DaddyBarlow

Redline trans fuild, oem in the diff and ATI 10% Underdrive Damper.

Engine Dyno, 685hp at the crank
Dynojet vehicle dyno, 622 RWHP

azZ06Mike

dyno numbers good tool for mods! Take it to the track and see how she really does. I have 540 rwhp and run mid 10's!

LS9Drew

What did u dyno stock? Take that and do the math to see how much drivetrain loss u had from 505hp and use that percentage to see what your crank HP is. That will give u the closest answer without putting it on an engine dyno.

Track has just as many variables as dynos so going to the track won't always tell the full story

04_Z06_CE

My tune/inate/exhaust ( no header) and ported stock upper LS7 intake made about 480 rwhp if I beleive. On the same dyno you used to dyno your car @ CMS
If you have no exhaust work , I think your numbers look great .

OJCrush08

Two more thoughts. I think to help level the playing field, when mentioning dyno readings, we should add what type of dyno and what measurement standards were used. As I mentioned earlier, ECS tested mine on thier dynapack which is connected directly to the hubs. They claim this dyno is considerably more accurate than most. Comments? My measurements were 547 rear h/p and 535 rear torque using the SAE J1349 Standards, which I believe are pretty strict? No STD numbers or playing with smoothing numbers to include h/p spikes.

Second, I still would like if some tuners would step in and explain what they measure (standards used) and what they consider to be an acceptable drivetrain loss number for the Z06.

I thought my 12% loss figure was very reasonable but if not, I would like to be educated re what is appropriate.

Thanks!!

dapopa9

500rwhp with 12% loss would actual equal 568hp crank

azZ06Mike

From a dyno jet to a dyno pak my car varies 21 rwhp and more shown on the dynapak!

VictoryRedZ06

LOL How about DYNOmite dynos vs Dynapacks? DYNOmite is a load bearing dyno...

mirage2991

your math is wrong, 800 rwhp would be 910 with a 12% loss

for fly wheel, you would have 800/x=0.879. Solve for x and you have x=800/0.879, x=910, where 0.879 is 12%

and why the % difference?: physics. It takes more energy to accelerate something at a faster rate than at a slower rate. Friction has a role in that, since the gears are in oil (trans and rear end) you have hydraulic friction which basically the faster something rotates the more friction (or drag) you get....no free lunch...hence you see some small % changes in powertrain loss between two different motors on the same car...

vrybad

You are right about on the money.

HP loss is closer to a fixed amount(i.e. - 55hp) than a fixed percentage.

OJCrush08

I am really curious what results I would get testing on another type of dyno. When I get time later this year, I may run down to a race shop in Richmond that I know keeps their dynojet in the best condition, and knows how to properly test.

I do know that Doug at ECS told me that the reason why they spent so much more money to buy their dynapack was because it gave the most realistic results...

Actually, I am more confused than ever how to translate these figures. I really wish some tuners would provide input here...

Bill Dearborn

It used to be that 15% was considered the proper figure for drive line loss. When did it change to 12%?

Bill

CanadaGrant

Driveline loss would be the same in the same car if you were putting out 400 or 800 horsepowerer so how does percentage work? When your horsepower doubles your driveline loss doesn't, so why would the percentage be even close to the same?
Driveline loss for the same car is fixed. Engine horsepower isn't and when you monkey with the motor, driveline loss doesn't increase. I think driveline loss in a C6 Z06 would be roughly 60 to 70 hp. and would remain the same no matter what you did to the motor. It isn't a fixed percentage. It's the amount of horsepower it takes to run everything and subtract it from your bench horsepower.

double06

I would tend to agree with some type of fixed HP but there is some linear loss on these. Lingenfelter did a test I think with different HP and the % did drop butt not as much as one would think. For example (I do not have number in front of me) Say the Z06 has 505 and 430 crank / wheel or a 15% loss (75 hp total) and then you say have another car with 700 motor hp and the loss is say 14% or 98 hp. So the overall loss goes up but the % loss goes down a little. Some of the engine car builders could better speak on this with their experiences.

CanadaGrant

The driveline loss in your example is going to remain the same. If you have a "75 horsepower total" driveline loss, it doesn't matter if you are running 200 horsepower or 800 horsepower. Your driveline loss is going to remain the same. Not 13%. Not 8%. Not 38%. It will be 75 horsepower no matter what motor you put in front of it...
It's not percentage. It's constant driveline drag for a particular car no matter what the horsepower.

double06

I would agree with what you are saying but for some reason it is not. The Z06 has a driveline loss of say 65-70 hp while the ZR1 is closer to 90-100 hp. Both cars have the same driveline.

double06

I agree with what you are saying it should be constant but for some reason it is not. The Z06 has a 65-70 hp loss and the ZR1 is closer to 100 hp loss but yet both cars have the same drivetrain?

vrybad

Consider this:

Z06...............2010 ZR1 (Quikag's car)
450whp............555whp

450/505 = .89 or 11% loss

555/638 = .869 or about 13% loss

Could there be an additional 2% parasitic loss due to increased load during the ZR1 dyno pull?

It is possible.

CanadaGrant

All I'm saying is that if you have 440 wheel horsepower then you lose about 65 or 70 from GM's 505 estimate. You increase the horsepower by let's say 100, you are still going to have the same 65 or 70 drivetrain, alternator, ac loss. It is only a percentage if you go by GM's given standard. It's a horsepower loss to turn stuff, not a percentage loss. Increase the horsepower to 800 and it's still the same loss, not a percentage.

double06

I got this from a tech bulletin which is what I was trying to remember why. Basically the more power you make the more friction you create but striaght % or fixed numbers are not the right answer. The last sentence kind of summarizes it. The best we can do is make a estimate to get in the ball park.

" It's also worth noting that the more powerful you make your engine, the greater the thrust force and angular acceleration it's able to exert on the drivetrain, generating even more friction and heat in the process. But because both steady-state and dynamic friction vary depending on engine speed, engine load and the efficiency of the engine and drivetrain's design (how well they limit friction and the associated thermal conversion of torque to heat), there's no way to apply a universal percent loss to it. Nor is it possible to apply a fixed drivetrain loss figure to your car (say 60 whp from my RevUp G35 example), because as you modify the engine and increase its output its ability to generate thrust force and angular acceleration also increases (though not in a linear fashion).

In the end, there's no easy way to estimate the drivetrain loss your vehicle experiences on the road or even on the dyno. Coast-down tests are sometimes used on a dyno to attempt to measure frictional losses, but because this test is not dynamic (meaning they're not done while accelerating, but rather while coasting to a stop with the direct drive gear engaged but the clutch depressed so that the engine and transmission aren't linked) it really only captures steady-state drivetrain losses as well as rolling resistance. So rather than attempting to convert your vehicle's dyno-measured wheel horsepower to a SAE net horsepower figure using a percentage or a fixed horsepower value, you're far better off accepting the fact that these two types of horsepower measurements aren't easily correlated and forego any attempt at doing so."


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