[hdrewh]

I'm probably going with the BMW performance suspension, and pretty soon. In the 'might as well, since things are apart under there anyway...' category, what additional bits from the M3 suspension should I consider?

Thanks.

[luckyu]

Originally Posted by hdrewh

I'm probably going with the BMW performance suspension, and pretty soon. In the 'might as well, since things are apart under there anyway...' category, what additional bits from the M3 suspension should I consider?

Thanks.

You could upgrade front tension struts and control arms. These are the two links that together with the strut and steering link control the front wheel. They're relatively inexpensive, labor is relatively low, and it's not a disruptive change, meaning you don't have to change anything else.

Are you happy with the car as it is now?

I hesitate to say this, but I recommend caution upgrading to BMW performance. This is only based on my own experience; others do like it. For me it was a $1000+ mistake. I think it's better to look at upgrading shocks only. But, it depends what you want.

[mosx]

Originally Posted by luckyu

You could upgrade front tension struts and control arms. These are the two links that together with the strut and steering link control the front wheel. They're relatively inexpensive, labor is relatively low, and it's not a disruptive change, meaning you don't have to change anything else.

Are you happy with the car as it is now?

I hesitate to say this, but I recommend caution upgrading to BMW performance. This is only based on my own experience; others do like it. For me it was a $1000+ mistake. I think it's better to look at upgrading shocks only. But, it depends what you want.

Why are you unhappy with the BMWPS? I was thinking about this too.

[hdrewh]

Thing is I don't have sport suspension at all, so I would need paired struts and springs for the right upgrade. Pricing the standard items I see talked about most - Eibach Pro/Koni FSD, thicker front sway bar (included in the performance suspension) - the BMW price is right there with aftermarket.

Why do you consider it a mistake?

Thanks.

[turugara]

I was recently faced with the same dilemma where "my car's going under the knife anyways, why not upgrade all the suspension bits." I guess the upgrade will be limited by how much your willing to spend in addition to what your currently going for.

This thread is a great read.

http://www.e90post.com/forums/showth...27#post3441727

Originally Posted by Orb

Stage 0:

Reduction in under steer

• Front tension link

State 1:

A reduction in under steer with improved handling and feedback. A must for high tuned cars…keep the rear from dog tracking. Give the user the ability to increase spring rates effectively.

• Front tension link
• Sub frame isolator bushings


Stage 1.5

Same as stage 1 but for users that have camber plates.

• Front tension link
• Front wishbones link
• Sub frame isolator bushings


Stage 2:

M3 Equivalent suspension when used with after market suspension and camber plates.

• Front tension link
• Front wishbones link
• Sub-frame isolator bushings
• Rear steering link
• Rear wishbone link
• Rear guide link
• Rear ABS cable bracket

Stage 2.5:

With M 3 rear sway bar.

• Front tension link
• Front wishbones link
• Sub-frame isolator bushings
• Rear steering link
• Rear wishbone link
• Rear guide link
• Rear ABS cable bracket
• M3 Rear sway bar kit - 20 mm (hollow)


Stage 3:

Stage 2 plus the rear camber link/harware and a M3 after market rear shock

Orb

[cvc 22349a]

Originally Posted by hdrewh

I'm probably going with the BMW performance suspension, and pretty soon. In the 'might as well, since things are apart under there anyway...' category, what additional bits from the M3 suspension should I consider?

Thanks.

A huge consideration is your tires. Are you going to stick w/rft's?

[luckyu]

Originally Posted by hdrewh

Thing is I don't have sport suspension at all, so I would need paired struts and springs for the right upgrade. Pricing the standard items I see talked about most - Eibach Pro/Koni FSD, thicker front sway bar (included in the performance suspension) - the BMW price is right there with aftermarket.

Why do you consider it a mistake?

Thanks.

I need to know more about what you value and why you're upgrading to answer your question more properly. I value a certain precision feel, and was trying to eliminate certain problems my 328i ZSP had (which I couldn't articulate at the time). The BMWPS made the problems eventually worse, and didn't deliver the precision feel I want.

I'm not saying BMWPS is garbage. There are handling advantages to stiffer springs, people like them.

I would suggest considering buying an OE ZSP suspension used. In addition to springs and shocks, you'll need front sway bar and bump stops front and rear. Possibly different front shock mounts, if your car's old? I forget.

OE ZSP will lower your car by about 0.5" I think. BMWPS is reputed to lower 0" - 0.5" from ZSP, so up to 1" lower from non-sport. Personally I think that's too low, but many people think it looks pretty. OTOH, the performance kit is changed since I bought it, maybe they fixed some things...

[tibra1]

All of em IMO..the issue w doing a few is it will hi-light the weaknesses in the areas you dont do..and also when using these proper coilovers and LSD are a must

The complete M3 list:

Front Strut Brace
Front Wishbone w/Headlight Regulating Rod
Front Tension Rod
Front Sway Bar

Rear Guide Rod
Rear Upper Link
Rear Lower Camber Link w/Headlight Regulating Rod
Rear Sway Bar
Rear Subframe Bushings

Toe Control Arm..is the only rear piece that cant be used off the m3. Megan Racing and Velocity Motorcars makes one thats good.

Incidentially..I have just looked at the pricing and these m3 bit have skyrocketed since last year when I purchased.. which really sucks for new buyers..all around it is an expensive proposition..by the time you are done you will be in $7K territory

[hdrewh]

I've been looking at realoem.com for the parts you guys are mentioning and the terminology is different, and I'm a bit of a suspension novice so I don't know how to translate your terms to realoem to order parts. For example, the following terms are not found in the M3 suspension pages HERE or HERE:

tension link (is it the tension *strut*?)
sub frame isolator bushings
control arm

about RFT's - I will replace them when they wear out, whatever upgraded suspension I decide on will be there before the RFTs are gone.

I'm looking for basic handling improvements: tighter more precise steering, conservative drop, less brake dive. Car won't be tracked and I live in the NY/tri-state area so I *may* stick with 17" due to pothole concerns especially if I go with the performance suspension because I know its lower and tighter than ZSP.

I'm not particular about the technical subtleties of various suspension dynamics, I just want my car tighter, lower and more "flickable" while maintaing decent comfort.

Put another way, if I had to do it over again I'd get ZSP and not think twice. If I could find a very low-mileage full ZSP suspension for my exact car I'd go that route, but I haven't found it yet and I'm a little hesitant to piece together used suspension items out of concern for exact fitment and a less-than-satisfying end result

So maybe the OEM performance suspension is overkill for my modest requirements, but the piece of mind of brand new, BMW-warrantied parts and installation is worth something to me as well.

Thanks for the input.
Howard

[cvc 22349a]

Originally Posted by hdrewh

I've been looking at realoem.com for the parts you guys are mentioning and the terminology is different, and I'm a bit of a suspension novice so I don't know how to translate your terms to realoem to order parts. For example, the following terms are not found in the M3 suspension pages HERE or HERE:

tension link (is it the tension *strut*?)
sub frame isolator bushings
control arm

about RFT's - I will replace them when they wear out, whatever upgraded suspension I decide on will be there before the RFTs are gone.

I'm looking for basic handling improvements: tighter more precise steering, conservative drop, less brake dive. Car won't be tracked and I live in the NY/tri-state area so I *may* stick with 17" due to pothole concerns especially if I go with the performance suspension because I know its lower and tighter than ZSP.

I'm not particular about the technical subtleties of various suspension dynamics, I just want my car tighter, lower and more "flickable" while maintaing decent comfort.

Put another way, if I had to do it over again I'd get ZSP and not think twice. If I could find a very low-mileage full ZSP suspension for my exact car I'd go that route, but I haven't found it yet and I'm a little hesitant to piece together used suspension items out of concern for exact fitment and a less-than-satisfying end result

So maybe the OEM performance suspension is overkill for my modest requirements, but the piece of mind of brand new, BMW-warrantied parts and installation is worth something to me as well.

Thanks for the input.
Howard

You might want to do some reading in this supension forum.
The M3 front control arms and rear subframe bushings tighten up alot of the slop in this car BUT will be pretty harsh with rft's, so I'd wait to do those.
'Flickable and decent comfort' don't really go together.
Lot's of folks are happy with the reduced roll, dive and squat of the BMW perf susp, but imho the non-M3 BMW dampers suck.
Another option, which I like, is you can buy slightly used zsp spings for cheap and pair them with Koni sport dampers. I don't know what sway bars came on your car, but the rear arb install is expensive unless you do that in conjuction with the rear M3 subframe bushings, which is 4-6 hrs labor.
g/l

[woodga16]

tibra, I know I've already asked you...but please post what you sent me. The first m3 bits to buy for those with a budget that give the most positive feedback vs. cost. I believe you said front control arms and rear bushings? If you have LSD, then front AND rear sways. I'm not sure how affective just adding m3 front sway is alone w/o rear.

[tibra1]

Originally Posted by woodga16

tibra, I know I've already asked you...but please post what you sent me. The first m3 bits to buy for those with a budget that give the most positive feedback vs. cost. I believe you said front control arms and rear bushings? If you have LSD, then front AND rear sways. I'm not sure how affective just adding m3 front sway is alone w/o rear.

Yes..if your on a budget or just getting started your best bet is the front control arms..and subframe bushings..the thing is in order to do the subframe bushings you will drop the subframe..so it makes sense to do the rear sway and rear arms if the budget allows it..The rear sway is even more important than the front sway..the 335 rear sway is 13mm..the M3 is 20mm..both 335 and M3 front sways are 26.5mm..but keep in mind the sway bar bushings for the M3 are much stiffer than the 335 so u get that added benefit as well to size upgrade in the rear

Doin the rear subframe bushings also presumes you have coilovers already..the OEM suspension will not be able to handle the stiffer subframe bushings...

My order of priority would be:

Tires
Coilovers
M3 Front Arms / Sways
Rear Subframe Bushings
Rear Arms/ Sways
LSD

[cvc 22349a]

^ What parts of the oem suspension will not be able to handle the stiffer subframe bushings?

[luckyu]

Originally Posted by hdrewh

tension link (is it the tension *strut*?)
sub frame isolator bushings
control arm

I'm looking for basic handling improvements: tighter more precise steering, conservative drop, less brake dive. Car won't be tracked and I live in the NY/tri-state area so I *may* stick with 17" due to pothole concerns especially if I go with the performance suspension because I know its lower and tighter than ZSP.

Yes tension strut is right. The other two sound right too.

tighter more precise: springs, shocks, subframe bushings
conservative drop: springs obviously
less brake dive: shocks

I think the ZSP equipment will address your needs very well. I have only driven in a non-sport a short time (when shopping for the car), but it is very soft.

Be careful lowering the car below ZSP level. Look into "bump travel" or "compression travel" and make sure you have enough. These cars can be lowered, but it's tricky to do it well.

For example: coil bind. Let's say you lower the rear to 13.5". In the rear of our cars is an approx. 12" spring that operates at about 7-9" long compressed while driving. At 7" the spring is quite nonlinear and at 5.5" it coil binds. But the bump stop limits travel before coil bind occurs. (I am making up these numbers but they are within 0.5" of the truth.)

So, let's say you lower the car and find you lack travel, so you shorten the bump stops or use a short body shock in order to get more travel at the shock. Now you risk coil bind because you're allowing the spring to compress more than before. In the front, there's also the roof of the wheel well to worry about at some point, and the bad geometry of the struts. At a point in its compression arc the front wheel starts tucking inward. Meantime the bump stops are being partly triggered because of short travel space, throwing your car around and making your life miserable...

So, I'd be careful going below ZSP height.

[tibra1]

Originally Posted by cvc 22349a

^ What parts of the oem suspension will not be able to handle the stiffer subframe bushings?

The OEM springs/dampers..w such a low spring rate they will be working overtime to compensate for the stiffer subframe bushings..the biggest benefit hands down will be upgrading to coilovers..modding other points in the car w/o addressing this would be counter-intuitive

[luckyu]

Originally Posted by woodga16

tibra, I know I've already asked you...but please post what you sent me. The first m3 bits to buy for those with a budget that give the most positive feedback vs. cost. I believe you said front control arms and rear bushings? If you have LSD, then front AND rear sways. I'm not sure how affective just adding m3 front sway is alone w/o rear.

I'm not tibra but... tension struts. Tension struts are the answer to your question. They don't make a huge difference, but you can feel something, and they're cheaper. Subframe bushings cost $250 for parts and $500+ for labor. Their improvement is subtle unless you are working on eliminating problems in the rear with stiff springs.

The M3 front bar is a tiny bit stiffer than the ZSP front bar.

[tibra1]

Originally Posted by luckyu

I'm not tibra but... tension struts. Tension struts are the answer to your question. They don't make a huge difference, but you can feel something, and they're cheaper. Subframe bushings cost $250 for parts and $500+ for labor. Their improvement is subtle unless you are working on eliminating problems in the rear with stiff springs.

The M3 front bar is a tiny bit stiffer than the ZSP front bar.

The front M3 arms are sold as a kit..they include the tension rods, wishbones, and the headlight regulating rod..(without the proper headlight regulating rod you headlights will be pointing up in the air)..The wishbones will also add .75 degrees of negative camber on their own..If you are on a budget this is a good start..but you will have to eventually address the rear if you want max grip when putting down power.

The M3 bar maybe slightly stiffer than ZSP but I assure you the M3 sway bar bushings are MUCH stiffer.

[hdrewh]

Originally Posted by luckyu

Be careful lowering the car below ZSP level. Look into "bump travel" or "compression travel" and make sure you have enough. These cars can be lowered, but it's tricky to do it well.
So, I'd be careful going below ZSP height.

even more reason to go with BMW performance vs aftermarket. Specific to my car, should be designed well to address "compression travel", etc.

What specifically did you dislike so much for you to call it a '$1,000+ mistake'?

Thanks.

[hdrewh]

Originally Posted by tibra1

The front M3 arms are sold as a kit..they include the tension rods, wishbones, and the headlight regulating rod

They're listed as separate parts and prices an realoem.com. Where are they sold as a kit?

Thanks.

[luckyu]

Originally Posted by hdrewh

even more reason to go with BMW performance vs aftermarket. Specific to my car, should be designed well to address "compression travel", etc.

What specifically did you dislike so much for you to call it a '$1,000+ mistake'?

Thanks.

The shocks are weak, the springs are higher rate than I need, and my car is upset over majority of bumps.

[luckyu]

Originally Posted by tibra1

The OEM springs/dampers..w such a low spring rate they will be working overtime to compensate for the stiffer subframe bushings.. [...]

I think whoever told you that was pulling your leg, tibra

[luckyu]

Originally Posted by hdrewh

They're listed as separate parts and prices an realoem.com. Where are they sold as a kit?

Thanks.

hpautowerks.com