Tire choices
Race Director
Joined: Jan 2007
Posts: 14,935
Likes: 3,343
From: NYC NY
I'm not trying to ruffle feathers but go find me a winning C4 in ANY auto-x class that has ANYTHING but a square setup. Good Luck.
These cars NEED more FRONT rubber not rear rubber that will make understeer worse.
ZR1's handle like crap. Soft suspension and nose heavy compared to a standard C4 with Z07/Z51 suspension.
The 84 Z51 rear spring is too stiff and hence nasty oversteer due to the high roll center in the back of these cars.
These cars NEED more FRONT rubber not rear rubber that will make understeer worse.
ZR1's handle like crap. Soft suspension and nose heavy compared to a standard C4 with Z07/Z51 suspension.
The 84 Z51 rear spring is too stiff and hence nasty oversteer due to the high roll center in the back of these cars.
Instructor
Joined: Sep 2014
Posts: 237
Likes: 11
From: Houston Texas
I'm not trying to ruffle feathers but go find me a winning C4 in ANY auto-x class that has ANYTHING but a square setup. Good Luck.
These cars NEED more FRONT rubber not rear rubber that will make understeer worse.
ZR1's handle like crap. Soft suspension and nose heavy compared to a standard C4 with Z07/Z51 suspension.
The 84 Z51 rear spring is too stiff and hence nasty oversteer due to the high roll center in the back of these cars.
I wish some of you could come drive my C4. I've got more "your car looks like it rotates perfectly" comments than you can count.
I'll leave some results here for you to ponder. http://stcsolo.com/content/results/2...lts-Event4.pdf
Notice some of those names. Pallotta 3X National Champion, Ferchak, Pearson, Ryan=ALL Trophy level winners at nationals this year.
You don't keep up with these guys without having a "properly" setup car. Yes, I have some driver mod, but not as much as I would like.
http://stcsolo.com/content/results/2...lts-Event4.pdf
Only 2 cars faster on street tires. I beat many others on R-comps in Raw time. My competition Greg Vincent is a VERY good driver (didn't have the results at nationals he wanted but still very fast) 1K custom front bar, and 4K shocks on that S2K. I have factory Z07 stuff and some $600 Koni's.
If you are not running Bridgestone RE71R's or Rival S's then likely your going to be slower than you could be at least with 200TW tires. I bet the RE71R's can rival many 100TW tires. They are THAT good.
You all run and setup what you like but YOUR WRONG IMHO.
You'll notice TurbineSurge is running a square setup. I don't get how the staggered setup is somehow better. The results/experience prove otherwise?!
I'd be happy to share my car's setup if anyone cares.
These cars NEED more FRONT rubber not rear rubber that will make understeer worse.
ZR1's handle like crap. Soft suspension and nose heavy compared to a standard C4 with Z07/Z51 suspension.
The 84 Z51 rear spring is too stiff and hence nasty oversteer due to the high roll center in the back of these cars.
I wish some of you could come drive my C4. I've got more "your car looks like it rotates perfectly" comments than you can count.
I'll leave some results here for you to ponder. http://stcsolo.com/content/results/2...lts-Event4.pdf
Notice some of those names. Pallotta 3X National Champion, Ferchak, Pearson, Ryan=ALL Trophy level winners at nationals this year.
You don't keep up with these guys without having a "properly" setup car. Yes, I have some driver mod, but not as much as I would like.
http://stcsolo.com/content/results/2...lts-Event4.pdf
Only 2 cars faster on street tires. I beat many others on R-comps in Raw time. My competition Greg Vincent is a VERY good driver (didn't have the results at nationals he wanted but still very fast) 1K custom front bar, and 4K shocks on that S2K. I have factory Z07 stuff and some $600 Koni's.
If you are not running Bridgestone RE71R's or Rival S's then likely your going to be slower than you could be at least with 200TW tires. I bet the RE71R's can rival many 100TW tires. They are THAT good.
You all run and setup what you like but YOUR WRONG IMHO.
You'll notice TurbineSurge is running a square setup. I don't get how the staggered setup is somehow better. The results/experience prove otherwise?!
I'd be happy to share my car's setup if anyone cares.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Yes, they did some testing and found even with lower spring rates the car handled just as good. In fact back in the day the early 85-87 cars are regarded as better handling cars than the later cars at least at low speeds. However, I feel this is not true today due to the newer rules about tire sizes and and tire availability at least in B Street class.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I'm not sure why you are getting excited, I don't think anyone has doubted any of your suggestions. I think everyone is in agreement 315 square is the way to go. I also agree that the bmh rear spring is too much unless you are running a xtreme spring up front. The only reason why I am running it is because I had a little splintering on my nyu spring. And as always I would love to drive your car or any one else's autocross machine. Locally my car gets around like a ****, I let anyone whom I think can handle the car drive it and I like to try as many other cars as I can. I could drop names of solo national competitors around town that I race with but what's the point. The guy asked about tires and I gave him my opinion based on what I experienced. If you want to be the fastest you use purple crack, there really isn't a street tire class for our cars and if there was you would have to spend lots of money on custom 18" wheels to run 315 rivals.
I guess I just want people to do stuff the most right way? IDK? I like seeing C4's being competitive so....
I bet you had to drop the rear bar down in size to run the BMH spring? Yes/No?
Unless you are running B Street or STU they have no home on Street tires. Yes, they moved the C4 into STU BUT not the LT4 or ZR1 cars.
I'm rolling on C5 Wagon wheels shod with 275/35/18 RE71R's. Even in STU that is the widest tire Bridgestone makes in an 18". So you really don't need the custom wheels. Unless, you run a Rival S, but I perfer the Stones' over them.
Instructor
Joined: Sep 2014
Posts: 237
Likes: 11
From: Houston Texas
LOL, yeah your probably right. I just keep seeing, "my 275/315 combo is great." Well, it might be but....
I guess I just want people to do stuff the most right way? IDK? I like seeing C4's being competitive so....
I bet you had to drop the rear bar down in size to run the BMH spring? Yes/No?
Unless you are running B Street or STU they have no home on Street tires. Yes, they moved the C4 into STU BUT not the LT4 or ZR1 cars.
I'm rolling on C5 Wagon wheels shod with 275/35/18 RE71R's. Even in STU that is the widest tire Bridgestone makes in an 18". So you really don't need the custom wheels. Unless, you run a Rival S, but I perfer the Stones' over them.
I guess I just want people to do stuff the most right way? IDK? I like seeing C4's being competitive so....
I bet you had to drop the rear bar down in size to run the BMH spring? Yes/No?
Unless you are running B Street or STU they have no home on Street tires. Yes, they moved the C4 into STU BUT not the LT4 or ZR1 cars.
I'm rolling on C5 Wagon wheels shod with 275/35/18 RE71R's. Even in STU that is the widest tire Bridgestone makes in an 18". So you really don't need the custom wheels. Unless, you run a Rival S, but I perfer the Stones' over them.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I run 12mm spacers on all four as the C5 wagons are not correct offset. 61+ instead of 56+, I'm taking advantage of the +/- 7mm rule as well.
Thread Starter
Racer
Joined: Oct 2012
Posts: 298
Likes: 0
OK guys. My NT01s just got delivered and Im hoping to get them mounted tomorrow. We have our points event next weekend so I don't really have much time to try differant pressures so for those that have run them before wheres a good pressure to start with ?
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Advanced
Joined: Dec 2013
Posts: 70
Likes: 2
I've always had better luck with the higher than I think most people like. Around 32-34 all around. I have just under 2 degrees of camber front and back.
Instructor
Joined: Sep 2014
Posts: 237
Likes: 11
From: Houston Texas
http://949racing.com/using-a-tire-py...49-Racing.aspx
Is your car lowered? What class are you in?
Last edited by TurbineSurgine; Oct 16, 2015 at 02:17 PM.
Thread Starter
Racer
Joined: Oct 2012
Posts: 298
Likes: 0
I run about 28F/26R, the best way to find your optimal pressures and camber is with a probe type pyrometer.
http://949racing.com/using-a-tire-py...49-Racing.aspx
Is your car lowered? What class are you in?
http://949racing.com/using-a-tire-py...49-Racing.aspx
Is your car lowered? What class are you in?
Instructor
Joined: Sep 2014
Posts: 237
Likes: 11
From: Houston Texas
I would make all your ride height adjustments before taking it to the alignment shop, lower the front and you should be able to get around 2 deg with stock arms and bushings. Be careful not to lower the rear too much or you will end up in the bumpstops. Pull out all your front shims and have them put about 1/8 toe out, If there is a big difference in camber L/R then add a little to get within .5 deg. In the rear I would run 1/8 toe in and -1.5 camber. Get a tire pyrometer or find one to borrow and take temps I/C/O to adjust pressures and note if more camber is needed. I would probably start with 35 psi cold all around and lower as you go. I was having trouble getting heat into the tires so I may have been too low in pressure. If you only had -.5 deg of camber then a good alignment will make a big difference, plus the new tires, you should be ready to rock.
let us know how it goes!
let us know how it goes!