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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > how to kill this under-steer



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      05-27-2013, 05:03 PM   #23
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Originally Posted by longliven54 View Post
koni yellows all around
zsp springs from e92 mt(i believe mt e92 have the shortest springs)
dinan camber
m3 front control arms
sp lowering perches
cusco strut bar
megan racing toe
no LSD
245's upfront/255 rears to minimize stagger(pirelli rosso)

^^^ That's a problem....try doing LSD first.

Yellows should be matched to what springs you use....

Eibach Sport springs [linear] do good things up front.

Don't neglect the effect your rear suspension has on steering! That LSD works a wonder, as do M3 subframe bushings.

Delrin's a big thing, maybe bigger than any weight of alloy, M3 arms.
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      05-27-2013, 05:50 PM   #24
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Wow. Just freakin' wow. The level of intelligence wrt chassis dynamics on this forum continue to shock and surprise me. And not in a good way.

OP, if you can answer me this. When and where is your chassis understeering, at corner entry, mid corner, or at corner exit, and if you can tell me which of your extremities induced the understeer, your hands, your right foot, your left foot, or your middle leg, then there's a slight chance I might be able to suggest changes that will resolve your issues.

ANYONE here telling you any sort of modification could solve your chassis's problem has zero idea what they are talking about. I've driven in anger at least a dozen E9x chassis and many more BMW chassis, and while I'mmgoing to tell you they ALL understeer, how they go about doing that are all slightly different based on the stage of tune and frankly, not because the way you all here think they do.

Don't know why, maybe it's the twin turdbo on the 335i, but this particular generation BMW seems to attract the least intelligent "enthusiasts" amongst us. Almost like the Civics and Integras did in the 90's. :sad:
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      05-27-2013, 06:02 PM   #25
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Hahahaha. Anyone who says that a modification won't possibly solve a understeer issue has no idea what they're talking about either and comes across as an obnoxious smartarse. It obviously takes both ability and the chassis to back it up, but to suggest that one is worthless without the other is silly.
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      05-27-2013, 06:24 PM   #26
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I would suggest to change the way you drive/learn the chassis first before paying for any type of modicfications Of course, any type of modicfication can go either way, and depending on the driver and experience, it might or might not help the car corner better at all. When I learned to drive on the track i always went bone stock and took the time to learn the chassis and behaviour of the car first. How a car naturally behaves and what techniques/driving input will have the most effect on the car. Whether you're talking about entry, mid corner, or corner exiting, every car behaves differently and learning it takes time as well as trail and error.

I think the E9x chassis is wonderful, yes it is prone to understeer greatly, but the number one thing to fix in any car is always the driver first. Cheers!!
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      05-27-2013, 07:57 PM   #27
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Quote:
Originally Posted by The HACK View Post
Wow. Just freakin' wow. The level of intelligence wrt chassis dynamics on this forum continue to shock and surprise me. And not in a good way.

OP, if you can answer me this. When and where is your chassis understeering, at corner entry, mid corner, or at corner exit, and if you can tell me which of your extremities induced the understeer, your hands, your right foot, your left foot, or your middle leg, then there's a slight chance I might be able to suggest changes that will resolve your issues.

ANYONE here telling you any sort of modification could solve your chassis's problem has zero idea what they are talking about. I've driven in anger at least a dozen E9x chassis and many more BMW chassis, and while I'mmgoing to tell you they ALL understeer, how they go about doing that are all slightly different based on the stage of tune and frankly, not because the way you all here think they do.

Don't know why, maybe it's the twin turdbo on the 335i, but this particular generation BMW seems to attract the least intelligent "enthusiasts" amongst us. Almost like the Civics and Integras did in the 90's. :sad:
I was wondering when you were gonna post . OP, this guy may be blunt, but his advice is spot on.

Anyway, OP, have you ever given any though that maybe your driving style might be a contributing factor. Yes there're plenty of mods out there but if there's something you can change about your driving that might be worth looking into. The best mod you can make is to the driver.
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      05-27-2013, 08:02 PM   #28
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OP, what is your definition of understeer?
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      05-27-2013, 08:22 PM   #29
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OP, what is your definition of understeer?

Yeah, OP's probably feeling the weight of the car as understeer. But anyone who says handling, and steering response, can't be improved from stock is, well, enjoying a diff reality.

Yo! I'll challenge anyone to show that a LSD does not greatly contribute to handling performance....and that it is not hugely superior to the stock e-diff.
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      05-27-2013, 09:11 PM   #30
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Yeah, OP's probably feeling the weight of the car as understeer. But anyone who says handling, and steering response, can't be improved from stock is, well, enjoying a diff reality.

Yo! I'll challenge anyone to show that a LSD does not greatly contribute to handling performance....and that it is not hugely superior to the stock e-diff.
i think weight/body roll has a lot to do with what i feel. corner entry is fine with plenty of front end response. by mid corner body roll kicks in and i cant seem to have similar grip. i am pushing into the door by the end of the turn. i know it is not happening, but surely feels as if car is riding on inner 2 wheels and outer wheels are in air. this is best i can do to describe.
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      05-27-2013, 09:36 PM   #31
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Needs Driver Mod.

The majority of the car's weight shouldn't be on the front wheels anymore by the time you're turning.

+1 to stiffer front sway bar though. and get an LSD if you want to have fun in turns. (yes, you can feel the difference)

To the guy saying OP has hardcore mods....you must be stock.
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      05-27-2013, 09:41 PM   #32
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i know this is not a race car, nor are any of my modifications done to make this car a track rat special.
my aim is to have a car where i am the limiting factor in going any faster confidently. currently its the car that cant give me enough confidence thru mid corner and corner exit to continue pushing it. snap oversteer is not fun with an open diff.

its not a race or competition that i seek to participate in. its the safe planted feeling that i am after. feeling that i am in full control and can alter the direction if need be.

never thought about installing LSD or m3 subframe bushings. issue seems to be more related to body roll. if anyone thinks lsd or subframe bushings can help with that, please correct me.

for now, i am planning on installing e93 rear sway+ rear cam
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      05-27-2013, 09:48 PM   #33
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as far as driver mod is concerned, yes i do agree that professional training would surely help. if this was the only reason, then why can i go thru corners better n faster in a different car.
my car is non-sport from factory and reading the specs on sports package, it came with beefier sways front n rear. this could very well be the extra reason of slopiness that i feel
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      05-27-2013, 09:55 PM   #34
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i just scored front n rear sways from an e93 from a local member who just upgraded to eibachs. i am going to give it a try and if it helps, i will upgrade to an aftermarket sway set. thanks for all the inputs and suggestions. this forum has always been very helpful
cheers
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      05-27-2013, 10:59 PM   #35
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Stop wasting your money on stock parts, the amount you spend to get them installed would be the same amount if you spent it on some quality parts.

Get some H&R Sways or at least go for some off of a M3.
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      05-27-2013, 11:04 PM   #36
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Stop wasting your money on stock parts, the amount you spend to get them installed would be the same amount if you spent it on some quality parts.

Get some H&R Sways or at least go for some off of a M3.
its a DIY project for me, and e93 sways came free. atleast its beefier than what i have and wont require LSD for now. if it provides any improvement, i will surely upgrade. dont want to spend money unless i know for sure that its beneficial at all to my driving style n need
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      05-27-2013, 11:38 PM   #37
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its a DIY project for me, and e93 sways came free. atleast its beefier than what i have and wont require LSD for now. if it provides any improvement, i will surely upgrade. dont want to spend money unless i know for sure that its beneficial at all to my driving style n need
Good luck on installing the rear sway bar.
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      05-28-2013, 12:00 AM   #38
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Good luck on installing the rear sway bar.
i know its not going to be fun.
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      05-28-2013, 12:56 AM   #39
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i know its not going to be fun.

Rear sway looks intimidating but is very easy. Just drop the subframe 3-4" and you've all the room you'd every want to R&R that bad boy.

If you need some direction, I gotta thread, but it's meant as assistance rather than step-by-step instruction. Is there a detailed drop subframe recipe? Haven't seen any, maybe 'cause not hard to figure out.
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      05-28-2013, 01:01 AM   #40
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And while you have the subframe dropped, why not install M3 subframe bushings? A few hundred bucks for many thousands o'miles improved driving.

Recommend HP Autowerks' bushing rental R&R tool - makes life soooooo easy.
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      05-28-2013, 08:53 AM   #41
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Quote:
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as far as driver mod is concerned, yes i do agree that professional training would surely help. if this was the only reason, then why can i go thru corners better n faster in a different car.
my car is non-sport from factory and reading the specs on sports package, it came with beefier sways front n rear. this could very well be the extra reason of slopiness that i feel
You answered your own question - they're different cars. Why can a Ferrari 360 Challenge take a corner faster than a Chevy Suburban?

Do listen to what others have said about 'driver mod'. The car is not at fault here; you're just asking too much of it. The car will understeer/oversteer only when the driver makes it do so.

A weekend worth of instruction with BMW Club or PCA is in your best interest:
http://www.bmwclub.ca/
http://pcaucr.org/
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      05-28-2013, 08:59 AM   #42
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OP,

I don't track my car much either, but I wanted to car to handle the way my image of BMW said it should handle. So I did what is shown at the bottom of this post. Pricey. It certainly did what you want to do, and more. As someone else said, balance is the key. And to piggyback what someone else said, now the car is further beyond my capability to exploit fully. But it now feels the way I thought it should feel from the beginning.
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      05-28-2013, 09:20 AM   #43
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A weekend worth of instruction with BMW Club or PCA is in your best interest:
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This.
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      05-28-2013, 09:41 AM   #44
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Wow. Just freakin' wow. The level of intelligence wrt chassis dynamics on this forum continue to shock and surprise me. And not in a good way.

OP, if you can answer me this. When and where is your chassis understeering, at corner entry, mid corner, or at corner exit, and if you can tell me which of your extremities induced the understeer, your hands, your right foot, your left foot, or your middle leg, then there's a slight chance I might be able to suggest changes that will resolve your issues.

ANYONE here telling you any sort of modification could solve your chassis's problem has zero idea what they are talking about. I've driven in anger at least a dozen E9x chassis and many more BMW chassis, and while I'mmgoing to tell you they ALL understeer, how they go about doing that are all slightly different based on the stage of tune and frankly, not because the way you all here think they do.

Don't know why, maybe it's the twin turdbo on the 335i, but this particular generation BMW seems to attract the least intelligent "enthusiasts" amongst us. Almost like the Civics and Integras did in the 90's. :sad:
A bit harsh, but yes, a lot of recommended mods that really should be a lot farther down the list of parts. Honestly, tires. The less you care about ride comfort/treadwear, the more you can prioritize handling. Tires will net you better turn in, more mid corner stability, more traction for exits, greatly improve braking--just about every aspect of handling can be improved with a set of dedicated summer tires with the sacrifice of tire comfort.

Slap on a set of r's and you'll think you're driving an m3 for the first few minutes..
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