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

[Dana Pants]

What balance issues do most people struggle to cure?

I tried to make my post more clear in case that's the source of your question. I'm trying to balance left-right camber and tire grip at this moment.

In the general sense, my answer to your question would be understeer. These cars have a big issue with steady-state understeer.

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[TeeLew]

I tried to make my post more clear in case that's the source of your question. I'm trying to balance left-right camber and tire grip at this moment.

In the general sense, my answer to your question would be understeer. These cars have a big issue with steady-state understeer.

I assumed you were dealing with some asymmetries. It looks like you've addressed it to some extent. I was speaking in a more general sense.

 

[TeeLew]

Maximize total acceleration capability by limiting the amount of steady state cornering. Most autocross courses have very few corners that actually have anything other than transients.

Well said. I've only had my car for a month & I haven't been to any autocrosses or similar. In the playing around I have done, I haven't come across any glaring handling issues. If anything, it feels as if the front is quite sharp. Keep in mind, I have an Eco HPP, which is meant to be the version of Mustang with the least amount of U/S and the fact that I personally favor U/S. Yes, I'm sure I could overrun the fronts on a low-speed autocross hairpin, but that's hardly the type of corner to use to define a general handling balance.

So here's my question. I see many people running roughly the same amount of static camber both front & rear (the front is usually a few tenths higher). If understeer is a limiter & power-down (wheelspin) is an issue, why don't people tend to run the rear at a somewhat lower number, say -1 deg. instead of around -2 deg.? This would tend to trade lateral grip for longitudinal, which seems like a reasonable choice.

I'm not criticizing what anyone has done, but, instead, trying to understand the process of how it was derived. Any insight would be appreciated.

 

[Dana Pants]

Power down is rarely an issue in my experience. IMO the issue is that throttle usually pushes the front tires straight ahead instead of rotating the car. There is no “good” reason not to try less rear camber if you are willing to give it a shot.

all I can say is that just shy of -2 gives pretty good rear tire shoulder wear at ~32-33 psi.

 

[Dana Pants]

So I did my first event with the Strano rear sway bar on full stiff and these are my observations:

1) Car is a joy to drive... Throttle causes rotation like its supposed to (not push).
2) Front end bite is so much higher. This gives me confidence to carry speed deep into turns.
3) Inside of front tires are smoking hot showing that the whole front tire is now working in turns (Technically the entire front tire is smoking hot). I was spraying twice between runs.
4) I never had a problem with applying the needed amount of throttle, but did do some wild sideways stuff a run or two when I applied more throttle than the car could take.
5) I need to increase my courage in the slaloms. I didn’t hit a single cone yesterday. I think this is because the back of the car moves out of the way now.

Here is a video proving it works:

 

[TeeLew]

So I did my first event with the Strano rear sway bar on full stiff and these are my observations:

1) Car is a joy to drive... Throttle causes rotation like its supposed to (not push).

I'm happy for you that you have something you like, but that car would be too loose for me.

 

[strengthrehab]

So I did my first event with the Strano rear sway bar on full stiff and these are my observations:

1) Car is a joy to drive... Throttle causes rotation like its supposed to (not push).
2) Front end bite is so much higher. This gives me confidence to carry speed deep into turns.
3) Inside of front tires are smoking hot showing that the whole front tire is now working in turns (Technically the entire front tire is smoking hot). I was spraying twice between runs.
4) I never had a problem with applying the needed amount of throttle, but did do some wild sideways stuff a run or two when I applied more throttle than the car could take.
5) I need to increase my courage in the slaloms. I didn’t hit a single cone yesterday. I think this is because the back of the car moves out of the way now.

How did you place? Car seemed pretty loose. Personally I would not be happy driving a car with those handling characteristics. Looked like you spent a lot of time catching the car.

But...that's why we do this...to have our own spin on our cars.

 

[Dana Pants]

How did you place? Car seemed pretty loose. Personally I would not be happy driving a car with those handling characteristics. Looked like you spent a lot of time catching the car.

But...that's why we do this...to have our own spin on our cars.

1 of 8 in FS with a 2.6 second gap to 2nd place.
12 of 56 on PAX.

handling characteristics are much closer to a “real” autocross car based on my pervious experience in CAM and hopping in the drivers seat of better cars owned by better drivers.

 

[strengthrehab]

Congrats on the placing.

I guess I wouldn't like a "real" autocross car.

 

[Dana Pants]

Congrats on the placing.

I guess I wouldn't like a "real" autocross car.

Lol. Find some good STR videos and you will see that catching is a pretty regular occurrence.

 

[Dana Pants]

Relatively underpowered RWD cars?

200 hp / 2200 lb isn’t so far away from 460 hp/ 3800 lb.

My CAM Mustang drove like a giant Miata.

 

[Dana Pants]

In terms of its ability to overwhelm tires, there's a fairly significant difference. STR cars have a different shaped friction circle than a Mustang and must be setup differently (more like a momentum car). Most STR cars outside Miatas aren't nearly that light either...2500-2800 more like.

preliminary analysts: I can more or less keep up with STR on sweepers with about a 0.1g deficit at similar MPH, I’m losing about 10mph and 0.3 g in the slaloms. 50 mph vs 40 mph. Power can’t save me in a slalom.

Analysis provided by my buddy in STR who was 4th on PAX.

I will make some traction circles later. I have STR s2000 and 1LE camaro data in my inbox.

 

[TeeLew]

1 of 8 in FS with a 2.6 second gap to 2nd place.
12 of 56 on PAX.

handling characteristics are much closer to a “real” autocross car based on my pervious experience in CAM and hopping in the drivers seat of better cars owned by better drivers.

It doesn't surprise me that you placed well. You had good discipline in making your apexes. It also doesn't surprise me you were putting a lot of heat into the front tires, because you give it some big steering inputs without loading the front tires much, which will induce understeer. It's one of those deals where you've tuned the car around your style & it works for you.

I know I'm happiest with a fair bit of understeer, more than most like. We just like different handing cars.

 

[Dana Pants]

To add, one of our alien drivers gave the advice that a lot of front-back weight transfer upsets a car and makes it slow...The advice seems plausible.

and it seems plausible that I’m using front tire scrub as a brake.

 

[Dana Pants]

So here are a bunch of traction circle overlays and food for thought.

The stiff rear bar drastically reduces my urge to brake on turn entry... good.
The traction circle with stiff rear bar overlays really well with a stock Camaro SS 1LE on the tires it comes with. After alignment and tires the Camaro will eat me for breakfast.
STR has higher peak lateral g, lower linear acceleration, and LOL quick left-right transition times (not shown)

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