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04-25-2014, 05:29 PM | #23 |
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That was the first setup I tried but it felt like the track view was too small and the rear view mirror was a major obstruction (the RSX has a smaller mirror). Thinking there's gotta be something in between that won't also interfere with my helmet. Outside the car like Kgolf might be the way to go, but you lose the view of the apex on right handers...
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04-25-2014, 05:40 PM | #24 | ||
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A dual duty car needs as a minimum to have single adjustable digressive shocks so that firm springs feel acceptable daily but can be tightened up at the track. Try any high-end sports car with adjustable suspension modes. The spring rate is constant but the difference comes from adjusting the damping. We can achieve the same thing manually with a single adjustable shock. A shock that provides reduced damping at high shaft speeds (i.e. digressive damping) is key to smoothing out the fine sharp texture of daily roads. The OE shocks don't do this, hence expansion joints and speed bumps feel harsh. Adjustable shocks on springs that are too soft encourage you to overdamp to get the controlled body feel you want but then they feel harsh because the transmissibility increases with increased damping. That can make you think your springs are too firm. My suggestion would be to live with your tire wear for now - manage it by flipping your tires and by being a bit less aggressive (damn hard to do when you are chasing a Cayman or an M3!) until you can get an adjustable coilover suspension. Shocks with sport springs are an expensive half-measure that you will outgrow quickly if you track your car extensively. By the way OP, good call on developing your car incrementally and not being in any hurry to lower it. |
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04-25-2014, 05:49 PM | #25 | |||||
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Unfortunately, there is no good way to mount a camera, you're going to compromise somewhere. BTW - I feel sorry for your car and its weight. I'm at 3053 lbs with 1/4 tank. Quote:
For reference, I'm at #400 fronts (which are relatively soft in the game of springs) with TCK DA Shocks at -3* camber and still getting outside wear. I'm actually going to -3.5* on the car. BMWs chew through front tires, you will never eliminate this. Quote:
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I typically run an external mic to the exhaust, but I didn't have batteries this weekend. Quote:
BTW, with #400 fronts, #700 rears...the car is just a bit stiffer than M Sport. |
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04-27-2014, 08:06 AM | #26 |
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F15 X5 xDrive35i [9.17] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.53] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [8.93] |
If you're really plowing as much as you say you are I think you should save up for a 17x8.5" 245 or 255 square fitment. That's sorta surprising though because I recently met a member here running 235/255 and everything else stock and his entry into corners looked good. You only saw the effects of the stock suspension during quick transitions where the car didn't look settled. How's your entry speed on these corners relative to others? If you're going in that much hotter maybe try slowing down a tad so you're not overloading the scrub angle. You have any videos?
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04-28-2014, 09:32 PM | #27 | |
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It rained all day on the 1st day, which helped work on the race line, and smoothness of inputs to the car. My RE-11's were beyond the wear bar in the front (no tread left on out half of the tire), and at the wear bar in the rear. It made it more challenging to control the car and DSC kicked in often. I was humbled by letting every participant pass me that day. The car was hydroplaning and needed more traction, but it was neutral. At these lower speeds, and with lack of traction, understeering was not as much noticeable, but oversteer was. I had a chance to discuss about my issue with different instructors that sat in the car, and mentioned I was running -3.2* camber in the front. He mentioned that with that much camber, and little traction in the wet, I was effectively reducing the front tire contact patch, and that I should try reducing my camber, or lowering my front+rear tire pressure to 30 PSI hot. I lowered the pressure, did not change the camber, but did not notice a big improvement. The next day, was an eye opener. Conditions were much better and the track got dry. This was my first track event on asphalt pavement with this car, and RE-11 tires. I had been lapping at a local cement track (ICAR Mirabel). I did not adjust my tire pressure from the previous day, and was getting serious grip, and no understeer, with slight oversteer under power, to rotate the car - just the way I like it. I started getting more traction and bite than I ever had, built up my confidence level, and passed a lot of cars that day. What a great feeling that was. The damn tires stuck like glue on the dry ... What the heck was that about. Could the asphalt track be the solution to my understeer or was it lower tire pressure? I dont see the pressing need for suspension mods anymore. Im still perplexed by the massive gain of traction and control of the car. I am still trying to determine whether the asphalt pavement made that much difference, or the lowered tire pressure did. I monitored the tires and brake pads after every session. The RE-11 fronts are not corded yet, but outside half of tire now looks like full race slick ... (no tread left). Im going to be hitting the cement pavement track again soon, and compare how the tires handles relative to asphalt pavement, and monitoring tire pressure closely. I expect less traction and RE-11 tires might not be as good on cement surface (airport track). To be continued ...
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Last edited by dcaron9999; 04-29-2014 at 05:28 PM.. |
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04-28-2014, 10:18 PM | #28 |
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Great follow up dcaron. Thanks for posting that. I have found pressures to be a minor, but impactful adjustment. My last time at Sonoma in November, even the RFTs were really good (as good as they can be) in one of the warmer sessions around mid-day, but then the next session the shadows started to come out and it was like driving on ice.
My general rule of thumb is to start a couple PSI below the door jam numbers when it's cold in the morning, then continue to drop a little more as it warms up, and start adding it back in if it starts getting cool again late in the day. I have a temperature probe to help add some data to make the right adjustment, but you have to be diligent about coming directly to the pits as fast as possible to get reasonably reliable readings. Last edited by 02rsxpilot; 04-29-2014 at 01:33 PM.. |
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04-29-2014, 07:14 AM | #29 | |
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No tread is good in the dry, bad in the wet. Assuming the rubber hasn't aged out, your best dry grip will be once the tread has worn down. But to get some more life out of your tires, flip them on the rims so you can wear out the other side at your next track day. Cords appear very quickly once you get to the slick state, and they will end your track day as soon as they appear, unless you have another set of tires on hand. Tires with a broad traction peak and progressive break away characteristics invite over driving them, which is very hard on the rubber. It might be worth paying more attention to tire noise and also the point at which more steering does not result in more cornering force. If you can drive at or just below the cornering force peak, as opposed to beyond it, you will find big gains in tire life. I have always enjoyed track days that start wet and end dry (as opposed to the opposite). When grip builds over the event, it always seems to leave me particularly satisfied with the event. |
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04-30-2014, 03:55 AM | #30 | |||
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Of course, any new tyres you choose to fit will continue to degrade in this uneven manner - until the vehicle setup is corrected (assuming the same driving technique and same circuits attended). Quote:
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For track-prepped vehicles, setup is everything! |
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04-30-2014, 08:36 AM | #31 |
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Excellent feedback timbo_3101!
Street wheel/tire setup for wet days, dedicated track wheel/tire for dry days. I see your point about choosing between a tire budget or suspension budget ...
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04-30-2014, 08:41 AM | #32 | |
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IMO, I'm running -3.6* up front with TCK DA Suspension and I'm still going to get outside wear. BMWs need around -4* + to see even wear up front, our cars do not like front tires. IMO, get a tire with a hard sidewall (Like Dunlop Z2s) to compensate for the lack of camber and reduce outside wear |
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04-30-2014, 08:45 AM | #33 | ||
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Mother nature could not have planned it better for us on these two days. First day held us back, and made us focus on finesse.
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04-30-2014, 08:47 AM | #34 | |
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Second year actually..
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04-30-2014, 08:48 AM | #35 | ||
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04-30-2014, 08:50 AM | #36 | |
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Unless you're doing Time Trials, or being competitive, there is no need for more tires. Z2s should be a bit stiffer than RE11s. IMO, the RE11s are garbage, they cannot handle heat like Hankook, Dunlop of BFG. They grease over too easily and their grip threshold sucks |
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04-30-2014, 08:59 AM | #37 | |
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I wonder if this is related more to autocross/motorkhana, which can produce greater lateral loads than circuit racing. On pyrometry, my E82 at -3.3o front camber produces minimal temperature gradient across inside and outside tyres on a fast, flowing circuit and on power circuit (light cornering). If anything, there may be marginally higher temperatures of the inside shoulder - suggesting camber need not be as high as 3.0o unless a driver is capable of exploiting an aggressive setup. |
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04-30-2014, 11:31 AM | #38 | ||
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Btw someone else made a good point, if you're dealing with uneven wear consider flipping them if the conditions are dry as directionality makes little difference then. Me personally, I'm too lazy to flip because I know it'll only give me another 1-2 weekends even after setting my alignment. I'll only do it if it's the last event of the year and I need to get through the weekend but something you should consider... Quote:
Last edited by 3002 tii; 04-30-2014 at 11:37 AM.. |
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04-30-2014, 01:56 PM | #39 | |
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PS - I'd be hesitant on the V2s. Haven't heard really much on them yet besides they get to temp a bit quicker. Nothing on wet performance. The Z2s blow the old V1s out of the water. No comparison. |
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04-30-2014, 02:24 PM | #40 | |
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I saw a review where the ZII is supposely harsh on the streets (to be expected with a stiffer sidewall), and noisy due to their tread pattern (hum above 20MPH). Have you experienced this? Have you tried these tires at high speeds both on cement and asphalt pavement? Im convinced I will stick with extreme performance tires for now, and stick with my stock 261 RIMS (225/40R18 and 255/35R18 max tire sizes) due to limited budget. I obviously dont have enough experience for R-comp yet. My top two choices are: Dunlop Direzza ZII's, and Yokohama AD08R. Nick from Tirerack suggest that I choose one of these two for better sidewall stiffness. He thinks the ZII may be more appropriate for operating temperature range, and various surfaces (cement or asphalt). Thanks.
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04-30-2014, 03:01 PM | #41 | |
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The tires when new are indeed loud, and will hum. I ran them in fairly low temperatures (read like 35F) to get the mold release off and it sounded like a 4x4 with oversized tires. Since a couple autocrosses driving to a restaurant or something during the event and having the tires on...the noise has gone down considerably. But the hum is still there. Other than that, I transport my tires to and front events. Highest speed saw was highway driving. It will change though when I get on the track |
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05-03-2014, 06:35 AM | #42 |
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I tried a quick experiment with my rear 255/35R18 RE-11 tires on stock style 261 18x8.5 ET52 RIMS, by installing them in the front (with a 10mm hubcentric spacer), and switched my 225/40R18 RE-11 on stock style 261 18x7.5 ET49 RIMS in the rear. Although my test drive was on the street, I was impressed with tighter turn-in, and noticeable better grip in the front. I threw the car in hard sharp turns and esses to load the suspension and listened for rubbing and got none.
I may buy a used set of style 261's and set my 135i up with a square set of 255/35R18 Extreme Perf tires for dual duty. With the added rubber in front, I may stick with RE-11 tires too, as they are relatively quiet, even if they sport a traction rating of "A" versus the optimal "AA" traction rating (better grip on pavement and cement). I would love to try the Dunlop ZII's but read many complaints of road noise (dont want to deal with 4x4 mud tire noise on the highway). I have no budget for two dedicated sets of RIMS/Tires this year. Do any of you guys run hubcentric spacers on your cars which see track time? Is it safe to do so, and can it damage wheel bearings or other components?
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Last edited by dcaron9999; 05-03-2014 at 06:45 AM.. |
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05-03-2014, 09:10 PM | #43 | |
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ZIIs are noisy. They seem to get noisier with use, but then you put a new set on and they are noisy from the get go. You should listen to a set though because "noisy" is very subjective. Personally, I can live with them, but depending on my passenger on the street, I sometimes find myself apologizing for the noise. For what you propose hubcentric spacers will not cause any problem because you are not widening the track (which is measured between wheel center lines). If you significantly widen the track you do introduce more overhung moment on the wheel bearings, but in the 135i you can't do this without running into the fenders. Really you are just proposing to use the spacers to fix what is the wrong wheel offset for the location. Tracking your car is hard on the front wheel bearings. When they start to go they make quite a racket too (long before you can feel any play develop). I am on my second set of front wheel bearings. I changed them at about 80,000 km. Well done with the practical experiment with materials at hand. |
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05-04-2014, 02:20 PM | #44 |
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I have no rolled or pulled fenders on my 2011 135i. Just M3 control arms and camber plates set for max negative camber (-3.2*).
I just did a quick test drive with sharp sudden lef-right turns at moderate speed, and heard no rubbing. I will now do some static tests (put a block of wood under one of the front tires, and let the weight of the car load the suspension on that corner, while I take a few measurements. Will also try full lock-to-lock steering turns to verify clearance. Will try to snap pictures with my cell phone and post here ...
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2011 X3 35i with M pack + 2011 135i w/6SPMT | 255 square tire setup | Quaife 3.46 LSD | Diff lock down bracket | Bilstein B8+Swift SpecR springs+H&R FSB | CDV delete | BMS Oil Tstat bypass | ER FMIC & CP | N54Tuning DP | GC Street Camber Plates | M3 FCA +guide rods+RSFB's+Tranny mounts | Manzo toe arms | Cobb Stg2 agressive tune | Hawk DTC70 brake pads | RB SS brake pistons | Goodridge SS brake lines | Custom brake cooling ducts
Last edited by dcaron9999; 01-10-2015 at 03:54 PM.. |
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