Suspension Upgrades

[OKC S550]

Looking for recommendations on suspension upgrades for a modest budget,<$1000. Currently have oem PP shocks and struts paired with BMR performance springs, BMR front chassis brace, cradle lock out and MM caster/camber plates.

Even with a squared stance (19x11's w/ 305 tires) and -2.3* camber in the front I still have to fight understeer. Not too sure where to go from here and if I can make any significant improvements with my limited budget.

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[wildcatgoal]

These cars understeer - they are very long and the way the front suspension moves when turning actually sort of lifts the inside of turn corner of the car up a little. Watch when parked and you turn the wheel lock to lock for what I mean. I'm convinced this isn't helping the understeer situation at all. BMWs actually sort of sink down at that same corner. Installing an adjustable rear sway bar and tightening that up until you get the balance you want would be my next step. I run my rear bar tighter than the possible front adjustments on my Steeda bars... seems to help.

 

[Eritas]

These cars understeer - they are very long and the way the front suspension moves when turning actually sort of lifts the inside of turn corner of the car up a little. Watch when parked and you turn the wheel lock to lock for what I mean. I'm convinced this isn't helping the understeer situation at all. BMWs actually sort of sink down at that same corner. Installing an adjustable rear sway bar and tightening that up until you get the balance you want would be my next step. I run my rear bar tighter than the possible front adjustments on my Steeda bars... seems to help.

You have no clue man. What you're talking about is caster. All cars have it and do it. Caster has a jacking effect and effectively increases camber with steering lock, which reduces understeer. BMWs tend to have a lot of caster and do the same thing (I've owned a few M3s before my S550).

Do you bind your rear swaybar by tightening down the bushings or do you "stiffen" your rear bar by shortening the length of the arm?

In stock form the GT & GTPP are fairly well balanced cars and can be driven fairly neutral. With poor driving, they will push like crazy (straight line braking and turning into a corner on throttle).

OP - save your $ for track days and just get seat time. There is far more to be gained by improving the driver than the car.

 

[wildcatgoal]

I realize I'm talking about caster. I know what it does. I was being speculative.

Can't agree more with your last statement.

Six BMWs in my building parking garage where I live, all "car guys" and I'm the odd man out with a Mustang. Where I keep my Mustang is a primarily German race/track car club/storage place with me and another couple Mustangs. Not one of the varying years of BMWs I've come across jack up the body above inside wheel of a turn like the S550 does. Not one. The 2008 M3 I had in Germany when I lived there didn't do that either. The BMW 120d my company gave me after realizing they gave me an executive car and shouldn't have didn't either. They all seem to hunker down at that corner. I honestly don't know what effect that difference might have but I've never experienced understeer even on something as trivial as an onramp to the degree I did with my stock S550 in any BMW. I've never driven a BMW that's as long as an S550, though.

Stop spending your time increasing your mysteriously low post count and justifying your magical recent appearance out of the woodwork by following me around this forum attacking me. You're better than that, I hope. Offer your advice and move on.

Anyway, the strano rear sway bar (solid vs hollow) is cheap and has an understeer-reducing effect. That's why it exists. Tightening up my Steeda rear sway bar (at the end links, not the mount bushing which has no adjustment) reduces understeer as well. Hey, are we about to get into a debate about how putting my end link through a different hole in the sway bar actually does nothing? Let me grill my chicken first. Num num num!

 

[Eritas]

I've owned an E90 &36 M3 and had been a bimmer guy my whole life. This is my first American car. Please stop posting horrible recommendations and nonsense about bimmers and car setup.

I'm not following you, I'm clicking on threads that interest me and you have a horrible habit of saying dumb stuff in them.

 

[wildcatgoal]

I'll try to be better for the next forum plant.

 

[Eritas]

I guess Mustang owners are as big of tools as BMW guys.

 

[wildcatgoal]

Hahahahaha. Well... that's true.

Did we just become best friends?

Hey at least your Mustang won't need a new injector setup after 30K miles or have dash displays that stop working at 60K.

 

[Eritas]

Nah, I don't make friends with jerks like me.

I put over 200k on my 36 with only a climate control failure (a $0.20 capacitor and soldering the replacement in to fix it) and changing out pretty much all the crappy stock bushings out for poly twice, a brake caliper rebuild, and a short shifter mainly to replace the worn rubber in the linkage. Man, German rubber sucks. My E90 was flawless for over 100k. Maybe I was just lucky twice?

Forums can be great for troubleshooting and DIYers.

 

[wildcatgoal]

Agree in the rubber. My ex's 335 had to have its windshield rubber outer liner thing replaced at 35k... along with injectors and needing the dash cluster orange LCD fixed. Baffles me...

 

[EFI]

Dampers and sway bars all around. That should help quite a bit.

Also some toe out in the front.

 

[ddozier]

Looking for recommendations on suspension upgrades for a modest budget,<$1000. Currently have oem PP shocks and struts paired with BMR performance springs, BMR front chassis brace, cradle lock out and MM caster/camber plates.

Even with a squared stance (19x11's w/ 305 tires) and -2.3* camber in the front I still have to fight understeer. Not too sure where to go from here and if I can make any significant improvements with my limited budget.

When is the car understeering, turn in, mid corner, corner exit? You need to address understeer or oversteer by looking at exactly what is causing the effect in the first place. It is possible that the car is understeering in all cases but that would be very rare based on your current setup listed. Also what tire are you running and what track?

Dave

 

[OKC S550]

When is the car understeering, turn in, mid corner, corner exit? You need to address understeer or oversteer by looking at exactly what is causing the effect in the first place. It is possible that the car is understeering in all cases but that would be very rare based on your current setup listed. Also what tire are you running and what track?

Dave

Corner entry, and it is not every time but still happens enough that I want to try and address it if possible. I currently use sport cup 2's on track. I'll get understeer on several tracks MSR Cresson, Hallett, TWS and most recently COTA. I'll see if I cant get a video example from COTA to show what I mean.

 

[BmacIL]

Corner entry, and it is not every time but still happens enough that I want to try and address it if possible. I currently use sport cup 2's on track. I'll get understeer on several tracks MSR Cresson, Hallett, TWS and most recently COTA. I'll see if I cant get a video example from COTA to show what I mean.

Tire pressures?

You may look at doing something like a Strano or GT350R rear bar. The setup you have shouldn't have an abundance of understeer. What are your toe settings front and rear?

 

[OKC S550]

Tire pressures?

You may look at doing something like a Strano or GT350R rear bar. The setup you have shouldn't have an abundance of understeer. What are your toe settings front and rear?

28 psi cold both front and rear. I do the best I can to get an accurate hot psi reading after coming off a session and it is typically in the 34-36 range.

I am thinking I will try the rear bar route and see how that helps. I want to say the toe settings are 0 front and rear but i will need to look at my most recent alignment sheet to confirm.

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