[abhishriv]

Hi everyone, I've had my 335i for 4 years now and over that time i've managed to do quite a few upgrades to it. More recently though i've been getting into taking my car for lapping days or going up to the twisty roads for a nice drive, and i feel like im lacking somethign in my front suspension, i want quicker and more precise response from steering, especially when on S turns. what can i do to improve the responsiveness and direct steering feel?

Below is a list of my current suspension/drivetrain mods:
- kw v2 coilovers
- dinan camber plates
- M3 front control arms
- M3 rear control arms
- M3 rear sway bar
- Powerflex Black subframe bushings
- Wavetrac LSD
- Michelin PSS 245/275

[justpete]

M3 control arms. Adding these or their equivalent is even better - http://store.bimmerworld.com/bimmerw...kit-p1860.aspx

[edit] You might want to start with adjustable camber plates (Vorshlag, Ground Control, etc.) before changing the control arms [/edit]

[abhishriv]

already have control arms and camber plates.

Originally Posted by justpete

M3 control arms. Adding these or their equivalent is even better - http://store.bimmerworld.com/bimmerw...kit-p1860.aspx

[edit] You might want to start with adjustable camber plates (Vorshlag, Ground Control, etc.) before changing the control arms [/edit]

[justpete]

The Dinan camber plates, iirc, don't provide a solid spherical ball joint for the top of the strut to eliminate compliance play with the body. This can cause soft steering as can the lack of a spherical joint in the lower control arm. It's a big difference over just M3 control arms, ime anyway.

[justpete]

Originally Posted by abhishriv

More recently though i've been getting into taking my car for lapping days or going up to the twisty roads for a nice drive, and i feel like im lacking somethign in my front suspension, i want quicker and more precise response from steering, especially when on S turns. what can i do to improve the responsiveness and direct steering feel?

How is the front alignment set up? Running any toe out for quicker turn-in? What's the camber set at in front? How do you have the rebound set in front? And do you have adjustable ARB end links so the preload can be set to zero when static? How much wedge/dewedge do you see when transitioning in an ess?

[neoduffer]

+1 on alignment. This can have a dramatic effect on the dynamic behavior. As justpete mentioned, minimal toe in or toe out will make the steering more responsive. Caution with too little toe in or actual toe out, the front end will wander or dart around, instead of tracking straight.

[abhishriv]

Originally Posted by justpete

How is the front alignment set up? Running any toe out for quicker turn-in? What's the camber set at in front? How do you have the rebound set in front? And do you have adjustable ARB end links so the preload can be set to zero when static? How much wedge/dewedge do you see when transitioning in an ess?

ill have to dig up my alignment sheet from a couple months back but my camber in front is -2.4 and i am running dampening setting of 10/14 up front. i forget what the other figures are for the front though.

i the rear i have camber at -2.1, and dampeing set at 8/14... again im forgetting the other figures but i do have slight toe in at the back.

what toe settings should i be looking at for something that will be ok for daily driving also?

[justpete]

Originally Posted by abhishriv

ill have to dig up my alignment sheet from a couple months back but my camber in front is -2.4 and i am running dampening setting of 10/14 up front. i forget what the other figures are for the front though.

i the rear i have camber at -2.1, and dampeing set at 8/14... again im forgetting the other figures but i do have slight toe in at the back.

what toe settings should i be looking at for something that will be ok for daily driving also?

Maybe a sixteenth toe out in front, rear should still have toe in though. Depending on tire pressure it might be a problem on the street if you're not used to it being darty. Have you used a tire crayon across the tread and onto the sidewall a bit to see if the tires are rolling over in turns or if the full tread width is or isn't being fully utilized?

[The HACK]

Toe-out.

[abhishriv]

thanks everyone

[abhishriv]

so jsut an update. i took my car to the track this past weekend and it was a blast! def. hooked on the track days! it was a rainy and wet day but it was a good day to learn the dynamics of my car and its limits. my instructor let me do a couple laps with traction on and then with DTC and eventually turned eevrything off. he said it was the only way to really learn the limits of the car without the nanny being there to keep me out of trouble. i realized the rear end of my car is super snappy and jsut wants to slide out.. which was a bit hard to control in really wet track and traction completely off.

I ended up spinning-out a couple times by the slightest tap of the accelerator coming out of turn. By the end of the track day, however, i think i had it undercontrol.

One of my friends in the bmw group here mentioned i should look into a front sway to help balance and counter the oversteer that im experiencing since i have stiffed up the rear end so much. But i've been reading the opposite on these forums regardign front sway.

should i look into the front sway option to help tighten up the front end and counter some of the oversteer? im thinking maybe more track days in the dry are needed first.

[justpete]

With a "soft" front bar the car can easily be prone to oversteer with an M3 rear ARB. Better if the front bar is stiff and the rear not. FWIW

[ashmostro]

Agreed. This behavior will be particularly pronounced in the wet, even with an LSD.

[AWDBooSTIn90]

I wohld get an e92 or even an e93 m3 front sway bar. And you might want to go with a slightly softer rear sway bar. I think a non-M e93 rear sway bar is slightly smaller than what you have now, but slightly thicker than stock.

The new m3 front sway bar will make a nice difference in front steering feel and crispness. Im actually surprised you dont alrdy have an m3 front bar.

[ashmostro]

Originally Posted by AWDBooSTIn90

I wohld get an e92 or even an e93 m3 front sway bar. And you might want to go with a slightly softer rear sway bar. I think a non-M e93 rear sway bar is slightly smaller than what you have now, but slightly thinker than stock.

This. Totally agree.

[StealYourFace]

+1 on the e93 M3 front bar in the front, the e90 M3 bar is the dame diam as the regular sport pack bar. For the rear either e93 335i bar (15mm vs 13) or e90 M3 rear bar at the largest. I'm using the later but my car doesn't have the power of the 335i. I've never spun on track, but late trail braking from a higher speed straight can induce some oversteer if I'm not careful.

[ashmostro]

I can attest if you ever have plans to track your car in the rain, even with an LSD, a bar thinner than the e90 M3 on the rear is more appropriate. On the street in all conditions it's fine, but at 9/10ths in low traction conditions you can lose the rear pretty easily with such a stiff bar.

[justpete]

Originally Posted by ashmostro

I can attest if you ever have plans to track your car in the rain, even with an LSD, a bar thinner than the e90 M3 on the rear is more appropriate. On the street in all conditions it's fine, but at 9/10ths in low traction conditions you can lose the rear pretty easily with such a stiff bar.

Ever try disconnecting the rear bar in the wet at the track? Thinking about disconnecting it permanently.

[ashmostro]

Originally Posted by justpete

Ever try disconnecting the rear bar in the wet at the track? Thinking about disconnecting it permanently.

No, I never got around to that bc I was just fed up with the traction "events" in inclement weather, including snow. My car is a year-round daily even in blizzards!

The Hotchkis rear sway with the e93 up front feels perfect now. The LSD can really work.

I think if I had a clutch type LSD I probably wouldn't have had as much of an issue with the e90 sway.

[justpete]

Originally Posted by ashmostro

No, I never got around to that bc I was just fed up with the traction "events" in inclement weather, including snow. My car is a year-round daily even in blizzards!

The Hotchkis rear sway with the e93 up front feels perfect now. The LSD can really work.

I think if I had a clutch type LSD I probably wouldn't have had as much of an issue with the e90 sway.

A daily through the blizzards, there's some fun right there. Or not. Have driven in whiteouts in central Illinois, absolutely zero fun.

Interesting observation about the LSD type and its interaction with the ARB. I've had a couple of instances of wheel spin on the track during weight transfer over the top of a chicane while turning that leads me to believe the stock rear ARB is too stiff to allow all the traction the car's capable of. How that'd work on the street though isn't really clear. Luckily no blizzards here although most drive like there is if the sky clouds up...

[ashmostro]

Yeah the last time I was out at the track and going pretty quick it was raining on and off the whole day and what I found really revealing was how I could only use maybe 20% of the throttle I would normally use while the steering was turned *at all*... forget feathering this was like a baby's breath! And then what drove it home for me was when unwinding onto a the front straight and again going pretty quick, I had unwound the wheel to maybe fifteen degrees off center and started to get on it and I got into a six or seven-cycle tankslapper that was over before it began. I think the thicker rear bar on this platform stores too much energy for the shocks (even my JRZ RS1's) to handle.

PS, I still got into Group Two that day!

[justpete]

Originally Posted by ashmostro

Yeah the last time I was out at the track and going pretty quick it was raining on and off the whole day and what I found really revealing was how I could only use maybe 20% of the throttle I would normally use while the steering was turned *at all*... forget feathering this was like a baby's breath! And then what drove it home for me was when unwinding onto a the front straight and again going pretty quick, I had unwound the wheel to maybe fifteen degrees off center and started to get on it and I got into a six or seven-cycle tankslapper that was over before it began. I think the thicker rear bar on this platform stores too much energy for the shocks (even my JRZ RS1's) to handle.

PS, I still got into Group Two that day!

Yeah, oversteer is something I really want to avoid no matter what. Not really into that much excitement at speed any more.

Too much torque will really get your attention when traction starts to get optional that's for sure. I think it's the stiffness of the bar causing the inside wheel to get light enough to allow the outside wheel to break it free regardless of the LSD since one wheel's essentially off the ground and torque's gonna get steered to the wheel just waiting to break the other one loose. Definitely something to be avoided at all costs I guess. I don't think you can set rebound on the JRZs or the HVTs to avoid this possible condition which is why I'm thinking of just pulling the bar if removing the end links works ok.

Made it into group two with all the car control testing? Nice! Musta been successful then.