[DrRobert]

Yeah, I want the subframe bushings so this is my chance to swap the RSB but staying LSDless for now. Definitely not putting the M3 RSB on but hoping the 15 mm RSB will be OK without LSD. AFAIK the E90 ZSP RSB is 14 mm (is that correct?) so hopefully a 1 mm increase is noticeable, beneficial and tolerable.

[solishe]

Originally Posted by DrRobert

Yeah, I want the subframe bushings so this is my chance to swap the RSB but staying LSDless for now. Definitely not putting the M3 RSB on but hoping the 15 mm RSB will be OK without LSD. AFAIK the E90 ZSP RSB is 14 mm (is that correct?) so hopefully a 1 mm increase is noticeable, beneficial and tolerable.

CVC has the 14mm rear bar and wished he had gone with the 15mm. Aiming for the 15mm is probably best way forward.

[cvc 22349a]

Originally Posted by DrRobert

Yeah, I want the subframe bushings so this is my chance to swap the RSB but staying LSDless for now. Definitely not putting the M3 RSB on but hoping the 15 mm RSB will be OK without LSD. AFAIK the E90 ZSP RSB is 14 mm (is that correct?) so hopefully a 1 mm increase is noticeable, beneficial and tolerable.

No. It's 13mm. I'd do some more research on roll bars and talk to Barrett at Sonic before you keep throwing money at random parts. Harold gave you some good advice btw and has tried many suspension combos on this chassis.

[DrRobert]

Thanks for the replies. I haven't spent any money on "random parts". You guys and Harold all seem to agree on the FSB, front control arms, and subframe bushings. The only part I haven't figured out yet is the rear sway bar, and I will figure that out before I proceed. I will call Barrett on Monday like I said, appreciate the referral. Harold said he didn't recommend a rear bar with an LSD, but I am not getting the LSD now after all. Maybe I'll ask him.

[ajsalida]

Pardon me if you know this already.

Part of the issue and various opinions with the rear bar and RSB is it is, unlike many other cars, very expensive to do either if you pay someone, because the subframe has to come down to do either. So you want to do both at once. The full RSB job is very time consuming. You can easily rack up 1k or more install costs in addition to parts.

Even if you do it yourself is is not something you want to do often to try out various bars or bushings etc.

I am not a fan of making a whole bunch of mods at once. Better IMHO to do couple of things, evaluate, take the next step. So for example in your case the easiest thing to do is the front bar. You can do that in your driveway, no alignment needed. See what it feels like.

Lot of vendors here (gasp) are here primarily to make a living selling BMW owners stuff they maybe don't really need. You may find you love your car with just a new front bar on it. I am not sure all the M3 bits are worth the cost and install expense at that stage. But who knows.

If you know cars and fast driving you may find the rear getting squirelly mid corner over bumps or under power, and may want a bit more neutral/oversteer feel for sub limit handling. If that sense develops over time then rear bar and RSB.

Separately If you find the front not precise enough or wish it to respond better than it does, then the M3 bits. Same for M3 bits rear (but only after the RSB as they are the weakest/sloppiest link in the whole rear).

I guess what I am saying in my long winded fashion is there is an element of skill and experience needed to appreciate many of these mods, and their downsides and trade-offs. Most folks would find driving a race car on the street uncomfortable and even painful, but a few hard core folks would find it awesome.

Part of all these mods is to find out where you are on that spectrum. But where you are changes too. Many times I've been to the place with a car where I loved it but wanted jut a little bit more of this or that, did the mod, then realized I just ruined the car for 90% of what I use it for. The way you avoid that is do the mods one at a time where feasible, and evaluate.

[DrRobert]

Thanks for that, ajsalida. Appreciate the input and reality check. Like I said I'm not a DIYer so I will be paying someone to do all the mods for me. It is hard for me to get the car into the shop, so I want to combine mods to make efficient use of time, while not going overboard and doing too much at once. I might just start with the front M3 front control arms and sway bar like Edge suggested. My local indy could probably even do that. Still waiting to hear back from Harold and Sonic tomorrow.

[CALWATERBOY]

Originally Posted by cvc 22349a

^ I actually had FSD's on my car for a couple years and gave my experience with them; hope you like them better than I did and hope you used the PS bumpstops. Forget Edge; get the TRW control arms from the internet and have Barrett at Sonic MS install them and align your car to M3 specs; he knows.

Well, not your cup o'tea. Did you run Sport or similar springs?

[DrRobert]

FYI here's what Harold said this time:

"The sport rear bar is 13mm so going up to 15mm is hardly an upgrade, and not one I would really recommend with or without LSD. The affect of a larger rear bar in a corner is that the inside rear tire is being lifted off of the ground while the opposite side is being pushed down. Even though it will never really come off of the ground, traction is reduced. The car will drive off of the corners better with the stock bar. The largest front bar off of the E9x M3 is the way to go.

In place of the rear anti roll bar, I do recommend M3 rear guide rods, which will provide more traction because they flex much less. You will also save a couple pounds of weight as well."

[cvc 22349a]

Originally Posted by CALWATERBOY

Well, not your cup o'tea. Did you run Sport or similar springs?

That was meant for the OP but yes I used them with oem Sport springs and have posted my experience with FSD's many times.

[DrRobert]

CVC - thanks for the tip about the PS bumpstops. I was not aware of that. I have ordered them and will have them installed when I get the M3 bits and alignment done. Ride is a little bouncy still, hopefully that will help. And yes, I know you told me not to get the FSDs - hopefully I won't wind up replacing them like you did, but if I do, you told me so!

Robert

[swagon]

This thread is helpful for me. Am planning to do some mods on our E82, too.

Thanks.

[nikitino25]

Would a stiffer rear sway bar have any effect on rear end squat on acceleration? Specifically, would a stiffer rear sway bar help to cut down on acceleration squat or would it have no effect at all?

[DrRobert]

Update - E93 M3 front sway bar installed yesterday. First impression - I like it! Very noticable improvement in body roll, car stays much flatter in turns, large bang for the buck with this upgrade methinks. Steering feels grabbier (is that a word?) but still not as precise as I'd like. Overall feeling of stability in turns is remarkably improved, but rear still a bit jittery in turns on uneven pavement at moderate speed. Need to drive it more but suspect I'll add more M3 bits in pursuit of the perfect ride. Really appreciate all the help I've been given here - thanks again everyone!

[AWDBooSTIn90]

Nice! Thats good to hear!

So what is your current setup as of right now? Mods? Wheel/tire setup?

What do you think still needs to be improved?

Whats your nxt step?

Im in the same situation as you. My e92 335i is pretty much stock right now. I have oem sport suspension. However the shocks need to be replaced soon. So im trying to plan out my next mods.

M3 Rear subframe bushings IMO are a must! As well as M3 diff bushings!

Anthony

[DrRobert]

See my sig for my current setup. Wheels are 18", tires 225 front and 255 rear.

Steering precision and responsiveness still need improvement. Car still understeers (though not as bad since upgrading the front sway). I am hoping the M3 front control arms will improve that further. Rear end still feels unstable when hitting bumps mid-turn; the M3 subframe bushings should take care of that from what I've read. There is also some excess bounce after going over a crest while driving straight, which I hope is also due to the subframe bushings and not the FSDs.

I really like doing mods one at a time to feel the effect of a single part swap. However, for practical reasons (I don't DIY and I hate having my car in the shop) my next step will include multiple mods. My plan is to get the following done next week, all at once:

1. M3 front control arms (for reason stated above)
2. M3 subframe bushings (ditto)
3. M3 rear guide rods (in lieu of rear sway bar, as recommended by Harold)
4. BMWPS bumpstops (which I should have done when I installed the BMWPS springs )
5. alignment

After that I should be able to tell whether or not my decision to go with the FSDs was a good one.

[nikitino25]

Originally Posted by DrRobert

See my sig for my current setup. Wheels are 18", tires 225 front and 255 rear.

Steering precision and responsiveness still need improvement. Car still understeers (though not as bad since upgrading the front sway). I am hoping the M3 front control arms will improve that further. Rear end still feels unstable when hitting bumps mid-turn; the M3 subframe bushings should take care of that from what I've read. There is also some excess bounce after going over a crest while driving straight, which I hope is also due to the subframe bushings and not the FSDs.

I really like doing mods one at a time to feel the effect of a single part swap. However, for practical reasons (I don't DIY and I hate having my car in the shop) my next step will include multiple mods. My plan is to get the following done next week, all at once:

1. M3 front control arms (for reason stated above)
2. M3 subframe bushings (ditto)
3. M3 rear guide rods (in lieu of rear sway bar, as recommended by Harold)
4. BMWPS bumpstops (which I should have done when I installed the BMWPS springs )
5. alignment

After that I should be able to tell whether or not my decision to go with the FSDs was a good one.

Are you getting any other arms in the rear besides just the M3 rear guide rods?

[DrRobert]

Originally Posted by nikitino25

Are you getting any other arms in the rear besides just the M3 rear guide rods?

no

[DrRobert]

Another update: M3 front control arms, rear guide rods, subframe bushings installed by Edge Motorworks and custom alignment done. Signature updated to include all mods to date. Steering is dialed in pretty much to my satisfaction. Really feels nice entering turns now. The rear end doesn't skip around anymore when I hit a bump while cornering. It finally feels like a BMW! Overall the car really feels transformed compared to when I first got it, but there are still a couple things that don't feel quite right when driving hard on the mountain back roads:

There is still more body roll in turns than I would like. I no longer have that feeling during hard cornering like the whole body is shifting sideways on the frame, but it now feels like there is a lesser amount of sway or compression occurring at the wheel/axle level, and the car does not stay quite as flat in turns as I would like. There is also still a minor but annoying vertical rear bounce going over bumps (2-3 oscillations after a hard hit) when driving fast on a straight road. This all makes me wonder if the FSDs are mismatched with the BMWPS springs, or if there are any other parts that could be upgraded to address these complaints. What do you guys think?

Thanks again for the help - I really appreciate it!

Robert

I'd swap those shocks out for sure (Bilstein B8, Koni yellow, etc). I highly doubt they are well matched for anything past OEM sport springs; if that. Add upgraded rear upper shock mounts (Dinan, Powerflex, etc.) and you should be good to go.

[DrRobert]

Originally Posted by FCobra94

I'd swap those shocks out for sure (Bilstein B8, Koni yellow, etc). I highly doubt they are well matched for anything past OEM sport springs; if that. Add upgraded rear upper shock mounts (Dinan, Powerflex, etc.) and you should be good to go.

I thought the after market rear upper shock mounts were to increase shock travel on lowered cars. The BMWPS springs only lowered my car 1/2" from ZSP height - you think that's enough for those mounts to make a difference? Along the same lines, I thought the Bilstein B8s are for cars with lowering springs and the B6s are for cars without them - is the small amount of lowering from the BMWPS springs enough to require the B8s rather than the B6s?

[solishe]

Originally Posted by DrRobert

I thought the after market rear upper shock mounts were to increase shock travel on lowered cars. The BMWPS springs only lowered my car 1/2" from ZSP height - you think that's enough for those mounts to make a difference? Along the same lines, I thought the Bilstein B8s are for cars with lowering springs and the B6s are for cars without them - is the small amount of lowering from the BMWPS springs enough to require the B8s rather than the B6s?

I'd advise against B8s with PS springs. I ran that for a bit. Rear felt solid but front felt off. Not a tuned setup and no adjustability. I think your best options for PS springs are the V2 kit dampers or Koni sports with adjustability. My 2 cents...

[DaFish]

Originally Posted by TSM330i

BTW: Lighter rims and wider tires will help too. I'm running 255/35 up front and 265/35 rears. My rims are also 10lbs lighter per wheel!

This is huge.... a square or near square setup is a MASSIVE help on these cars.... I really want to do this... Plus you get the rims you want.

TSM330i what offsets and sizes of the rims please, plus a pic would be nice.