First Autocross in an S197

Goose428

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Hello everyone,

This is my first post here. I'm so happy that I have found a legitimate suspension forum for our cars. I finally feel at home! A little bit of backround on me: So I have been autocrossing and open tracking for nearly three years. I have autocrossed many different kinds of cars for seasons at a time in those three years. So I know car control pretty well. With that being said, I am brand new to the s197 mustang.

So yesterday I took my new to me 2008 Bullitt to an autocross. The car did better than I expected. Sadly it did have lots of body roll, excessive brake dive and a lot of understeer. On the street+canyons, the car understeers like a pig, and it also understeers on an autocross course. But the car was very comfortable with countering said understeer with throttle oversteer, so I was able to keep the car pretty neutral while on course. The car was a handful and made me work hard, but ended up being very fun and decently fast.

With that being said, what are the best first steps to get rid of or lessen this understeer? I am on Pirelli P Zero Neros, and yes I know they are a joke of a tire, but the previous owner put them on and they are still brand new. So i would like to "deal with them" until they get worn out if possible.

I would really like to try and spend around $1k. Would really like to spend less if possible. I have done lot's of research on parts, but I figured I would ask here before I pulled any triggers. Also I don't run in SCCA anymore, so modifications and class restrictions are meaningless for me.

Thanks again and looking forward to your responses!
 
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kona302

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A larger front bar will help with understeer, and higher tire pressure in the front to start I suppose.
 

noldevin

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A larger front bar will help with understeer, and higher tire pressure in the front to start I suppose.

Typically you want to stiffen the opposite end to counter understeer, unless you are specifically understeering because the body roll is lifting the inside wheel too much. The sway bar would also ideally be the last thing you adjust to fine tune your car, not fix a large understeer problem.

I am on Pirelli P Zero Neros, and yes I know they are a joke of a tire, but the previous owner put them on and they are still brand new. So i would like to "deal with them" until they get worn out if possible.


Goose, are you running a staggered wheel setup? Those tires aren't doing you any favors, and ultimately your tire is what decides your grip. If you're staggered that will make it even worse. They are really the first thing you should address.
 
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Goose428

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Typically you want to stiffen the opposite end to counter understeer, unless you are specifically understeering because the body roll is lifting the inside wheel too much. The sway bar would also ideally be the last thing you adjust to fine tune your car, not fix a large understeer problem.




Goose, are you running a staggered wheel setup? Those tires aren't doing you any favors, and ultimately your tire is what decides your grip. If you're staggered that will make it even worse. They are really the first thing you should address.

Thanks for the reply. I am not running a staggered setup. 235/40/18 at each corner. I had a feeling I would need to get better tires first, but I just thought that maybe if I got better suspension, I could use the current tire more effectively? Is this silly to think that? And I have also heard the opposite, you don't want more front bar usually.
 

frank s

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If the car has standard suspension, as it seems, the first question is:

"How much of the original street-driving comfort am I willing to sacrifice in order to go a little faster on an autocross course?"

Everything you do to eliminate what you've seen as undesirable dynamics is going to cost you some easy-ride characteristics.

A stiffer front anti-sway bar will emphasize understeer. A stiffer rear bar will increase the sense of quicker turn-in and lessen understeer. Both without much effect on street-driving comfort.

If you don't mind street-driving a brick, springs, shocks, camber adjustments, lower-profile tires on wider wheels will all move you toward the autocrossest Mustang you can imagine.

I can't offer anything other than discouragement if your ambition is to be a fast autocrosser in a comfortable car.

I have the stock convertible suspension on my '14 GT, except for an H&R 26mm rear swaybar. Seems to balance out the wimpy front bar, and it seems pretty neutral at extremes, with no loss of comfort (my wife will actually ride in this car, as contrasted with previous spring-shock-widewheel-lowprofile Mustangs).

On another being said, the car in the photo was a decent compromise, just a little rougher-riding than stock, with FRPP "P" springs, KONI Sports, Steeda front adjustable bar, the H&R 26mm rear bar, and 285-40 tires on GT500 9.5x18-inch rims. See how the right front wheel is not carrying much weight in this 80mph corner at Chuckwalla Valley Raceway.

More Chuckwalla photos here: https://www.flickr.com/photos/fyougitive/albums/72157625089604277

5105543277_8da5af13a3_b.jpg
 
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SoundGuyDave

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Just as a contrarian position, whether or not the "normal" logic applies with S197 front swaybars is still out for discussion. On mild builds, yes, but once you've lowered the car, etc., camber gain due to suspension deflection becomes the overriding factor, and a huge bar set full stiff goes a long way towards mitigating that. Yes, the big bar unloads the inside front tire in a corner, and that hurts net grip. BUT, it also prevents the outside front tire from going so far into the camber curve that you ride on the outside edge of the tire, which buys you MORE grip than you lost by unloading the inside... YMMV, batteries not included, etc. Flat contact patch a peak latG trumps load distribution. The REAL bottom line is to take your current bar, go full stiff, and see what the stopwatch says...
 

Goose428

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Thank you all for your replies. The car is totally stock suspension, but it is a BULLITT, so it is different shocks and springs compared to a GT. At this point in time, I don't mind having the car ride worse. It's too plush as is. So don't consider ride quality as a factor in giving me advice.

So at this point in time then, what do you guys think would be my best option/biggest bang for the buck? Shocks, springs, camber and tires? Or could I get away with only doing something like a thicker rear bar and camber?

Thanks
 

Norm Peterson

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I have run 16 track days, having only replaced the shocks, struts, front and rear sta-bars, and the rear lower control arms. Add a mild track-oriented alignment that cost me exactly $0, and some DIY brake ducting that was nearly as inexpensive. Probably less than $1500 all told in that. I've made two steps up in wheel widths, and three tire size upgrades, as more or less separate upgrades.

Brake pads have become a significant expense, though, at 5, maybe 6 days per set of fronts and 6 - 8 days per rear set.


I just swapped in some stiffer springs (BMR GT500 Handling springs), and with the Konis dialed way back my wife will still ride in it, at least as long as I don't go out of my way to find all the worst stretches on the poorest roads. IOW, not too much different than with the OE springs. This setup hasn't seen the track yet, as I'm stuck in the middle of a repair/upgrade waiting on a couple of parts. But the car was at least reasonably composed at speed as described above; some understeer on corner exit and too much nose dive/tail rise under braking being slight weaknesses that I'm now addressing.


Norm
 
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noldevin

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If you're on 235s I have my doubts that suspension will really help you much.
If you want to compete I'd figure out what the max size tire your class allows and go for that. Otherwise, the more tire the better (and keep it square).
 

Thenorm

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sorry cant help you. my GT track pack started with massive oversteer, that I had to work at dialing out.

i think my car has only ever understeered once or twice during autocross.


PS add camber.
 

Senna1

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So at this point in time then, what do you guys think would be my best option/biggest bang for the buck? Shocks, springs, camber and tires? Or could I get away with only doing something like a thicker rear bar and camber?
I'm not nearly as experienced as some here, but from my point of view it depends what your goal is.

Faster times? Tires. And tires again. Those PZ Nero all-seasons are hamstringing you awfully, guaranteed. Did I mention you want better tires yet?

Tires likely won't change the balance of the car, though the limits that you encounter loss of grip at the limited end will obviously be higher, and may be hit less frequently (only you can determine if that 'fixes' the problem). Roll/dive/squat won't change, and may even feel worse if you're pushing harder.

I'll let others comment on struts/shocks/springs/sways as I'm still working it all out myself, but that's where you're going to want to go purely to change the handling balance and improve your confidence in the car's behavior - which from your posts might be what you're after.
 

El_Tortuga

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I have run 16 track days, having only replaced the shocks, struts, front and rear sta-bars, and the rear lower control arms. Add a mild track-oriented alignment that cost me exactly $0, and some DIY brake ducting that was nearly as inexpensive. Probably less than $1500 all told in that. I've made two steps up in wheel widths, and three tire size upgrades, as more or less separate upgrades.

Brake pads have become a significant expense, though, at 5, maybe 6 days per set of fronts and 6 - 8 days per rear set.


I just swapped in some stiffer springs (BMR GT500 Handling springs), and with the Konis dialed way back my wife will still ride in it, at least as long as I don't go out of my way to find all the worst stretches on the poorest roads. IOW, not too much different than with the OE springs. This setup hasn't seen the track yet, as I'm stuck in the middle of a repair/upgrade waiting on a couple of parts. But the car was at least reasonably composed at speed as described above; some understeer on corner exit and too much nose dive/tail rise under braking being slight weaknesses that I'm now addressing.


Norm

What is the spring rate on the BMR GT500 Handling springs?
 

Norm Peterson

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SP072 is 260 front (linear), 220 rear (dual-rate).

The soft rate for the rear springs is not given (I'm guessing it's something like 150 lb/in), but the 220 rate is what the suspension sees at its static ride height and what it operates at most of the time.


Norm
 

El_Tortuga

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SP072 is 260 front (linear), 220 rear (dual-rate).

The soft rate for the rear springs is not given (I'm guessing it's something like 150 lb/in), but the 220 rate is what the suspension sees at its static ride height and what it operates at most of the time.


Norm

Thanks Norm
 

Pentalab

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What is the spring rate on the BMR GT500 Handling springs?

Norm reported the GT-500 handling springs resulted in a .5" front drop....and a 1" rear drop. (as opposed to the 1.5" f/r drop from BMR GT springs.) 1" front drop is the max I would want for a DD, even then, it scrapes those skid pieces once in a while. 1" rear drop is fine, much more than that creates other issues. A .5" front / 1" rear drop would be ideal.

The GT-500 handling springs... combined with your favorite strut /shock....like the Vorshlag Bilsteins would be a good ticket.
http://www.bmrsuspension.com/?page=products&productid=1470&superpro=0 Click on features.
 

Goose428

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Hello everyone,

Thank you all for the replies, and sorry for my late reply. The more I drive the car, the more I realize how awful these tires are... I really WANTED them to work, but now I think I have to change them.

What tires do you recommend for a car that gets autocrossed once a month? I want to spend less than $1k, and I want them to last at least 10-15k miles. Also what is the most tire that we can fit under our cars and still have it be square? 295?

Thanks
 

oldVOR

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With 18x11 rims, max 315's by using CC plates. With 18x10 rims, max 285's. You can mount wider but it's not generally recommended. Typical recommendation is to stick to within 1/2" of rim width to measured tire contact patch width.
I'd recommend a second set of rims with tires dedicated to autox. This exceeds your budget though. Otherwise, it's a compromise between DD street tires and good performing autox tires.
 

El_Tortuga

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Fastest autocross tires in the 200 tw classes are the Bridgestone re71rs. The new rival s are close and offered in the really big sizes, but are in short supply.

My recommendation would be to sacrifice some speed for longevity. Ziti starspecs, RS-3s, etc. Good tires, but not going to wear like the top flight 200 TW. Tire wars have made a joke of treadwear being a good indicator. My old rivals were sooooo much more wear resistant than current, even though they both sport the same 200 number.


Not wanting to rain on your parade, but you won't have enough seat time experience to take advantage of that difference for a while. The common formula is 75% driver, 20% tires, 5% car. Granted some mods make it easier to drive, but nothing matters more than driver. By the time you wear out this set of tires, you'll be much better equipped to make an informed decision your next set.

You can't throw too much tire at our cars, and they actually get easier to drive with big meats. It's expensive though. I paid $1800 for my current set of tires (315s on 18x11s all around)
 

El_Tortuga

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If you are in the game for the long haul, you'll probably want a dedicated set of autocross (track?) tires. To get the biggest tires to fit in front, you'll need to run a lot of tire killing camber. Check out the wheel/tire forum here on s197
 
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It's much cheaper to stay in the Street/Stock class. I would go with a cheap set of stock rims and use the Bridgestones in the 265 size. The Hankook RS-3 is another good option if you're looking to save money.

To save even more money, you can move to 17" rims and tires. About $250 cheaper on a set of tires.
 

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