We put our cars on the rollers today

[UnknownWarrior]

so me, my mom and brother got our cars on a dyno today, i noticed something wrong with my moms print out and she is about 10HP/20TQ short from me and my brother, all cars are LS3/M6 cars


my car made 374RWHP/373RWTQ (Only mod is GMPP Axle Back Exhaust)







My brothers made 372RWHP/372RWTQ(100% stock)







My moms car made 363RWHP/355RWTQ(only mod is GMPP axle back exhaust)









now can some one tell me why my moms HP and TQ curve got all ****ed up after 110MPH and wasnt smooth the whole way through?

I think my moms factory tune is messed up, or something fishy went on with her dyno

[v6sonoma]

My guess is bad gas. Is everything stock? If so burn off most of the gas do the fuse pull and see if you can feel a difference.

[Epitaph]

How many miles do each of the cars have? I have heard that the HP increases (slightly) within the first few k miles.

[wbt]

http://www.camaro5.com/forums/showthread.php?t=131745

[TOMS1SS]

If everything is stock you can expect up to a 20% loss of power from the factory ratings. So if thats the case every car is right on the money with what GM quotes, even your mom's.

[csjcsj]

[mxkx250]

Maybe she doesn't drive as aggressively as you youngsters. The car has the "learn function" on the tune.

[wbdinger]

or maybe Mom put in a tank of regular gas and not priemum ?

[UnknownWarrior]

every one says she didnt put premium in her car, thats one thing we do for sure we wont budge all 3 cars get premium only

[Doc]

How many miles on the car? Is the air filter clean? The power delivery is very unsteady on that dyno sheet. Have the dealer check the driveshaft; it may not be running true. Those wobbly lines could indicate what the driveshaft is doing. That can eat up 5-10 hp right there.

[Gene Culley]

Quite frankly I just think it is not as strong of an engine. You're not going to dyno 20 like vehicles with the same options and all and get 20 of the same numbers. You're going to get vehicles with higher horsepower, some in the middle and some at the bottom.

I can certainly tell you from working with the Corvette race team that I used to, that not all engines put out the same power. We would use the same parts, same tolerances, same everything and some engines wouldn't put out the same amount of power as others.

[TOMS1SS]

Originally Posted by Gene Culley

Quite frankly I just think it is not as strong of an engine. You're not going to dyno 20 like vehicles with the same options and all and get 20 of the same numbers. You're going to get vehicles with higher horsepower, some in the middle and some at the bottom.

I can certainly tell you from working with the Corvette race team that I used to, that not all engines put out the same power. We would use the same parts, same tolerances, same everything and some engines wouldn't put out the same amount of power as others.

Every engine is different even when built on the same line at the factory. If you do the math at 20% drivetrain loss from 426 net horsepower in an LS3 you come out to 340.8hp which, would be an assumption of at the wheel power. Your car would be at 467.525 net horse power using the 20% assumption and your mom's would be at 450.1 net horse power. Now this is where I'll drop out of this debate because there is a lot of voodoo math that goes into calculating horsepower. Depending on who you ask you'll generally be told that the loss from net to wheel horsepower is anywhere from 10% to 20%. Just remember that these engines are put together slightly different each time so your results will never be exact. If this was a larger gap in horse power in torque I'd be concerned, but at for a small amount like that.

[Bad70supreme]

Thats very true, all engines are going to run a little different! That is just the way it is, yes they will be close but thats it. You ever wonder why some guys cars are just faster with the same bolt-ons...there car is just stronger and it starts right from the factory.

[TOMS1SS]

Now if we all want to get real crafty and pull some dyno numbers for rear-wheel horsepower, calcuate back to net and then back to GROSS like the supposed muscle car era (pre-1972 gross to net conversion) that would be interesting. The results are down right scary how much power modern cars compared to 40 years ago, even mom's Accord. Don't forget stock muscle cars ran high 14s and low 15s back in the day.