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05-26-2017, 04:26 PM | #1 |
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Improved but modest upgrades.
I do a few autocross events per year, and a couple of HPDE events.
I like what was in this thread: http://www.1addicts.com/forums/showthread.php?t=819476 I'll add I have 245 RE-071R on DForce 9" 41mm wheels. 5mm spacer because rubber was contacting strut under hard cornering. Square setup. It rubs. A little. Fender. Over hard bumps. I like that build because it's modest and looks like it would save a lot of drivability. I got a set of the Dinan Camber plates. (Swapped for a set of brake pads from my M3 which I couldn't use.) I like the idea of these because I can always go to a much better camber plate. We won't discuss the fact that under-steer is on the window sticker as a FIO. So they should give me at least SOME neg camber and help alleviate the rub. I'd like to do it stepped in this order. Thoughts and advice? Thanks! -Code out the nanny -Dinan front camber plates -Bilstein B12 suspension and M3 rear subframe bushings. -E93 M3 sway bars front and rear -Wavetrac 3.08 LSD Thanks, |
05-26-2017, 05:53 PM | #2 |
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1) get subscribed & follow your progress 2) compliment & endorse your "under-steer is on the window sticker as a FIO" comment Have you thought about using the M3 control arms as another method of addressing understeer?
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05-30-2017, 08:47 AM | #4 | |
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Better rubber already has, and every car I've owned getting better negative camber, lowering and suspension bits has as well. Not concerned so much about Autox as just improving over all handling for HPDE. Thanks! |
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05-30-2017, 09:41 AM | #5 |
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The camber plates definitely will help with understeer. Getting some camber under the car (ideally 3+ degrees) is critical, and while the Dinan plates won't provide that much, it's a step in the right direction.
However, I would also say that if this is actually going to be a tracked car or a somewhat serious attempt to improve the car, you should skip the Dinan plates and go to real camber plates. The extra adjustability and maximum camber attainable is worthwhile. Mark
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05-30-2017, 12:29 PM | #6 | |
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The other mods aren't going to help under-steer, specifically. Most people I've seen argue an lsd will promote under-steer a bit since rear traction will be improved. That is until you hit the limit of course where power over-steer will quickly take over when both rear wheels break traction at the same time. I am actually starting to think the e-diff plays a big role in promoting under-steer. Application of the rear brakes mid turn seems to cause the car to either run wider or shift weight causing the front tires to loose traction before the rear. Once my track pads are hot (PFC-08), the car feel like it bucks through a turn if I turn too sharply spinning the rear tires a bit. I can't wait to get a mechanical LSD, but I may code out the e-diff and run an open diff in the mean time. Plenty of fast autocross cars run open diffs. Mclaren founded the concept of usign the brakes to steer the car in F1, and from an interview I found stated: "You need a very progressive brake material that has a flat friction/temperature curve, so that it doesn’t grab. Some other teams used material with higher peak friction but more temperature sensitivity. A driver would have more trouble regulating the brake-steer on that material.” which seems to be exactly the type of problem that seems to be upsetting the cars balance mid-turn... a square tire setup, greater later g's than BMW programmed for, different brake bias, different pad material, it all effects e-diffs functionality along with how DSC is programed if you run with that on too (I don't). Last edited by bbnks2; 05-30-2017 at 12:37 PM.. |
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Luftmeister33.00 |
06-03-2017, 06:01 PM | #7 |
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I also went the... we'll say frugal... route of B12's and camber plates but I honestly wish I had just saved up bought the right stuff the 1st time. I autoXed and PDXed the b12's with over -3* camber but the car didn't start to rotate with that setup until I had a 20mm rear bar and subframe inserts to induce oversteer. I was also running an e93 M3 front bar that didn't help the cause.
The B12 kit was fun on the street but severely lacking on track. The dampers were great for what they are but the springs were just way to soft for what I was trying to do. If you are running SCCA be careful with the street touring rules in regards to camber plates and swapping the lower control arms. It is a one or the other thing. I am running the TCKline camber plates with offset delrin bushings in my lower control arms to get to -3.2*. I was able to get close to -3.5* on the b12's because you can shove the strut top under the hole in body. That doesn't work with top adjusters. If I had to do it all over again I would have started my build with a call to TC Kline... shortly followed by a call to diffsonline.
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