Hey everyone, back in June I totaled my 2008 335i. Thankfully everything worked out for the best and I got a sapphire black on black 2010 135i with 30k miles for a great deal! First thing I did was the stage 1 MHD tune. I'm planning on getting an FMIC and meowless pipes and going stage 2 and calling it quits as far as power mods go. However, before I do all that I need to fix the handling on this car. The car just does not feel as planted or stable as the 335i did. Now I know this in part due to the shorter wheel base, but that does not explain the rather floaty nature of the car or lack of high speed stability. The car is currently completely stock as far as the suspension is concerned and I'm still on the oem runflats. I have done some research and it seems that people say the best mods for handling are better tires, E93 M3 front sway bar, M3 subframe bushings, M3/1M front control arms, and coilovers. My issue is not grip or traction so I dont think I'm in need of new tires at the moment, especially since the oem ones I have on right now are pretty much brand new. I will eventually get better tires, but not until these ones are done for. I'm a bit skeptical about coilovers because I'm not looking to slam my car, I'm looking to improve the performance but it seems everyone talks about coilovers in terms of aesthetics and not performance. I'm not opposed to coilovers if they will make a noticable improvement to the handling of the car, but I do not want to spend over a thousand dollars just for a ride height drop. So will coilovers help with performance or not? As far as the M3 subframe bushings go, I'm ashamed to admit that I do not know what subframe bushings are, what they do, or how M3 bushings will improve handling. Can any of you shed some light on this? I'm just trying to make the car feel more planted and less rolly or floaty. Any advice on where I should begin to achieve this goal? Thank you.
I have a 135i so I know exactly what you're talking about! First off, tires definitely make a big difference; so when the time comes invest in some good ones and you'll immediately see a difference - a lot of people stay away from run flats for this reason; handling isn't great and they feel "bulky". Coil-overs are also a massive improvement; look at ST Suspension for those - great quality, as they're basically KW V1s and pricing is on point as well. As far as bushings; without getting overly tech; the M3 ones are a lot stiffer; so less play in them = better feel/handling. It seems like you're all about handling, which is where my interests are; so those M bushings, control arms, end links are a great start. Let us know if you have any other questions and best of luck!
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As much as I would like to get an LSD, Front Sway Bar, Bushings, and control arms, I'm not well off enough (yet!) to really do all that, especially since all those would cost around 5k dollars to do, plus another 2k for DPs and FMIC. I'm really looking for just that one suspension mod that will make the biggest difference for the price. So which would you personally recommend I do?
What tires are you currently running? This matters a great deal more than you seem to think.
Coilovers are a waste for your application. BMW designed suspensions are generally excellent for their designed task. Now, your car is not an M car. It is not stiff like an M car and does not have the damping characteristics of an M car. It will therefore not handle corners or racetracks with quite the same aplomb or panache. However, all BMWs are made to be excellent autobahn cruisers with above-average handling characteristics. Aftermarket dampers will not improve your ride or the stability at speed - the car is already designed for that.
Further, cheap coilovers are universally garbage quality compared to an OE part, and are tuned by people generally FAR less qualified than BMW's suspension engineers. You wind up with a suspension that rides harder and has less ultimate grip due to loss in compliance, but because most people associate a stiff ride with "race car, yo" and they just replaced completely shot dampers, they think their car's performance has increased. Note that this does not hold past about the $3k mark, where kits start becoming far more specialized to their platform, better designed, and better tuned - mostly for racetrack use. For a DD, BMW designed suspensions are excellent.
There is a lot of rubber in a suspension. On non-M cars, there is more air-filled or hydraulic-filled rubber in the suspension. This gives extra compliance, and gives a softer, floater feel to the car. This seems to be what you're wanting to get rid of. The subframe bushings on the 135i have a lot of air in them, which can lead to the rear end of the car feeling vague and disconnected, especially under hard driving. The M bushings will solve this, with a slight increase in NVH. Not so bad as the Polyurethane bushings everyone seems to go nuts over (I hate them - noisy, low life, junk). Likewise, the M control arms and other parts will have stiffer joints (non-rubber surrounded ball joints, solid rubber bushings, etc) that will increase the rigidity of the steering without giving up too much comfort. The anti-roll bars should decrease cornering lean without too much increase in ride stiffness, but beware - they could do funky things to the handling (the over/understeer characteristic), since the spring/dampers are not tuned for them.
The first thing I would do in your shoes is tires. Plain and simple. They are your only connection to the road. If you want a summer tire, the Michelin Pilot Super Sport. If you need an all season, the A/S3+. If you value deep-snow capability either run winter tires (in the winter only...) or do some research into A/S tires which are better in the snow - but know that you'll give up dry weather and handling prowess in the pursuit of snow capability.
This is anecdotal, but so is everything on a forum - my 190E came with some awful "ultra high performance" all-season Hankooks. I ran those tires for 3 years. I thought that the piss-poor handling was just a quirky characteristic of the car. It was floaty, it was vague, and i just couldn't feel the limit of the tires. When I replaced the wheels, I put a nice set of bridgestone RE760's on it. Holy hell did the car change - most of the problems disappeared and the car is supremely fun to chuck around now, even if it does have the body roll of an old Merc.
If that does not satisfy your demands for increased dynamic stiffness, I would start going in and doing bushings and M suspension parts.
Last edited by lithium726; 08-09-2017 at 05:47 PM.
stick with suspension stuff before hp stuff
i suggest the following
e9x m3 subframe bushings
e9x m3 control arms up front
e9x m3 rear control arms, toe links
e9x m3 front and rear sway bars
bilstein b12 suspension kit (bilstein and eibach springs)
dinan camber plates
obviously switch to a nicer tire and lighter wheel set
it's easy to go fast in a straight line, going fast around a corner requires seat time.
Last edited by PSangavaramM3; 08-09-2017 at 11:04 AM.
"Now I know this in part due to the shorter wheel base, but that does not explain the rather floaty nature of the car or lack of high speed stability." [/QUOTE]
Have you considered new/better shocks? I admit to being new to BMWs, but in other cars, when the ride gets "floaty," we get new shocks...
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