Set Up ideas for Toyo R888 wanted!

Technical and Repair Discussions
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PostPosted: Thu Aug 25, 2016 5:06 pm
Originally on the General Section - "fits" better here:
I am setting up my "Non-Spec" SPU, former SREN for a test and run in a week at Sebring.
I'm still in a basic Sports Rambo configuration. We'll string and scale the car early next week.

My GYs were shot and decided to take a trial with the TOYO R888s. I like the comments I'd seen here from their use in the 25 Hours, wear, general performance, and from the Formula Ford users. There are some things I've seen on the Interweb regarding they can be a bit "squirmy" - mostly referenced on heavier cars (BMW,Corvette, Porsche). The Formula Fords using them are a bit lighter, but seem generally impressed with them.

I've read that the car needs to be able to slide a little in order to use R888s to their max. This may take a bit of time to sort out. But, I am ready to; "Ride the Slide."

I am planning on making my initial setups for toe, camber, caster, swaybar, and tire pressure. I am looking for ideas, so I can start testing with a reasonable baseline and not have to rebuild the entire setup track side! I would like to concentrate on; brake balance, tire pressure and bars track side.

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CAMBER:
Radials require a lot more camber than the bias ply Goodyears. I've read, to get the most out of the car I'll want camber at least above 3-3.5 degrees, maybe as much as 5 degrees with sacrifices to some tire wear. (Benton)
I guess relationship of the Front/Rear is 1 degree less on rear?


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CASTER:
Toyo says - as much as possible. Any experience here to suggest otherwise?


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TIRE PRESSURE:
Toyo Tires recommends Operating Temperature 160°F to 220°F guidelines for the Proxes R888. Alan Meaker, Motorsport Manager Toyo Tyres (UK): The pressures will initially depend on the weight of the car: Very Light (< 800kg): 17-22 psi (cold), 22-29 psi (hot). Then balance the
hot pressures side to side.

Surprisingly, the fast FF drivers in Canada run 24-28 PSI cold, slide the car more and don't need as much negative camber to get temps even. And, they stiffen the springs. The FFs cars may be near 1/2 my weight.

Starting point: F/R pressures: 21 cold in the front and 24 cold in the rear. Does this sound about right?
What pressures did you run at Thunderhill?


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BARS:
Front/rear balance -- sway bar settings to stiffen up the rear (or soften the front) to get the car back to neutral. I read that it would likely push badly with a stock setup.
Your experience?


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SHOCKS/TOE
I found no references to huge differences in shock settings or toe. Seems like just apply standard setup.


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SPRINGS
Apparently, the Toyo tires like softer springs than slicks require and they also like less damping than slicks do. Something I could adjust track side. Any experience here? I read with the aero package at Thunderhill had to go to stiffer springs - but that is not tires.


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OTHER SETUP:
Anti-squat: on a light (formula) car, can cause power and trailing-throttle/braking oversteer.
On power, it acts like increased bump damping, prevents the back from settling under power.
On braking, it unloads the rear wheels -- makes braking unpredictable.
Eliminate the anti-squat solves most of these issues.

This is essentially a formula car with full body. Thoughts on this idea?

Apologize for the long note - trying to summarize the chassis setup for Toyo R888s on a "non-spec" GEN1. Thanks to all in advance!
Pressing to get ready - 7 day countdown to depart.

Cheers - Jim
When I used to fly, I was called an AVIATOR.
Now, I race cars. So, am I called a PAVIATOR?
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PostPosted: Sat Aug 27, 2016 8:20 am
We ran a pretty modified car for the 25, so I'd suggest the Gen3 Hoosier setup as a starting point with slightly higher starting tire pressures (believe we targeted 28-30 hot on the 25 hour car).
Bob Breton - SRF 51 - San Francisco Region

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