Norm_427

Just wondering what the prevailing wisdom is on how the C6 Z06 will do up against the C5 Z06 in SS. The Porsche & Elise are top players, but I'm curious as to how guys feel the two Z's will do against each other.

Norm

Mojave

I don't think the C6Z06 will be any faster than the C5Z06. While the C6 does have 100 more hp, the gearing is also really tall. I believe someone said a C6 Z06 will go 90 mph in 2nd. While that will be great for longer courses, on smaller sites (like HPT for nats), even with all that torque, that is a big gearing hit to take.

I believe the C6Z06 is also wider. Not 100% sure on that, but if it is, it won't help things. Part of the reason the Elise does so well is it is so much narrower than the C5Z06 and GT3.

TedDBere

The C6Z hasn't been allowed to play in SS until this coming year, so we don't know how it will really perform. And only now are the 345 tires becoming available.

The bench racing has raised doubts as to it's performance. The MN6 tranny (tall gears) and 19 inch wheels (tall gearing) suggest that it'll have trouble matching the quickness of the C5Z with the MN12 and 18 inch rims. However, 100 more hp, wider tires and a shorter length are in it's favor.

The marketers wanted the C6Z to go 0-60 really fast so they geared it so it wouldn't have to shift to second. They got their numbers but keeping the wheels from spinning in 1st gear on an autox course is not going to be easy. Spin the tires = go slower. Also, keeping the car well balanced while taking your foot off the gas in 1st gear isn't going to be easy either.

This season will tell, but $75k for an Autox car will make a nationally prepped car hard to find IMHO. Let's see how Frank and Steve do this year in SS as they are the only ones I've heard of so far who are giving it a shot.

Time will tell. But the biggest issue hurting the Z06 this coming year is that SS is scheduled to run first heat. No rubber down on a slippery course will really hurt the high HP cars at HTP. Knowing the run order before the season starts may chase all the good drivers away from the Z06s and into other cars and classes. IMHO.

Norm_427

The new Z does 60 mph in 1st and 89 mph in 2nd. Plus it's 3.3" wider. Not a really good formula for autox.

Interesting comments about the run order ...

BrianCunningham

It's also got some BIG tires out back, great for power, but I will probably understeer a lot more.

Sounds like the L98/LT1/4 C4 vs ZR1 C4 debate.

greendot

Where did you find run order for the 2007 Nationals?

acrace

While Tuesday/Wednesday at Nationals is a near-certainty, I doubt that Super Stock will run first heat. SS ran first heat in '05, so my guess is that SS will be shuffled off somewhere towards the middle of the run order. Just my guess.

My opinion is that a C5 Z06, as compared to a C6 Z06, will do just fine in the context of Topeka/Nationals courses. Previously pointed out was the gearing and powerband issues. The C6 Z06 has the same front wheel size (width-wise) as the C5 Z06. I would anticipate that Nationals courses will continue to have a high emphasis on transitions, so the extra width of the C6 Z06 will be a disadvantage. I've seen a C6 Z06 (with Hoosiers) run locally (driven by a very accomplished driver), and the SS C5 Z06s have held their own.

What I would find to be an interesting proposition for a C6 is if the LS3 would come with the same current C6 Z51 gear ratios and if wider rims (than the current C6 base/Z51 set up) was available. Oh, let's say 9.5" wide fronts and 10.5" or 11" rears. Such as set up may be a better autocross combination than a C6 Z06 (again, in the context of SCCA Nationals/Topeka).

TedDBere

Al I've been looking at the C6 Z51 and I think you're right. If you could get shorter rear rims (18") and wider (so at least 315s would fit). Or you get rims that would allow the 19/325s to be used, then you may have something that could compete with the C5Z. They'd be basically equivalent except the C6 would be shorter in length.

Norm_427

I like what you're describing. That is pretty close to having a C5 Z06 in C6's clothing. Same tranny ratios, same 9.5" F and 10.5" R wheels, 18" rears & good torque. I wished GM had an option on the Z51 for wider wheels & tires. I just sold a C6 Z51 that I had CCWs 18x10 F and 18x11 R and I liked it for autox except that I had to run in ASP (no correct tires for autox in stock sizes). With the new Z06 I can at least stay in SS.

RX7 KLR

It is not out yet... For the most part if you run Tues-Wed one year you will change to Thurs-Fri the next. Sometimes due to class changes or entry #s etc some classes will run the same days two years in a row, BSP and FSP ran the same days in 05'-06', but they try to keep it fair. As far as time of day there is nothing that says you will not be the first run group every year, it is a matter of how the classes fill up and what flows best, they decide that in late Aug.

rhneff

As others have posted, too early to tell - not enough data points yet. Interesting, however, that McGeorge in his ASP C6 Z was well back from Johnson's C5 Z that won the class at HPT this year. Another data point - at a fairly recent Evolution school Andy Hollis during the Drivers Challenge when the instructors drive the students' cars to a time they're "challenged" to beat, Andy Hollis, one of the top autocrossers in the country, drove my C5 Z and another student's C6 Z (both on R-comps) and was about a second slower in the C6 Z. Surprised him, as well as the C6 Z's owner. Again, just another data point - have to wait to see who shows up to campaign the new Z this year - but Andy's on the SEB (along with RX7 KLR) that made the decision to class the new Z in SS and his comments to me seemed to say he doesn't think the new Z is faster in this context. Time will tell.

Norm_427

Reading all the posts in this thread (and many good, well-informed ones) I say that so far the concensus is that the new Z is probably going to be a tad slower than the old Z.

Very interesting!

acrace

However, I would still LOVE to have a C6 Z06!

XPC5R

They will need to be setup differently to work well. Focus on the strengths of the 60mph 1st gear - you could run a 345/19 hoosier rear, which will really help with 1st gear power application. Also running with more fuel to assist power down, and use more of the 427 torque.

All of the above may cause some push, but that is where front tire choice, bar (the front bar could be softened legally in SS) rake, and shock tuning will help a lot.

A car to watch may be the SRT10 viper, it has similar gearing, but more torque down low to use 2nd gear. 10" wide front wheels, 13" wide rears (for those 345's) and decent balance (and no lelectronic trickery) While heavier, it may point and shoot better with more torque and traction.

XPC5R

talon95

Yea, wider rear tires and more TQ would have been a plus on the West course this year. Not so much on the East.