After two days of TT's, notes on C6Z-C5Z

[DennyM]

We had an annual event last Sat/Sun - all Corvettes ('bout 60) doing essentially Time Trials over a 1-mile, 7-turn track. A well-driven C5Z could see 100+ on the longest straights.

There were two C6Z's there ... bone stock and with less than 1k miles on them. Both were under very experienced drivers with years of track experience; only thing they fiddled with was tire pressures ...
There were three C5Z's there ... bone stock on F1SC's (2) and FS Wide Ovals (1)
There were several C5Z's there running Kumho's or Hoosiers, some near stock otherwise, some with mods and putting down ~ 400 - 430 at the wheels.
There were several Race Prepared C4's and C5's and C5Z's, running with 4-bars to full cages.
Sat AM we ran in a light drizzle, resulting in a VERY greasy track.
It dried out Sat afternoon, but the track never really warmed up (low 60's air temp)
Sun was all dry, but never really got hot (was able to get tire temps up to what one would want for about 90 minutes in the early afternoon)
Times:
C6Z Stock - low 52's to mid-53's on Sun
C5Z on stock tires - mid 55's best on Sun
C5Z on track tires - mid-52's to mid-53's on Sun
Race Prepared - low 51's to mid-52's on Sun
My conclusion: C6Z is phenomenal out of the box ... time difference over C5Z is a little more G-load in corners, and acceleration on the straights ... no surprise ...

[jub jub]

A well prepped C5Z doesn't give up much, if anything to C6Z06 it seems!

[No Doubt]

Once again this is an apples to oranges comparison. "Well prepped" can mean different things to different people and one can't easily define the term since there is no standard definition for it. A "well prepped" Cavalier (or just about anything else) could run circles around a C5 or C6Z for that matter.

Can a modified C5 run with a stock C6Z? Sure. But what mods? What is the limit? Ask 10 people and you'll get 10 different answers. Apples to oranges.

Stock vs. stock the C6Z is hands down faster, period. By how much is a matter of degrees, but they are faster.

[chjw]

Originally Posted by No Doubt

Once again this is an apples to oranges comparison. "Well prepped" can mean different things to different people and one can't easily define the term since there is no standard definition for it. A "well prepped" Cavalier (or just about anything else) could run circles around a C5 or C6Z for that matter.

Can a modified C5 run with a stock C6Z? Sure. But what mods? What is the limit? Ask 10 people and you'd get 10 different answers. Apples to oranges.

Stock vs. stock the C6Z is hands down faster, period. By how much is a matter of degrees, but they are faster.

I've been waiting for the opportunity to say this: "Especially the black ones."

[PerforminNorman]

Thanks for the post. I enjoyed the read.

[GTB/ZR-1]

Nice post Denny--very informative...

I'm really surprised the stock-for-stock C5Z/C6Z diff was 3+ secs. The C6Z guys were certainly excellent pilots to equal race-tire shod C5Z times.
Was the course pretty wide open? If the C6Z got into 3rd--I'd could see where the diff came in.

We ran a similar type of event (no doubt a tighter course) & the diff between my C6Z & 2 very well driven C5Zs (both guys have had FTDs @ large events before) was only 1-2 secs (we were all on race-rubber).

[DennyM]

Originally Posted by GTB/ZR-1

Was the course pretty wide open? If the C6Z got into 3rd--I'd could see where the diff came in.

Only three straights to get speed ... standing start to about 80, then hard brake into a 120 degree right; sweeping increasing radius left downhill seeing about 90 into a 80 degree left, straight with a right kink seeing over 100 into a compound, decreasing radius left. I don't know what terminal speeds they were seeing before braking ... somewhere north of 100 so third gear was in play.

[GTB/ZR-1]

Originally Posted by DennyM

Only three straights to get speed ... standing start to about 80, then hard brake into a 120 degree right; sweeping increasing radius left downhill seeing about 90 into a 80 degree left, straight with a right kink seeing over 100 into a compound, decreasing radius left. I don't know what terminal speeds they were seeing before braking ... somewhere north of 100 so third gear was in play.

Got it...

That was alot faster than the speeds we reached. I briefly touched the limiter in 2nd (90ish) coming off a very tight 120 degree off-camber corner.
All other areas were fairly low speed, comparatively.

Thx Denny.