SCCA CAM-C Thread

[TeeLew]

To an extent, yes. Too much and it'll just load the tire too quickly.

I do run a coupler spacer between the main and helper. Eibach SPACER250, and the Hyperco CS100 helper.

Interesting. I wonder what this is telling us? Whatever it is, it's more than just an issue of roll couple.

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[Brian@BMVK]

Interesting. I wonder what this is telling us? Whatever it is, it's more than just an issue of roll couple.

The rear does have fairly good camber gain, so limiting overall squat via spring (to an extent) can keep the contact patch larger/more consistent. It could be that and a combination of how much anti-squat is built into the integral link design.

 

[TeeLew]

The rear does have fairly good camber gain, so limiting overall squat via spring (to an extent) can keep the contact patch larger/more consistent. It could be that and a combination of how much anti-squat is built into the integral link design.

Do you know anti-squat numbers? Do they change significantly through the travel? Is bump steer an issue? If it were a strut rear, I could see camber loss in roll as issue, but unless the camber gain is really through the roof, I'd be surprised if that's the issue, specifically because common static settings seem to be relatively high.

It's not a big deal, just more of a curiousity.

 

[Brian@BMVK]

Do you know anti-squat numbers? Do they change significantly through the travel? Is bump steer an issue? If it were a strut rear, I could see camber loss in roll as issue, but unless the camber gain is really through the roof, I'd be surprised if that's the issue, specifically because common static settings seem to be relatively high.

It's not a big deal, just more of a curiousity.

There definitely is bump toe. How much of that and anti-squat I am behind on getting plotted...

 

[TeeLew]

@boardkat ran a base EB/V6 bar before, which is in the ballpark of what you're looking for. He settled on stock GT PP bar though when it was still an autocross focused car, as have I. 22.2 mm vs the 24 mm you have now. It's still a very significant difference. I know that the base GT bar is 21.7 mm, also. The base EB/V6 is smaller still but I don't remember the size.

20mm is the V6 bar I've found. I'm going to give it a run next time out. In talking with Maier about the Fontana surface, he commented that the grip is low enough you have to basically put a rain setup on the car. Well, this is kind of doing that, although if it were really raining, I'd be unhooked.

 

[Dana Pants]

Rain setup you say...Never heard of it.

Rain tires and the rain driving line I am aware of because cars accelerate and stop better than they turn in the rain.

 

[TeeLew]

Rain setup you say...Never heard of it.

Rain tires and the rain driving line I am aware of because cars accelerate and stop better than they turn in the rain.

Well, it's a thing.

In the same way driving is biased towards longitudinal grip, the car is biased for it. It's fairly impressive how little braking grip is lost in the wet. Cornering grip goes straight into the toilet, so you soften everything up to slow the tire loading rates (disconnecting both ARB's is common). Drive traction is also limited, so anything you can do to improve hook up on exit is a big deal.

I wasn't fighting drive traction problems, but I was carrying too much speed on entry, sliding wide in the middle & delaying throttle application while I waited for the thing to recover from my stupidity. I ran the exact same speed with the rear bar on & off, I just did it in different ways.

 

[Norm Peterson]

This ^^^

Tire grip (mu) is not only sensitive to how much vertical load it's seeing (a static snapshot in time), there's also some sensitivity to how fast the load transfer is applied (the whole video).

I think the reason for softening the setup in the wet is analogous to when drag racers have to fix a case of "hitting the tires too hard" on launch.


Norm

 

[strengthrehab]

Had an event yesterday to warm-up for the Texas National Tour. I scored 3/7 in class losing to two great drivers. I had a quicker run later in the heat, but it was during a double run and was dirty. That run would have been barely in 2nd or barely in 3rd. The guy who won was driving a ZL1 Camaro. My co-driver actually ran about 0.8 seconds quicker with a run that would have won the class, but he was just testing the car to prepare for the tour so not in class.

This was the first event since upping the front spring rate from 325 to 560 (with softening the front bar).

Overall, the car is setup perfectly thanks to @Brian@BMVK.

 

[SteveW]

Had an event yesterday to warm-up for the Texas National Tour. I scored 3/7 in class losing to two great drivers. I had a quicker run later in the heat, but it was during a double run and was dirty. That run would have been barely in 2nd or barely in 3rd. The guy who won was driving a ZL1 Camaro. My co-driver actually ran about 0.8 seconds quicker with a run that would have won the class, but he was just testing the car to prepare for the tour so not in class.

This was the first event since upping the front spring rate from 325 to 560 (with softening the front bar).

Overall, the car is setup perfectly thanks to @Brian@BMVK.

The car looks so flat and hooked up! Hope you do great at the Tour!

Brian been meaning to ask if you've tried similar front spring rates on your car yet?

 

[Brian@BMVK]

Brian been meaning to ask if you've tried similar front spring rates on your car yet?

Soon. 475# for me.

 

[murphyslaww]

Still have the T-shirt from winning the texas tour in Cam-C as the only competitor in 2015

 

[strengthrehab]

10 competitiors next weekend. Tied with CS for biggest class.

 

[Brian@BMVK]

Soon. 475# for me.

Yeah....
This really works nice. First real test this Saturday (and probably last event of the season )

 

[strengthrehab]

Just as an FYI for you folks.

I got word today with Tire Rack and Bridgestone confirmation that the RE71R production has ended without a replacement in the works for the states. The RE71RS is now being produced for the Asian market, but no word on release in the US.

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