04 C5Z CE Possible autox car ?
12-28-2015, 04:21 PM
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04 C5Z CE Possible autox car ?
I recently bought an 04 Z CE for a good deal it had been autox before but the mods just weren't working the car was running in one of ss classes on slicks but it couldn't be driven on street as the pfadt swaybars were knocking and the coilover shocks were blown in one and also knocking. I put the stock bars back in with new adjustable endlinks and new Bilstein sports. Hankooks on the stock wheels. The problem is this car is so tail happy on the street in any gear on the 285/35/18 Im not sure if I want to proceed I thought about going 285 squared as I have the wheels. Since Im a rookie at this my background has been drag racing I was planning just to run As, now I am considering running the factory stagger with the biggest tire I can find and stick in the rear. The lack of tire choice I keep wondering which way to go to help stick the rear better.
12-28-2015, 05:22 PM
#2
Le Mans Master
I like 315s on all four corners on 17" or 18" wheels.
If set-up correctly the car should be neutral to slight oversteer.
If set-up correctly the car should be neutral to slight oversteer.
12-28-2015, 07:09 PM
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C5 Z06 subject:
If the car is going to have a stiff suspension and custom wheels then put the 335/30-18 Rival S on the back and the 315/30-18 Rival S on the front. Basically, that's setting up the car similar to SCCA T1-LP rules. And the rear tires would stick out. (Well, the offset for the 12" wide rear wheel would have to be calculated based on inner clearance measurements relative to the current wheel and tire. I have an application that does the calculation correctly and not like the internet apps.)
On the stock wheels, well, put a set of rear wheels on the front and run the Rival S in 275/35-18 front or 315/30-18 front and 315/30-18 rear.
Actually, there are Oz Superleggera wheels available and inexpensive Forgestar wheels available. Or three-piece CCW wheels are popular.
Here's an easy setup in 18/19:
Front, 275/35-18, R-S3 Version 2 tire, 18 x 9.5 54mm wheel
Rear, 305/30-19, R-S3 Version 2 tire, 19 x 11 58mm wheel
For a suspension, there are GM T1 springs and swaybars. Or there are aftermarket "track" leaf springs
.
If the car is going to have a stiff suspension and custom wheels then put the 335/30-18 Rival S on the back and the 315/30-18 Rival S on the front. Basically, that's setting up the car similar to SCCA T1-LP rules. And the rear tires would stick out. (Well, the offset for the 12" wide rear wheel would have to be calculated based on inner clearance measurements relative to the current wheel and tire. I have an application that does the calculation correctly and not like the internet apps.)
On the stock wheels, well, put a set of rear wheels on the front and run the Rival S in 275/35-18 front or 315/30-18 front and 315/30-18 rear.
Actually, there are Oz Superleggera wheels available and inexpensive Forgestar wheels available. Or three-piece CCW wheels are popular.
Here's an easy setup in 18/19:
Front, 275/35-18, R-S3 Version 2 tire, 18 x 9.5 54mm wheel
Rear, 305/30-19, R-S3 Version 2 tire, 19 x 11 58mm wheel
For a suspension, there are GM T1 springs and swaybars. Or there are aftermarket "track" leaf springs
.
Last edited by joes68340s; 12-28-2015 at 07:20 PM. Reason: add more info.
12-28-2015, 07:27 PM
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I ran 17x11 GS offset C4ZR1 style wheels front and rear with 315 Kumho V710s all the way around. Car stuck like Glue. Great autocross and hpde setup. On the street I ran the stock 275/17 front and 295/18 rear. That worked fine on the street and very good as a wet tire for HPDEs.
Bill
Bill
12-28-2015, 10:40 PM
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Its on stock springs I put back as close to stock as possible as it was so screwed up. Front spring was slammed on the stock bolt nose down with a blown front shock. They were older Penski coilover shocks.
Last edited by joes68340s; 12-28-2015 at 10:41 PM. Reason: add info
12-29-2015, 09:24 AM
#7
Melting Slicks
If you are going to autocross moderately or more make sure you look at the rules for the groups you are running in whether it is SCCA, NASA, NCCC, etc. Each has different rules to follow. If you are going to run in the Street Tire class some groups limit it to 200 tread-ware and others allow lower. That is the most important criteria to make your decision. In the 200 ratings you current best choices are BFG Rival S and Bridgestone RE-71R. In AS, on Z06 wheels, the top guns ran the BFG's because of the larger rear tire set up. That said the Bridgestone 275/35x18 square set up (using a standard C5 rear wheel on the fronts or equivalent) would beat any other setup (excl. BFG) regardless of size of tires.
For great advice and parts on a SCCA set-up contact Stano Performance.
For great advice and parts on a SCCA set-up contact Stano Performance.
12-29-2015, 04:56 PM
#8
Pro
If the car is crazy tail happy, have a look at the rear toe setting.
Even the tiniest bit of toe out will be quite unsettling, might work to get the rear end around on an Autocross course but not good for anything else.
Even the tiniest bit of toe out will be quite unsettling, might work to get the rear end around on an Autocross course but not good for anything else.
12-29-2015, 08:45 PM
#9
Burning Brakes
I will second this. Sam has been awesome in helping me get my car setup since I got the suspension from him. He also carries more stuff than he lists on the website, so don't be afraid to ask if he has something.
12-29-2015, 08:46 PM
#10
Burning Brakes
Like others have said. I'd also talk to Sam Strano. His swaybars are great. He won't steer you in the wrong direction either.
12-29-2015, 10:03 PM
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Im not familiar with the Penske shock but the only way to adjust them as I can see is by high pressure nitrogen. and they didn't seem like you could adjust them on he car. I like things simple.
12-29-2015, 10:10 PM
#12
Burning Brakes
Penskes are one of the top tier shock available. While it's a possibility that they are a non adjustable set, chances are there is some form of adjustment. Usually at the end of the shock shaft in the form of a dial on **** sometimes disguised as a hex head w/ a hole through it. If you still have the shocks, I'd take a picture of them and post them here. Should be able to tell if adjustable then. Otherwise they are still worth some $$$ and can be sold.
12-29-2015, 10:15 PM
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Penskes are one of the top tier shock available. While it's a possibility that they are a non adjustable set, chances are there is some form of adjustment. Usually at the end of the shock shaft in the form of a dial on **** sometimes disguised as a hex head w/ a hole through it. If you still have the shocks, I'd take a picture of them and post them here. Should be able to tell if adjustable then. Otherwise they are still worth some $$$ and can be sold.
12-30-2015, 01:31 PM
#14
Check and make sure that your Limited slip diff is working the way it should. I chased a very lose car for 2 years before I found out my diff was shot. Nothing would get the rear to stick the way it should, but sure did turn in good.
12-30-2015, 02:41 PM
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12-30-2015, 03:03 PM
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I remember when it was warmer the tires would have a scuffed look of a sticky tire when I drove it. Now when cold they just look like a normal tire. So I will just have to wait for temps to come up. This being said are the Hankooks a better morning tire or afternoon when warmer. As far as autox is concerned.
01-04-2016, 06:46 PM
#19
For autocross they will be faster in the afternoon most of the year. They are at their best in the 80’s to low 90’s air temps, but they are not bad after a few runs in mid 60’s temps.
I really liked the RS-3’s but they are now a step behind the Rival S and Bridgestone RE-71R. If you get the Rival make sure it’s the “S” I hated the original Rival on my S2000. Right now I run RE-71R in 275/35-18 front and Rival S 315/30-18 rear on stock width wheels for A-street. I run the miss match because I could not get the Rival in the 275/35-18 size when I needed them.
I would recommend starting out in A Street. Some A-street legal wheels and tires and Talk to Sam about a big front sway bar and you will be set for A-street starting out.
For A-street the wheels have to be the same width as OEM, +/- 1 inch diameter and +/-7 mm offset.
I really liked the RS-3’s but they are now a step behind the Rival S and Bridgestone RE-71R. If you get the Rival make sure it’s the “S” I hated the original Rival on my S2000. Right now I run RE-71R in 275/35-18 front and Rival S 315/30-18 rear on stock width wheels for A-street. I run the miss match because I could not get the Rival in the 275/35-18 size when I needed them.
I would recommend starting out in A Street. Some A-street legal wheels and tires and Talk to Sam about a big front sway bar and you will be set for A-street starting out.
For A-street the wheels have to be the same width as OEM, +/- 1 inch diameter and +/-7 mm offset.