Tiger Shark

I'm curious to know if the rwhp has really changed much from the 2001, since I've seen where 2001 Z06s already make around 400 net hp and were therefore underrated (as with some of the past Corvettes).
I know Corvette engineers made some changes to the 2002 to increase hp, but they also made a few other changes which cause hp to decreased.

Has anyone seen dyno results for a 2002 Z06?

Scott97

I have a dyno day set up here in Austin for tomorrow morning and there is supposed to be an '02 in attendance.

If he dynos I'll post the results tomorrow morning.

Tiger Shark

Cool! Thanks. It will be interesting to see.


[Modified by TargaC5, 12:27 PM 9/7/2001]

Mopar Jimmy

As you may or may not know the 02 Zo6 has exactly 20 more ponies at the crank than the 01 z06. 405crank ponies (in the 02) vs. 385 crank ponies (in the 01 Z06)

Hope this helps. :smash:

Tiger Shark

Those are Chevrolet's "official" net hp ratings. I'm interested in the rwhp numbers, not the net numbers. Chevrolet has a history of underrating the crank numbers. I'm curious to see if the rwhp numbers are close.

5150 BRD

Interesting question. I too would like to know.

CFIVEM3

Should be about a 17 hp difference with a 15% loss. Almost seems to be within the margin of manufacturing tolerances.

:chevy

Ram Air Tony

there have been several dyno reports in the Z06 section

349 rwhp and 341 rwtq all the rest I have seen were LESS :U

they are only a few more than the 01s I have seen dynoed

RAT II 345 rhwp and 342 rwtq
RAT III 343 rwhp and 345 rwtq

all mentioned were BONE stock

they have a few more, but arent under rated as much as the 01s were

thanks

robsvette

2002 405hp ZO6!?!?!?!? you're kidding, right? :eek: :eek: :eek:

Tiger Shark

Thanks RAT, that's what I was looking for.

Ram Air Tony

NO I am SERIOUS

Bob got 349 and 341 .... Jim Hall got 337 or something like that :mad

check it out on the Z06 section !!!!!

thanks

R
A
T

LT1GMC

This leads to an interesting dilema: If one has an 01 Z06, which of the 02 Z06 improvements would you want to try, cause maybe some of them are negative, cancelling out the ones that really help? Hummm

don527

To answer your question...

I bought the 2002 rear shocks and checking the UPS web site regularly, it left Ken Fitchners on Montanna and are on their way to Florida

This will be my first major mod next to the ACI rear fasica pieces.

My thinking? The rear shocks are 1 of only 2 suspensions changes made to the 2002 suspension... the other being the aluminum stabilizer links. But the links offer no performance advantage except weight saving.

I've driven Les' '02 Z and made my decision immediately afterwards. I didnt try highway driving but in the city, the car was noticeably quieter.

My OBSERVATION was that the ride was noticeably smoother and absorbed those little bumps you feel and in Les' car. That enuff is worth the $108 a piece in my book... my wife will like the improved ride

My THEORY is that with the revalving of the rear shocks that it may help reduce the wheel hop I experienced at Moroso once and think that it may help in the rear squatting just a little more for a more solid lauch. Again it is only theory and I'm not a suspension specialist so hopefully I'll update ya on if I feel they are worth it.

As for the other '02 changes?

Intake not worth it. People have been saying the hole is not much bigger than they hoped... go with a donaldson or a Sidewinder.

Cams and valves? Not worth it... might as well do a stage I or stage II on the extreme end.

Removing the pups and putting in '02 CAT setup? If it's cheap then I'd like to do this also... GM has said pupless is good for 5hp (prob at the crank) but the sound it makes that I heard in Les' 02... IMO you wouldnt need to go aftermarket for sound improvements. That '02 sounded REALLY nice. :yesnod: I think it's just a bolt on affair.

don

[Modified by don527, 10:13 AM 9/8/2001]

2thDr

Well, at the Austin Dyno Day today, there was a 2001 Z06 and a 2002 Z06 (both with K&N filters) that dynoed basically exactly the same (I think the 2001 may have even had a few more HP than the 2002).

Hope this helps.

need-for-speed

Don't overlook the break-in factor. These motors seem to gain as much as 10 hp after 5,000 miles or so. The '01 models will the advantage there.

Tiger Shark

Just a quick refresher on different ratings of horsepower. :cool: (Source for definitions: edmunds.com)

Gross Horsepower: measurement of engine horsepower taken at the flywheel with no engine accessories attached, no restrictive exhaust system, and in a perfect state of tune (this is how the automotive industry primarily rated a car's engine prior to 1973)

Net Horsepower: measurement of engine horsepower taken at the flywheel with engine accessories and exhaust system in place and in a normal or typical state of tune (this is how the automotive industry rates a car's engine today).

Driven Wheel, Rear Wheel, or Brake Horsepower: measurement of horsepower taken at the driven wheels on a dynamometer, reflecting how much power is available after an engine's accessories, exhaust system, emission control system and driveline losses have taken affect (very useful to know since it's a realistic measure of horsepower in the real world - rwhp).

Both gross and net horsepower ratings are usually taken at the crankshaft.

Visceral

Im under the impression that brake HP is the HP on a non-inertia dyno. This makes more of a difference with turbos and such, but does have some effect on the numbers given. An inertia dyno measures acceleration of a weighted drum, a brake dyno, wether water brake, hydraulic brake, etc, measures a power output at a constant RPM, which is not accelerating. We talk about rwhp all the time around here, and its not Brake HP, that I know of. Since I cant remember where this info came from, I only profess 99% accuracy.

Chris
350.4 rwhp and rising
? bhp

Visceral

I do want to say though that chevy puts these motors on an engine dyno hundreds of times before releasing #s. They could very well be wrong, but I dont think they have much interest what the rwhp is (unfortunately).

Also, until a 2001 and 2002 (both worn in) can have their dyno's overlayed, we wont know how much faster the 2002 really is. It could have far fatter torque and noone tlaking peak HP #s would know.

chris

Tiger Shark

If I remember correctly, the 375 hp (net) ZR1s were also underrated. They dynoed very close to the 405 hp (net) ZR1s, more than their net ratings would indicate.

What goes around, comes around.

So in both cases, ZR1 and Z06, it would appear that Chevrolet has underrated the first models, then tinkered with this and that and then bumped the net rating to what it should've been to begin with to make it seem like the engine output has actually improved drastically when the reality is that it has remained relatively constant. I think further dyno results will confirm that the 2002 Z06 rwhp is within 10 hp of the 2001 Z06. That's just my opinion.

:cheers:

ArizonaZ06

it would appear that Chevrolet has underrated the first models, then tinkered with this and that and then bumped the net rating to what it should've been to begin with to make it seem like the engine output has actually improved drastically when the reality is that it has remained relatively constant.

Exactly.

Could it be that the so called improvements actually reduced GM's cost on the Z06. i.e. 02 cast wheels vs. 01 forged. Less costly exhaust system.

One performance robbing 02 improvement is the redesigned tighter fitting rings. These rings might counter the performance improving new cam and valve stems.

All said, in my opinion there's not much hp difference in the 01 vs. 02. :rolleyes: