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

[z3papa]

Wow -- I was being all lazy and using RPM calculators which factor in or adjust for tire size, gearing ratios of the gears, rpm limits and what not. Now I have to factor in some .3% impact due to tire deflection or rotational variances. Alternatively, I could use a data acquisition and simply run it out to the limiter on a few tire sizes but what fun is that. Got it.

Disclaimer edit -- I probably fall in Tom's category of folks not driving the 550 and should be taken with a grain of salt but like the information exchange and people here.

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[SteveW]

Steve - As an FYI my rear settings are the same at about 12K miles as they were at around 2K. However the are still at the original factory setting with no attempt at adjustment. Rear tire wear on both 5K plus sets of RE-71Rs is no more than the front wear except slightly more mid tread wear in the rear. Camber is about -1.7 LR and -1.5 RR with very little toe in. Lots of tire spinning Pro Solo practice and competition "drag race" starts but mostly interstate and highway driving other than autocross.

Something had to have slipped on my car. I go to a friend's shop and normally they hook my car up to the machine and I do all the work myself. I didn't have time this summer when I got the car so had them do it instead.

I'm thinking one or both of the following happened: the apprentice there didn't fully tighten down the rear camber bolt on both sides and/or the gouged up old log yard I get to run on locally made it slip. The weird thing is the steering wheel remained on center through whatever happened and I never noticed it until the tire wear became excessive. So it slipped equally on both sides. Weird. Live and learn I guess.

On my old car that I drove tens of thousands of miles on I could tell when I had an alignment issue because either the steering wheel was off or gas mileage/throttle input changed when cruising. I just didn't have that data on this new car so nothing to clue me in on there.

Thanks for the reply. It's hard to know what's normal or not with such a new car. I'll make a baseline tape measure measurement of toe at both ends across a tread groove so I can tell if a big change happens.

Btw, toe and camber are very interactive on the rear of these cars!

 

[Whiskey11]

I have autocrossed at various times since the 1970's, but have been out of it for several years now due to personal difficulties involving heat stress (and one emergency room visit because of this). The only 'new' thing to me here is the rev limiter behavior.

You apparently thought I was just another keyboard jockey, so I gave you evidence otherwise. I'm making no claims as a driver, but at least I'm not making any big setup errors, which comes back to understanding what's going on.

Understanding concepts can be just as useful as direct experience, just in a different way. At the very least it gives a better sense of direction to what car behavior(s) your experience is telling you needs tweaking.

As far as my participation here goes, it seems kind of short-sighted to ignore what I might be getting into a little ways down the road - my 2008 probably isn't going to last forever and stick axle cars are now all relegated to history. So I might as well start the learning curve ahead of time and in return share what I do know that might help.


Norm

FWIW Norm, I value your perspectives and posts, so keep them coming. You and I speak very similar languages, although you are far more likely a "native" speaker and this is like the 2nd language I took a class on in college, once! I tend to operate in a similar manner. IE: Conceptualize, put into practice, analyze. Something that came from my background in engineering I guess. Probably part of the reason Strano and Fair both would rather see me shoo'd off to the loony bin! The nice part is I'm rarely surprised when I try something and when I am it is because I left out something in my concept that played a key role and had an unintended consequence.

Practical experience is nice too but I don't operate on a budget that allows me to try dozens of different setups unless that setup can eventually be used later if I move classes (for instance buying both swaybars was a practical decision since I can use both later when/if I go to STP). That's part of what makes choosing components a long process for me. It took me several years to decide to buy the Ground Control Coilovers for my 2009 car. That's several years of back and forth on the cost/performance argument.

 

[dontlifttoshift]

FWIW, the data from the DL1 shows 60-60.7 on the rev limter with 285/35-19s in second gear. I couldn't find the mathematical number in this thread for what it should be, but I thought 59.xxx was the number.

So the 20" wheel gets you to maybe 62.....downhill......with a tailwind.

Somewhat related, has anyone dug in and figured out what TPS signal we are getting out of the OBDII port? It seems like it is actual throttle blade position as opposed to throttle pedal position. It doesn't really matter, I'll just feel less like a Sally if I know the ECM is regulating tourqes instead of me.

 

[Inigo]

What do you guys run for alignment?

Front toe/camber
Rear toe/camber

 

[DickR]

Per my DL1 Obd data throttle position seems to track pedal position until rev limiter starts to back off fuel then the data shows throttle position reducing even though pedal stays on the floor.

 

[ABQautoxer]

Disclaimer edit -- I probably fall in Tom's category of folks not driving the 550 and should be taken with a grain of salt but like the information exchange and people here.

No. You don't have the own the car because you know about the top level competition and trying to make things work. Not having either and telling people information or correcting others is what I find annoying.

Sorry for the sidetrack.

 

[Simmons-Racing]

Per my DL1 Obd data throttle position seems to track pedal position until rev limiter starts to back off fuel then the data shows throttle position reducing even though pedal stays on the floor.

I am so glad I don't have to deal with this in STP. :cheers:

Simmons

 

[Whiskey11]

What do you guys run for alignment?

Front toe/camber
Rear toe/camber

I posted mine earlier. Zero toe all around, front camber is at "whatever 2mm got me" which is somewhere around -1.9 to -2.0. Rear I have -2.2 for camber which is more than most but the car works well for me and comes out of corners like a raped ape when I pull my head out of my ass far enough to drive worth a dang!

EDIT: For anyone who isn't convinced that the 18" setup is going to be slower than the 19" setup and shifting, the 18x9 PF01's in ET45 do fit with the 5mm spacer, they DO NOT fit with a 3mm spacer. The barrel rubs on the reliefs around the bridge bolt on the brake caliper. It clears fine with the 5mm spacer as the PF01's have a taper right before you get to the spokes. A 5mm spacer yields 7 turns of a set of splined lugnuts required/used for most aftermarket wheels on the S550 chassis. This is the same number of turns I run on my stock wheels with stock lugnuts and a 5mm spacer that I autocross on... FWIW... I plan on going full baller status with my PF01's and turning them into winter wheels! How lovely!

 

[Competition Orange]

I posted mine earlier. Zero toe all around, front camber is at "whatever 2mm got me" which is somewhere around -1.9 to -2.0. Rear I have -2.2 for camber which is more than most but the car works well for me and comes out of corners like a raped ape when I pull my head out of my ass far enough to drive worth a dang!

EDIT: For anyone who isn't convinced that the 18" setup is going to be slower than the 19" setup and shifting, the 18x9 PF01's in ET45 do fit with the 5mm spacer, they DO NOT fit with a 3mm spacer. The barrel rubs on the reliefs around the bridge bolt on the brake caliper. It clears fine with the 5mm spacer as the PF01's have a taper right before you get to the spokes. A 5mm spacer yields 7 turns of a set of splined lugnuts required/used for most aftermarket wheels on the S550 chassis. This is the same number of turns I run on my stock wheels with stock lugnuts and a 5mm spacer that I autocross on... FWIW... I plan on going full baller status with my PF01's and turning them into winter wheels! How lovely!

Great information! Do you have any pictures, both up close, and the car as a whole?

Also, I'm assuming you got a 9.5" wide out back? What are the specs on that one? 18x9.5et45 as well?

 

[DickR]

I am so glad I don't have to deal with this in STP. :cheers:

Simmons

How does the limiter function work with your tune and others? I assume pull fuel just like oem but don't know. If so won't it do the same thing as stock but at higher rpm? You will hit the limiter but not as soon/often.

 

[boardkat]

I have a soft limiter at 7850 but it will rev out to fuel cut at 8000

edit: just went back and reviewed my tuning notes. i was wrong, i actually have a soft limiter at 7700 (throttle closure) with a fuel cut at 7850. reason being that a straight fuel cut is too hard on the drivetrain, according to my tuner.

 

[Whiskey11]

Great information! Do you have any pictures, both up close, and the car as a whole?

Also, I'm assuming you got a 9.5" wide out back? What are the specs on that one? 18x9.5et45 as well?

I do have some close up photos of the clearance that I posted over on S197Forums but I haven't put them on the car all the way around. Also, these are JUST 18x9 ET45's. I don't have the 18x9.5's because I bought these wheels and the tires on them for when I ran my 2009 Mustang GT in STX. Being as they weren't selling, I've opted to utilize them as a set of winter tire wheels and go full baller status by driving around on Enkei's in the winter time!

Here is a picture of the front caliper clearance to the 6 pot Brembos with the 5mm spacer:


As soon as I get the snow tires mounted and balanced I'll be taking a photo of the car with everything on there.

 

[Competition Orange]

Gotcha, thanks.

 

[DickR]

I have a soft limiter at 7850 but it will rev out to fuel cut at 8000

edit: just went back and reviewed my tuning notes. i was wrong, i actually have a soft limiter at 7700 (throttle closure) with a fuel cut at 7850. reason being that a straight fuel cut is too hard on the drivetrain, according to my tuner.

Thanks. I didn't understand how the soft and hard limiters work. Throttle plate first then fuel cut if that doesn't work for both stock and tunes? Certainly the data from my car seems to be that way but about 1K lower rpm.

Does power fall off "much" before the limiter starts? That is are you using the high rpm primarily because shifting and autocross don't work well?

Thanks,

Dick

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