CDH76

My brother ran with a z06 the other day in his tuned audi s4 up North. Best gas they have there is 91 octane. I was trying to get a idea on dyno numbers for 91 octane around 3000 elevation.

Thanks for the help!

ZoratZ06

A8: 520-550rwhp
M7: 540-575rwhp

Thats what I've seen posted around here.

DP RS

CDH76

Great thanks!

JoesC5

There is no reason that the driveline losses on the C7 Z06 with the manual transmission should be greater than the driveline losses of a C6 with the manual transmission.

Plenty of reputable shops have dynoed the C6's with between 12% and 13% driveline loss. For a C7 with 650 BHP that would be around 566 to 572 at the rear wheels.

C6's with A6's usually dynoed with around 15% driveline loss. The A8 is supposedly more efficient than the A6 so it should have less than 15% driveline loss. So, 553 to 559 at the rear wheels.

UBNZO6D

Greg

jbsblownc5

My car is on it's way from the train station to the dealer, Hope to have it this week!

I'll get to the dyno as soon as I have the car, put 500 miles on it, and have dropped the oil a few times...

In other words, give me a week or less to get that all done.

ZoratZ06

SAE certified 650hp. After that...conditions, dyno type, dyno operator, transmission type etc. You can say 'there is no reason for this or that' blah blah...but those ARE the numbers people are seeing...and occasionally they are seeing 10.41 quarter mile times to. Anything else?

There are also plenty of people out there who think the LS7 was 'underrated' from GM. Closer to 525-530hp, which makes a lot of sense when you see 450rwhp-455rwhp...10% loss is a little 'too' good.

Darion

JoesC5

Wake up!!!! The LS7 was the first engine that GM used the new SAE certification, that the SAE certified C7 Z06 also uses.

Yes, the LT4 is SAE certified at 650BHP as is the LS7 is SAE certified at 505BHP.

Just because some people with no engine dyno of their own believes the LS7 was "under rated" by GM/SAE doesn't make it a "fact".

Post up some SAE certified engine dyno graphs, other than GM's that prove the LS7 was "under rated" by 20-25 BHP.

The 10.41 you speak of. Is that on Michelin Super Sports? Are all the "stock" aero bits installed on the car? How about the front tires?

I just checked the C7 Z06 fast list(stock with stock tires) that was last updated on 10-12-2016 and there are 11 cars listed and all but one were A8's. GM says the A8 is .25 seconds quicker than the M7 both 0-60 and 0-1320(do you want to argue that also?).

The lone C7 Z06 with the M7 ran 10.901 @ 127.08. The quickest C6 ZR1 ran 10.664 @ 132.92(stock with stock tires). Which one is making more power?

The quickest A8 on that list(stock with stock tires) ran 10.41 @ 134.27(and there was quite a bit of discussion about that MPH). Add the ,25 seconds that makes the A8 quicker than the M7 and you have 10.66 seconds. Exactly the same as the 638 BHP ZR1 ran. BTW, eight of those C7 Z06's with the A8 ran slower than a ZR1 with the M6. So, who's making more power?

Now which one is putting down more power? Are you also claiming GM lied about the 638 horsepower of the LS9 and it's around 700? LOL.

No, it's making it's advertised SAE certified 638 HP.

6Speeder

The OP asked specifically about on 91 octane gas, and at 3,000 feet altitude. That altitude will pull about 10% power, 91 octane fuel will induce a bit more KR, even at 3,000 feet.

Bottom line, in those conditions, ACTUAL rwhp will be at least 50-60 less than what's usually quoted here.

Sucks, but it is what it is. Could be worse, consider, I'm at 6,000 feet, and the DA is usually even higher than that.

I dyno'd on a dynojet here, got 580 SAE RWHP, but my ACTUAL RWHP here on that day was only 488.

NicD

One big difference, the gearing and final drive between an A6 and the A8. While you could dyno A6s in the 4th gear (1.152, close to 1:1 gear ratio) and not have excessive tire speeds on the dyno the A8 needs to use 5th gear (1.27) instead to keep speeds down with the gearing in the rear. That alone will skew dyno numbers down for the A8s compared to the A6s so it's not a true comparison.

Either way here in AZ with our crap 91 octane gas and crap air on a standard non-user configurable dynojet with no dyno tricks we are around
A8: 520-530 rwhp (5th gear 1.27:1)
M7: 550-560 rwhp (4th gear 1:1)
SAE corrected

PRE-Z06

Actually 6th gear(1:1) should be used on the A8 for an accurate comparison, but most don't want to spin the rollers to over 200mph which is required to reach redline with the 2.41 rear gears.