Barbara_S

I've spent the winter doing changes to the suspension of a ZR1 I bought to autocross with a few local clubs. It's not really working out and I'm now considering trading it in for an 02 Z06.

... but I'm wondering how much added sortinga Z06 needs. I'm looking to understand what it's negatives are for autocross.

Is the suspension lacking? I've poured money into my ZR1 - I'm just wondering how much I have to put into this car if I switch rather than keep trying to get the set up right on the C4.

tia, barbara

wtknght1

It's a great car. But, before you begin slapping a ton of stuff on the car and making a bunch of mods, drive it first to see it's capabilities...then drive it some more to explore THE DRIVER'S capabilities. When you reach that limit, then think about mods. Until then, drive the wheels off of it and enjoy!!

VetteDrmr

C5 Z06 is an incredible car for autox out of the box. There are only two things I'd plan on in the beginning: add a harness bar and harnesses, and convert the seat backs to the C5 sport seat configuration. This will allow you to run the shoulder straps through the seat over your shoulders as opposed to around them.

Other than that, get a set of repro wheels and tires if you don't want to beat up on your street tires.

HTH, and have a good one,
Mike

gkmccready

Wouldn't changing the seats throw you out of SS?

talon95

Yes. I'm just using a sternum strap now. Works ok and is cheap.

And actually, a harness bar that rigidly connects the 2 sides of the car together is probably illegal too, although quite a few people use them.

Dave G.

VetteDrmr

I've heard comments yes and no concerning changing out the seat back throwing you out of stock class.

However, the original poster was discussing "sorting out" a Z06, so I assumed that she didn't care about SCCA classification. If that assumption was incorrect, then I apologize.

Have a good one,
Mike

mikahb

I agree with the rest here. C5 Z is awesome out of the box. It took me probably 20 autocrosses in mine before I even started making changes. I did alignment first - that was a huge difference. After I adjusted to that, I bought some race tires - another huge difference. Had to add harness bar and 5-points after tires to keep me in my seat Next up for me is some better shocks, and then I'm maxed out in SS class for mods.

The car is amazing and there are not a lot of drivers out there that can extract 100% even from a stock car. Work your skills and only open your wallet when you're sure you're at a plateau.

Solofast

Do an alignment, lower the car and corner weight it, slap on a set of Hoosiers, and you will have 99% of what you need to do... All for about as little as you can expend in preparing any car for autocross.

While a harness is a nice thing, you don't have to do that right away either, a chest strap will do almost as well and it costs almost nothing.

After a season on the stock shocks, upgrade those and you will be able to have about as much fun as can be had in a car (with the possible exception of the back seat of my old man's Cadillac )

Barbara_S

Sort of - I mostly care about getting something that doesn't need a huge amount of work done to have some fun autocrossing since that's all I've been doing on the ZR1 I bought and it's still an enigma to me as far as setup goes. I'd buy race tires and work the alignment but I didn't want to to deal with all kinds of gues work on suspension changes if they were needed to have a neutral car. Anyway, this is all good input.

thanks!

VetteDrmr

Then a Z06 is what you're looking for. The suspension is outstanding right out of the box. The only "upgrade" I've made on my car's suspension (mine's an FRC, not a Z06), is to upgrade the Z51 sway bars and shocks to Z06 standards.

Getting the car aligned accurately, even just to the stock Z06 settings, and a set of tires, will give you the hardware to get up into the top group of whatever club you run with.

Of course, then you're limited to your driving ability. I've been running mine since '02, and only now are the locals beginning to ask how my times are doing. If I were to go up against the SCCA regionals I'm sure I'd be into a greasy pulp.

Have fun!
Mike

yakisoba

Very, very good out of the box. I have not auto crossed too much; mostly practice sessions with the local club. In those, with the stock Z, I'm slower (raw times) than just one car: A C6Z! I've got a couple of years road course experience, but auto cross is a very different thing.

2K3Z06

I don't know if you can ever really get it "neutral" on a tight course. The Z06 is a wide car with a longer wheel base than say an 911 or Lotus or Miata. You will push the front tires if don't slow down enough, in the tight stuff. You kinda have to "drive around" the tight corners with throttle and/or slide the tail just a little on corner entry.

A Z06 will keep up with or be faster than a lotus or Gt3, but you have to really smooth and precise with the steering and the throttle. And anticipate the slides in the tight corners.

My .02

Robert Lewis

TedDBere

Second set of rims, alignment, front bar and shocks. It cost me about $5k to equip the car to be nationally competitive. Car finished 3rd in the DC ProSolo behind Stewart and Salerno.

You can save a lot of money by upgrading to the '04 shocks, or just bite the bullet and buy some really good ones like I did.

Good luck.

Bill Dearborn

Your big advantage is dropping 400 lbs when you go to the Z06 from the ZR1. You can sort a ZR1 all you want but 400 lbs on an autocross course is a lot to overcome. With the Z06 you will be running close to the same size tires, have better brakes, much less body flex due to the stiff frame and it is easier to get into.

Bill

Diesel68

I'll attest to everything above. In stock form it is a very quick car.

Quick question though for those who know about aftermarket shocks. Has anyone measured a performance increase over the 04 shocks? I have no complaints, but I am use to Koni's in my previous autox cars and I am curious to know what I might be leaving on the table by continuing to use the OEM shocks. Thanks.

VetteDrmr

For a non-adjustable shock the '04 Z06 shocks are right up there with the Bilstein Sport shocks (tuned for C5s). Most people running Konis that I read about on the forum are running adjustable shocks. At that point I don't think you can compare them.

HTH, and have a good one,
Mike

talon95

Although it's tough to get a definitive number, I ran my car ('03 Z) with the new Koni yellows and Addco 32mm bar back to back with a friends car ('01 Z) with the stock front bar and '04 shocks. I was about .7sec faster in my car. There was no doubt that my car was faster in transitions/slaloms. Both cars were on similar aged Hoosier A6's.

I did think his car had better balance in the longer sweepers, probably due to the front sway bar difference. This was on a fairly large course (49 sec runs) at HPT (nationals site) in Topeka.

Dave G.

talon95

Also, I looked in the solo rule book. There is a clarification in the back in regards to harness bars:

"HARNESS BAR
A harness bar which attaches only between the upper seat belt
mounts on the B pillars complies with 13.2.H provided the
constraints of 13.2.H are met."

So I think a bar like the Hardbar would be legal since as I recall, it just goes between the seat belt mounts. Anything that ties to other locations may not be technically legal, even though it does not in reality add any rigidity.

Dave G.

VetteDrmr

The Arizona Speed and Marine bar complies also.

BrianCunningham

ZR1's are really a track car, but I knew a guy in Mich who could really put the times down with his.

Why don't you start another thread on it before giving up.