Adjustable Suspension Questions

GT Premi

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Suspension gurus, I need your help/advice! I have all of BMR's adjustable suspension goodies on my car from front to back and need help dialing in my setup. The car handles great except when it comes to REALLY tight corners at speed. It goes into some alarming understeer. I was playing around in the mountains a few weeks ago and came upon a tight right hander. The car had been mostly fine up until that point. It seemed as if the front end just went away without warning. (Full disclosure, I was climbing in altitude and the temps were dropping pretty fast.) I wasn't even going that fast, maybe 35MPH. I went to take the turn and got nothing from the steering input other than the front tires squealing!

Thank goodness no one was coming in the other direction! I'd hate to end up being "that guy" all over the internet car forums. Then again, the car went so straight so fast that I probably would've cleanly cleared anything coming the other way before being able to make contact. (There was a small parking lot on the other side of the road to runoff into, thankfully.) Easing off the steering did nothing, and I didn't want to hit the brakes for fear of snap oversteer into the ditch beside me because of the cold road surface. The only thing I could really do was ease off the throttle and wait for the front end to catch up. Which it didn't until it was solidly into the other lane.

Anyways, I have both the front and rear sway bars on full hard. BMR says the harder the rear, the more straight the car will track off the line. It seems to be working to some degree. My car doesn't try to get sideways as badly when getting on the gas in a straight line. (Also the brackets touch my exhaust in any other position.) I have the front on full hard because... Well the rear is full hard. Why not the front, too? :shrug:

What can I do to dial out understeer? Soften up the front or the rear?

I also have their adjustable front sway bar end links. I only bought them because BMR recommends them due to the flimsiness of the stock end links. What reason would I have to adjust the end links and what effect does it have?

Thanks!
 
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BMR Tech 2

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Soften the front up if you want to get rid of understeer. The stiffer the front bar, the more understeer you'll get.

You want to have the bar set level, so with the car on the ground, loosen the endlinks and adjust until the bar is parallel to the ground.
 

GT Premi

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Thanks! So is that the only need for adjustable end links, to make the sway bar parallel to the ground? Guess I'll be putting it up on ramps again to check it.
 

barspen

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You already have aftermarket sway bars, so that should help since the poly bushings up front make a big difference vs stock when diving into a turn.

Don't underestimate the impact the tires have on understeer. Depending on the type and amount of wear, this may contribute to what you experienced.

I installed Caster/Camber plates last year and set -1.7* of camber for street and track driving. These really helped to allow the full contact patch of the tire hit the ground on spirited turns. Didn't eliminated understeer, but helps a lot.
 
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Tob

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_Understeer.JPG
_understeer1.JPG

From Filip at Cortex.
 

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GT Premi

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Thanks, guys!! That's some very helpful info that I will put to good use for sure. Concerning tires and tire pressures, I have Continental Extreme Contact tires on all four corners; 255/35F 285/35R. Before that drive, I reduced the pressures from the factory recommended 35psi all around to about 32psi front and 31psi rear. I found that 35psi makes the care feel... "light" is the best word I have to describe it, when entering corners. Almost like there's not enough grip anywhere to keep from drifting wide off the road or entering into an oversteer situation. The little mountain roads I like to drive on don't allow for that kind of margin of error going into a turn. 35psi is fine for most of the freeway on-ramps around here because they're sweepers with a wide enough berth to allow for a slight drift and time for correction.

My best handling has actually been on even lower pressures [on hot days]; something like 29psi rear and 31psi front. But that was before the adjustable LCAs, sway bars and end links. With the cooler temps rolling in, I think I'll soften up the front bar and put the pressures back to factory spec and see how that goes for a while. If you guys have anymore suggestions, I'm all ears.
 
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GT Premi

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So, it's been a year and 9 months, and I still haven't adjusted my front bar yet. I have added a Watts link, and it makes the front feel even more "light." I had to find this old thread to remind me what adjustment(s) I need to make.

After spending more seat time in my R, it makes my GT500 feel sloppy by comparison, in spite of all the aftermarket suspension bits. It handles with aplomb. It just doesn't inspire great confidence in doing so. (Still worlds better than stock, though!) Where my R is like "Yeah! I got you, buddy! Let's do this, dog!" and probably gives too much confidence, my GT500 is more like "Here. Hold my beer and watch this." You're kinda confident it can do what it says, but in reality you're not entirely sure WTF is going to end up happening.

I've been thinking about replacing my Eibach Pro Kit springs with some constant rate springs to maybe calm down the sloppy feeling. I'll definitely still be making the sway bar adjustment, though. I have more incentive now than ever.

Oh, and I had some lightweight engine mounts installed, and somehow that made the front feel even more light! It was only a 6 lbs reduction, so there's no way in heck that would be felt. The installer did mention that when he went to disconnect the k-member, one of the bolts was only hand tight. :eek: Maybe now that everything's cinched down the way it should be, it's flushing out the issue. But I would think a "loose" k-member would've been feeling weird all along...
 

Black Cobra '99

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Since you have adjustable parts I strongly recommend taking it to a shop to fine tune and dial in your suspension. Fine tuning plays a big part in how the car feels.
 

GT Premi

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Since you have adjustable parts I strongly recommend taking it to a shop to fine tune and dial in your suspension. Fine tuning plays a big part in how the car feels.

I wish I could find a shop! Every time I take it somewhere and tell them what I want, they look at me like I'm speaking Klingon. It's kind of ironic when you think about it. We have tons of professional race shops in the area ranging from NASCAR to Le Mans with just about everything in between. You would think some of the side shops would know what an adjustable suspension is. There are some shops that do German cars, but when I've tried them, they acted like they were appalled that I even had the gall to drive a Mustang into their parking lot, much less ask them to work on one. (I'm talking about you, Underground Racing. "Eww! The only American cars we touch are Vipers! And that's only with a 10' pole and a hazmat suit.")

I'd just call Kelly at BMR and see what he recommends or suggests. The guy knows suspension

I've talked with him a couple times. I think the adjustments I need will need to be done by a professional shop. I still can't even get anybody to adjust my thrust angle. I don't think that's something I can properly do in the driveway. I know something needs to be done because I'm getting tired of throwing parts at it. Now I'm looking into a set of strut tower and shock tower braces to tighten up the chassis.
 

Catmonkey

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If your front is lowered, you might look into a bump steer kit. That could be part of the reason the front end is fighting you.
 

GT Premi

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It's not fighting me at all. I might not be describing the sensation correctly. Ah!! It just hit me! It kind of feels like the steering wheel is disconnected from the front tires, and there's something "in between" the tires and steering wheel. Maybe I'm now feeling the EPAS more than actual steering input and feedback. ??
 

1st usa car

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why not do the quick and simple thing that was suggested by BMR and change the front bar setting? just remove 2 bolts and put them in the other hole - each hole is radically stiffer than the other. like 1st hole is 30% - 2nd hole 80% 3rd hole 120% stiffer than OEM -- Try the loosest hole and see if that helps the understeer
 

Black Cobra '99

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I wish I could find a shop! Every time I take it somewhere and tell them what I want, they look at me like I'm speaking Klingon. It's kind of ironic when you think about it. We have tons of professional race shops in the area ranging from NASCAR to Le Mans with just about everything in between. You would think some of the side shops would know what an adjustable suspension is. There are some shops that do German cars, but when I've tried them, they acted like they were appalled that I even had the gall to drive a Mustang into their parking lot, much less ask them to work on one. (I'm talking about you, Underground Racing. "Eww! The only American cars we touch are Vipers! And that's only with a 10' pole and a hazmat suit.")

Well that sucks!
I guess you have to work on it yourself, I'm in the same boat only we don't have any decent performance shops. I know I'm gonna have to work on mine and as such I've been adding parts systematically to feel the effect of each one. Its gonna be tough but I like the challenge.
 

GT Premi

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I loosened the front sway bar by one hole. That made a big difference. I pushed it hard in the mountains over the weekend. No oversteer or understeer at the limit, and the car didn't feel as "flimsy" (for lack of a better word) at the front end. At this point, I think the only thing that's going to give me the steering feel/response that I'm chasing is a faster rack.

That was actually my first time really pushing the MPSS tires since having them mounted last year. These tires are amazing! The MPSC2s on my R must be nothing short of incredible on the same roads.

Also, I still can't say enough about how well the Watts link (in conjunction with the MPSS tires) keeps the rear planted. So planted that, as I accelerated hard out of a sharp curve, I could swear it lifted the right front tire! In any other configuration, that would've either pushed straight forward or the rear would've started coming around. If any of you are still "thinking about" getting a Watts link, stop thinking about it and just do it! It's worth every penny.
 

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