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Discussion Starter · #1 · (Edited)
Dyno Numbers

Had my first Dyno and tune today. Stock with a few bolt ons - exhaust and cai. Rolled in about 2PM, 83 degrees outside and a fully warmed up motor after driving an hour in traffic. Dynojet model 248C - Put down RWHP SAE Corrected 335.4 and 323.6 Torque on the first pull.

Then had an 'LS2 edit' tune done. Put down 352.9 HP and 348.3 Torque after the tune. Does this sound good for the mods I have? Does anyone have any numbers from a totally bone stock GTO? Unfortunately, I did not dyno mine before I made my first mod.
 

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Had my 1st Dyno at 300 miles, Bone stock....338HP/340TQ.......
added CPE CAI, X-pipe, & mufflers....Dynoed again 352HP/349 TQ....
Then had some tuning done @ 2500 miles........
365.61HP/362.11TQ.....all on the same Dynojet...

Tuning is the trick :D
 

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Discussion Starter · #5 ·
So it seems my numbers may be a bit low?? They told me different dynos will give slightly different numbers and also that if they did a pull with the motor much cooler, then I would see better numbers.

Why is the flywheel HP only coming out to be about 402 after all this when it is supposed to be 400 from the factory?
 
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NO two motors from the factory will produce the exact same result and NO motor from the factory will ever make what its rated at. You got 2 extra hp and your worried? :)
 

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NO two motors from the factory will produce the exact same result and NO motor from the factory will ever make what its rated at. You got 2 extra hp and your worried?

This is true, and there are governmental guidelines the variance has to be less than 5%. I've heard GM's internal goal is 3%. And yes, GM does have to prove it as well.
 
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18% drivetrain loss for a manual puts you as follows:

you dyno at 335.4 and make 409.02 at the motor
you dyno at 352.9 and make 430.37 at the motor

you take your dyno number, divide it by .82 and arrive at your motor horsepower level.
 

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Your numbers seem pretty decent to me. I put down 330/333 with cai before tuning, after tuning was 356/363 with 900 miles on odo. I've also been using 18% for drivetrain loss, I saw that gmhtp used 13% but I thought to myself there's no way if that was the case, I would only be making 409 at the crank after tuning, cai. Someone was telling me about a magazine article where they took a ls2 from a gto and put the engine on the dyno and it made 430hp, they didn't say what mag it was though.
 
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big_mike said:
18% drivetrain loss for a manual puts you as follows:

you dyno at 335.4 and make 409.02 at the motor
you dyno at 352.9 and make 430.37 at the motor

you take your dyno number, divide it by .82 and arrive at your motor horsepower level.
From the research I've done the T56 has a 12% loss and the 4L60 is 18%.

Although, dynos do not win races! Take it to the track!
 
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