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09-29-2014, 04:19 PM | #1 |
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135i understeer--
Whats the best solution to keep the 135i from understeering--H&R Springs and strut brace are the only suspension mods at this point -- thanks G
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Ganicki 2008 135i • 2011 328xi |
09-29-2014, 04:26 PM | #2 |
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I put on a strut brace.
Also 4 x 12mm spacers on front and back. This helped a bit, and gives the 135i a bit more firm grip and stance.
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09-29-2014, 05:04 PM | #4 |
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fat sticky tires and big negative camber is the biggest change you can make. everything else helps, but the swaybar taxes your tires even more heavily.
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09-29-2014, 09:31 PM | #6 |
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Fat tires and better suspension geometry. I have 255 square, and it's not nearly enough. If this car could run 18x10 square with some 285s like the 350/370Z guys, it would be much better off.
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09-30-2014, 03:55 PM | #7 | |
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Rear subframe bushings are #1, but I am guessing that you don't really want to hear that. |
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09-30-2014, 03:58 PM | #8 |
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09-30-2014, 05:14 PM | #9 |
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Rear subframe bushing will do absolutely 0 to help understeer, especially at the limit.
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09-30-2014, 08:15 PM | #10 | |
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Not quite sure why I took the OP's bait, given that his first (or second) mod was a strut brace (aka useless). Faint hope he might appreciate actual information I guess. And DietTab, sticky tires give you grip, but they don't give you balance. Negative camber saves your tires when cornering hard (and uses them up, when not) but doesn't change the balance all that much. Sorry to say, but the best mod is the least glamourous one. |
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10-01-2014, 12:53 AM | #11 | |
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You are sorely mistaken. compliance steer? Way to make up imaginary things that don't exist. FWIW i have bushings on my car. They don't do a thing for understeer.
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10-01-2014, 06:02 AM | #12 |
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The rear subframe bushing mod is needed anyway. I found that adding M3 SFB upgrade by itself had a net effect of promoting understeer, but its a lot better than the nervousness and unpredictable effect of the stock subframe bushings. I'd go so far to recommend you don't use too much front camber with stock subframe bushings, as its not a nice feeling at the limit. Frankly, the stock rear subframe bushings are a total disaster and really don't belong on a BMW. The 1 series has a short wheelbase, so you will get pretty decent turn-in just by adding some front camber.
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10-01-2014, 10:37 AM | #14 |
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Here is a list in order of what you'll need.
Rear Subframe Bushings Camber Wider Wheels/Tires Caster Alignment for Toe Adjustments Front Swaybar Rear Swaybar and honestly the list goes on. There is a 100 ways to skin a cat, helping reduce understeer can be done multiple ways with multiple methods. Do for what works best with you and your budget. |
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10-01-2014, 10:53 AM | #15 | ||
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10-01-2014, 12:42 PM | #18 | |
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Other than that, this forum is loaded with folks that swear this car has horrible suspension and understeer and is virtually undriveable at the limit and yada yada yada and you need to spend thousands of dollars to make it road worthy. And not one of them could come within 10 seconds of Randy Probst time in a bone stock '09 135i with run flat tires at Laguna Seca (1:46), which tells you all you need to know about what the most important modification is. At the end of the day, if you really think you need to fix understeer, you can do two things: increase front grip, or decrease rear grip. Make sure that for any modification you do, you understand how those two components will change as a result, because a lot of people on here will give you bad advice that might help mask bad driving habits but will actually decrease your overall grip, making you slower and a worse driver.
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10-01-2014, 01:50 PM | #19 |
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OK first things first--Kgolf--what would be the first thing to do to help me out--then 2nd, 3rd, etc-- knowing that I can't do everything at once--Thanks
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Ganicki 2008 135i • 2011 328xi |
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10-01-2014, 02:28 PM | #20 |
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Im assuming that you will be lapping/autocrossing your car ...
Most meaningful and cost effective solution for me was to first do Front M3 Control Arms and Camber plates for about $1000 in parts and 2.5 hours of labor. Second was to go with a square 255/35R18 Extreme Performance tire setup.
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10-01-2014, 03:31 PM | #21 | |
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1) brake in a straight line 2) release the brake as you turn in 3) turn in smoothly 4) maintain a balanced throttle to the apex 5) don't add throttle until you start unwinding the steering 6) add throttle smoothly 7) if you are overcome by the urge to spend money on your car, modify your car per Kgolf's list, starting at the top pausing to check the results whenever you run out of money Sorry to have taken your bait. I knew you really didn't want to hear the answer. |
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10-01-2014, 03:49 PM | #22 |
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[QUOTE=fe1rx;16717894]Clearly we need to step back even further:
1) brake in a straight line 2) release the brake as you turn in 3) turn in smoothly 4) maintain a balanced throttle to the apex 5) don't add throttle until you start unwinding the steering 6) add throttle smoothly 7) if you are overcome by the urge to spend money on your car, modify your car per Kgolf's list, starting at the top pausing to check the results whenever you run out of money Sorry to have taken your bait. I knew you really didn't want to hear the answer.[/QUOTE No. That's exactly what I wanted to hear. Just like golf. Get the basics down good and strong practice practice practice. Then when I feel that equipment will help the cause, I can try some things. Thanks |
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