Tips for minimizing under-steer - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 26 Old 04-26-2009, 08:39 PM Thread Starter
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Tips for minimizing under-steer

Looking for tuning tips to help minimize our beloved Mustang's under-steer. I know by me running off-set tires it adds to this but I am sure I can do other things before I ditch the big ole 18x9 and 18x10's. I mean they just look so damn good on the car.

I have softened up the front struts and that helped a bit but throughout most of my runs the front tires scream for mercy. The car actually feels pretty good but it takes a bit more "persuasion" on my part to get the car to go where I want it to in tight corners. I have almost every suspension mod allowed for ESP except sway bars. I'm still running the stock bars and bushings. I'm pretty new to autocross but I can tell from what experience I have that the pushing going into corners does hurt my times.


'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #2 of 26 Old 04-27-2009, 10:13 AM
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I don't see any c/c plates on your list and you don't say anything about your camber or caster settings. Slow down more on corner entry and wait longer to get on the gas.

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post #3 of 26 Old 04-27-2009, 10:28 AM
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Besides alignment, throttle control is key. Most folks whether on a big track or small go into the slow corners too fast. I don't know your experience so maybe I'm not saying anything new, but enter slower then use throttle control to get thru with minimal push.
Or maybe put the 10 inchers in the front. LOL

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post #4 of 26 Old 04-27-2009, 11:17 AM Thread Starter
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No CC plates my alignment specs are:

Front
-1.3 camber
-4.2 caster
1/8" toe out

Back:
-1.1 camber
1/8" toe in

How can you tell if you are going in too fast? The car feels pretty good (at least to me) and it not like I am killing the front tires. Its just that the car doesn't seem to want to rotate the back end and it takes more work to get the nose pointed where I want it. In transitions and sweepers it feels great but in the tighter elements the front just doesn't seem to bite as much as it feels like it should be. My latest event I softened up the front struts a little and took 2 seconds off my time. So I know there are some tweeks here and there that'll help given my current skill level.

Granted I am still pretty much a noob but things are starting to slow down now that I'm not driving on just reflexes and andrenaline. I've actually been managing to keep my eyes up and ahead for the most part. A big "Woot!" for me when it comes to tightening the nut behind the wheel.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #5 of 26 Old 04-27-2009, 11:17 AM
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Having run staggered tire/wheel fitments before(even bigger drag tires rear/reg. smaller street tires in front), you really hafta just bow up and stop for those turns if you want to not frustrate the crap outta yourself.

You know the back is gonna stick(well I did because it was a drag radial), so the quicker you can get the car hauled down in a straight line, the quicker you can start your turn...........THEN hammer the gas to get out out of the turn.

Slow in, fast out is not just a suggestion on bigger rear tire'd Mustangs, it's damn near Biblical.

But MFE was on the money when he mentioned camber.

FWIW i'm running -3 degrees with "all mustang suspenion crap including t/a", and with my rear swaybar set 3/4's in the stiffest setting.....it's got OVERsteer with a 275 front and 315 rear tire.
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post #6 of 26 Old 04-27-2009, 11:34 AM
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Get some c/c plates and dial in a lot more negative camber for events. You can put them right back where they were for the drive home.
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post #7 of 26 Old 04-27-2009, 12:06 PM Thread Starter
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Since I don't know from experience; how much less of an under-steer effect would there be if I went away from the staggered wheel/tire sizes?

Basically I am looking for pointers to be better with the way the car is currently set. Since I am still learning I think it would be more of a mistake to jump ahead and mod the car further. I am still getting faster each run so that means the car has more to give than the driver can get out of it.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #8 of 26 Old 04-27-2009, 12:54 PM
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If you're pushing on corner entry, try trail braking. This will help the rear of the car rotate. I have an undersprung mustang that pushes pretty bad. I tried trail braking the car to sort of fling the rear of the car into the corner this past weekend. It definitely helped the car get through the corner and I picked up 1.5 seconds at Thunderhill using this technique.

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post #9 of 26 Old 04-27-2009, 01:37 PM Thread Starter
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Thanks for all the suggestions. I'll definately put CC plates and a stiffer rear sway on the "to-do" list once I get more seat time.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #10 of 26 Old 04-28-2009, 10:19 AM
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Sounds like you are headed in the right direction... Another idea might be to work with your tire pressures a little more. A few pounds one way or the other can have a pretty significant impact on how the car handles. If it's understeering, try dropping the fronts a little, or bumping up the rear pressures to see what happens. use your markers on the tire to tell you how far you are rolling over. Find the sweet spot and try to stay in it by resisting the urge to spin the rear tires, or slide the fronts. Another thing Ive done before, and have seen done is to buy a cheap garden sprayer, and spray down the tires between runs. Usually any water that might still be on the tires is gone by the time you've gotten out of the start gate.


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post #11 of 26 Old 04-28-2009, 11:43 AM Thread Starter
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I have my front pressures set at 39 psi and my rears at 37 psi (dependant on outside temps of course). For the fronts at least that seems to be the perfect pressure in regards to rolling over the side wall. The wear is about halfway down the shoulder blocks of the tread. Maybe I'll try upping the pressures out back a few psi and see if that helps the back end rotate a little more.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #12 of 26 Old 04-28-2009, 12:00 PM
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Quote:
Originally Posted by OzzDOA View Post
Thanks for all the suggestions. I'll definately put CC plates and a stiffer rear sway on the "to-do" list once I get more seat time.
Sounds like you are on the right track, work on the driver mod before spending more money. This is where I am at, in my third year autoxing. I agree with 4eyed...work with the tire pressures, I think you'll find this can do a lot to help out with the pushing problem. It may be worthwhile to ask an eventmaster that happens to be a local fast guy to drive your car while you are in the passenger seat. This has obvious benefits! Keep it between the cones!

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post #13 of 26 Old 04-28-2009, 12:30 PM
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I have almost every suspension mod allowed for ESP except sway bars.
Were you the green Mustang in ESP at CBP on Sunday? I was in ESP in the Subaru. If it was you, your car looks really good.

That course sure brought out the understeer in my car too. I don't have enough front camber to use all the tire and I have to be very careful to go in slow or I just push out wide and lose time. I consistently screwed up the big left turn in the center lot.
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post #14 of 26 Old 04-28-2009, 01:33 PM Thread Starter
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Yup that was me. Those open sweepers in the first two lots is where I had the toughest time as well. Wanted to give it more gas but didn't want to screw the pinch off-sets before the straight chutes.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #15 of 26 Old 04-28-2009, 05:14 PM
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I'm going to try and oval out my front lower strut mount hole to get at least -2 deg camber. Seems like a cheap solution that might help with a bit more front end grip.
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post #16 of 26 Old 04-28-2009, 05:35 PM
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Quote:
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I'm going to try and oval out my front lower strut mount hole to get at least -2 deg camber. Seems like a cheap solution that might help with a bit more front end grip.
That worked fine for me for years.
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post #17 of 26 Old 04-28-2009, 09:31 PM
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Have you let a more experienced driver take a run in the car?

It is a pretty rare newbie who doesn't brake too deep when trying to go faster.

If they don't brake too deep, they yank the wheel or stab, or something else understeer inducing.

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post #18 of 26 Old 04-28-2009, 09:44 PM
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ahh really? i was thinking about going out sunday too but i didn't have time to get my tires mounted!!
last time i raced with philly i only got 4 runs though, do you usually get more than that?

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post #19 of 26 Old 04-29-2009, 08:24 AM Thread Starter
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Philly events are usually full-up with 150+ drivers participating. Runs start at 10 AM and end around 5 ish PM. That's with everyone only getting 4 runs.

After looking at some detailed pics from this past event it is pretty clear that the outside front is rolling over into positive camber during cornering. I'll see if I can dial in more negative camber with the stock plates and if not CC plates just got bumped to the top of the to-do list.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #20 of 26 Old 04-29-2009, 08:59 AM
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Philly events are usually full-up with 150+ drivers participating. Runs start at 10 AM and end around 5 ish PM. That's with everyone only getting 4 runs.
Yes, you can only expect 4 runs with Philly region. You should also note that this event was filled very early (180 people cap) and people were being turned away, so pre-reg is a must.
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post #21 of 26 Old 04-29-2009, 10:15 AM
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I'll see if I can dial in more negative camber with the stock plates and if not CC plates just got bumped to the top of the to-do list.
Don't waste your time, just get the c/c plates and be done with it. If you want to see why, then take good note of where your strut tops are located. Now jack the front of the car up and watch how far they move. When your eyes are done bugging out, place your c/c plate order and get them on the car.

At the very least you'll be able to switch back and forth between street and track settings in about as much time as it took to read this.
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post #22 of 26 Old 04-29-2009, 01:43 PM Thread Starter
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Which of the two CC plates would you recommend as far as adjustability and quality: MM or UPR? I can get a pretty good deal on either brand.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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post #23 of 26 Old 04-29-2009, 01:48 PM
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I agree wholeheartedly with MFE. There is no way you will be able to get enough adjustment out of the stock plates, and the movement from the upper bushings is terrible. Spend your money wisely, on some MM plates. I will say that the best price I've seen so far on them is from artsperformanceparts.com - art's a cool guy, and does really well, considering he's a one-man operation.

IMO, run from anything with UPR written on it... No offense to anyone, but too many of their parts are cheap reproductions of much better designed products. /rant off

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Last edited by 4eyedconekiller; 04-29-2009 at 01:58 PM.
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post #24 of 26 Old 04-29-2009, 03:45 PM
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Found this thread while looking for something totally unrelated:

http://forums.corner-carvers.com/showthread.php?t=1655
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post #25 of 26 Old 04-29-2009, 05:32 PM
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Which of the two CC plates would you recommend as far as adjustability and quality: MM or UPR? I can get a pretty good deal on either brand.
I can't speak for UPR's c/c plate quality because I wouldn't trust them on my car on principle. If you want to see how much value a company can bring to the forum that may be worth spending a couple bucks on even if the parts were equal, do a search on posts by Jack Hidley (from Maximum Motorsports) and [email protected] (from UPR).
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post #26 of 26 Old 04-30-2009, 03:55 PM Thread Starter
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MM caster/camber plates on the way.

'99 SVT Cobra #2085 -- MAC Cat-Back, MAC O/R H, C&L Intake, Steeda UDPs, FRPP 4.10s, B&M Pro Ripper Shifter, UPR Clutch Quadrant/Adjuster, Hawk HPS Pads, Brembo Drilled/Slotted Rotors, Too Much Suspension Stuff to List, Custom Tuned by Tillman Speed -- 306 whp/301 wtq
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