need feedback from owners with Dinan Stage III suspension - The Unofficial BMW M5 Messageboard (m5board.com)

olis1 · 24th May 2006, 22:43

I have the Stage III suspension from Dinan. Its the Koni setup. I bought the car with this setup so I can't really tell how it is compared to stock since I've only briefly test driven M5's with stock suspensions and that was all before I drove this car.

Anyways, I notice you can still drive the car a but beyond the suspension. What I mean is things still move around quick a bit at times. I'm referring to maybe getting on the power hard and going through a 40 miles an hour sweeper with a bump or 100mph plus on freeway gradual sweep with a bump. Car just rocks around more then I'd like.

I don't know how to quantify this but just want to get an idea if this is normal. Its almost like the rebound is slower then it should be. I checked the front and its set at 3/4 turn from full soft which is the dinan spec i got from the previous owen. Can't check the rear.

Most of the rocking seems to come from the rear. Keep in mind my base point for comparison is my 97 M3/4 that I sold. That car never moved around on you and you could never really get it to a speed that caused suspension movement that made you nervous.

I guess what it comes down to, is.. is this normal for a heavier, higher center of gravity car?

I do love the current ride for comfort.

Anyone in South OC with same suspension so we could compare?

Thanks,

Jon

KirklandM5 · 24th May 2006, 23:31

well the guys at dinan told me...from the factory... the M5 has a front spring rate within 5% of where they did their 540i suspension....so I assume Dinan takes the understeer out by relatively stiffening the rear...with stiffer rear and a bigger bar out back..

With a firmer rear setup, I'm not surprised you made the comments you did....maybe try reducing the shock damping out back or going to a softer rear bar setting.

EM5PWR · 25th May 2006, 02:29

it gets a little wiggly at times, you just need to get used to the movement i guess..

i have now , at first i didn't care for it , but it's the driver not the car..

Need4Spd · 25th May 2006, 04:40

Quote:

I'm referring to maybe getting on the power hard and going through a 40 miles an hour sweeper with a bump or 100mph plus on freeway gradual sweep with a bump. Car just rocks around more then I'd like.

Your '97 M3 did not have 400 bhp and the torque of the M5. Going on the accelerator hard in a corner and hitting a bump at the same time will break traction and give you some wiggle, even with a Dinan setup. To reduce this, you could try playing with tire pressures or moving the rear bar links one hole further out (softening roll stiffness at the rear). That will take some load off the rear and make the front tires work harder relative to the rears.

MCarRacr07 · 25th May 2006, 04:41

I have the JRZ set-up with the camber plates installed up front.....and I have not experienced any of that "butt bounce" you describe....what type of bushings are in your rear sway bars???...if anything my set-up might be a bit "too firm"......though I'm not sure what the big diff is between the JRZ and the Koni.
I went with JRZ only to try something different as I already had a koni set-up in my last car....
Good Luck
MCar

olis1 · 25th May 2006, 05:41

Quote:

Originally Posted by MCarRacr07

I have the JRZ set-up with the camber plates installed up front.....and I have not experienced any of that "butt bounce" you describe....what type of bushings are in your rear sway bars???...if anything my set-up might be a bit "too firm"......though I'm not sure what the big diff is between the JRZ and the Koni.
I went with JRZ only to try something different as I already had a koni set-up in my last car....
Good Luck
MCar

I have the Dinan bushings. I only know this because I broke a sway bar brkt and switched from stock to beastpower brackets. Had the bushings out and they had a dinan stamp.

I'm surprised the replies are suggesting softening up the rear sway or softening up the damping. I was kind of thinking I need a little quicker damping or a little less roll but maybe is a combination of the car settling down due to all the torque.

The car definitely has very little understeer. In fact I think it could probably follow the M3 through a long sweeper a the same speed. Grip is good.

KirklandM5 · 25th May 2006, 06:07

Yeah, the M5 actually has plenty of grip even from the factory, but what we don't like is the "balance"....

Yes, when you hit the M5 throttle, there is quite a bit of weight transfer to the rear.

As regards to JRZ, those shocks probably have more optimal damping curves for high and low speed damping than what the Koni can do. The whole idea of us using fancy 2-4way dampers in racing, is to smooth out the bumps and be able to lay down power where the track is bumpy.

The LSCMAn can probably comment on what do with valving and anti-roll bar setup.

Quote:

Originally Posted by olis1

I have the Dinan bushings. I only know this because I broke a sway bar brkt and switched from stock to beastpower brackets. Had the bushings out and they had a dinan stamp.

I'm surprised the replies are suggesting softening up the rear sway or softening up the damping. I was kind of thinking I need a little quicker damping or a little less roll but maybe is a combination of the car settling down due to all the torque.

The car definitely has very little understeer. In fact I think it could probably follow the M3 through a long sweeper a the same speed. Grip is good.

gsfent · 25th May 2006, 20:41

Quote:

Originally Posted by olis1

I have the Dinan bushings. I only know this because I broke a sway bar brkt and switched from stock to beastpower brackets. Had the bushings out and they had a dinan stamp.

I'm surprised the replies are suggesting softening up the rear sway or softening up the damping. I was kind of thinking I need a little quicker damping or a little less roll but maybe is a combination of the car settling down due to all the torque.

The car definitely has very little understeer. In fact I think it could probably follow the M3 through a long sweeper a the same speed. Grip is good.

I have the same setup, car came that way. I have no float at all. The only thing I have considered was slightly stiffening the front between and 1/8 and a 1/4 turn; the compression is a little soft for my taste. Otherwise I find the combination of ride and balance on the street incredible. This is how it should have come from the factory IMHO.
Regards,
Jerry

SDImolaS2 · 25th May 2006, 21:47

Quote:

Originally Posted by olis1

Anyways, I notice you can still drive the car a but beyond the suspension. What I mean is things still move around quick a bit at times. I'm referring to maybe getting on the power hard and going through a 40 miles an hour sweeper with a bump or 100mph plus on freeway gradual sweep with a bump. Car just rocks around more then I'd like.

Most of the rocking seems to come from the rear. Keep in mind my base point for comparison is my 97 M3/4 that I sold. That car never moved around on you and you could never really get it to a speed that caused suspension movement that made you nervous.

Anyone in South OC with same suspension so we could compare?

Interesting,

For the most part my car s/ Stage III is pretty locked down. The time the softness in roll stands out to me is in rapid transitions from hard cornering side to side. The car just takes much longer to transition and take a set than my stock M3/4. However once there it's very precise and stable to bumps and small adjustments. You can unsettle the suspension somewhat with large throttle adjustments, but it is still quite controlable and entertaining.
My M3's shocks are starting to go and that can create a side to side wobble that's simular to what you are describing. How many miles on your M5's shocks? I'm not sure what the life span on koni's are........ the instability doesn't sound normal on your M5. What kind of tires and pressure are you running?
If your are ever down in San Diego and want to compare. I also will be driving up to LAX several times next month mid-day/mid-week.

Regards,
Paul

Regards

mr_bock · 25th May 2006, 23:01

Did you check all mounting bolts/nuts for proper tightness? Check rear sway bar brackets, etc... make sure all is in working order. I had the Dinan front camber plates but the put too much negitive camber (wore the insides of the front tires out). The shop said the plates are non-adjustable? I went with K-Mac hybrid camber plates and a neutral alignment. I don't notice the rear bouncing like you are describing????

Good Luck, hope you get this sorted out!!!!