Chris Murphy

Have some questions after a lousy first autocross experience, about what direction I should go for prep.
The magnetic suspension was ditched in favor of c6z upgrade shocks.
Currently the car has 20" wheels, with crappy brand 225/35 zr 20 Front, and 285/30zr20 rear.
I was literally sliding all over the course.
I plan on moving to c6 Grand Sport 18x9.5f and 19x12r wheels, (no decision made yet on the rubber) but it has been suggested to me that I might get better experience keeping the crap tires on it and learning the car.
I had fun, but it was more of a drift event for me, which isn't the point.
Brakes and sway bars are factory. This is a DD that I play in, not a purpose built race car, so any help is much appreciated.

firebirdfan

Get rid of the bling wheels and get some stockers. The grandsport wheels don't fit C5s anyway. There are no reasonable tires available for the 19" rims, either.

Put reasonable (don't need super sticky) tires on them in factory sizes. Something like a Pilot Super Sport, or an RE-11, or maybe a Sport Comp 2.

Get a more aggressive alignment. I suggest max camber in front and rear (don't worry about caster). Zero the front toe, got about 1/8-1/4" toe-in in the rear.

Don't mod the car.

Don't mod the car.

Don't mod the goddamn car.

Drive it for at least a year in this format.

THEN you can debate changing things and getting better tires.

The first autocross for EVERYONE sucks. Nobody gets out there and is immediately a God of Driving. Nobody.

Yes, you're going to be slower than most. Yes you're going to get your *** kicked by a Miata in ES. It happens.

Modding the car without having any concept of driving is a damn fine way to make your life hard in this sport. It's VERY easy to **** up a car's performance with tons of modifications without knowing what you're doing.

Put the car to stock, DRIVE IT, LEARN IT, and PERFECT IT. Ride in other people's corvettes (especially those who know what they're doing). Ride in cars that aren't corvettes to get an idea of how they drive.

THEN you can think about modification.

Chris Murphy

Thank you for the information on the grand sport wheels. Just saved me a lot of time and money. Is it the offset that prevents the wheels from working?
I appreciate the other advice as well. And yes, I not only got whipped by many miatas, but several civics as well
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mattastick

That'll happen. Civics and Miatas are very fast around autocross courses, even at the top level. You can't beat physics, when it comes to fitting a big car through a small gate.

I'd highly recommend the new Conti Extreme Contact Sport as a good daily driveable tire that will work as a starter autocross tire. It's available in tons of sizes, so you can probably find factory sizes to work with factory wheels.

Other than that, I agree 100% with firebirdfan. Work on the driver first and the car later. You can easily beat a significantly faster car with more driver mod (I've done it, even on worse tires than a car with 150+ more hp).

JLZ06TR

I am running C6 Z06 wheels on my C5 Z06 (18x9.5 front, 19x12 rear). front looks good and fit well. Rears stick out about an inch from fenders and can rub on inner fender sometimes. But the setup is pretty good. U can run those wheels with an extreme type tire (200tw). since you daily the car i would reccomend something like the RS3v2 or RS4.

Chris Murphy

Just for clarification, the 20" wheels were on the car already, and they are fun for a daily driver, cause its easy to slide for fun, and the shocks werent for modding purposes, the magnetic f55 (i think) were broken, so this was the cheapest option to get the vehicle serviceable.
I appreciate all of your input, and suggestions. I guess the big hit to me, was my ego, because for fun, a couple of years ago, I had run a Ford Edge awd SUV on a couple courses and it didnt do badly for what it is. However, being heavy, and underpowered, there wasnt a need for a lot of braking, just letting off the gas for the turns kept the understeer manageable.
Now, im in a much lighter, much more powerful car, and along with letting my expectations override my reality, I realized that I was trying to use that same driving style with the corvette, and didnt carry speed enough into the corner, and use more braking.
So, thanks again, and I plan on taking this advice, and looking for a second set of wheels that will work, in factory sizes, and have them equipped with suggested brand tires.

nickb45502

First, ditch the wheels. Then decide what class. C5 vettes typically dominate in AS or BS () class. Stock wheels are cheap and good rubber is available.
Then read:
http://www.racershq.com/street-class...n-just-3-mods/
Tires are the #1 thing (next to seat time) to make that seat time valuable.
Crappy tires are a waste of time. Every slide is lost time and 10 lost seconds can go by pretty quick.
Don't start with an aggressive alignment. This will eat those nice tires.
I ran my first year on Conti DW 340 TW tires and went from 8 seconds back to 3.5-4.0 of the fastest guy there ( in a C5 in AS).
Start with TC on then if you are running into it go to Comp mode. Then go to full off.
A nice 255 front and 285 rear will work wonders.
Good Luck!

Chris Murphy

I ran can s, not because I thought I would be competitive, but I remembered how much I s pushed in school when my freshman teams scrimmaged with varsity. I wasn't at all frustrated about being second to last in class. The alignment wasnt too aggressive, used specs from pfadt for a good street driver / track combo.
Thank you for your input!

v10climber

Yeah... this is pretty common at auto-x. And a reason why I think a lot of people don't come back. The good guys do hundreds of runs a year to get fast and they use data and go to schools and have fast co-drivers. It's like any other sport where you have to put in the time before you'll be any good at it. People struggle to appreciate the effort that goes into being fast.

I'd agree and disagree with this. Definitely get some new wheels and tires. That stagger (225f/285r) sounds horrible. It sounds like the car would be eligible for street class with new wheels so if it's a C5z you'll run in AS and if it's a base c5 you'll run in BS. Either way picking up a stock set of wheels is a good idea. They're cheap, pretty light, fit well, and keep you in street class where there will probably be competition locally.

However, put an aggressive alignment on the car. Max out the factory cams and get as much camber as you can. Then add 1/8" of toe in at the rear. I assume you'll just have one set of wheels and tires that are both the street tires and auto-x tires? You'll probably still wear out the outside edge autocrossing even with the all the camber available.

Chris Murphy

Something else I hadn't thought of, how much do you guys rely on the active handling and abs? Mine is all currently disabled, so Im strictly using driver input. Should I expect that's causing me to leave a lot of time out on the track?

mattastick

You'll want ABS, but AH isn't needed. I think the newer (late C6 and C7) systems are better, but the C5 is better suited to just turn it off.

eric1855

Turn it all off, the one button push, don't use competitive driving mode. You should have ABS though that isn't turn off-able unless something is not working correctly.

v10climber

I really really really like having ABS. It makes the car significantly easier to drive and not flat spot tires. The traction control/active handling all get turned completely off.

Chris Murphy

​​​​​​None of it is working at all. C1214, I think. The relay in the ebcm is out. I just haven't taken the time to fix it yet

eric1855

There's your biggest problem, the car with no ABS is a bear at AutoX. I had mine go out at an event and the car was TURRIBLE.

Send it off to ABSFixer.

nickb45502

Yes definitely need ABS working.

apex26

You go, get severely embarrassed by almost everyone, and now your self confidence hits a new low. It's true--don't mod anything, just keep signing up. It's just amazing how a few 60 second runs packs in so much experience, but it does. I went through this 2 years ago, and after the initial frustration of getting lost and being slow, which was numerous events, was well satisfied with the progress by the end of year one. By the end of last year, did 2 FTD's--against some hard charging specialists. (on Nittos and Hoosiers) Turn the nannys off. Use a go pro so you can critique yourself later, and recognize that there guys on here who you may never beat--they have decades on us and are wicked fast. I'm not even there to win (donated the trophies back which dropped jaws), but to learn better car control for track events, which eventually we will master.

v10climber

Most regions either have instructors available at the events or schools a few times a year. Take advantage of them. If neither of those are available ask one of the local fast guys to ride with you and give you pointers. You'll progress waaaaaay faster than trying to figure out what you're doing wrong yourself.

apex26

This is very true and helpful. In all, most experienced people were very helpful. Several offered rides, which was a huge help. Others offered to ride with me, also very helpful. Great bunch of people who enjoy the same passion.

Bill Dearborn

C1214 can be more involved than fixing the relay in the EBCM. Most of the time the relay failure is a symptom of the actual failure which occurs in the BPMV Vs the EBCM. Find one of the many threads on debugging C1214 with complete diagnostic instructions that give you the information on how to check the BPMV.

It sounds like you have a C5 coupe Vs a C5Z. The C5 coupe and vert wheel sizes are a little narrow for the tire choices you may want to go with. The C5Z wheels are an inch wider front and rear and are better choices. I don't know what class they would put you in but those wheels do help.

Since you use the car as a daily driver it may be uncomfortable to max out the camber as cars with maxed out camber will follow ruts quite easily and will dart around on the road a lot more. Try a - 1.3 front camber setting which will still let you get a nice caster setting. Set rear camber as close to -1.0 as you can get it. I couldn't get either my 97 C5 or 03Z above -.9.

You don't say which transmission you have. If you have an M6 you will find low gear is a little too low and 2nd gear is a little too high.

As you get better at autocrossing you will start to discover the trailing throttle over steer characteristic of the C5 which can be used to rotate the car to get around a corner quicker.

Bill