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

[DickR]

Both my previous 15 and my current 18 were delivered with very close to the nominal factory spec camber and toe so I never changed either of them. Because of the very long highway trips to/from Tours, Pros, and Nationals on RE-71R's I wanted to stay with the factory settings. Also I did a lot of Pro Solos and Pro Solo practice starts and, with the bigger rear bar got a lot of power oversteer. My gut feel was that the factory settings were the best for even tire wear and to minimize wheelspin. Plus I had no clue what would be better.

Note that even with factory toe and camber the insides of the rear RE-71R's tended to wear a little faster than the outsides but the center wore slightly faster than either inside or outside. As noted previously no rotating or flipping.

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[Dana Pants]

Both my previous 15 and my current 18 were delivered with very close to the nominal factory spec camber and toe so I never changed either of them. Because of the very long highway trips to/from Tours, Pros, and Nationals on RE-71R's I wanted to stay with the factory settings. Also I did a lot of Pro Solos and Pro Solo practice starts and, with the bigger rear bar got a lot of power oversteer. My gut feel was that the factory settings were the best for even tire wear and to minimize wheelspin. Plus I had no clue what would be better.

Note that even with factory toe and camber the insides of the rear RE-71R's tended to wear a little faster than the outsides but the center wore slightly faster than either inside or outside. As noted previously no rotating or flipping.

My car came with 1/4 inch rear toe-in and about -1.35 camber. The camber would be OK, but that toe-in was not OK. Car needs rotation desperately.

 

[77FS]

I have an S197 not the S550, but this seems to be the only active Mustang autocross forum I have found.

Ok, looks like the PP cars have been well covered, but what about tires/wheels for the plain vanilla base GT (non-premium, non-PP) that comes with 18x8 wheels? Right now I have 245/45-18 RE71R's on the stock wheels but they are a little skinny for this heavy of a car. I've got a few more events to run this season and will then need new tires. Was there any available stand alone option for the base GT to get a wider wheel? Is my best option to just run 255/40-18 on my 18x8 wheels or run 19x8.5 wheels from the premium and 275/35-19? Is there another option I haven't thought of? Thanks for any suggestions.

 

[DickR]

I have an S197 not the S550, but this seems to be the only active Mustang autocross forum I have found.

Ok, looks like the PP cars have been well covered, but what about tires/wheels for the plain vanilla base GT (non-premium, non-PP) that comes with 18x8 wheels? Right now I have 245/45-18 RE71R's on the stock wheels but they are a little skinny for this heavy of a car. I've got a few more events to run this season and will then need new tires. Was there any available stand alone option for the base GT to get a wider wheel? Is my best option to just run 255/40-18 on my 18x8 wheels or run 19x8.5 wheels from the premium and 275/35-19? Is there another option I haven't thought of? Thanks for any suggestions.

I have a copy of the 2014 Mustang order guide. My understanding of the rule is that in general a base car cannot run options from a premium version.

HOWEVER for you 2014 , , ,

It looks like the base cars had an appearance pack option 542 which came with 19x8.5 inch wheels.

FP8 Appearance Package
• Black Painted Outside Mirror Skull caps
• Black Painted Decklid Spoiler
• Body-Color Quarter Window Louvres
• 19" X 8.5" Bright Machined-Aluminum Wheel with Black painted
Windows (64X)
Note: Not available on Convertible or with GT Track Package, Brembo™
Brake Package or Spoiler Delete
542

19" X 8.5" Bright Machined-
Aluminum Wheel with Black
painted Windows
Optional on GT Premium
{400A/401A} (64X) & with FP8
Appearance Pkg. {542}

You "might" have to add a decklid spoiler and/or the quarter panel louvers to be strictly legal if you car doesn't have a decklid spoiler.

 

[Norm Peterson]

I understand it about the same way . . . and I think any existing spoiler would have to be the same as the 542 package spoiler.

Possible grey area - it might be possible to argue that the skull caps and the louvers fall under "appearance, comfort & convenience items that don't affect performance or materially affect weight" and avoid having to add those on that basis. Probably be considered OK at the regional level but I don't know if it'd stand up to a protest at Nationals.


Norm

 

[SteveW]

My car came with 1/4 inch rear toe-in and about -1.35 camber. The camber would be OK, but that toe-in was not OK. Car needs rotation desperately.

Be careful about using rear toe alignment settings for rotation. I would look to rear rebound settings for rotation, swaybar and maybe toe for corner balance and toe-in along with front bar/rear compression settings for power down and corner exit adjustments.

 

[77FS]

I have a copy of the 2014 Mustang order guide. My understanding of the rule is that in general a base car cannot run options from a premium version.

HOWEVER for you 2014 , , ,

It looks like the base cars had an appearance pack option 542 which came with 19x8.5 inch wheels.

FP8 Appearance Package
• Black Painted Outside Mirror Skull caps
• Black Painted Decklid Spoiler
• Body-Color Quarter Window Louvres
• 19" X 8.5" Bright Machined-Aluminum Wheel with Black painted
Windows (64X)
Note: Not available on Convertible or with GT Track Package, Brembo™
Brake Package or Spoiler Delete
542

19" X 8.5" Bright Machined-
Aluminum Wheel with Black
painted Windows
Optional on GT Premium
{400A/401A} (64X) & with FP8
Appearance Pkg. {542}

You "might" have to add a decklid spoiler and/or the quarter panel louvers to be strictly legal if you car doesn't have a decklid spoiler.

---------------------------------------------------------
Thanks for the info. I had forgotten about the FP8 Appearance Package. Now I need to find some take off 19x8.5 wheels, or maybe try something like the Konig Ultraforms 19x8.5 ET45 that weigh in about 20-22 lbs. I'm at best a mid-packer so not sure how much benefit I would get from lighter wheels over factory for the additional cost. More to think about over the next month or so.

 

[Norm Peterson]

Be careful about using rear toe alignment settings for rotation. I would look to rear rebound settings for rotation, swaybar and maybe toe for corner balance and toe-in along with front bar/rear compression settings for power down and corner exit adjustments.

Isn't 1/4" (about 0.5°) rear toe in about double the factory preferred spec and kind of up there in "hates rotation" territory?


Norm

 

[Dana Pants]

Isn't 1/4" (about 0.5°) rear toe in about double the factory preferred spec and kind of up there in "hates rotation" territory?


Norm

Exactly. 1/4 inches is outside of the spec in the undesirable direction. 1/4 in toe is also likely to kill tires if you do many street miles.

 

[NightmareMoon]

Exactly. 1/4 inches is outside of the spec in the undesirable direction. 1/4 in toe is also likely to kill tires if you do many street miles.

IDK about 1/4", I usually run a little rear toe in, maybe 0.3" total, but it seems to help the car behave predictably under power. I haven't seen any S550s running rear toe out that didn't behave unpredictably. I haven't personally tried 0 rear toe.

OTOH, increasing the rear rebound adjustment with the SA Konis DID have a surprisingly large effect on getting the car to rotate early in the corner. Didn't make me or my codriver much faster through the course, but it did have a huge impact on feel.

 

[Whiskey11]

IDK about 1/4", I usually run a little rear toe in, maybe 0.3" total, but it seems to help the car behave predictably under power. I haven't seen any S550s running rear toe out that didn't behave unpredictably. I haven't personally tried 0 rear toe.

OTOH, increasing the rear rebound adjustment with the SA Konis DID have a surprisingly large effect on getting the car to rotate early in the corner. Didn't make me or my codriver much faster through the course, but it did have a huge impact on feel.

1/4" = 0.25"... 0.3" total would be 0.05" more than a quarter inch... or did you mean 0.3° total toe? You can make a degrees symbol by holding alt down on the keyboard and hitting 00176 then releasing the alt key if you are on a standard QWERTY keyboard with number pad. (or just type degrees).

 

[SteveW]

Isn't 1/4" (about 0.5°) rear toe in about double the factory preferred spec and kind of up there in "hates rotation" territory?


Norm

Exactly. 1/4 inches is outside of the spec in the undesirable direction. 1/4 in toe is also likely to kill tires if you do many street miles.

Since we're talking about an autocross setup in this sub forum isn't the factory alignment spec irrelevant? Although I get it that tire wear on the street may be a concern.

Dana Pants, I don't recall you saying anything about issues putting the power down on corner exit so, make a mental note of that and compare to what the car does when you put rear toe back to factory spec. If it changes for the worse then you know why and can make a judgement call on what's a bigger priority. Or go back to the toe setting that worked for corner exit and adjust rebound to get the rotation you desire.

 

[SteveW]

IDK about 1/4", I usually run a little rear toe in, maybe 0.3" total, but it seems to help the car behave predictably under power. I haven't seen any S550s running rear toe out that didn't behave unpredictably. I haven't personally tried 0 rear toe.

OTOH, increasing the rear rebound adjustment with the SA Konis DID have a surprisingly large effect on getting the car to rotate early in the corner. Didn't make me or my codriver much faster through the course, but it did have a huge impact on feel.

The way I look at an over rotation thing from an increase of rear rebound is just don't lift as much next time and carry more speed through the same element. Less of a lift to get the car through the same element = faster run

 

[Norm Peterson]

Since we're talking about an autocross setup in this sub forum isn't the factory alignment spec irrelevant? Although I get it that tire wear on the street may be a concern.

It's still useful as a point of reference.

Actually, given that factory alignment settings are established to protect drivers of only average to lowest-common-denominator skill levels against tailhappy behaviors, I'd take the factory rear toe spec as the amount you at least don't want to be any more 'in' than (and probably want to be less 'in' than, while still being 'in').


Norm

 

[NightmareMoon]

The way I look at an over rotation thing from an increase of rear rebound is just don't lift as much next time and carry more speed through the same element. Less of a lift to get the car through the same element = faster run

Hey, this is an FS thread. You STP guys can powerslide around corners in your own thread

Getting that rebound dialed really seemed to affect the steady state cornering, but knowing how shocks work, yeah, I was probably lifted and decelerating a bit from cornering friction. That was 2017. For me, 2018 is all about not lifting as much (driving into the corner), and/or not trail braking more than whats needed to get the front wheels pointed towards the apex.

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