SCCA C Stock Discussion

[7thgear]

so after a double header at an airport, with pyrometer testing and logging, the R1R's in 235/40 seemed to like to be around 38 hot...


does this match the experience of others?

[rx3]

I have the Toyo R888 in 235/40 17 on 8" wide rims and run them at 31 psi (hot) and 35 psi when it's wet. Oftentimes the rear tires don't get as hot as the front tires, so I usually run them at a higher pressure.

What rims and tires (size and type) do the CSP guys run?

[SeanRTR]

I thought people were running high 20's / low 30's on R1R's...

Did you get your set shaved or running at full depth?

[Sccabrz192]

Originally Posted by rx3

I have the Toyo R888 in 235/40 17 on 8" wide rims and run them at 31 psi (hot) and 35 psi when it's wet. Oftentimes the rear tires don't get as hot as the front tires, so I usually run them at a higher pressure.

What rims and tires (size and type) do the CSP guys run?

I'm not aware of any attempts at a CSP build to-date. I don't expect anyone to make any real effort at this for 3 reasons:
1) CSP is spec-miata class, general consensus is the twins don't have a prayer.
2) A legit build really makes the car pretty much un-streetable and means you have to modify body work to fit appropriate tires.
3) All signs point to SP being the next rule set and classing structure to get completely re-vamped very soon... maybe even displaced in favor of "prepared light" intermingling in prepared classes and/or increased SM classing structure.

[7thgear]

Originally Posted by SeanRTR

I thought people were running high 20's / low 30's on R1R's...

Did you get your set shaved or running at full depth?

-1.3/-1.2 camber, 0 toe front, -1.1/-1.1 camber, 1/16th toe in rear, using an IR Pyrometer i was getting colder readings in the center of the tire compared to the outer and inner parts... basically telling me that i need more air


38psi is where they seemed to have balanced out


measurements were taken less than 15 seconds after the completion of a run and with no cone stop box no hard braking was performed at the end.


also 20psi hot? what? lol

[mrazny]

Originally Posted by Sccabrz192

I'm not aware of any attempts at a CSP build to-date. I don't expect anyone to make any real effort at this for 3 reasons:
1) CSP is spec-miata class, general consensus is the twins don't have a prayer.
2) A legit build really makes the car pretty much un-streetable and means you have to modify body work to fit appropriate tires.
3) All signs point to SP being the next rule set and classing structure to get completely re-vamped very soon... maybe even displaced in favor of "prepared light" intermingling in prepared classes and/or increased SM classing structure.

Anything you do towards CSP would translate upward into SM...

[neurokinetik]

Originally Posted by mrazny

Anything you do towards CSP would translate upward into SM...

Where you can then get slaughtered by cheating-bastard-AWD cars like the Evo and GTR.

[vroom4]

Originally Posted by 7thgear

-1.3/-1.2 camber, 0 toe front, -1.1/-1.1 camber, 1/16th toe in rear, using an IR Pyrometer i was getting colder readings in the center of the tire compared to the outer and inner parts... basically telling me that i need more air


38psi is where they seemed to have balanced out


measurements were taken less than 15 seconds after the completion of a run and with no cone stop box no hard braking was performed at the end.


also 20psi hot? what? lol

No matter what psi I run on race tires/street tires I always have a near cold inside shoulder. How are you using that part of the tire at all?

[renfield90]

Originally Posted by vroom4

No matter what psi I run on race tires/street tires I always have a near cold inside shoulder. How are you using that part of the tire at all?

How much camber do you have?

It's also worth noting that depending on the brand, an IR pyrometer measures a fairly large circle for heat. Not knocking 7th gear's methods at all here, he's shared a ton of valuable data for us all, but a probe pyrometer is usually better. (I just acquired one, if I get anything useful out of it I will share.)

See point number 1 here: http://www.thermoworks.com/blog/2012...d-thermometry/

Points 2 and 3 are irrelevant if you're always measuring the same tire compound and are only trying to ensure that temperatures are even across the tire.

[vroom4]

I am maxed on stock crash bolts...like the rest of us. I think I got -1.2 on both sides. Seriously, my tires are ready to be flipped on the rim, the inside shoulder is brand new.

[7thgear]

Originally Posted by renfield90

IR pyrometer measures a fairly large circle for heat..

please note that I was getting down on my knees to do the dirty work


so I was measuring about an inch away from the tire.

Originally Posted by renfield90

but a probe pyrometer is usually better.

most def, but only if your goal is to get accurate readings in terms of absolute temperatures




otherwise, the IR Pyrometer is a great tool to quickly asses the relative distribution of the temperatures. ie, I'm not overly concerned as to what the core tire temperature is, the short stints combined with a lack of any real ability to tune the car means that I've only pressures to play with,


for this, an IR tool is great to quickly figure out whether you've got too little or too much

Originally Posted by vroom4

No matter what psi I run on race tires/street tires I always have a near cold inside shoulder. How are you using that part of the tire at all?

if you are under inflated the center will be colder or same temp as the inside. I was going off 30 cold, which is what I read online, and it wasn't until I got to 38-39 hot (which translated into around 34 cold) that I was getting the center to start working more.

[7thgear]

Originally Posted by vroom4

I am maxed on stock crash bolts...like the rest of us. I think I got -1.2 on both sides. Seriously, my tires are ready to be flipped on the rim, the inside shoulder is brand new.

food for though: you could be overdriving your car.


Too much steering input and hard braking during the wrong time could lead to premature tire wear.


but I don't know you as a driver so hard to judge,

[mrazny]

Originally Posted by neurokinetik

Where you can then get slaughtered by cheating-bastard-AWD cars like the Evo and GTR.

http://scca.cdn.racersites.com/prod/...s%20FINAL1.pdf

SM, the ruleset that let's you do anything, cheating? Also, slaughter? Oh you meant you'd get slaughtered because you haven't developed to the limit of the class like Panda did, and the twins should just be given classes that they don't need to spend time developing within?

[neurokinetik]

Originally Posted by mrazny

http://scca.cdn.racersites.com/prod/...s%20FINAL1.pdf

SM, the ruleset that let's you do anything, cheating? Also, slaughter? Oh you meant you'd get slaughtered because you haven't developed to the limit of the class like Panda did, and the twins should just be given classes that they don't need to spend time developing within?

Ya got me, I must have been thinking of Pro Solo, where AWD has such a huge advantage.

As for the cheating bastard AWD comment, that goes way back to the Audi in Trans Am days, where AWD was banned because it worked too well and was deemed an unfair advantage. I rib my friends for their cheating bastard AWD and their cheating bastard turbos all the time (the latter because of the history of turbo boost level not being policeable in pretty much any form of motorsport).