suspension mods; staging and order of upgrades

[tuj]

Hey all:

Here's what I'm thinking of:

"Stage 1": M3 control arms front and rear, M3 rear subframe bushings. M3 28mm front sway bar. Stock springs and struts/shocks. From everything I have read, this will gain me more front neg. camber and less slop in the rear. Are stock springs/struts/shocks ok with this setup?

"Stage 2": Some kind of coilovers or springs/strut/shock combo that is adjustable. Need some help on suggestions here... This is a daily driver, so I do not want to get too low. I'd like something adjustable as I have experience autocrossing and adjusting shocks to conditions.

Thoughts?

Another crazy question: Will BMW support the warranty on the suspension if I use genuine BMW parts for "Stage 1"?

[jafo1701]

I have the M3 subframe bushings, BMW performance springs, Koni Sport shocks/Struts, Din an rear shock mounts and Dinan Camber plates. I'm very happy with the result. Front struts are adjustable as well as rear shocks. However to adjust the rear shocks they need to be removed. They do make Koni Sport shocks that can be adjusted without removing, but they cost around $250 more. I'm more of a set it and forget it person. Even when I had AST coilovers on my M3 once I found a setting I just left it. I've auto crossed it at a test n tune day, so got plenty of runs. Very happy with the result. Car handled beautifully once I figured out how to best drive it. A little bit of front body roll, will add the M3 sway bar in the near future. First track day is the second weekend in June so I'll see how it handle on the track. With the above set up I was able to get -2.1 degrees camber on both sides up front.

[wjk_glynn]

Originally Posted by tuj

"Stage 1": M3 control arms front and rear, M3 rear subframe bushings. M3 28mm front sway bar. Stock springs and struts/shocks. From everything I have read, this will gain me more front neg. camber and less slop in the rear. Are stock springs/struts/shocks ok with this setup?

What does that run, parts & labor?

Thanks.

Karl.

[tuj]

Originally Posted by wjk_glynn

What does that run, parts & labor?.

Well, DIY is always cheaper, although maybe not the most time-effective....

But I'm trying to get a quote from my dealer if they will cut me a deal and I'm also working with an independent shop that specializes in Euro cars. I'll see if I can't get a couple quotes on the labor. But the parts run list at:

m3 rear subframe bushings rear 146
m3 rear subframe bushings front 130
m3 control arms front 563
m3 control arms front hardware 39
m3 control arms rear 743
m3 control arms rear hardware 45
m3 sway 300
(all BMW parts)
Total: 1960.

[uberschnell]

Originally Posted by tuj

m3 rear subframe bushings rear 146
m3 rear subframe bushings front 130
m3 control arms front 563
m3 control arms front hardware 39
m3 control arms rear 743
m3 control arms rear hardware 45
m3 sway 300
(all BMW parts)
Total: 1960.

Much better deal on the rear control arms:

http://www.ecstuning.com/BMW-E90-335....0L/ES2622633/

[tuj]

Yes, the TRW parts are cheaper for sure, but I was spec'ing everything using BMW parts.

[blutattoo]

Originally Posted by tuj

Well, DIY is always cheaper, although maybe not the most time-effective....

But I'm trying to get a quote from my dealer if they will cut me a deal and I'm also working with an independent shop that specializes in Euro cars. I'll see if I can't get a couple quotes on the labor. But the parts run list at:

m3 rear subframe bushings rear 146
m3 rear subframe bushings front 130
m3 control arms front 563
m3 control arms front hardware 39
m3 control arms rear 743
m3 control arms rear hardware 45
m3 sway 300
(all BMW parts)
Total: 1960.

I'd add the front anti roll bar as well. you can get both front and rear from hpashop.com for like $383

You can get all of the stuff from them they are genuine OEM BMW parts.

If you want call Harold he's always been helpful when I've had questions.

Don't forget to factor in a professional alignment afterwards since you'll definitely need it. Most likely the car won't be drivable after you install the parts.

[tuj]

front anti roll bar as well.

Sway bar, anti-roll bar, same thing. Didn't realize the m3 rear was compatible as well, I will throw that on the list.

Any problems using stock springs with the m3 setup?

[uberschnell]

Would not suggest the M3 rear sway bar if you are not running an LSD.

[tuj]

Mtek: I plan on moving to an LSD, but I'm curious why you say that? Do you feel the M3 rear sway adds too much to the spring rates during corner-exit? If so, wouldn't that actually help add traction to the inside wheel?

[IGoFast1589]

Originally Posted by tuj

Mtek: I plan on moving to an LSD, but I'm curious why you say that? Do you feel the M3 rear sway adds too much to the spring rates during corner-exit? If so, wouldn't that actually help add traction to the inside wheel?

Because a stiffer sway bar may cause you to lift your inside wheel on tight autocross like corners and in that situation the open differential will prevent you from being able to put down the power. Sometimes you see really tightly sprung cars an an autocross course lift their inside wheels and dog leg around a corner. Will this actually happen to you? Maybe if you're REALLY diving into a corner and hooning the car around, but I haven't seen any factory suspension that's taught enough to really do that. A limited slip is the number one thing to do on these cars in my opinion though.

[tuj]

Because a stiffer sway bar may cause you to lift your inside wheel on tight autocross

Hmm, I've certainly seen that phenomena on FWD cars like Golfs on corner-entry and mid-corner, but with a RWD car, usually the inside front wheel lifts on corner exit because of the weight transfer (and if you have good shocks). My RX-8 would do that.

That said, I am planning on a LSD, I just can't decide which one:
-Quaife
-WaveTrac
-Dinan

Any suggestions would be appreciated re: the LSD. I know most people have Quaife's but I'm seriously considering the Dinan unit since it would preserve my warranty.

[IGoFast1589]

Originally Posted by tuj

Hmm, I've certainly seen that phenomena on FWD cars like Golfs on corner-entry and mid-corner, but with a RWD car, usually the inside front wheel lifts on corner exit because of the weight transfer (and if you have good shocks). My RX-8 would do that.

That said, I am planning on a LSD, I just can't decide which one:
-Quaife
-WaveTrac
-Dinan

Any suggestions would be appreciated re: the LSD. I know most people have Quaife's but I'm seriously considering the Dinan unit since it would preserve my warranty.

Yeah, definitely more common on the Evolutions, STis, SRT-4s etc. And true, good shocks along with driving the car a little differently will help you avoid wheel lift.

I have the Wavetrac and love it. Best thing I have done to the car without question. Operates as quietly as a factory unit, no weird twitches or feelings. Just smooth as butter and awesome power delivery. So much easier to control slides.

[uberschnell]

IGoFast1589 is right on the money. A few people who have done the rear sway have complained of lift. As for the LSD, I've done both the Quaife (335i) and the Wavetrac on my 1. Both are excellent and almost indistinguishable performance wise.

[blutattoo]

I did the M3 bits at the same time as the lsd to cut down on install costs so I can't really say how it effects the car without an lsd. As much as I love the performance of the Dinan diff I'd recommend against it since I'm on diff number 2 and it still makes a bunch of noise. Plus if you're not trying to get a warranty with it there are less expensive options.

[tuj]

As much as I love the performance of the Dinan diff I'd recommend against it since I'm on diff number 2 and it still makes a bunch of noise.

Really, the Dinan lsd is that bad? I heard someone else complaining about noise from their WaveTrac unit but then another said they had no noise whatsoever and blamed the installation.

[IGoFast1589]

Originally Posted by tuj

Really, the Dinan lsd is that bad? I heard someone else complaining about noise from their WaveTrac unit but then another said they had no noise whatsoever and blamed the installation.

The only audible sound I get from my Wavetrac is a very faint thump when stopped, in neutral, and I select first gear. Otherwise, you'd have no idea it was there.

[John_01]

Originally Posted by tuj

"Stage 1": M3 control arms front and rear, M3 rear subframe bushings. M3 28mm front sway bar. Stock springs and struts/shocks. From everything I have read, this will gain me more front neg. camber and less slop in the rear. Are stock springs/struts/shocks ok with this setup?

Obviously its your car, so only your opinion really matters. To me the standard springs and especially the shocks are too soft for a car with sports aspirations. I think it won't cost much more to get the firmer BMW Performance springs and shocks (of your choice) installed at the same time. I would expect a saving over doing it in two stages.

[tuj]

I think it won't cost much more to get the firmer BMW Performance springs and shocks (of your choice) installed at the same time.

I was thinking of going with coil-overs as 'Stage 2'. I was thinking about KW-V2's.