: Is the ZR1's horsepower overrated?



Blackout
10-08-08, 10:20 AM
I just saw this on another car forum and I'm not too sure what to make of it. I guess you be the judge.

*taken from LS1tech
http://i120.photobucket.com/albums/o184/svtspeed04/th_ZR1013.jpg (http://s120.photobucket.com/albums/o184/svtspeed04/?action=view&current=ZR1013.flv)

"graph of before and after..small spike makes it read a little higher then I posted above"

Stock vs Tuned
http://i120.photobucket.com/albums/o184/svtspeed04/ZR1.jpg

MauiV
10-08-08, 10:29 AM
Thats wheel HP on the graph. GM states the car has "6XX HP", well thats at the crank. You can figure a 20% loss for an IRS car to the wheels.

Just like the V was advertised as "400" HP", well that to is at the crank, 320-330 is about the best you will see at the wheels stock. Thats what Maggies are for.

Blackout
10-08-08, 10:49 AM
Last I heard GM has said 638 hp for the ZR1. So when you dyno the car and get almost 100 hp less then what GM is claiming, that is not a good thing. As much as I hate to bring this back up the GT-R is dyno'ing right where Nissan said that car would be and some have been even higher. But 100 hp difference is HUGE especially when your shelling out $100k+ for one of them. I never heard of a Ford GT dyno'ing 100 less hp then what Ford claimed. I hope this is a fluke because if not GM is going to have a big problem

MauiV
10-08-08, 11:07 AM
638-20% = 510.4 638-15%= 542.3

Advertised crank HP and Dyno numbers are NEVER the same. Driveline loss happens in EVERY CAR. The guys that ran this dyno test on the ZR1 got the numbers up to 580 with a bit of tuning. Seems the ZR1, just like the V run a bit rich from the factory.

C&C
10-08-08, 11:12 AM
Blackout, you have to know the difference between gross hp and net hp. The frictional loses are for all vehicles, and I am sure that the 638 claimed hp has been SAE certified on a certified dynometer by GM (Chervrolet) in the presence of a representative of SAE (I believe it stands for Society of American Engineers)

Blackout
10-08-08, 11:15 AM
You would be correct. Just saw this one


The car was off the charts rich with the stock calibration. Suprisingly timing was around 25deg tapering off to 23deg with a coolant temp of 190, IAT at 75. 10psi boost. I was expecting the car to have very low timing from the factory.

I ended up setting the air/fuel ratio at 11.5-11.6 and did not modify the main timing table. I did slightly modify the power enrichment vs timing table. No hint of knock and the factory IAT vs timing table remains stock.

The car was allowed to cool off between runs but was brought back up to 190 deg coolant temp for each run in an effort to maintain consistency. (there was no super cool-down money shot)

LS1Mike
10-08-08, 12:00 PM
Right that is WHP VS CRANCK HP
LS1 F-bodies were all rated a 305ish, different form year to but most dynoed right around what advertised crank HP they were underated.

I would say that was spot on for the ZR1, even a little better than expected with drivetrain loss.

At least GM didn't put a launch control in the car that if you use voids your warranty and breaks your transmission...Ahem Nissan GT-R
http://www.nagtroc.org/forums/index.php?showtopic=25361
I would rather have a shitty Dyno (which this one is not) then a car I couldn't use all the features on. ZR1>GT-R

The Tony Show
10-08-08, 12:14 PM
Wow- nice reading in that thread you linked to, Mike. Looks like teh grate GT-Arrrgh warranty experience is worse than a CTS-V. :lol:

01STS
10-08-08, 12:15 PM
Every stock Z06 that I have dyno'd has put down 425ish to the rear tires on our Mustang Dyno. I have done some GT500's as well and they put down similar 420ish numbers in stock form. I would say that those numbers are correct but may improve as the motor breaks in over time.

Keep in mind that some dynos rate higher numbers as they are not loaded and do not simulate real rear wheel hp numbers.

LS1Mike
10-08-08, 01:43 PM
I would say that those numbers are correct but may improve as the motor breaks in over time.

Keep in mind that some dynos rate higher numbers as they are not loaded and do not simulate real rear wheel hp numbers.

Spot on. Didn't the GTR Number come from one of the Dynos that you actually put the lugs through so it dosen't have the mass of the turning tires, to get the number they got?

Night Wolf
10-08-08, 04:12 PM
Right that is WHP VS CRANCK HP
LS1 F-bodies were all rated a 305ish, different form year to but most dynoed right around what advertised crank HP they were underated.

I would say that was spot on for the ZR1, even a little better than expected with drivetrain loss.

At least GM didn't put a launch control in the car that if you use voids your warranty and breaks your transmission...Ahem Nissan GT-R
http://www.nagtroc.org/forums/index.php?showtopic=25361
I would rather have a shitty Dyno (which this one is not) then a car I couldn't use all the features on. ZR1>GT-R

wow... thats pretty bad

Rolex
10-08-08, 07:33 PM
Right that is WHP VS CRANCK HP
LS1 F-bodies were all rated a 305ish, different form year to but most dynoed right around what advertised crank HP they were underated.

I would say that was spot on for the ZR1, even a little better than expected with drivetrain loss.

At least GM didn't put a launch control in the car that if you use voids your warranty and breaks your transmission...Ahem Nissan GT-R
http://www.nagtroc.org/forums/index.php?showtopic=25361
I would rather have a shitty Dyno (which this one is not) then a car I couldn't use all the features on. ZR1>GT-R


:major blackeye: on this "supercar"

I see a forthcoming uprising on behalf of the new GT-R owners. Who buys a 80k car that advertises sub 4 second 0-60 times and then drives them around like a little old lady? If these cars' transmissions can't handle the hp/tq Nissan is going to be in DEEP doo doo.