[nikitino25]

Laguna Seca Blue, your car does look fine with 19's. I'm thinking about getting some AST's but afraid if I have to lower my car much further, it will look goofy with my 18" stock 189's-not to mention having to worry more about scraping the lower front bumper (I have M-Sport front lip add on). Any body know how much stock 18" 189's weigh? Also, there is no problem with putting non run flat tires on these wheels is there? Also, where can I find the AST's on sale?

[CJ421]

Originally Posted by Laguna Seca Blue

CJ421 - I was looking at the Advan RS's before eventually deciding on the M3 Comps. Unfortunately, I couldn't justify spending $600 per wheel. They are very nice and definitely would have been my first choice if money wasn't a factor.

I want to spend around 2k on suspension upgrades right now. Basically, im looking at making it as drivable as possible in the short term, while spending money fine tuning it over the course of ownership. I plan to keep my 335i until the wheels fall off, so im in no rush. M3 bits sound fun!

Really, thank you all for kind input, I'm really appreciative of the steep learning curve I'm experiencing.

With $2k for suspension upgrades I'd go for upgraded shocks/springs too; I think you are on the right track. The M3 bits are more like icing on the cake.

These are some great intro articles to suspension philosophy:
http://www.motoiq.com/tech/the_ultim..._handling.aspx

This is a good BMW-specific article, it is focused on the M3 but a lot applies to the E9X non-M as well:
http://www.m3post.com/forums/showthread.php?t=339168

Originally Posted by nikitino25

Laguna Seca Blue, your car does look fine with 19's. I'm thinking about getting some AST's but afraid if I have to lower my car much further, it will look goofy with my 18" stock 189's-not to mention having to worry more about scraping the lower front bumper (I have M-Sport front lip add on). Any body know how much stock 18" 189's weigh? Also, there is no problem with putting non run flat tires on these wheels is there?

Quite the opposite - I think the car would look significantly better if lowered. Add wheels later to complete the look.
And yes you can run non-RFT tires no problem. Those RFTs are garbage. The stock 189s are pretty heavy, upper 20s I think.

[Laguna Seca Blue]

Sweet, thanks! The article on the M3 discussion board was great

[stressdoc]

I would call Terry at Vorschlag for the ASTs.

Couple of things about doing suspensions piecemeal:
(1) something will always be out of synch with the rest of the system, a weak link.
(2) labor costs -- with some installs, once you get into it, it saves a ton to get everything done at the same time. E.g., install LSD, rear sway, and M3 subframe bushings at same time, as you need to lower the subframe for all three jobs. Small savings to do M3 control arms etc. at same time with coilovers.

Your plan to go with coilovers like AST first is a good one. I would follow that up with M3 front control arms & tension rods. Then the rear end with LSD etc. ($$$). For me the LSD was the biggest positive change of all the mods I have done. But I love to power oversteer.

Originally Posted by Laguna Seca Blue

Thanks stressdoc, what you're saying makes a lot of sense. Do you recommend upgrading to the AST's first and then doing the LSD and M3 bushings, or do you think it's worth doing everything at once? I'd rather not spend money unnecessarily if the AST's will resolve the skittishness.

Yeah, I realize my tire/wheel setup is on the heavy side, but they have improved things tremendously over the stock 189's with run flats, so until I wear my tires bald, I'm not going to drop anymore money in that department.

Haha, I think I've already burnt the bridge with Harold@HPA. After repeatedly not answering my questions fully, I lost my temper and basically told him to go f*** himself. I think he deserved it, but now I need to find another vendor to sell me the AST's

Thanks again for the advice, very helpful, stressdoc. That's 2 out of 3 advising I go with the AST's, so all I need now is a place to buy them. Any suggestions?

[Laguna Seca Blue]

Originally Posted by stressdoc

I would call Terry at Vorschlag for the ASTs.

Couple of things about doing suspensions piecemeal:
(1) something will always be out of synch with the rest of the system, a weak link.
(2) labor costs -- with some installs, once you get into it, it saves a ton to get everything done at the same time. E.g., install LSD, rear sway, and M3 subframe bushings at same time, as you need to lower the subframe for all three jobs. Small savings to do M3 control arms etc. at same time with coilovers.

Your plan to go with coilovers like AST first is a good one. I would follow that up with M3 front control arms & tension rods. Then the rear end with LSD etc. ($$$). For me the LSD was the biggest positive change of all the mods I have done. But I love to power oversteer.

Stressdoc, thank you for your response. I just saw it unfortunately. Managed to get myself embroiled in a flame war over in the N54 section and forgot about this thread.

Anyway, you answered the last of my questions, and I'm very grateful!

[Laguna Seca Blue]

I drove in an e90 with PSS10's and I'm now leaning towards Coilovers again. However, this guys car made a weird creaking sound when cornering hard. Apparently it's a design flaw with the PSS10's but it doesn't effect the driving dynamics ...

I'll update this thread once I've made my decision. Thanks everyone again. The wealth of information you guys provide is great!

[Laguna Seca Blue]

Haha, Stressdoc just noticed the comment about loving to power oversteer! That too was one one of my favorite pastimes in my E46 M3 until my mechanic seriously fu*ked up my alignment and I sent my car hurtling into a guardrail. Not ideal.

[swifty]

For a few hundred dollars more you can get the Ohlins Road & Track as it is the most comfortable coilover out there for the road and amazing quality.

Pss10 at the max height has only a finger or more gap between tire and fender. Another member put up pics because I was facing the same dilemma. Just do a search.

[Laguna Seca Blue]

Thanks Swifty, I'll check them out too...

[Laguna Seca Blue]

OP Updated!

[nitehawk]

Nice. How did you decide on those spring rates?

[Laguna Seca Blue]

Originally Posted by nitehawk

Nice. How did you decide on those spring rates?

A combination of two things

1. BMWsky mentioned that his firmer setup was only really comfortable if the dampeners were set to the softest settings. I figured if I went slightly softer on the springs It would give me a little room to play around.

2. I was looking at the spring rates sticky Mr. 5 posted, and everything but the most hardcore coilovers had spring rates on the sifter side especially up front. I'm not ever going to track my car, so if I don't loose too much in steering sharpness, I'd rather not compromise ride comfort completely.

That being said, I am concerned I may have gone a little too soft. I do like to drive hard, so I'll update you guys once the AST's are on.

[AlterZgo]

When choosing spring rates, people sometimes forget that softer springs can sometimes results in worse ride quality. Why? Because softer springs causes the car to bottom out more. Once the spring/shock blows completely through it's travel (which happens even more frequently because most people w/ springs/shocks, coilovers, etc. have their cars lowered), it hits the bumpstops and your spring rate is basically infinity.

From my experience, high spring rates when paired with properly damped shocks, results in firm, yet comfortable suspension. The car will not be super pillowy soft, but when you hit mid and large size bumps, the suspension absorbs it so much better because it doesn't bottom out.

Just my 2 cents.

[Laguna Seca Blue]

Yikes, well, we'll just have to wait and see. I'm just waiting for my AE Exhaust to come in from Vishnu and then I'm gonna get everything installed together. I'll start a new thread with my impressions.

Thanks for your input, Alterzgo. One thing though, I'm not going to lower my car anymore than where it's at right now (stock sports package), so hopefully the bump stop issue doesn't cause too much of a problem.

[swifty]

Originally Posted by AlterZgo

When choosing spring rates, people sometimes forget that softer springs can sometimes results in worse ride quality. Why? Because softer springs causes the car to bottom out more. Once the spring/shock blows completely through it's travel (which happens even more frequently because most people w/ springs/shocks, coilovers, etc. have their cars lowered), it hits the bumpstops and your spring rate is basically infinity.

From my experience, high spring rates when paired with properly damped shocks, results in firm, yet comfortable suspension. The car will not be super pillowy soft, but when you hit mid and large size bumps, the suspension absorbs it so much better because it doesn't bottom out.

Just my 2 cents.

It all depends on what kind of dampers it's paired with and what other mods to suspension have been done. There is a reason why Ohlins offers 342b/in Front and 400lb/in Rear with their R&T kit. The reason for the soft rates in the rear is that the rear sub-frame bushings are very soft and deflect a bunch with higher rates. Some guys are upgrading the the Motorsport sub-frame bushings which allows the use of a higher rated spring in the rear, which the car definitely likes but if you are running stock bushings, stick with the lower rated springs.

If you look at other threads there are many guys who have gone with the higher spring rates and are having issues with it. Btw, my opinions are based on feedback I have received from other racing shops/ohlins main distributor.

[Laguna Seca Blue]

Originally Posted by swifty

It all depends on what kind of dampers it's paired with and what other mods to suspension have been done. There is a reason why Ohlins offers 343lb/in Front and 286lb/in Rear with their R&T kit. The reason for the soft rates in the rear is that the rear sub-frame bushings are very soft and deflect a bunch with higher rates. Some guys are upgrading the the Motorsport sub-frame bushings which allows the use of a higher rated spring in the rear, which the car definitely likes but if you are running stock bushings, stick with the lower rated springs.

If you look at other threads there are many guys who have gone with the higher spring rates and are having issues with it. Btw, my opinions are based on feedback I have received from other racing shops/ohlins main distributor.

This entire spring rates thing makes no sense to me. If you look at Mr. 5's list, BMW's own performance springs are 505lb/in rear. Surely they were aware of the soft rear sub frame bushings when they designed those springs, no?

Id certainly like to learn more, so if anyone else wants to weigh in as well, That would be awesome.

[swifty]

wow really, 505 in the Rears? I didn't know it was that high. From my research they were able to go lower so the Ohlins shocks can do all the work as it is capable of doing.

Nway, I too am interested in learning more about this before I get new coils. Just asked another member with JRZ RS1 suspension what his rates are but he has M3 bushings. I know JRZ recommends Ac Schnitzer sport springs but I can't seem to find the rates for those.

[nitehawk]

Originally Posted by swifty

Nway, I too am interested in learning more about this before I get new coils. Just asked another member with JRZ RS1 suspension what his rates are but he has M3 bushings. I know JRZ recommends Ac Schnitzer sport springs but I can't seem to find the rates for those.

I take it your TCKs leave much more to be desired?

[swifty]

Originally Posted by nitehawk

I take it your TCKs leave much more to be desired?

Lol ya, it depends on what I compare it to. When I rode in a car equipped with KW v1s, I was definitely happy I got the Tcklines. It's so much more comfortable etc but in respect to ohlins or JRZ, I don't there is any comparison from all the threads I've read and other guys running them on EVOs etc.

[swifty]

Originally Posted by Laguna Seca Blue

This entire spring rates thing makes no sense to me. If you look at Mr. 5's list, BMW's own performance springs are 505lb/in rear. Surely they were aware of the soft rear sub frame bushings when they designed those springs, no?

Id certainly like to learn more, so if anyone else wants to weigh in as well, That would be awesome.

Hey,
I made a mistake as the Ohlins pdf shows 400lb/in in the rear. I have corrected the original post. However this is still lower than 672-800lb/in various vendors are suggesting for the rear.