LS4 Front-Drives 2005-2009 - For those who think our intake is restricted

http://www.ls1tech.com/forums/generation-iv-external-engine/1173799-introducing-stage-2-intake-porting.html

Check that out. Fasterproms is now offering stage 2 porting. I am getting this done to mine. Should help to lessen the horrible intake we have. :) We are getting closer to having a modifiable car.

o and i already talked to Jeremy, he can do this for our intakes as well.

the LS4 intake is stupid restrictive.....so is the cam and so is the exhaust.

well thats why this stage 2 intake would be great, that way people can get the benifit of having a new intake without having to retrofit a ls6 intake to fit

post pics when you get yours done.

That looks great. I might be doing this soon.

o i will, i have an appt for the 13th to get it done. expect my post that night :) o and thats going to include a before and after dyno too

Will you be getting the heads/cam done at the same time?

well thats why this stage 2 intake would be great, that way people can get the benifit of having a new intake without having to retrofit a ls6 intake to fit

Oh I agree, it should help. I think the area behind the TB is the big restriction though. One person had good success fitting an LS2 intake on his LS4. Never got any hard numbers but IIRC he said the SOTP improvement was big.

That intake is so restrictive I wouldn't be surprised it hear 20hp improvement just by switching to a stock LS6/LS2 intake.

I will be doing the heads and cam next week than a tune and the intake on the 13th.

He did have good sucess but it required a lot of money and modding. Also if you do the stock intake you cna keep the DOD

DOD = GARBAGE. I still don't get how my vette could get 30mpg on the freeway but a smaller engine with DOD can't.

We can get 30mpg highway.........

If we had more than 4 gears it might be even better.

i get well over 30, and neilz you had put different heads on right?

Yeppers.

DOD = GARBAGE. I still don't get how my vette could get 30mpg on the freeway but a smaller engine with DOD can't.

It's about 1000lbs lighter.:(

And the low drag coefficient helps too....

It's about 1000lbs lighter.:(

so you're saying the grand prix weights 4200 lbs? hardly, try 400. Shouldn't make that big a difference.

Mine has gotten 30 mpg, with DoD tuned out.

I'm sure weight to power ratio and more gears helps a little too.

So you guys can't swap over to an LS6 intake, or any other intake for that matter?

Also is the exhaust that restrictive??

LS4 powered cars are the stepchild of GM. Either the oil pressure sender or the power steering stuff is in the way. The rear manifold is terrible.
http://img388.imageshack.us/img388/4479/dsc00233ag1.jpg

actually thats really good from a factory stand point if ya think about. But their concern is for profit not power so there is room for improvement.

so you're saying the grand prix weights 4200 lbs? hardly, try 400. Shouldn't make that big a difference.

I was being a bit sarcastic, but everyone else got the point. :eyes: Really you don't think 400 lbs is that much. I wish I could lose 400 lbs from my car now, night and day difference. Plus the extra gears in the vette don't hurt either.
Besides I can get 30+ MPG in the GXP on the highway over a 4 hour drive pulled 30.8 MPG and that's doing the math. DIC actually showed a very optimistic 34.3 MPG.

I was being a bit sarcastic, but everyone else got the point. :eyes: Really you don't think 400 lbs is that much. I wish I could lose 400 lbs from my car now, night and day difference. Plus the extra gears in the vette don't hurt either.
Besides I can get 30+ MPG in the GXP on the highway over a 4 hour drive pulled 30.8 MPG and that's doing the math. DIC actually showed a very optimistic 34.3 MPG.

Extra gears? I have a 2.73 geared 4 speed....wait was that sarcasm too?

400 pounds is a lot...for acceleration and city driving, not a HUGE difference in highway mileage.

Here's a question for you....what kind of freeway mileage does your G8 get?

^^ For weight, my Impy was 3880lbs with me in it, my brothers G8 4100 with him in it.


He gets mid 20's for MPG's on the highway.

Intake is a POS! sorry.... I still think its restrictive. I wish somebody would slap it on to another ls motor and dyno test it on a engine dyno, or flow bench it for us. All of that money on heads, cam and valve train and your going to stick with the stocker!
Also, I don't think that the Z06 cam is a good choice. I looked at the specs and think that a cam with a 112-114 L/S (broader tq curve after each shift) and about 10-15 degrees more exhaust duration then the intake lobe would be a better choice since our exhaust manifolds are so restrictive. Personally I like our stock cam it pulls past 6K. I'm thinking about getting a non dod version made with the dod lift. Keep in mind that your now increasing your power band so you may now have to shift at a much higher RPM. (Duh... right?) Which means your going to need more gear and a better intake manifold to support the power band/upper rpm hp and tq. I'm only saying this cause, I just reach the top of second when going through the 1/4 mile and if I increased my power band to 6500 I'd be still going through at 5900 and would be 500-600 rpm short of going through at full speed and acceleration.
I admire you determination and I hope you succeed your goal,. keep it up!

you'll never realize the true potential of a cam with that shit intake on there. Haha.

again, the point of this tread was to show that we can get OUR STOCK intake ported VERY aggressivly. I know that even with a stage 2 porting it will still be restrictive but it will be much better.
Also i choose the zo6 cam because of its high drivability. This is my daily driver. Also i already make peak power at 6300rpm. With these mods i should move my peak power band to 7000rpm.
I have built everything up in the engine to sustaine revving up to 7k.

again, the point of this tread was to show that we can get OUR STOCK intake ported VERY aggressivly. I know that even with a stage 2 porting it will still be restrictive but it will be much better.
Also i choose the zo6 cam because of its high drivability. This is my daily driver. Also i already make peak power at 6300rpm. With these mods i should move my peak power band to 7000rpm.
I have built everything up in the engine to sustaine revving up to 7k.

i will be very impressed if you can rev out to 7k, i got my fingers crossed for you.

Extra gears? I have a 2.73 geared 4 speed....wait was that sarcasm too?

400 pounds is a lot...for acceleration and city driving, not a HUGE difference in highway mileage.

Here's a question for you....what kind of freeway mileage does your G8 get?

Thought you had a manual car, so yeah you got me there. Weight will still be a factor even with highway mileage. Not as much but the less the engine has to work to keep something moving the less fuel used to do so.
As far as the G8, I don't have DOD/AFM turned on anymore. I turned it off when I got my tune for intake,headers and x-pipe. I still pull a good 26.8 going from San Antonio to Wichita Falls (about 8 hours) keeping right at 75 the whole way. Again done with calculating after having to refuel. I don't trust the trip computers that much. The G8 weights in at 4025 lbs +/- with me in it.:(
Tate

i will be very impressed if you can rev out to 7k, i got my fingers crossed for you.

well i dont see why not, the only thing more i could do would be to balance the engine

well i dont see why not, the only thing more i could do would be to balance the engine

It can be done, just control the valve train and it will do it......now, how long will it live at 7K?? There's more you can do than just balancing, you can get light weight and/ or stronger rotating assembly.

I have an old carcraft I need to scan and post up here for you guys. It's based on an SSR 5.3 build up.

I am all for gettting some more volume in the plenum, but let's not forget the throttle by wire system does not allow the throttle to open all the way. I forget the numbers, did the math some years back, but, from memory, we only get something like 72% of the throttle body area open at WOT with the throttle itself only opening in the high 70% range. I would argue that is a greater restriction than the intake plenum. I would not expect results for a ported LS4 manifold to be as good as on a ported LS1 piece.

I am also getting a ported tb, they modify it a lot

I am all for gettting some more volume in the plenum, but let's not forget the throttle by wire system does not allow the throttle to open all the way. I forget the numbers, did the math some years back, but, from memory, we only get something like 72% of the throttle body area open at WOT with the throttle itself only opening in the high 70% range. I would argue that is a greater restriction than the intake plenum. I would not expect results for a ported LS4 manifold to be as good as on a ported LS1 piece.

It does open all the way. There is an issue with the reported sensor reading for TPS. I believe that the maximum TPS reading is 88%, but this is an issue relating to the reference voltage used in the calculation. The correct PID you want to record when scanning is ETC (electronic throttle control) - this PID does go to 100%.

:cheers: