best to wait and make sure the rest of your system (plugs, wire, etc..) are in optimal condition before you add these expecting some sort of tremendous gain

Another LS1tech expert.....:(

Let me first put up a disclamer because another member is salty with me because supposedly I gave out bad 'adise' (as he spelled it) and he went and bought a set of truck coils for $200, then drove an hour to have his car dyno'd and he only gained 5hp and he was pissed at me.

With that said. I went and picked up a set of d585 coils because the way I look at it, it's a better factory peice than the stock ls1 coils. I went in and bumped up my dwell time a little bit and have noticed a good amount of decrease in misfires at idle and low rpms as well as better tip in throttle response. I didn't dyno the car because, A: it's been 7 years since it was last on a dyno, B: I don't have the time to drive my car much less take it and get it dyno'd, C: I would rather compare actual data on the road than worry about dyno graphs.

I did notice about a 2-3mpg gain in mileage as well, which could be a result of better light off and reduced misfires at low rpms.

Fact is, the truck coils or ls2 coils are better than the original ls1 coils that gm tossed onto these cars 10-12 years ago, so for less than $200, it's a decent preventative maintenance item.

I like how you sidestep the question.in other words you can't tell me how more spark is going to make more power if your ignition system is working properly with no misfires.
you're the one who said you can feel more spark,just trying to figure that out.Maybe you should read what you typed.
plugs and wires aren't going ot make more power-unless they are bad.if they have more resistance than the coil can overcome you will start having misfires.The main reason for aftermarket plug wires is to prevent spark leakage.If an engine is running rough that is a misfire.the main reason for having different spark plugs is to have different heat ranges and electrode designs to reduce detonation.
The only way possible for more ignition to help is that if you can widen the plig gap and have a better flame kernal.and that is pretty iffy.

You need to quit reading what these companys say to sell their products.This is what i do for a living-i have tested all of this stuff-where do you get you info from-the internet,if you havn't done it personally it's just hear say from another person.

First off, let's pull some plug wires on a running engine and both pee on two spark plugs - one LS type, and one from an old points-type distributor - and see if we can feel the difference. You first... :D
Seriously and from experience, if you grab a hot wire with twice the current of the last one you grabbed, you can generally "feel" it :P though I was (again) referring to the measured results in the video.

Seriously, these *companies* is referring to what? I see no "company" selling exactly what we're discussing here, unless I missed it. It may complement their business but there is no direct gain that I see at this point. These guys, ostensibly at Megasquirt, measured and compared the output of the various LS coils using an o-scope and other tools of the trade. I didn't read the site at all, only watched the video. Did you even take the time to look at the video and see the output results? Based on your response, my guess is "No."

Intuitively, a hotter spark burns the fuel/air mixture more quickly and more completely. Simple physics. This results in more power and more efficiency. Is it measurable? Obviously yes it is at times, not so much in others. Does it require tuning or other adjustments? I guess time will tell as results are logged with different combinations and different variables. So far, it seems to make a small positive gain a slight majority of the time. Another way to look at it is - how much unburned fuel is being sent out the exhaust? If the car is running rich, say only burning 98-99% of the fuel, a hotter spark will enable more combustion of the fuel. It's pretty easy to see that could be 1-2% more power potential. Simply put, more electrical energy has the clear potential to burn more fuel more quickly. Otherwise, why would EVERY manufacturer continue to upgrade ignition systems? Why did GM choose the hotter coils for vehicles that see high loads? Why do all the FI guys seem to like these higher output coils?

Again, and you seem to have missed this or just didn't respond because it's not consistent with your view - plugs can be worn out but not cause misfires. Guys with a serious tune/electrical REPAIR background know this. (This basic knowledge is often lacking in speed shops who are good at making cars faster but not always at troubleshooting basic issues. I'm not saying that's you but I've seen it MANY times.) Put in new plugs and wires, and bang! more power even though there were zero misfires. Same principle applies with a hotter coil. Simply put, you can have less energy getting through the wires and to the plug, but it can still get there regularly enough to not cause any misfires. Weak but completely unbroken flow of current. This concept should be pretty clear to someone with an extensive electrical and tuning background.

Aftermarket wires are also used for other reasons - including to block out EMI noise, to allow more energy through the wires, to make a shop money, and for aesthetic appeal. Fact is, GM wires are typically excellent and not prone to leakage under anything approaching normal applications. LOTS of fast LS cars out there on the completely stock ignition system, showing the LS platform has been endowed with a robust ignition system. LS cars and trucks have LOTS of fuel issues when it comes to driveability, and a few air-related also - but PRECIOUS few when it comes to spark/ignition. This is why I was a bit skeptical about truck coils at first, but the concept is sound and I am anxious to see more results and know more of the back story on each.

I'm still open on the flame *kernel* issue though.

I didn't sidestep a thing - I took the time to answer each of your questions/comments in several ways, some direct and some by related example, some by both....again, though you've not yet done the same in return.

By the way, this is fun! Interested to hear more...and see more dyno results and details.

I love how people have said that 375 is a "weak h/c stalled" car. No one mentioned if the car had a 9inch or was on a mustang dyno. In that case 375 is not that weak. Not everyone runs a 10 bolt,t56, on a dyno jet.

Another LS1tech expert.....:(

No expert by any means sir but in regards to the subject at hand I have taken the time and researched these claims and info that was in 15+ page thread that originally started the "myth". I apologize if you are disappointed in me not letting one person's/shop's results be the "end all" of the truck coil theory. You ought to know that there are people who see the info on this site, immediately try to duplicate or discard the info without further investigation....:(:lurk:

Sounds like this was a good test. Stock LS1 coils or truck you cant go wrong.

Fact is, GM wires are typically excellent and not prone to leakage under anything approaching normal applications. LOTS of fast LS cars out there on the completely stock ignition system, showing the LS platform has been endowed with a robust ignition system. LS cars and trucks have LOTS of fuel issues when it comes to driveability, and a few air-related also - but PRECIOUS few when it comes to spark/ignition. This is why I was a bit skeptical about truck coils at first, but the concept is sound and I am anxious to see more results and know more of the back story on each.

You're absolutely right...the only benefits I see to SOME aftermarket wires...are cut to fit (when coils are re-located for cosmetic reasons), and some tend to have a bit better resistance to heat in certain applications (like when you have turbo plumbing near them)...but rather than get off topic, I will stop talking about wires.

Regarding the fuel issues versus spark issues...you're right again, ESPECIALLY with 99-2000 cars where the injectors are smaller, and basic bolt ons get the duty cycles up too high. The LS ignition is indeed very very robust, especially evidenced by the fact that people retrofit the coils from LS1's and other gen3/4 engines to all sorts of other vehicles...but everything eventually has it's limitations...and the stock LS1 coils start to be limiting when cylinder pressures get very high, and plug gaps don't come down...decreasing the plug gap to nothing to get the thing to spark under high load, is working backwards, beefing up the strength of the coils instead so that you can keep the plug gap up high despite the higher cylinder pressures is working in the right direction...and the D585's ARE stronger coils and they DO show benefits in the right applications.

I love how people have said that 375 is a "weak h/c stalled" car. No one mentioned if the car had a 9inch or was on a mustang dyno. In that case 375 is not that weak. Not everyone runs a 10 bolt,t56, on a dyno jet.

the car did have a 9" working against it and it was a dynojet dyno

I love how people have said that 375 is a "weak h/c stalled" car. No one mentioned if the car had a 9inch or was on a mustang dyno. In that case 375 is not that weak. Not everyone runs a 10 bolt,t56, on a dyno jet.

...honestly...if you notice the people providing real information, based on real experience, don't really care about that cars number...it's just a number...on a dyno none of the rest of us have used, in a car that none of us built or have worked on.

I am NOT saying dyno's lie...but comparing one number from one dyno, to another number from another dyno, is pointless...comparing time slips from different tracks in different parts of the country on different days is equally pointless, and since we're not all in the same place at the same time racing on the same track and tuning on the same dyno...there's no sense in arguing about the empirical number at all...it's just a number, it doesn't mean anything...but if the car is strapped to the dyno, and makes a few pulls, the coils and tune are changed, and a few more pulls are made and the dyno shows a new number...THAT is absolutely NOT a dyno lieing, and that gain DOES mean something. The fact that the OP showed no real gain, means that his setup didn't need it...and it also shows that he's probably not actually making a whole lot of power, and thus his cylinder pressures aren't all that high, and his stock coils are more than capable of making a healthy spark at whatever plug gap he's running. The fact that Kurt picked up power, means he IS making a lot of power, has a lot of cylinder pressure, and coils that weren't D585's were not strong enough to create a healthy spark...at least not as healthy as the D585's are creating on his setup.

I'm sure there are thousands of cars on this board, and in general, that would gain nothing from D585's, but there are also quite a few others that are making good power...that could make even more by just swapping the coils and flashing the correct dwell tables into the PCM and making some minor adjustments to the tune.

dynos lie! et's dont! to the people who say they pick up xxhp and xxlbs with there truck coils did your times change?

I was wondering about this as well, but you would almost have to make a few runs, swap out the coils at the track and then make a few more runs and hope the weather/DA doesn't change much during that time frame.

I am curious if others have gotten that good of an increase in mileage that The Alchemist received.

I have not seen any change in MPG...but my engine is stock, so the stock cam is very happy at the 1750ish RPM that I spend an AWFUL lot of time at in 6th gear...if I had a larger cam and thus unhappy/unstable chambers at lower RPM, I'd expect to see an MPG gain from a better ignition...just like the people seeing gains at full throttle, not all setups will...but not all won't either ;)...and although I've currently seen no appreciable gain from my free upgrade to D585's...I do know that any future upgrades, will not find my ignition being the weak link in keeping the setup optimized.

So has anyone pulled the stock tune out a vehicle with these coils to see the difference in dwell time??

My truck has them, how do I edit my sig??!?!

Intuitively, a hotter spark burns the fuel/air mixture more quickly and more completely. Simple physics. This results in more power and more efficiency.
do you mean "hotter spark" literally? how does one measure temperature of the spark in a cylinder? And, spark doesn't burn anything, it IGNITES. It's like saying that you have better barbeque because you ignited the fire with nicer matches...

If the car is running rich, say only burning 98-99% of the fuel, a hotter spark will enable more combustion of the fuel. It's pretty easy to see that could be 1-2% more power potential. again as far as I know, only definite amount of fuel can burn with given amount of oxygen, and it's chemically limited. Once mixture is ignited, it's all equal.

Am I wrong somewhere?

My truck is turbocharged, I like it that way!!
This thread has degraded to a pissing contest for some reason. I just wrote my findings with my 6.0 in my truck, this has caused me to use the truck coils in many cop engines because they produced more power with no ill effects. One thing I think most will agree with is that the truck coils won't hurt performance and they are long lasting parts at a reasonable price. If you need coils on a new build it would be foolish not to use the truck coils, and if you have any other coil and your engine does not misfire rock on if you so desire!! I have shared information I have on my testing which was done back to back in my favorite A-B-A method, it has me convinced the added amperage is helpful.

KurtKurt, Isn't your truck turbocharged? I bet the spark was weak...not completely out...but weak under boost, with the stock coils, and was therefore not misfiring, but was having trouble initiating combustion.

If anything, I'd bet specifically in a setup like that, you'd be able to get away with less spark advance under boost once you went to the stronger coils and still make the same, if not more power...could probably get away with a little more plug gap too, and possibly pickup more power and necessitate LESS advance.

If you can light off the mixture really well...you don't need to light it off so early to get max cylinder pressure at the optimal time...if you're having trouble getting it lit off well, you need to ignite it earlier so that your max cylinder pressure happens at the right time...and that max pressure is probably ever so slightly lower (as evidenced by your increase in torque when going to the D585's).

I'd bet you saw little to no difference before the turbo spooled, and then as it spooled, if you had enough resolution in the dyno, you probably saw it gain proportionally to the total torque (torque is an excellent indiactor of how much total charge there really is in the chamber) until peak boost was achieved, and then as torque started to drop off (if it did) you probably saw the gain begin to diminish as well.

Shawn, wouldn't you agree that your last post seems to agree with this?

Anyone else care to debate (rather than just make angry BS posts)? It's the best way for us all to learn.

My truck is turbocharged, I like it that way!!
This thread has degraded to a pissing contest for some reason. I just wrote my findings with my 6.0 in my truck, this has caused me to use the truck coils in many cop engines because they produced more power with no ill effects. One thing I think most will agree with is that the truck coils won't hurt performance and they are long lasting parts at a reasonable price. If you need coils on a new build it would be foolish not to use the truck coils, and if you have any other coil and your engine does not misfire rock on if you so desire!! I have shared information I have on my testing which was done back to back in my favorite A-B-A method, it has me convinced the added amperage is helpful.

Kurt

And I couldn't agree with you more. I hope I didn't offend you, I was trying to help avoid the pissing contest.

I have no problem with anybody!! It is always nice to see what others come up with.

KurtAnd I couldn't agree with you more. I hope I didn't offend you, I was trying to help avoid the pissing contest.

I find it hilarious that the guys who are bashing the truck coils after one member reports no gain are probably the same guys who bashed the truck coils because "only a couple" members posted up that they saw gains. :lol:

"MYTH PROVEN" - get real. :lol: One car's dyno result doesn't prove jack shit. Show me twenty or twenty-five independent results before I conclude whether they are a good mod... or not.

I am accustomed to seeing HP and TQ vary by 2-3 (HP or Ft-lb) on back to back dyno pulls when nothing has been changed. So when some members picked up 10 RWHP (or more with Spectacle's customer) on back to back pulls where only the coils had been swapped, I thought it was intriguing enough to pick up a set of those coils and slap them on my Procharged car. I didn't feel that a couple people showing gains is conclusive at all, but for the price of a nice used set of coils, I was intrigued and willing to experiment. With the cylinder pressures in an FI application, I felt the stronger spark from the D585 coils might be a good thing and can't hurt.

I am accustomed to seeing HP and TQ vary by 2-3 (HP or Ft-lb) on back to back dyno pulls when nothing has been changed. So when some members picked up 10 RWHP (or more with Spectacle's customer) on back to back pulls where only the coils had been swapped, I thought it was intriguing enough to pick up a set of those coils and slap them on my Procharged car. I didn't feel that a couple people showing gains is conclusive at all, but for the price of a nice used set of coils, I was intrigued and willing to experiment. With the cylinder pressures in an FI application, I felt the stronger spark from the D585 coils might be a good thing and can't hurt.

X2. I got a good deal on my d585's for my procharged car and will be taking both coil sets with me when I get a tune. If they don't make more power oh well. I'm only out 140 bucks. I'm sure they would resell for that on here or ebay no problem. I've seen a couple threads of positive gains and this the first negative. Odds are still in the positive gains favor. :engarde:

ok so i never saw the answer to this... were both coils brand new?

LoL,

TO ANSWER A QUESTION

The tuning for just the ignition dwell alone is different for each year as the cars get newer- I would need a list of every change in coils to match them with every tune.

If you guys think that the coils are no different then you are being ignorant. Are they better than a stock ls1 coil? If they are more heat efficient then they are better.

With electrical, heat is a form of resistance - if they manage heat better than you can expect them to be more efficient.

And I can't believe we have an engine builder saying " If there was no knock then there is no gain"

Ive had cars come to me for tuning where they left making 400hp with no knock, check the plugs after the dyno pull and the reason the car needed tuning was because it needed 3 new spark plugs. Car made 403 after the plugs- This dyno test doesn't prove anything. Its just another post about someone trying it out and needs to be locked or deleted as anyone claiming they figured everything out in one car's test is posting bad information.

Like I've been saying, the D585 coils, as well as the ls2, ls3, ls7 coils are simply better than the ls1 coils, so if you can get a set that are in good condition for low cost, why wouldn't you make the change?? Not everything is about making more power.

coils were new

do you mean "hotter spark" literally? how does one measure temperature of the spark in a cylinder? And, spark doesn't burn anything, it IGNITES. It's like saying that you have better barbeque because you ignited the fire with nicer matches...
again as far as I know, only definite amount of fuel can burn with given amount of oxygen, and it's chemically limited. Once mixture is ignited, it's all equal.

Am I wrong somewhere?

Sorry, but yes. Let me be more precise. "Hotter" = higher energy, i.e. more amps. Literally, more current.
More current = more energy to burn the fuel mixture.

LoL,

TO ANSWER A QUESTION

The tuning for just the ignition dwell alone is different for each year as the cars get newer- I would need a list of every change in coils to match them with every tune.

If you guys think that the coils are no different then you are being ignorant. Are they better than a stock ls1 coil? If they are more heat efficient then they are better.

With electrical, heat is a form of resistance - if they manage heat better than you can expect them to be more efficient.

And I can't believe we have an engine builder saying " If there was no knock then there is no gain"

Ive had cars come to me for tuning where they left making 400hp with no knock, check the plugs after the dyno pull and the reason the car needed tuning was because it needed 3 new spark plugs. Car made 403 after the plugs- This dyno test doesn't prove anything. Its just another post about someone trying it out and needs to be locked or deleted as anyone claiming they figured everything out in one car's test is posting bad information.

Amen!
(except the lock/delete comment, that's silly.) :)

this guy gets the concept.

fuel air and spark makes fast cars go vroom vroom, so i should get a bad ass intake badass fuel injectors, and leave spark alone?



and a cam is a cam? fuck it i'm going back to stock...

Wow. If its working then yes. a car makes hp through burning fuel. Energy is stored in fuel, adding the spark and air allow you to ignite the fuel and therefore release the energy. The sparks only role in makin HP is igniting the mixture. If it is doing it properly than you will not see a gain from ignition upgrades plain and simple.

Think of it this way.

I have a cigarette, to smoke it I need a cigarette (fuel), ignition(spark), and me breathing in(air).

Say I want to get more smoke(hp) while smoking, I can go to a bigger cigarette(more fuel) and breathe in more (more air), but if my original ignition, lets say a lighter, is lighting it fine, am I really going to gain anything by lighting my smoke with a torch? No im not.

Now if you have an issue with spark than yes an upgrade is needed, but for the majority of mild compression NA motors it isnt.

Wow. If its working then yes. a car makes hp through burning fuel. Energy is stored in fuel, adding the spark and air allow you to ignite the fuel and therefore release the energy. The sparks only role in makin HP is igniting the mixture. If it is doing it properly than you will not see a gain from ignition upgrades plain and simple.

Think of it this way.

I have a cigarette, to smoke it I need a cigarette (fuel), ignition(spark), and me breathing in(air).

Say I want to get more smoke(hp) while smoking, I can go to a bigger cigarette(more fuel) and breathe in more (more air), but if my original ignition, lets say a lighter, is lighting it fine, am I really going to gain anything by lighting my smoke with a torch? No im not.

Now if you have an issue with spark than yes an upgrade is needed, but for the majority of mild compression NA motors it isnt.

I have to dissagree. If this were the case, then theres a whole lot of MSD 6AL owners that should send them back for a refund.

If people here knew anything about explosives, they would understand that what generates force is the rate of combustion. The faster the rate, the more pressure, which is more torque.

You might not be able to visualize this, but it actually takes a little while for a weaker spark to ignite a fuel mixture than a hotter spark. Again, we are talking in milliseconds here, but at higher rpm, the quicker you can light off the air/fuel mixture, the less timing you'll need, and the more torque you'll make.

Went to the dyno today and did a back to back dyno on the truck coils/stock ls1 coils. I did two dynos with each. The results were I gained 3 Hp and 2 Tq going back with my ls1 coils. So basically in my application they did not gain anything. My car is a 99 z28 cam only full bolt on car. Take it as you will. This is just my results.

I've been biting my lip for some time, waiting to do some real oscilloscope testing with both coils in question before posting anything, but I can't keep quite any longer.

Too many people posting in this thread have no idea how an ignition system and/or coil works.

First thing, even the lowly LS coils are probably CAPABLE of 25Kv output. That is MORE than enough spark energy to jump a wide gap, and light a very dense charge.

(potential Kv output = # of secondary windings x # of primary windings. Primary magnetic field collapses when circuit is interrupted. Several hundred volts of primary "potential" jumps across to the secondary winding looking for a path to ground, and is multiplied by the amount of secondary windings.)

Just because a coil is CAPABLE of XX amount of spark energy, DOES NOT mean that that is the coils NORMAL OUTPUT. The secondary output of a coil is determined by the secondary resistance, WHICH INCLUDES the density of the charge. FWIW, most of the time the spark energy across the plug gap is only about 1-3 Kv. I have countless scope screen shots showing this. Of course, the higher the cylinder pressure, the higher the Kv required to jump the gap and hence light the charge.

Just because the truck coils are capable of a higher spark energy, DOES NOT mean that's what it's going to put out.

As soon as I can get my hands on a set or two of the truck coils, I'll do some actual scientific testing to try and come up with some real numbers, other than chassis dyno numbers. So far, my research for any type of specs on them is proving to be futile.

I've been biting my lip for some time, waiting to do some real oscilloscope testing with both coils in question before posting anything, but I can't keep quite any longer.

Too many people posting in this thread have no idea how an ignition system and/or coil works.

First thing, even the lowly LS coils are probably CAPABLE of 25Kv output. That is MORE than enough spark energy to jump a wide gap, and light a very dense charge.

(potential Kv output = # of secondary windings x # of primary windings. Primary magnetic field collapses when circuit is interrupted. Several hundred volts of primary "potential" jumps across to the secondary winding looking for a path to ground, and is multiplied by the amount of secondary windings.)

Just because a coil is CAPABLE of XX amount of spark energy, DOES NOT mean that that is the coils NORMAL OUTPUT. The secondary output of a coil is determined by the secondary resistance, WHICH INCLUDES the density of the charge. FWIW, most of the time the spark energy across the plug gap is only about 1-3 Kv. I have countless scope screen shots showing this. Of course, the higher the cylinder pressure, the higher the Kv required to jump the gap and hence light the charge.

Just because the truck coils are capable of a higher spark energy, DOES NOT mean that's what it's going to put out.

As soon as I can get my hands on a set or two of the truck coils, I'll do some actual scientific testing to try and come up with some real numbers, other than chassis dyno numbers. So far, my research for any type of specs on them is proving to be futile.


GREAT info man!

This thread has been all over the place.

When we modify our engines we typically have to go thru a process of eliminating choke points in order to improve performance incrimentally. The choke point moves around from component to component as you alleviate the previous one. At 400 hp, the choke point isn't the ignition. There are alot better places to spend your money. That's the point that I believe that Shawn is trying to make.

Jmilz is correct in that more spark almost always yields more power but how much and at what cost? On a stock car, $600 will buy you a cam and almost a set of springs. Properly selected, it could be good for 30-50 rwhp. $600 for a set of truck coils to yield 3-5hp is not the best use of a budget.

I've been biting my lip for some time, waiting to do some real oscilloscope testing with both coils in question before posting anything, but I can't keep quite any longer.

Too many people posting in this thread have no idea how an ignition system and/or coil works.



I will send you a set of stock D585 coils and a set of Accell coils for testing if I can get a deal on something....:angel: Oh and as for the dwell times the Megasquirt vid talks about them.....

Hey Sweet check out my sig....(just poking)....

As soon as I can get my hands on a set or two of the truck coils, I'll do some actual scientific testing to try and come up with some real numbers,



I've got a set(complete) that I'll send ya if we can "work" something out...pm me:D

On a stock car, $600 will buy you a cam and almost a set of springs. Properly selected, it could be good for 30-50 rwhp. $600 for a set of truck coils to yield 3-5hp is not the best use of a budget.

Umm...if you're spending $600 on a set of coils you are WASTING your money...you need to look harder, there are literally THOUSANDS of truck coils in salvage yards, that are perfectly fine, and they really don't want much for them. Lots of vehicles in salvage yards are there because they're smashed...not because they're dead from millions of miles on them, I paid $400 for an entire running LQ4 with 35K on it, including the coils...thats 317 heads, a 4" bore iron block, coils, and a bunch of other useful parts...and 35K miles is NOTHING on coils, I'm confident they'll last a long long time in my car.

edcmat-l1, if you do that testing, please keep in mind what the stock dwell settings are in vehicles running the respective coils you're testing. While you're right about what different coils might be capable of...how long are they capable of it if the dwell time is cranked up higher than stock? Stock dwell settings from a truck are different than an LS1 car, and stock dwell settings seem to result in coils lasting a very very very long time...when I put my D585's on my Camaro, I also opened up the tune from my friends 2002 Yukon that I did this past spring (that has D585's stock) and copied ALL dwell related stuff into my cars tune.

So me personally, I'd like to know what they're all doing, at the dwell settings that GM decided to control them with, not what they're capable of if the dwell goes up...because none of us on here have the equipment to do a failure or life cycle analysis on the coils if the dwell times are turned up.

edcmat-l1, if you do that testing, please keep in mind what the stock dwell settings are in vehicles running the respective coils you're testing. While you're right about what different coils might be capable of...how long are they capable of it if the dwell time is cranked up higher than stock? Stock dwell settings from a truck are different than an LS1 car, and stock dwell settings seem to result in coils lasting a very very very long time...when I put my D585's on my Camaro, I also opened up the tune from my friends 2002 Yukon that I did this past spring (that has D585's stock) and copied ALL dwell related stuff into my cars tune.

So me personally, I'd like to know what they're all doing, at the dwell settings that GM decided to control them with, not what they're capable of if the dwell goes up...because none of us on here have the equipment to do a failure or life cycle analysis on the coils if the dwell times are turned up.

First off, I have MANY FI cars out there with the stock LS1 coils, and the dwell cranked up, and NOT ONE has had a coil failure, and some of them have been on the road for at least a couple years.

Second, and this is gathered info from other ignition systems, not necessarily LS based, but MOST later model PCM driven ignition systems havee current limiting features, that do just that. If the dwell time exceeds XX amount of time, they go into current limiting mode. It's evident on a scope, as the voltage that's normally pulled down to ground, will have a step in it, where it's no longer pulled down to ground, but is pulled down about half way. Basically going into a mode where it has not yet released the "pull down", but is at or past the point of coil saturation, and the semiconductor/driver knows it, and limits any further build up of current, or flow of electrons into the primary winding.

Below is a scope shot of a common coil charge and discharge. What you're looking at, the top trace, channel 2 is primary voltage. 12+ volts are applied to one side of the coil. That's the line starting at the left. The voltage is "pulled down" by what ever switching device, in this case the PCM. The bottom trace is the actual coil amperage, taken with an inductive pickup. What you're watching in the bottom trace is electrons rushing in to saturate the primary side of the coil. Back to the top trace. After the coil is near saturation, the "pull down" is released, that is the sharp step up, and the inductive spike upward, past the top of the screen. This is the collapse of the primary coil, and the bottom trace shows the collapse as a straight downward line as the electrons basically evacuate the premises. Back to the top trace, the squiggly line after the high inductive spike is the spark jumping the gap of the plug, or "burn time"

http://i125.photobucket.com/albums/p58/edcmat-l1/96Avengercoilcold1.jpg

The scope shot below is the same car, same ignition system, but longer dwell time. You can clearly see the system go into currently limiting mode. It is evident by the step up in the top trace, the primary voltage. The dwell time is clearly longer, causing a higher level of coil saturation, and for whatever reason the driver didn't like it, and the last few milliseconds, the voltage was pulled down to about approx 5 or 6 volts, as opposed to being pulled down to ground, clearly limiting the amount of coil saturation, and therefore the amount of primary/secondary output. I've done tons of reasearch and have found no clear answer as to why this happens with different systems, the only thing I can come up with is sef preservation.

http://i125.photobucket.com/albums/p58/edcmat-l1/96Avengercoilhotbad.jpg

Wew!! After all that, the moral of the story is, (and I haven't confirmed on these particular systems) these late model ignition systems are so far advanced, that chances are regardless what we do to them, modify the dwell, swap coils, whatever, that they are going to perform to a level that's adequate, not much more.

If we crank up the dwell too high, chances are they'll go into current limiting mode to save themselves. If we put higher output coils on, chances are they're only going to output enough spark energy to get the job done. After all, that exactly how they function.

Thats really cool info. I had no idea that the LS1 PCM (though I recognize you said you haven't verified the LS1 PCM yet) would be abe to step the voltage down like that based on the coil and not on the dwell time in it's lookup tables.

Thank you for teaching me something new.

Went to the dyno today and did a back to back dyno on the truck coils/stock ls1 coils. I did two dynos with each. The results were I gained 3 Hp and 2 Tq going back with my ls1 coils. So basically in my application they did not gain anything. My car is a 99 z28 cam only full bolt on car. Take it as you will. This is just my results.

great info thanks a lot!! can we agree a cam only car will be making even less cylinder pressure than stock? therefore easier for the plug to ignite the mixture, showing the no gain?

ction.


very impressive.
have you tested the response of the circuit with the ls1/truck coils? is there a chance that whatever is controlling this current limiter has the ability to dynamically adjust itself to coil specifications, perhaps the engineers would do this for flexibility toward future applications, or future problems/recalls with current coils?

coils are not coils are not coils...

great info thanks a lot!! can we agree a cam only car will be making even less cylinder pressure than stock? therefore easier for the plug to ignite the mixture, showing the no gain?

Nope, because that is not always a true statement. The cam design, valve events, cylinder fill, overlap etc play into the cylinder pressure.

great info thanks a lot!! can we agree a cam only car will be making even less cylinder pressure than stock? therefore easier for the plug to ignite the mixture, showing the no gain?

If the engine is making more power, it's making more cylinder pressure.

i was refering to DCR

Not always true. Different cams can move peak cylinder pressure to a higher rpm without raising the actual pressure. More power cycles per second result in more power.

KurtIf the engine is making more power, it's making more cylinder pressure.