My STX 09 autocross future and questions

[Whiskey11]

So, about everything?

For all the typing Chris what I never seem to get from these posts is what exactly you want the car to do different. Yes, I think the differential is an issue in general, they are pretty poor stock. I am not a fan of the RC where you have it, and can't figure out why you haven't tried changing it and bar settings some before changing a hundred things. I do think you can do much better than D-specs, I think if you can tolerate some more spring on the street that would help make the car more nimble. I think the most rubber down possible would help. I think based on my experience that R-S3's might be a superior tire as to me they feel more like R-comps and the car is big and heavy and needs grip and response help from the tires.

Hah I do type a lot in a vain attempt to stem off questions before they are asked and usually fail!

The whole premise of this was to find time in the car setup during the off season and what mods left to do are going to make the largest impact on reducing the times. I realize that the biggest one is the nut behind the wheel and that is always in need of tightening but I'm thinking about things that have quantifiable differences on times like how much do wider tires actually drop in time assuming nothing else changes. I guess to answer the question of "what do I want the car to do differently" is "I want it to drop time off my runs so I PAX better!"

I know about the RC issue it's just that I don't learn quite as fast as you do when you jump in a car about what the changes did so it has taken an event or two for me to really tweak the settings on the car as I find out whether or not the previous change eliminated the problem (push any time throttle is applied with a settled chassis). I'm hoping our region does a Test'n'Tune at the start of next season like they did last season and A LOT of the tuning will hopefully be done there. I'm a WIP as much as the car is but there has to be some place to find time in chassis set up to.

 

[Sam Strano]

So you want what everyone wants, to go faster... fine. But the problem I have is very simple. I have not driven your car. You have. The only source of information I have about how the car can go faster is to find out what you want it to do better. And as much as it's easy to say "go faster", we both know that's what every single person in the world wants and isn't very much to go on unless you want me to just make educated guesses.

Here is the blunt part.... If you can't tell me what the car is up to, etc, how can I know what to recommend to fix it above something else? As it is I'm going on just my own knowledge of the car in general, not off anything specific about your car.

Are you telling me the car has a power on understeer? If so, raise the roll center. I think it's WAY too low. But I can't figure out if that's what you are telling me for sure.

 

[DILYSI Dave]

A huge part of developing as a driver and a builder is learning to listen to the car, and learning to relay what you are feeling to others. For instance - It took me forever to be able to identify different behavior in the first half of the corner versus the second half. Dunno why, but it did. Cracking that nut was a HUGE step for both my building and driving. I think that is where you and Sam are disconnecting. He's looking for specific issues, while you are not developed enough to give him that.

One thing that would absolutely help you is getting someone faster / more experienced in the car. You would get good coaching, but you would also get a more finely tuned ass for feeling out the car itself. Another thing is don't be shy about messing with the car. That roll center has been bottomed out for months, and it is theoretically something that could be changed between runs. Don't be shy with the wrenches.

 

[Whiskey11]

So you want what everyone wants, to go faster... fine. But the problem I have is very simple. I have not driven your car. You have. The only source of information I have about how the car can go faster is to find out what you want it to do better. And as much as it's easy to say "go faster", we both know that's what every single person in the world wants and isn't very much to go on unless you want me to just make educated guesses.

Here is the blunt part.... If you can't tell me what the car is up to, etc, how can I know what to recommend to fix it above something else? As it is I'm going on just my own knowledge of the car in general, not off anything specific about your car.

Are you telling me the car has a power on understeer? If so, raise the roll center. I think it's WAY too low. But I can't figure out if that's what you are telling me for sure.

I think between my tipping this on my phone (at work and have limited access to a computer) and the time to elaborate is as much of a problem as my lack of experience. The while reason I made the post was to get thoughts on how much time is left on the table between my current modifications and the reasonable maximum preparation for the class. How much time is being left on the table by being on 245/45/18 Star Specs instead of 265/40/18 RS3s? How much time is left on the table with the stock diff (rebuilt), or lowering springs and d specs and coil overs, or having 165lbs of weight left in the car that could be removed with other lighter parts and so on.

I have a pretty good idea of what the car is doing and how to fix it but it takes me a couple of events to relearn the car after a change has been made to assess if further changes are necessary. The Nebraska region rarely hosts more than one event a month and sometimes those events fall on dates that other regions host their events that I would otherwise go to so the time is lengthened a lot more than it would be if the area I was in didn't all have their events scheduled on the same days.

The biggest issues that I can feel right now are the power on push associated with the slammed roll center which its an issue that I will fix for next season as my car is back to stock for winter right now.

The other issue is right now its transitioning speed. The car is much better than stock but I have hit a point where turning up the dial on the d specs causes that end of the car to slide easier even though the car feels better in transitions. I think, and you can correct me if I ask wrong, that this is the compression damping on the d specs coming in to spoil an otherwise good feeling car.

The last obvious problem that I notice is the tie wear associated with not having enough camber. The obvious solution its camber bolts but I am uneasy about those $30 jobs from Eibach or BMR (sorry Kelly) and at the time of writing the Ford bolts are not in the budget. Yeah that sound silly as they are like $90 but things have gotten tight budget wise here recently. I have already planned for next year replacing tires so maybe I should budget these in for next year as well.

I hope that is a little clearer.

 

[Sam Strano]

Hey, now we are getting somewhere. Let me read this a little more, I'll be back.

 

[Sam Strano]

I think between my tipping this on my phone (at work and have limited access to a computer) and the time to elaborate is as much of a problem as my lack of experience. The while reason I made the post was to get thoughts on how much time is left on the table between my current modifications and the reasonable maximum preparation for the class. How much time is being left on the table by being on 245/45/18 Star Specs instead of 265/40/18 RS3s? How much time is left on the table with the stock diff (rebuilt), or lowering springs and d specs and coil overs, or having 165lbs of weight left in the car that could be removed with other lighter parts and so on.

I have a pretty good idea of what the car is doing and how to fix it but it takes me a couple of events to relearn the car after a change has been made to assess if further changes are necessary. The Nebraska region rarely hosts more than one event a month and sometimes those events fall on dates that other regions host their events that I would otherwise go to so the time is lengthened a lot more than it would be if the area I was in didn't all have their events scheduled on the same days.

The biggest issues that I can feel right now are the power on push associated with the slammed roll center which its an issue that I will fix for next season as my car is back to stock for winter right now.

The other issue is right now its transitioning speed. The car is much better than stock but I have hit a point where turning up the dial on the d specs causes that end of the car to slide easier even though the car feels better in transitions. I think, and you can correct me if I ask wrong, that this is the compression damping on the d specs coming in to spoil an otherwise good feeling car.

The last obvious problem that I notice is the tie wear associated with not having enough camber. The obvious solution its camber bolts but I am uneasy about those $30 jobs from Eibach or BMR (sorry Kelly) and at the time of writing the Ford bolts are not in the budget. Yeah that sound silly as they are like $90 but things have gotten tight budget wise here recently. I have already planned for next year replacing tires so maybe I should budget these in for next year as well.

I hope that is a little clearer.

Chris-- What is important to know/learn is that there aren't absolutes. I cannot tell you how much time is left on the table between tires. The only way to know for sure is to do a back to back test. You likely don't want to do that. And unless both tires are fresh, and on the same weight wheels, etc, the test isn't even that valid. Fresher, bigger tires are likely to be faster. Doesn't tell you the difference between the sizes and the tire models.

I am not a fan of camber bolts. Frankly you'd be better off slotting the struts like the Ford bolts require and just running the stock bolts. The Ford kit adds eccentric heads, which are not necessary to get the adjustment. Cheap, and you have much better bolts that will hold more torque.

Yes, you have found the achilles heel of D-specs. When I was in FS with the Shelby I had little wiggle room that actually worked. Koni's have much more because the rebound changes, but not compression. KW's also will do the same, because their adjustments are not linked either.

You are a customer of mine. I hope that continues to be the case. I try and help my customers through this stuff. I can't, or rather, I won't spew out a setup online. I can't, it's how I have protect what I know. If you want to call me as a past and hopefully current and future customer, please do. But this is the kind of information I need to help you.

 

[Whiskey11]

Gotcha. I realize that there isn't a hard and fast way to estimate time and of course it its in my over analyzing nature to assume that there is an estimate that can be given. I will have to give you a call and see where it goes. I don't want to take up too much of your time as I know you are extremely busy.

 

[Vorshlag-Fair]

I just hope there genuinely is 2.5 seconds of time or more between my piss poor driving (lets face it, a 2 year n00b can't be that good of a driver) and some car set up. I would be thrilled if that was true! I'm surprised Terry hasn't jumped in the conversation as he probably has more experience in the car in STX trim than any of us do. Between him and a few other of the veteran autocrossers lurking around here that opinions are strangely absent.

Sorry, just got back from a 4 day weekend vacation. Lemmie dig into this thread...

In case you don't know me, we did run an S197 in STX for the better part of 1.5 years. We shared all of our data and set-up with the various forums, and while we didn't do "well" in this class we learned a lot. We switched the car briefly to STU, and the car was much easier to drive on the wider wheel and tires allowed there. Then we moved to ESP in the middle of 2012 season, and the car was once again easier to drive and instantly more competitive on the larger wheels and tires allowed there. In the end I determined that our 2011 GT was hopelessly overweight for STX (we got it down to 3442 lbs in STX trim), and have stated publicly that any S197 Mustang is going to be fighting an uphill battle against 2700 pound RX8s and E36 325/328 models there. Also - STX caps maximum tire width for all RWD cars at 265mm, no matter what the car weighs, so you'll be on the same width tires as cars 500 pounds lighter.

Of course an S197 GT can make a LOT more power than any of those cars, but as many will attest, power is the least important aspect of autocrossing.

With almost no changes form our basic STX set-up, and only about 3 months of ESP development, we took the car to 4th out of 33 in ESP at Nationals and won ESP-L, plus did well in a ProSolo event against the top dogs, briefly leading the class and placing 2nd in the end. Hardly worth bragging about, not a pissing match, just wanted to state that we've run this big chassis in STX, STU and ESP. Although relatively new to the S197 chassis we have raced similar McStrut RWD cars for decades.

...my 09 GT in it's current, very unprepped STX self ... I was 3.879 seconds off of Bryan Heitkotter's winning 1994 BMW 325is ...

...car only has this on it:

Tokico D-Specs (all groans aside please )
Steeda Sport Springs
Steeda HD Plates (-1.7º camber, 0 toe, +7.5º caster)
Strano 35mm front bar (full stiff)
Strano 25mm rear bar (full stiff)
Fays2 Watts (pivot bolt slammed to the bottom hole, not wise, but I did it =\)
245/45/18 Dunlop Star Specs

There is A LOT left to do but I have NO IDEA how much time is realistically able to be dropped from maxing the car. The huge time cutters are the 265/40/18 RS3's I have planned for next year. Unless I run into a pile of cash that will be on the stock, heavy wheels, but eventually I'd like to run something like the TSW Nurburgrings in 18x9 which weigh 19.7lbs each and don't cost a fortune.

OK, glad that you listed it all out there. Like I've told you elsewhere, I think all of your S197 equipment is fine for a street car and casual autocross car, but not all of the parts are worthy of a top STX car. The swaybars and Fays2 Watts are fine, and I wouldn't swap them out.

There isn't really any magic in swaybars (these are a tuning tool and nothing more) or massive differences in the various Watts Links. If the Fays2 is too noisy on the street for you, of course you know I am a fan of the Whiteline Watts, which weighs the same but uses poly bushings instead of rod ends. We've pushed this unit to the extreme with 315mm R compounds on road courses and autocrossing as well - great results. But those are about the only parts I would keep from your current set-up.

Shocks is a big one, so let's start there. If this is indeed a dual-use street/autocross car then you should really think about proper monotube adjustable coilovers. Of course some here will expend pages of posts trying to push twin tubes over "fancy shocks", but I will disagree every time on this point. Yes, Sam and others have won Solo classes on twin tubes, and people still do at the National level, but more winners are on monotubes and this trend will continue. The larger pistons available in monotube dampers allow this modern shock style to more quickly deal with small impacts, they are more effective at low shaft velocities, and in the end they can ride better at higher spring rates. I can take anyone for a ride in an AST equipped car and show them the results first hand, and have done so hundreds of times (and this has sold hundreds of sets of shocks for me).

I have the entire 2012 allotment of S197 Mustang AST 4150 single adjustable monotube coilovers purchased for Vorshlag. The BMW E36 allotment, too. Should have these at the end of the month. Nobody else will get any because I bought all of them - because I have driven thousands of miles on these shocks, helped AST come up with the valving, and I believe in them. These ride like nothing else at the spring rates needed to keep cornering flat and brake dive under control.

Lowering springs are barely stiffer than stock, if any, and not what you want on a serious autocross car. I'd start with a 450 #/in front spring and a 175 #/in rear spring. We danced around all sorts of spring rates, up and down the scale, and kept coming back to this set-up. We've since stepped up the spring rates on our ESP set-up to 550#/in front and 250 #/in rear, but the STX tires didn't work well with these stiffer rates, for us.

Tires - again, we've tested many of the brands and sizes available to the STX S197 over the past 2 years, at autocrosses, practice events, and a dedicated STX tire test we held on our own (it wasn't a textbook perfect tire test but we still learned a lot). I wouldn't get hung up on which brand is better than another at this point, other than to use the guidelines of "what is winning", and bias that towards the heavier STX/U cars. The issue you need to work on now is get the MOST tire under the car as soon as you can afford to. Maximize wheel width and lower wheel weight as much as you can, too.

I think the 265/40/18 Hankook RS-3 is an obvious choice and it was fast on our STX S197 and didn't have overheating issues. We ran the 265/35/18 and it was fine, just too short for our application. The extra height of the 265/40/18 worked out best for our 2011 GT even with the tallest available 3.31 gears, because we were making too much power (430 whp/409 wtq) for the relatively skinny STX tire limitation, and anything to soften the torque to the wheels helped us. We had a ghetto traction control throttle map that helped, too. I have that set of 18x9" WedSports and a set of 265/40/18 RS-3 tires mounted and balanced and ready to sell for an STX S197, if anyone is interested. It was the lightest 18x9" we tested, and the tires have one event on them.

With your 2009 GT you are not "handicapped" with the excess of power that we fought with in STX. I think the 4.6 3V cars should do better in STX than we did, with potentially less weight and obviously less power fighting the rear tires. I wouldn't do ANYthing to add more power, but EVERYthing you can to lose weight. Weight is the number one handicap of the S197 in STX. (and you can't run STU anymore, as there is no longer an upgrade path/choice in any Street Touring class) Your car will never be close to the weights of the other STX contenders: the E36, the RX8 and the WRX will all be hundreds of pounds lighter.

Real adjustable camber plates help, if yours are not adjustable. I will agree with Sam and others that have stated that camber bolts are an imperfect solution. They don't give you the finite adjustment you need for testing, and they can and do slip in use. They also change your SAI and remove wheel room inboard to the strut. I'd start with -3° camber and test up and down from there. Pyrometer data is somewhat useful, but an imperfect tool. Real time IR arrays with data looked at in a corner is more useful, but still a bit difficult to set-up. The clocks don't lie, and we always tweak front camber settings and check times at our private test events and zero'd in with that. You cannot test in a 4 run autocross - dedicated practice events are crucial. I credit our entire GRM $2010 Challenge win and FTD at that autocross to our dedicated autocross test the week before that event, where we found seconds simply in set-up changes.

The other big one is the rear diff. My stock T-Lok was rebuilt with the stock style clutch packs about a month ago and had one event on it (on asphalt) going into yesterday's event so it should be pretty tight still. I'd love to go to the WaveTrac unit or DPI Platinum.

That's one thing I am still fighting with - the stock T-loc. We rebuilt it with the same Carbon clutch pack diff that many F Stock drivers use (which is legal in the '06-07 Shelbys), but it didn't last long with the power and tires we have abused it with. I'm also on the fence about the various new options like the WaveTrac, but I think a Torson T2-R is kind of a no-brainer, and at ~$678 it is more cost effective than the still unproven $1000 WaveTrac.

I would like to find a little more negative camber in the suspension. Stock the alignment was dead on side to side and fully maxed out at the Steeda HD plates one side was -2.0º and the other -1.6º so somewhere tolerance stack moved the camber off on one side and I would LOVE to have -2.0º on both corners or more. I'm not sure how to achieve that aside from camber bolts or a different set of camber plates. It may be prudent to just switch camber plates to a proper camber plate.

Yea, you are not even in the ballpark yet with those numbers, in my opinion. The tall ride height will limit total camber travel, of course, so coilovers with a 2.0 to 1.5" lowering will only add more. But yes, proper adjustable camber plates... very high on the list.

Eventually I would like to start focusing on weight. I have plans of finding out what the curbweight of MY car is as a baseline then start pulling weight. As optioned, with 3.55's, full leather interior, interior lighting package, GT comfort package (heated and power seats on both sides) is probably the heaviest way to get an 09 short of the glass roof option or a convertible. I'm glad I have neither! I'm estimating right now 3550lbs with the 5 speed manual and a 1/4 tank of gas and no trunk junk.

Yes, weight is crucial. After you had real shocks/springs/plates on the car, and proper wheels and tires (max width on both!), I would spend the remaining dollars on weight loss items. There is lots of weight to be found in the headers/custom exhaust, an AGM style race battery, seats, brakes, and more.

The last area of time gain is Power. I'm thinking between CAI, UDP's, Longtubes, high flow cats and a tune that I should be around 325 RWHP and 335 RWTRQ. That is probably a lot more than it will actually be but I can dream right? I really don't think this will kill that much time and may cause more problems than it solves. I don't know to be honest.

That is a good goal. Long tubes, custom exhaust, cold air and a custom dyno tune. The exhaust changes are more for weight but they will add torque and power everywhere.

This chart shows our ESP prepped 2011 GT, a bone stock 2013 GT and a stock 2013 BRZ. Ignore the total numbers (the air was crap that day - 100% humidity, and this wasn't even the best pull on the 2011 that day), as these are two 5.0 Coyote set-ups... instead look at the low RPM torque differences between the stock and the car with headers/exhaust/CAI. Big improvements everywhere, even with their biggest 1-7/8" primaries from ARH.

Of course driving can always be improved, and other than tires this alone is likely your biggest area to improve. I say that to everyone, and include myself - the nut behind the wheel can make the most difference. Find a more experienced co-driver and beg them to race with you for a season. Get a data logger (AIM Solo = $400) and log all of your runs. Overlay their data to yours and - assuming they are faster - figure out the difference in line, throttle application, braking points, and learn from that.

Good luck!

 

[Whiskey11]

Thanks for the responses!

Terry I just realized how strangely familiar this thread sounded to a thread I made over on Mustang Forums almost 5 months ago. Funny how the silly season works its way into your head. I'm sure I now sound extremely dense and I probably am for wanting to do well in a class the Mustang most likely won't! Thanks for the response and taking the time to answer the same questions again five months later.

Anyway, I am sorry that I didn't get back to you about those wheels and tires. I ran into a bit of a financial mess and the email I intended to send never got written and sent. If you still have them come tax season I would love to purchase them from you. When that time comes and if you still have them, maybe we could talk about me picking them up at spring nationals if you guys are making the trip up to help minimize cost of shipping. My thought process here is to continue using the Star Specs as DD and non-points event (maybe ) tires and use the RS3's for autocross only to help them last a little longer. Then when the Star Specs die completely switch to a "cheapy" all season (Conti DW? ) for DD work rather than waste the RS3's when I'm not racing.

I do have some concerns pertaining to lowering the ride height too much and it mostly comes in at that level when it comes time to clear the speed bumps and embankment into and out of work and the necessary negative camber necessary to not lose as much in body roll. The Steeda Sports have an aesthetically pleasing drop to me and I can't see going much lower as a viable option for the dual roll this car plays and my hope is that with the added spring rate of coilovers (when I get there) that I wont need to run gobs of negative camber.

On that note, I do have a question. I'm assuming that the Vorshlag CC plates can have Camber adjusted fully independent of caster right and loosening the 4 bolts to adjust camber isn't going to free up the caster adjustment? If that is the case is there anything stopping me from running a more conservative street alignment and then moving the plates near max (depending on how much I can get without dropping too far) the plates for autocross? The shop that I hope to do my alignment and cornerweighting has said that they can run multiple set ups like this to test the adjustments to see how much toe moves with the camber adjustment and the likes. I think that too will help make it viable. Of course at this point I am planning probably February 2014 if nothing else changes financially. I'm hoping and trying to get things to improve on that front!

 

[Vorshlag-Fair]

Thanks for the responses!

Terry I just realized how strangely familiar this thread sounded to a thread I made over on Mustang Forums almost 5 months ago. Funny how the silly season works its way into your head. I'm sure I now sound extremely dense and I probably am for wanting to do well in a class the Mustang most likely won't! Thanks for the response and taking the time to answer the same questions again five months later.

Yea, I should have looked for my old response to your previous thread.

I do have some concerns pertaining to lowering the ride height too much and it mostly comes in at that level when it comes time to clear the speed bumps and embankment into and out of work and the necessary negative camber necessary to not lose as much in body roll. The Steeda Sports have an aesthetically pleasing drop to me and I can't see going much lower as a viable option for the dual roll this car plays and my hope is that with the added spring rate of coilovers (when I get there) that I wont need to run gobs of negative camber.

Of course there are always compromises when lowering any car, and "over-lowering" can cause geometry problems at one end or the other. We've been keeping this in mind on our 2011 GT and have resisted going super low on this car, as it will bork the rear geometry.

These ride height numbers above (measuring from center of wheel to fender lip ignores tire height) show how tall the S197 cars can be in stock form (exception: 2006-07 Shelby) and how only an inch or so of lowering can really improve the looks and close up that massive wheel gap. Of course lowering an inch or inch and a half in springs lowers the CG of the entire car by that same amount, and that directly impacts handling and increases grip.

Note the rear ride heights above, to avoid the anti-squat problems with over-lowering at the rear without LCA relocation brackets

Our 2011 GT's ESP set-up is a tick lower than that 15" number in front now but the rear has stayed about the same. Lowering the rear too much threw the geometry all out of whack... until we added some LCA relocation brackets (which are not STX or ESP legal). We tested the LCA brackets to our car after the SCCA Nationals, for some track events (NASA TTS) we had planned. Then we lowered the rear ride height, and there seemed to be performance improvements without the drawbacks of geometry problems. These brackets (made by a variety of sources, including Whiteline) are not super easy to swap in and out, though, so doing a back-to-back test at an autocross has not happened yet. Regardless, they aren't STX or ESP legal, and might never be. If you don't race in SCCA classes that prohibit pick-up point changes, though, these brackets should be one of your first mods after you lower an S197.

Note the lower rear ride heights in the above two pictures, after we installed Whiteline rear LCA brackets

On that note, I do have a question. I'm assuming that the Vorshlag CC plates can have Camber adjusted fully independent of caster right and loosening the 4 bolts to adjust camber isn't going to free up the caster adjustment? If that is the case is there anything stopping me from running a more conservative street alignment and then moving the plates near max (depending on how much I can get without dropping too far) the plates for autocross?

Ahh, good question. Yes, our latest revision of Vorshlag S197 camber/caster plates was a new clean slate design, with a new bearing holder, main plate and adjustment style. On this 2012 version you can adjust camber by simply raising the wheel, loosening the 4 strut top studs, and sliding the wheel and strut in/outboard. Takes 60 seconds per side. The three distinct caster settings (stock, +0.5°, and +1.0°) are now adjusted by unbolting the spherical bearing holder from the main plate and moving it independently. If you look at the picture above, which has a bottom-view of our S197 camber/caster plate, you can see the slotted holes in the main plate and the fixed "bolt ring" that goes through the strut tower, as well as the holes on the bearing holder and main plate for the 3 caster adjustments.

Above at left you can see the hash marks for reference when sliding the S197 camber plate in/outboard for your camber setting. They are hard to see inside the strut tower hole, but with a flashlight they are visible. Many times racers will have two hash settings marked (with a black Sharpie), and pick a camber/toe setting for street use and a more aggressive camber/toe setting for autocross or track use. Since the S197 is a "front steer" car (steering rack mounted ahead of the front axle centerline) the toe will go "out" as the camber goes negative. This makes quick track-side camber adjustments easy... slide it into your reference mark for negative camber and the toe will go out slightly. Slide them back to max positive camber setting for street use and toe will go "in" slightly, for better tracking on the road and minimal tire wear. All of this means you don't have to adjust the toe each time you switch from track to street camber settings.

Caster adjustment is much less frequent, and in fact we recommend running that at the "minimal" caster setting (how we assemble and ship all S197 camber plates). That's usually +6° or more caster in the forward/stock caster setting anyway, and this setting gives you the most camber adjustment room in the tight confines of the strut tower opening. The picture above right shows our similar BMW E46 camber/caster plate with reference marks showing the forward and rearward caster settings for that car (the strut tower opening is bigger, which makes this more visible on the BMW than the S197). This picture is taken from the outboard drive's side, and caster is moving positive left to right, while camber would be going positive from "up to down" in this picture.

For maximum CG lowering for races but additional ground clearance and ride comfort for the street, I recommend using a taller street tire than your autocross rubber. Something in the 27" diameter range is best (stock S197 rubber is around 27.0" tall), most likely your Mustang's original OEM wheels or a stock wheel/tire take-off from newer S197 (GT500 stuff can be had cheaply). Even better is to go with the 18" OEM wheels and rubber, which will have more sidewall and compliance than shorter 18" racey tires or OEM 19" rubber. The 235/50/18 stock tires on my 2013 GT ride better than the 295/35/18 Nitto tires I have on there now, and all of that rides better than the 315/30/18 Hoosiers we race the 2011 GT on in ESP. More sidewall = better street ride. It can make a dramatic difference.

Doesn't look as good, and losing 60mm of tire on each corner definitely makes the 235s a bit comical to drive around on... but if your vanity can allow it, the street ride will be much better on tall OEM style ribber. Then you bolt on your race wheels/tires and instantly lower the CG (by half the amount of tire height change) and firm up response. At even the local level it is best to have a dedicated set of "street" tires and wheels for use in Street Touring. Sure, you can run one set of wheels for street and autocross use, but the tires will "compound out" much sooner, as street driving puts hundreds more heat cycles in the tires between autocross events. All rubber tires get harder over time, with exposure to heat cycles, and UV and oxygen. This can make a significant difference in your autocross tires, even on 140-200 treadwear "street tires". Keep your race tires for racing, and your street tires for street use.

Cheers,

 

[Whiskey11]

Thanks again for the response and taking time out of your busy day to respond.

One of our local CP guys uses a tape measure to switch his Maximum Motorsports plates from his street and autocross settings at the site but he its in a fox so the plate is on top of the strut tower unlike our chassis. Either way we will have to see what range things move between when in a few years I can afford the coil overs.

To be honest I rather like my stock wheels from an aesthetic standpoint and I don't mind the narrow tie look either as it all looks stock then and that is ok to me. It is my car after all and if I ever go to a show I can throw on the autocross wheels and tires. Right now my ties serve dual duty and after about 62 runs I am just over the wear bars. They need flipped on the rims badly to get the virgin insides to the outside.

Nice photo from nationals by the way. I know I keep saying that but it just tickles my fancy that one of my photos makes its way outside of my photobucket or flickr account! Sadly that is probably one of the best "still" photos I have ever taken of a car and it's nothing short of a miracle that it came out as well as it did as I am very much an amateur photographer!

 

[Sam Strano]

Generally in these cars you can change camber at the tower with little to no toe change. I know this because it's one of the things I generally check on when I'm doing my setups so I know what is going to change *IF* I have to add or subtract camber at an event.

I'd recommend you simply try yourself, and always try it on your own car, on a rack to see what toe-change you have with your parts, at your ride height. If you change it at the knuckle, it's HUGE, you don't want to do that.

Sorry for the short post.

 

[Norm Peterson]

One of our local CP guys uses a tape measure to switch his Maximum Motorsports plates from his street and autocross settings at the site but he its in a fox so the plate is on top of the strut tower unlike our chassis.

I'm sure that with a set of custom-fabbed gage blocks and Vorschlag C-C plates you'd have way better repeatability than tape-measuring on a Fox (and no "settings drift" over repeated resets).


Norm

 

[Whiskey11]

Generally in these cars you can change camber at the tower with little to no toe change. I know this because it's one of the things I generally check on when I'm doing my setups so I know what is going to change *IF* I have to add or subtract camber at an event.

I'd recommend you simply try yourself, and always try it on your own car, on a rack to see what toe-change you have with your parts, at your ride height. If you change it at the knuckle, it's HUGE, you don't want to do that.

Sorry for the short post.

Indeed. The toe change between stock and the 1" drop on the Steeda sport springs wasn't much. I didn't know what it was stock but after the drop it went to zero total toe and I imagine most of that change was from the drop more than an alignment change would change it. Either way you look at it a little toe out while autocrossing should help the car some to get started in the turn.

Norm you are correct. The driver has obviously checked and rechecked the measurements he takes from the hood channel to the top of the strut and knows what those measurements are for each side and what that corresponds with in degrees of camber. He is one off the many Mustang owners I trust and has been to nationals quite a few times and done decently in the past. His name is John Williams for those that know the CP crowd and he is one of the more fun to talk to autocrossers in the region.

Sam your posts may be short but they are still very detailed and I appreciate it. Anyone willing to sift throughmyramblings that I masquerade as a post and is still willing to respond is appreciated in my books!