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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Tracking, Autocrossing, Dragstrip, Driving Techniques > Rear sway only



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      08-13-2007, 03:16 PM   #1
leftcoastman
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Rear sway only

I figured it'd be more appropriate to post this in the tracking forum rather than the suspension forum.

Many of the magazine reviews state that the 335i is great in the corners and has a very neutral feel to it. Well, after a few track days in the E92, I simply do not agree. I think it pushes like a biotch.

To cure that, I'm considering adding a rear swaybar (H&R). Will that, in your guys' opinion, be a good or a bad idea? Will it make the car twitchier at the limit? As much as it pushes now, it is so damn predictable and controllable at the limit and I don't want a high-drama Lotus Elise'esque vehicle.

What are the disadvantages of beefin' up the rear sway on a 335i?
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      08-13-2007, 03:28 PM   #2
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Welcome to my world:

"I think it pushes like a biotch"

If I didnt do the suspension..I would have done just the rear sway...adjustable version would have been preferred. Now that I went non-staggered...I dont need a rear sway.
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      08-13-2007, 05:02 PM   #3
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Quote:
Originally Posted by S4to335 View Post
Welcome to my world:

"I think it pushes like a biotch"

If I didnt do the suspension..I would have done just the rear sway...adjustable version would have been preferred. Now that I went non-staggered...I dont need a rear sway.

So no disadvantages? It won't get all twitchy on me?
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      08-13-2007, 05:16 PM   #4
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If you keep the stagger...you should be ok..but try to get an adjustible one...so you can play with the settings.
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      08-13-2007, 07:00 PM   #5
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Rear sway is definitely advisable. The great thing about a rear sway is that you can dial out the stock understeer for a more neutral stance. You will also get better turn in under high speed cornering (think off ramps ). If you just want to make the suspension a bit more crisp and make the car more neutral overall, it's definitely an affordable way to go.
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      08-13-2007, 07:40 PM   #6
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I agree with the "Pushes like a Biotch" (tm) crowd. It does. I'm not sure what cars the magazines were driving, but it wasn't a stock 335.

I did suspension, front and rear sways and a corner balance all at the same time, so I can't comment on doing the rear sway only, but it definitely needs something. I'm also road coursing, not autocrossing. I've also gone up in tire size, but kept the stock level of stagger. Corner balance makes a huge difference imo.

I got the UUC sways because they are adjustable and have been pleased thus far. Orb felt differently about the set he ordered. Might want to read his review before purchasing.
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      08-13-2007, 08:17 PM   #7
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Yup pushes like a bitch. Nothing worse than taking a moderate speed sweeper and you can feel the front tires feathering/pushing while at the same time the ass end rolls over and get lose as hell. Not much you can do but drift or come out a wide which typically gives me white knuckles when there a cement barrier in the way. I did install H&R front and rear sway bars as my first upgrade. It made a huge difference and the car is very close to being perfectly balanced with a hint of under steer. I wished i did this alot sooner.

As for UUC bar there is nothing wrong with them. Just did want to deal with poor executing on there part although minor. One being the Delrin sleeves are not a good solution for wet environments and will not last and need re lubing yearly. Two, the rear sway bar should have come with adjustable links as you can’t set it mid way without preloading the bar which is complete BS and not acceptable.

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Originally Posted by Hegemony View Post
I agree with the "Pushes like a Biotch" (tm) crowd. It does. I'm not sure what cars the magazines were driving, but it wasn't a stock 335.

I did suspension, front and rear sways and a corner balance all at the same time, so I can't comment on doing the rear sway only, but it definitely needs something. I'm also road coursing, not autocrossing. I've also gone up in tire size, but kept the stock level of stagger. Corner balance makes a huge difference imo.

I got the UUC sways because they are adjustable and have been pleased thus far. Orb felt differently about the set he ordered. Might want to read his review before purchasing.
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      08-13-2007, 08:33 PM   #8
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I have the H&R rear sway. A night and day difference. IMO the car now behaves more neutral. I wish it was adjustable, to give you a little more options in tuning the suspension. In any case, I think the 20mm is probably the perfect size for the car
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      08-13-2007, 11:27 PM   #9
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I think lack of negative camber adjustment also plays a major roll in the E9x chassis handling dynamics.
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      08-13-2007, 11:47 PM   #10
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Quote:
Originally Posted by sg335 View Post
I think lack of negative camber adjustment also plays a major roll in the E9x chassis handling dynamics.
I believe there are a lot of factors in play, neg camber being one of them. I've been able to dial out some of the understeer through obscene use of differential tire pressure. That, of course, introduces other effects that I do not like.

Plenty of cars without neg camber are able to be neutral or tail-happy. I'm hoping to get closer to neutral through a rear sway. Hopefully I don't end up swappin' ends on my next track day.
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      08-14-2007, 12:01 AM   #11
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Agreed. But as you know, only to a certain extent. Too much pressure or too little can change a car's handling dynamics drastically. But I am with you on your concept and it is the only one available to those who dont' run camber plates.

What front/rear pressures have you found to be best in dialing out the understeer? At my next event, I am going to try 34 front and 30 rear cold pressures as one of many targeted pressures to see where the balance neutralizes. My car may behave much differently than yours because I will have -3.5 degrees camber in the front and -2.0 in the rear. I run .02 toe in front each side, and .09 toe in the rear each side. I also have 12 compression settings and 2.5 turns of rebound on my shocks to totally confuse me by the end of the day!
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