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Starting tire pressures should reflect the type of course being driven and the actual tire model.

Higher pressures could be helpful on tighter courses to gain better steering response or with tires that lack a stiff sidewall, like an all season.

On larger courses, one would probably want pressures at or near the factory recommended pressures.

I would not run anything more than the stock pressure on the stock Re50s as they're extremely stiff already from being a run flat.

On stock(ish) cars, the chalk test may be ineffective. Tire pressures may already be optimal, but the chalk may wear away due to inadequte camber angles.
 

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Discussion Starter · #22 ·
I would not run anything more than the stock pressure on the stock Re50s as they're extremely stiff already from being a run flat.
The OEM tires are not run flats. On an autocross course, stock pressures will roll the front tires. I have ran this car enough to know that stock pressures in the front will roll the tire on to the sidewall no matter the course.

All corners and then adjust. Now if really hot day/track back off a bit. Personal choice...did not want soft spongy tire any corner nor rolling onto side wall.
We also ran cool/cold nights.
Probably more knowledgeable and scientific process, this seemed to work w/o consequences. Held my own with vettes and Camaros
50psi all the way around is going to make the car way loose. The rears do not roll over any where near as much as the fronts, which is why 50 is not needed. 40psi sure...50psi nope. 50 psi is also the max pressure for the OEM tire too. I would not recommend starting there. The tire will be exceed the max pressure allowed during the run which may damage the tire. I have run the pressures I recommended and did not have roll over issues.
 

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Thanks for the advise. Any other tips and how did the RE050s do? The car seems to like to throw weight on the rear when getting in a corner hard.

I have tracking experience at various places & cars, but none in the SS.
 

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Discussion Starter · #24 ·
Thanks for the advise. Any other tips? The car seems to like to throw weight on the rear when getting in a corner hard.

I have tracking experience at various places & cars, but none in the SS.
It is a pretty neutral car with a slight tendency to understeer. Of course part of that is me but the OEM tires are not that great for autocrossing. Definitely slow in the turn and fast out.

The link below is my best run from last month. I just had my left hip replaced so I had a hard time left foot braking. Kept making her push.

https://www.youtube.com/watch?v=rcdw6p5S0a0
 

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The OEM tires are not run flats. On an autocross course, stock pressures will roll the front tires. I have ran this car enough to know that stock pressures in the front will roll the tire on to the sidewall no matter the course.
How much camber are you running in the front?
 

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Stock settings. Street classes for SCCA does not allow for camber adjustments that exceed factory settings.
That's not true at all.

In street, you may alter your aligment settings using the stock hardware or by any means listed in the factory service manual.

Adding negative camber at both ends will substantially improve your rollover issue without resorting to running higher than optimal pressures. The car will be able to corner at a higher speed as well.
 

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Haven't run the SS but think I ran mid 40's in the G8, a little higher in the rear to help the car rotate. It does vary by course and driving style, as well as the specific tire.
 

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Discussion Starter · #30 ·
That's not true at all.

In street, you may alter your aligment settings using the stock hardware or by any means listed in the factory service manual.

Adding negative camber at both ends will substantially improve your rollover issue without resorting to running higher than optimal pressures. The car will be able to corner at a higher speed as well.
It is true.

I didn't write you could not CHANGE camber settings...I wrote you could not EXCEED the stock settings. So, if it is in the service manual, then it is a stock setting. Might want to get those :nerd checked.

I'm just trying to give advice, with my experience with this car/tire, to someone NEW on what to do at there first autocross with the SS. Adjusting alignment specs is not something I would advise someone to adjust the first time out.

I agree with Brad02ss, everything varies by course and style.
 

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I keep meaning to get mine out for an event but I've just had too many other things going on during the weekends this spring. Right now would probably be the time to do it though, since I'm still waiting on my headers/exhaust and will be bumped to SM once they are on. Either way I don't expect to compete, although I didn't do bad 10 years ago in my little 300hp DSM (in SM at that!).
 

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Discussion Starter · #32 ·
I keep meaning to get mine out for an event but I've just had too many other things going on during the weekends this spring. Right now would probably be the time to do it though, since I'm still waiting on my headers/exhaust and will be bumped to SM once they are on. Either way I don't expect to compete, although I didn't do bad 10 years ago in my little 300hp DSM (in SM at that!).
You could go CAM-C after the exhaust install. The PAX is more forgiving and you will run with others on street tires in class as well.
 

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You could go CAM-C after the exhaust install. The PAX is more forgiving and you will run with others on street tires in class as well.
This

Cam is pretty much a catchall class to draw in the goodguys/restomod crowd.


Last season regionally here all corvettes were allowed in cam (one catchall cam class). On the downside it meant corvettes killed cam once they started showing in the later part of the season.

on the upside without them the class would have been nearly non existent.
 

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You could go CAM-C after the exhaust install. The PAX is more forgiving and you will run with others on street tires in class as well.
I was told I would be SM due to emissions delete and the driveshaft tunnel brace. Could obviously be wrong though...
 

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It is true.

I didn't write you could not CHANGE camber settings...I wrote you could not EXCEED the stock settings. So, if it is in the service manual, then it is a stock setting. Might want to get those :nerd checked.
I've been autocrossing with the SCCA for 8 years now. I'm very familiar with the rule book. I have a E36 M3 built specifically for STU (and maybe STR next year). I'm trying to help you out here, because it sounds like you've got some misinformation, unless your region runs some lame rule about factory only alignments in street.

Here's the section on alignment in street category:

2016 Solo Rules said:
13.8 Suspension
B. Both the front and rear suspension may be adjusted through their designed range of adjustment by use of factory adjustment arrangements or by taking advantage of inherent manufacturing tolerances. This encompasses both alignment and ride height parameters if such adjustments are provided by the standard components and specified by the factory as normal methods of adjustment. However, no suspension part may be modified for the purpose of adjustment unless such modification is specifically authorized by the factory shop manual.
You don't have to run the factory alignment settings in any class. You may run any alignment that can be done with the factory hardware in street. My E36 had crash bolts that I could run in street to give me a bit of extra camber. Some car's factory manual authorize notching the shock tower (like the E46) or lower strut attachment point (S197 Mustang).
 

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I was told I would be SM due to emissions delete and the driveshaft tunnel brace. Could obviously be wrong though...
Going catless puts you into Street Prepared. I don't think the SS was classed in SP yet, but it falls into ESP under the catch all.

The tunnel brace would be Street Touring, as long as it uses the stock attachment points. Bracing can be tricky depending how it is attached and how many attachment points it has.
 

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Discussion Starter · #37 ·
I was told I would be SM due to emissions delete and the driveshaft tunnel brace. Could obviously be wrong though...
CAM-C is wide open and allows for your mods. If you are going to run OEM tires, you will get crushed by anyone on R-comps in ESP. The PAX is also worse in ESP.
 

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CAM-C is wide open and allows for your mods. If you are going to run OEM tires, you will get crushed by anyone on R-comps in ESP. The PAX is also worse in ESP.
I anticipate getting crushed no matter what I run in :flag:

So the consensus is that with a tunnel brace, headers, no cats, intake, and tune, I'm in CAM-C?
 

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Discussion Starter · #39 ·
I've been autocrossing with the SCCA for 8 years now. I'm very familiar with the rule book. I have a E36 M3 built specifically for STU (and maybe STR next year). I'm trying to help you out here, because it sounds like you've got some misinformation, unless your region runs some lame rule about factory only alignments in street.

Here's the section on alignment in street category:

13.8 Suspension
B. Both the front and rear suspension may be adjusted through their designed range of adjustment by use of factory adjustment arrangements or by taking advantage of inherent manufacturing tolerances. This encompasses both alignment and ride height parameters if such adjustments are provided by the standard components and specified by the factory as normal methods of adjustment. However, no suspension part may be modified for the purpose of adjustment unless such modification is specifically authorized by the factory shop manual.

You don't have to run the factory alignment settings in any class. You may run any alignment that can be done with the factory hardware in street. My E36 had crash bolts that I could run in street to give me a bit of extra camber. Some car's factory manual authorize notching the shock tower (like the E46) or lower strut attachment point (S197 Mustang).
Like I said, if the crash manual ALLOWS for it, then it is allowed as a STOCK setting. You cannot use a crash part, happen to get uber amounts of negative camber, and be in the clear. You will get called out quick, I have seen it happen. After 20 years of doing this, I know when I need to add neg camber, take out neg camber, or just leave it alone. I also know that when someone new wants to autocross, I don't tell them to start messing with the alignment right out of the gate until they gain some experience.
 

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Ok bud. I hope your settings work out for you. Just trying to help you get faster. yeesh. I never told any novice to change anything about their car. FWIW, changing tire pressures drastically from stock will also have the same consequences as changing alignment settings.


For anyone else reading this, if you haven't been able to tell from my other posts, you are 100% allowed to dial in whatever alignment settings you want using the factory hardware in any class of SCCA autocross. What you are not allowed to do in Street, is change the hardware, such as using an eccentric bolt with a different cam profile, unless the factory service manual permits it. So if you can dial in -1.5 degrees of negative camber at the front on the stock eccentrics, go for it. Not only will it help optimize the cornering capability, it will also help save the outside edge of your tires from wearing down too quickly.
 
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