I know dyno's are just for tuning but everybody go's looking for some crazy huge number and never seem to be where they thought they were so anyway. I took my new 408 to the dyno last night for some tunning and this is what happend..should I be happy?

not makeing excuses but but here go's..the guy that owned the dyno told me before we started that it was 9rwhp lower than everybody elses..the motor only has about 100-150 miles so when it get a little more broke in I should gain a few. now for the big killers I have a moser 9" w/4.10s and a th350 w/4000 stall
it did 429rwhp and 400rwtq

I was gonna post it but I cant figure out how

 

really? out of a 408? maybe try another dyno? then again, you could always just race it, and say **** the numbers... whatever... but that seems low for anything...whats the info on the combo? I see in your sig that it says texas giant cam and fast 90/90, but what about heads, headers, etc etc... ( still want that water pump) lol.

 

Depending on how loose the stall is, and the internals in the rear end and trans, you could be perfectly fine. I'd run her at the track, and then see where i am at.

 

Track numbers are the only ones that matter, who dynos well with a big stall and built rear anyways?

 

If it makes you feel any better I know a guy that dynoed 340 rwhp through a TH350 and big stall but his car runs in the 11.1 range. Run it at the track and see how it does before getting bummed about it.

 

Well, it sounds like you know how these threads go. But, you still didn't mention track times. So, here goes:

Take it to the track and see how it does bla, bla, bla.

 

get it to the track and don't worry about the numbers so much

We had a 402/ETP/TH400/12 bolt 4.10 combo that had poor numbers too. The customer has some garbage converter in th car.

416 rwhp

100% full weight Z/28

11.0 @ 123 ... on the limiter thru the traps due a 26" ET Radial & 4.10

 

Here's my take on it.. for what it's worth.

I did a 408 for a guy with the same exact cam as yours, fast 90 setup, all bolt ons, etc. We used a set of heads VERY comparable to the ones you are running. The car was a 6 speed with 4.10 gears. It made right at 500rwhp/470rwtq. I don't like to guess at ****, but if I were guessing.. I would say his drivetrain is ATLEAST 10% more efficient than yours... maybe even more. So going by that ASSumption, 10% of 500 is 50 and add that back to your 430 and your there at 480. His 500 was done on the "good" dyno I use and not the one you used.

About 6 months after doing his car, he saved up some money and we changed out the other heads for a set of ETP 245's, cometic .040 gaskets, longer pushrods for the ETPS, and morel lifters. Besides those mods, we changed the rear gear from a 4.10 to a 4.30. Went back to the dyno and it made over 530rwhp. That's the highest dynoing 408 I've ever witnessed.

A few weeks ago I did a 402 LS2 based car on the same dyno with a 4L80 conversion and unlocked big stall... similar head/cam/intake combo as you.. but he had a stock rear.. 430rwhp.

I guess what I'm getting at is, don't sweat the dyno stuff.. .I think the car is making what it should for the heads and drivetrain setup. It should turn a good number at the track.

 

what was that you said "automatics and dynos go together like turds and hotdog buns" LOL

 

Why risk the motor and dyno the car with that few miles on it?

 

I had to. I put a "mail order" tune in from wait4me to break in the motor and it SUCKED!! car would barley run and when I called him about it he wanted to blame everything but his tune..funny thing is gomer just put a base tune in it to start with the dyno and it ran 100x better than ever

gomer you are the man!!

 

mileage ? why do you need miles on a motor prior to tuning ?

proper break in and heat cycles are all you need

change the oil and be on your way to new found HP

 

I betcha your losing 60RW from the trans and rear
With a locked A4 it would be close to 480RW......

 

Mileage?? You dont need no stinkin mileage!!
We've dynoed cars with less than 100 miles on the motor.
A couple heat cycles and make sure shes good to go, no leaks, cooling system working good, let er eat!!

 

I agree. 20 HP for the rear, and a good 35 is probably eaten up by the stall.

 

Dang, you got Gomer out.

 

I dunno, dropping a pretty penny on a motor and I'd like to take the needed precautions before it's making dyno pulls. I'm all for getting a base tune but you don't need to make pulls for that.

 

I agree with that. But I can have a tune pretty well dialed in in 50 miles or less.
And, all of our motors are tuned spot on as far as part throttle, before we start makin pulls.
Sorry bout hijackin this guys thread BTW.

 

I can echo this nearly exactly...

I did a 402/AFR225s/12 bolt 3.73s ... had a built 4l60e with a crappy loose non-name stall that would not lock (well it wouldn't stay locked) on the dyno..

419rwhp

100% full weight+some T/A with all factory power options

11.0 @ 124.5 first pass






The funny thing was.... this was a girl's car. She bought it to compete with her boyfriend. His car at the time was an M6, stock engine with an ls6 intake , headers, and a powerdyne supercharger at about 7psi, and his car put down 434rwhp on the same dyno and same day. That same night at the track where her car trapped 124.5 with her 419rwhp, his car trapped 117.5 with his 434rwhp/M6.

 

Just proves peak rwhp doesn't necessarily make the car fast.