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Discussion Starter · #1 ·
Need help with setup on long sweeping turns, like turn 12 at Carolina Motorsports park, VIR Oak Tree, and almost all of Robeling Road. The car just does not seem to do well and never has. I am on Hoosier bias ply's now. but the car was not good in those turns with Toyo RA1's. Lateral grip just does not seem to be there.
My setup
Front, GW upper control arms
520 springs
Bilstein race valved shocks
1 inch roll bar
3 degrese of positive caster
1.25 negative caster

Rear Street or Track 3 link with a watts link. I have played around with the roll center. The watts link seems to do a good job adjusting over/under steer conditions. Car is fairly neutral now.

Tires are asphalt oval, 10/27/15R and 8/26.5/15F starting with about 18 psi cold. getting to about 27psi hot'

The method I am using now is a 4 wheel drift using throttle steer, I have watched a ton of vintage RR and trying to drive like those guys. going to stick with bias ply tires for now.

Advice appreciated
 

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Need help with setup on long sweeping turns, like turn 12 at Carolina Motorsports park, VIR Oak Tree, and almost all of Robeling Road. The car just does not seem to do well and never has. I am on Hoosier bias ply's now. but the car was not good in those turns with Toyo RA1's. Lateral grip just does not seem to be there.
My setup
Front, GW upper control arms
520 springs
Bilstein race valved shocks
1 inch roll bar
3 degrese of positive caster
1.25 negative caster

Rear Street or Track 3 link with a watts link. I have played around with the roll center. The watts link seems to do a good job adjusting over/under steer conditions. Car is fairly neutral now.

Tires are asphalt oval, 10/27/15R and 8/26.5/15F starting with about 18 psi cold. getting to about 27psi hot'

The method I am using now is a 4 wheel drift using throttle steer, I have watched a ton of vintage RR and trying to drive like those guys. going to stick with bias ply tires for now.

Advice appreciated
Love that you’re running bias tires!

I’ve never run on TD’s, only Blue Streaks, so don’t know if they are the same. Here’s what I run and I absolutely love the way my car runs in the carousel (and everywhere else) at Heartland Park and Hallett.

Front springs were #540 but then I cut a 1/2 coil off.
Same shocks
1 1/8” bar
2.5° positive caster
-2.75° negative camber
Dbl roller perch
Roller upper and lower arms

Depending on ambient temp, I start at 20-22 psi, with the rears 1 lb less than the front.
I get awesome tire wear and this setup fits my driving quite well!

And the only true way to drive bias tires is drifting them. It’s almost like driving on ice


Mark
 

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Spammer Hammer
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Are you using anything like TrackAddict for data capture during sessions?

If so, what kind of speed are you carrying through those turns?

You could compare your data to others to get some idea of how far off you are. Might just seem more than you really are.
 

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Discussion Starter · #4 ·
Are you using anything like TrackAddict for data capture during sessions?

If so, what kind of speed are you carrying through those turns?

You could compare your data to others to get some idea of how far off you are. Might just seem more than you really are.
No data logging.. Just feels slow and having folks being able to take a tighter line to pass me in a turn ticks me off.

corrections to setup data
620 coils
-1.25 camber
I do have the roller spring perch too
 

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Spammer Hammer
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11,308 Posts
I would recommend TrackAddict. Simple to use on your phone. Gives good feedback. This is one of my sessions in the GT in 2020. Actually it was right before my oil pan cracked. You can see I was only 40MPH is turn 12. Super slow compared to Miatas which were likely 55MPH through that turn.

793557
 

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I race my 65 GT350 Tribute with SCCA, HSR and SVRA.
I think your suspension is too stiff to allow proper weight transfer to the outside corner, not this may not be allowing your car to take a 'set' and then the car breaks away when any road dip or imperfection is encountered.
Evidence would be overheated outside edges of tires - exactly what you show. That's a lot of tire pressure gain - from 18 to 27 - so there's a lot of heat being built up.
My Hoosier TD-R bias ply tires go from 23-28 at a normal race session. The LR at Sebring, which is notoriously hard on tires, goes from 23 or 24 to 30.
Same for Roebling Road which is full of fast right-handers, causing lots of wear on left-side tires.
Steven Piantieri
Orlando, FL
 
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