SCCA F-Street Setup. What's Everyone Done so Far?

[Dana Pants]

Wouldn't it be better to be able to put power down and not spin?

most (all) other people here prefer the front bar. As a driver, I want to control position and angle of the car. With the front bar, I felt I had no control over angle. My car just understeered and understeered both on and off throttle unless I did crazy things to upset the chassis.

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[Dana Pants]

If it helps you with positioning the car, then whatever works for you. I'd never be able to drive it with confidence in slaloms or high speed stuff, but it just has to work for you.

Did you ever try closer to zero rear toe or a good chunk of front toe out to get the nose in? Same tire pressures F/R? Lower pressures overall?

my rear toe was always 1/32” toe-in, which is effectively zero. My front toe has varied from 1/32” to 1/8” toe out, but I never tried anything higher.

My current pressures are 34f 32r. Definitely higher rear pressures have a similar impact to rear bar, but also causes spin city. I’m hesitant to go lower than 34f due to roll over. Higher front pressures Improve crispness but not really grip on my typical surface.

 

[Dana Pants]

Even when I ran -2.2 front, -1.7 rear camber I ran 31/29 on 275 square RE71Rs. Worked great. I tried higher and wasn't a fan. The little bit of sidewall flex made it easier to throw the car around and get power down. They don't wear flat unless you're running a lot more spring rate and another 1/2 degree to 3/4 deg more camber. Just part of dealing with RE71Rs.

I played with tire pressure yesterday. I started at 32R 34F and ended at 34R 35F after much experimentation.

Lower pressures caused unpredictable break away on whatever axle had the lower pressure. So oversteer rear and understeer front. Humorously, 36F also got pushy suggesting that I’m a real picky eater when it comes to tire pressure. I didn’t have a desire to find the upper limit for the rear.

I was more pax competitive with my friends vs the last event, so I’m gonna leave it at the moment.

Yesterday’s fastest run:

 

[Brian@BMVK]

I've only found that behavior when I ran the rear and front the same. If I keep a 2-3 psi (usually 3) stagger the car is predictable. Never over 29 hot rear for me though. Doesn't put power down well above 30.

 

[NightmareMoon]

On concrete at a test 'n tune event, my car didn't like 33/32 psi front/rear with 285 RE71Rs. Too much oversteer. Bumping the rear pressures to 33.5 seemed to fix it. At nats (when I went), at least one faster driver was on 36/36 and someone else was on 28psi rear with minimum koni rebound, which seemed unusual, but hey, they were both faster than me. I would usually run 33F/34R in FS trim.

With the wider 305s in CAM, I run less pressure (closer to 29-31) and the car does well.

 

[Brian@BMVK]

On concrete at a test 'n tune event, my car didn't like 33/32 psi front/rear with 285 RE71Rs. Too much oversteer. Bumping the rear pressures to 33.5 seemed to fix it. At nats (when I went), at least one faster driver was on 36/36 and someone else was on 28psi rear with minimum koni rebound, which seemed unusual, but hey, they were both faster than me. I would usually run 33F/34R in FS trim.

With the wider 305s in CAM, I run less pressure (closer to 29-31) and the car does well.

Just goes to show that the whole setup and the driving style it supports matters

Low rebound will transfer weight slower, so that's probably why the one worked.

 

[SteveW]

I played with tire pressure yesterday. I started at 32R 34F and ended at 34R 35F after much experimentation.

Lower pressures caused unpredictable break away on whatever axle had the lower pressure. So oversteer rear and understeer front. Humorously, 36F also got pushy suggesting that I’m a real picky eater when it comes to tire pressure. I didn’t have a desire to find the upper limit for the rear.

I was more pax competitive with my friends vs the last event, so I’m gonna leave it at the moment.

So, I've been harping on here and in person with a friend who runs his 2015 GT PP in FS to switch from a bigger rear bar to a bigger front bar. This past weekend were local autox events and on Sat afternoon we got to swap cars during fun runs. His FS car has Forgestars, BFGs, Konis and a rear bar and I found I had no trouble putting the power down, the car had a nice balance and would rotate nicely. It handled very similar to my CAMC car just way softer and mushy compared to mine. I had set TTOD and TOPAX earlier in the day with my car but out paxed myself with his car after just two runs.

I told him his car is great and not to change out the rear bar, lol.

 

[Dana Pants]

So, I've been harping on here and in person with a friend who runs his 2015 GT PP in FS to switch from a bigger rear bar to a bigger front bar. This past weekend were local autox events and on Sat afternoon we got to swap cars during fun runs. His FS car has Forgestars, BFGs, Konis and a rear bar and I found I had no trouble putting the power down, the car had a nice balance and would rotate nicely. It handled very similar to my CAMC car just way softer and mushy compared to mine. I had set TTOD and TOPAX earlier in the day with my car but out paxed myself with his car after just two runs.

I told him his car is great and not to change out the rear bar, lol.

my thoughts exactly. If you come from a cam car (which I did), then the stiff rear bar feels much closer to a properly behaving vehicle.

 

[Brian@BMVK]

my thoughts exactly. If you come from a cam car (which I did), then the stiff rear bar feels much closer to a properly behaving vehicle.

I do often forget that you still have a rear subframe that moves around like a belly dancer. That changes things.

 

[Dana Pants]

I do often forget that you still have a rear subframe that moves around like a belly dancer. That changes things.

needed but missing on the forum: haha emoticon

 

[NightmareMoon]

my thoughts exactly. If you come from a cam car (which I did), then the stiff rear bar feels much closer to a properly behaving vehicle.

Yeah I drove the rear bar for a couple of years, and later switched to the Front bar setup to see what all the fuss was about. I would agree with the above, rear feels closer to what I expected for a neutral handling car, and the the stiff front bar is clearly an understeering setup, (which isn't necessarily a bad thing, if it fits your driving style)

 

[Dana Pants]

Latest Fastrack:

Looks like FS will go relatively untouched for 2021 season.

Also, my Re-71Rs are dead. Had two spins last event that I feel I didn’t deserve. Bring on the Yokos.

 

[Brian@BMVK]

needed but missing on the forum: haha emoticon

It's available now!

 

[Dana Pants]

I went from 275 35 R18 front & 285 30 R 18 rear RE-71r tires to square 275 40 R18 Yokohama A052 tires and just ran my first event.

Surprisingly, it made the car EXTREMELY tail-happy and I softened my strano rear swaybar from full stiff to the middle setting at lunch. In prep for next week, I put the rear bar to full soft.

Front tire pressures seemed pretty happy at 39 psi and I didn't adjust much. RE-71r was at 35 psi.

Rear traction seemed best at 34 psi... which was the same as my RE-71r.

I didn't really place any better or worse than with the RE-71r tires, but hopefully I can get a bit more out of the car with some setup improvements to put the power down.

I'm left scratching my head a bit as to how the Yokos added oversteer. Concensus is that they make a car a bit pushy. Everything has to be different with me.

It seemed that the second run was best and any subsequent runs the tires were overheating and slowing down. Water spraying is obviously important with these tires.

There are many videos of sending it sideways, but this boring run was nearly a second faster than them:

 

[Brian@BMVK]

I went from 275 35 R18 front & 285 30 R 18 rear RE-71r tires to square 275 40 R18 Yokohama A052 tires and just ran my first event.

Surprisingly, it made the car EXTREMELY tail-happy and I softened my strano rear swaybar from full stiff to the middle setting at lunch. In prep for next week, I put the rear bar to full soft.

Front tire pressures seemed pretty happy at 39 psi and I didn't adjust much. RE-71r was at 35 psi.

Rear traction seemed best at 34 psi... which was the same as my RE-71r.

I didn't really place any better or worse than with the RE-71r tires, but hopefully I can get a bit more out of the car with some setup improvements to put the power down.

I'm left scratching my head a bit as to how the Yokos added oversteer. Concensus is that they make a car a bit pushy. Everything has to be different with me.

It seemed that the second run was best and any subsequent runs the tires were overheating and slowing down. Water spraying is obviously important with these tires.

There are many videos of sending it sideways, but this boring run was nearly a second faster than them:

I'm dumbfounded how you're making it work with 39 psi. That's FWD with basically zero camber type of pressure. You have enough camber to run substantially less, similarly for the rear. I'd expect you to be able to run ~33-34 front and 30-31 rear.

From what everyone who uses them tells me, their big advantage is putting power down, so prioritizing that is what you should go after.

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