SCCA Solo C Street Discussion

[DocWalt]

Originally Posted by vroom4

Maybe I missed it, how is anyone getting more camber from the front due to springs? That's not even geometrically correct....?

Yes it is. Control arm arc puts the bottom of the wheel further out, so you get more negative camber. Though since you're further into the camber curve you're more likely to start losing negative camber as the suspension compresses.

[markw]

Originally Posted by YawMomentRacing

Yes TRD springs and both bars.

What size tires are you running? Thinking of RE71R's to tear up on the SD tarmac. Starting to lean towards the 225/45's.

Thanks,
Mark

[YawMomentRacing]

My videos from the tour:


[ame="https://www.youtube.com/watch?v=AhyVDrNhoaI"]2015 Spring Nationals Champ Tour Day 1 - Dave Ogburn C-Street Onboard - YouTube[/ame]

[ame="https://www.youtube.com/watch?v=yatv7OxQ1lg"]2015 Spring Nationals Champ Tour Day 2 - Dave Ogburn C-Street Onboard - YouTube[/ame]

[YawMomentRacing]

Originally Posted by markw

What size tires are you running? Thinking of RE71R's to tear up on the SD tarmac. Starting to lean towards the 225/45's.

Thanks,
Mark

225s

[SeanRTR]

Originally Posted by YawMomentRacing

225s

No sound here at work, so I can' tell from the video, but how often were you up against the rev limiter (if at all) on each course? How about the Pro Solo?

[YawMomentRacing]

Once in the wet on day 1 (wallom about half way through). Once on Day 2 in the dry (right at the finish). I was at the top of 2nd in the main slalom at the Pro but not on the limiter anywhere.

[Jawnathin]

Originally Posted by YawMomentRacing

Yes TRD springs and both bars.

Having driven with and without them, what do you think of the new setup?

[renfield90]

Best clean left and right side runs from the pro:
[ame="https://www.youtube.com/watch?v=RocMberS9OM"]Manfred - Spring Nationals ProSolo 5-23-15 @ Lincoln - YouTube[/ame]

[SeanRTR]

Did you guys ever get a chance to test the RE71R and Rival-S back to back?

[renfield90]

Yes, but they changed the practice course RIGHT in the middle of the test.

Overall, neither of us believe one or the other is "the one true tire to rule them all." Both of us walked away happy with the tire we picked.

I personally found the Bridgestone too edgy for my taste - push the tire too far and grip falls off a cliff, and you're in a world of hurt - my times on that tire were slower than what I could lay down on the BFG. Could I adapt my driving style to that or learn where the edge is? Sure. I just don't wanna. :P

I'll let Dave chime in with his thoughts if he so chooses.

[YawMomentRacing]

Originally Posted by Jawnathin

Having driven with and without them, what do you think of the new setup?

Hard to give an indication of pace difference without a back to back test. My feeling is that the TRD setup makes the car more direct and quicker to transition in transient sections and gives you a bigger "tuning window" to change the balance to the drivers preference due to the increased roll stiffness. It is not a bolt on and go faster deal - you have to drive to take advantage of the benefits (higher slalom speed, quicker through quick hole-in-the-wall transitions, etc.

In some ways it makes the car a bit harder to drive/sort because it feels more knife-edged and a little less predictable. I'm not sure if this is do to the progressive rear spring or the change in kinematics due to the ride height drop.

Overall, my guess is that, depending on driver/course, it is worth anywhere from 0 - 0.5s on a National Tour course. It hurts in the rain (too stiff and more knife-edged) and on the Pro Launch where I got killed by the soft MX-5 (unless you are Manfred with huge BFGs in the rear!). Probably a wash/small gain at a Pro when you factor in the launch.

[YawMomentRacing]

Originally Posted by renfield90

Yes, but they changed the practice course RIGHT in the middle of the test.

Overall, neither of us believe one or the other is "the one true tire to rule them all." Both of us walked away happy with the tire we picked.

I personally found the Bridgestone too edgy for my taste - push the tire too far and grip falls off a cliff, and you're in a world of hurt - my times on that tire were slower than what I could lay down on the BFG. Could I adapt my driving style to that or learn where the edge is? Sure. I just don't wanna. :P

I'll let Dave chime in with his thoughts if he so chooses.

As Manfred mentiond, there were a couple of problems with our "test":
- Different tire sizes (245 BFG vs. 225 Bstone)
- We run very different pressures - without a skidpad or taking time test pressures, we just ran what each of us run on our cars
- Course change between sets (basically a gate was moved to avoid a part of concrete that was braking up which added distance and I would guess a couple of tenths to the lap time). I discovered this as I made my first lap on the Bstone.
- The course was honestly not very good, too low speed didn't seem to correlate to the National courses (typical for Lincoln test courses)

My lap times and comments (all in Manfred's car):
BFG: 48.208, 47.794
- More compliant than the Bstone and hard to point into the corner. Mid-corner grip is very high as is the accel traction on launch. Tolerates huge slip angles and is very forgiving.

Bstone: 47.745, 48.095
- Firmer feel and quicker response. More predictable and easier to drive quickly in slaloms. Higher gain (lower slip angles). Easier to saturate the front into understeer and lower lateral grip feel.

Overall, not conclusive. As Manfred said, one tire was not a world beater. Both can win but one might give a sight advantage - I'm just not sure which one that is. I am debating between stick with what I have driven on and know which is the Bstone vs. the BFG has too much grip to ignore and try it.

I have the Mineral Wells Pro coming up and then possibly going up to Colorado for the Tour so I'll burn through the Bstones that I have and then make a decision/guess for Nats.

[CatDaddysBBQ]

Originally Posted by SeanRTR

Did you guys ever get a chance to test the RE71R and Rival-S back to back?

My friends did this with their S2k over a 2-day autoX weekend. They previously used the "old" Rivals for the past couple of years for a third comparison...

Verdict: Re71R are stickier and faster, wear like tissue paper
Rival-S are nearly as good and wear slightly better
"Old" Rivals are slightly behind in grip but wear much better

[samjaw82]

First time poster.
This is my second full season auto crossing. Last year I was competitive in sp class with my legacy gt in my region and switched to my first Rwd car.
My mods are koni inserts, toyota bolts with max -1.4. (That I could muscle up) STRANO front bar, project mu pads and 225/45/17 falken azenis rt165....(didn't want the best tire but a tire competitive enough to learn Rwd at its limit and beyond).
I would be real competitve if I can stay clean but I can't as of now so Im not lol.
Just wanted to know if anyone else is running"old tires" or am I the only dummy.
Seems like these cars are amazing with tire wear. Iove it