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BMW 3-Series (E90 E92) Forum
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XI on Road course
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01-18-2017, 09:44 AM | #24 |
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As I said earlier, I went with the M3 rear bar first and found I needed a front bar, got the UUC front by itself. I wish I'd gone UUC or other adjustable rear bar. M3 is not adjustable though it is a very nice piece. The install is so painful on rear bar you really want to get the right one and never do it again.
Last edited by ajsalida; 01-18-2017 at 11:33 AM.. |
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01-18-2017, 09:55 AM | #25 |
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01-18-2017, 10:14 AM | #26 | |
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As for coil overs, it is easier to get the rake and corner weighting right, which is very hard on this car. But I really don;t like cheap coil overs so if you can get it done with Konis and springs do it. Beyond that $3k or so on up for good coil overs is what you're looking at, to get significantly better than the Konis. It tunrs out JRZ is making "budget" coil overs now for XI pretty cool. $5k-ish all said and done with springs, camber plates etc. I also agree BBK on these cars is a waste of money, or I should say decent braking improvement can be had with just better pads and rotors. There are some brass sleeved caliper pins out now that others say really improves feel but I have not used these myself. ECS has some with rubber boots, Bimmerworld some without that need frequent lubing. There was an issue with ECS's but supposedly fixed. I do not have these but want to try. Cheap, like $100 range. With the K/E or K/ZSP shocks & springs definitely get a front bar, esp since they may be going away soon. Then later see if you want a rear bar. WIll go a long way to curbing roll and maybe you can soften up the shocks a little. Finally for bushings, the Strongflex poly tension strut set has worked very well on my car, big improvement and cheap (like $60). I've had them in going on 2 years now, no issues, no noise etc. They are a little hard to install: I needed a hydraulic press. Well worth it. They are in Poland but I got mine in a week after ordering. Get the yellow ones. There is a thread somewhere here on these. Subframe bushings (rear) if you can swing it or inserts if you want to go cheap. I went with inserts, again cheap and easy, or easier, to install, big improvement not as much as full bushings though (Whiteline). Another cheap mod is rear upper shock mounts. Monroe makes super cheap ones, much better than stock, or you can go poly. I went with Powerflex but only because Monroe were not out at the time. There is a thread on them in the susp section. Like under $20/each. Far too much soft rubber in these cars esp the rear. But short of M3 arms and full bushing replacement everywhere ($$$) it is not worth swapping it all out for a street and occasional track car. In fact I'd probably want an LSD long before I did all that, and too little compliance really ruins a street car. The rear bar is a bear to install, you have to drop the subframe. So if you intend to go that way stack up a bunch of other stuff to do same time. Hope this helps. Last edited by ajsalida; 01-18-2017 at 11:01 AM.. |
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01-18-2017, 10:25 AM | #27 | |
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That is incredibly helpful, thanks. My question I was referring you to was further down
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01-18-2017, 10:51 AM | #28 | |
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One way to find out, drive a more track-oriented car and see how fast you are. I feel like the K/E set up is a good one. Not a great one, a good one. In fact the TC Kline race coil-over kit for XI (and I) is based on these same exact Konis, and plenty of all-out race cars use Koni yellows in stock McP strut housings. My old SCCA ITB car did also. KW V2's are supposedly re-badged Konis, as are Dinans. As far as how good you are or not can't tell you. But a good driver can drive anything fast, even a dead stock car right off the show room floor, often much faster than all out prepped track car with an inexperienced driver. It's just he will be that much faster in a well set up track car. One thing to do for feel without much trouble or cost is mess with tire pressures. Can you feel 2 lbs difference? 1 lb? Identify a spot where it feels like either the front or rear is not behaving the way you want and raise or lower pressure on that axle, see if you can feel it and if it got better or worse. This all gets very subtle but subtle is where faster is at usually, after all the big stuff is taken care of. IMHO people get way too concerned with tech + hardware and not enough with the skill part. My track days are long behind me but I learned in a stock Miata. Got very fast with very little HP or fancy suspension stuff. That served me well, even though compared to a race car it was "sloppy". Best thing about sloppy is things happen slower. Progress up in stiffness HP etc. things happen much faster. You want your skill to progress faster than the reaction times needed to control the car, otherwise things can happen too fast. Which is one reason why, slapping a huge rear bar (only) on a high HP car and risking snap oversteer is not a good idea IMHO. I've seen 2 guys get killed on track right in front of me who got over their heads too fast. Not something you ever want to see. This is also why it is good to mod conservatively, one step at a time, and not try to get your all out track set up done in one fell swoop. Learn how each piece works and changes handling, master it, then change it or do something else, but don't step into a totally tricked out car based on internet guru advice day one unless you have the skills to do so already, and have had them a long time. The thing to do is to get good enough to recognize what your car should be doing, or what you want it to do better, and then identify a solution. Try it and see if it works. Like that science thing I keep hearing so much about. Bolting on a complete new track suspension for novice/intermediate driver, hard to sort out what did what and then what you need to do to fix it. Is it a bad set up or just the skills not yet developed to use it? Hard to tell. To that end just modest shock + spring upgrade is a great first step. Wring all you can out of it, every last tenth or hundredth of a sec, to the point of being almost bored, move to the next step. Finally, at highest skill levels, suspension set up isn't absolute. It is very subjective. I worked for a race suspension shop for a while (but on the military R&D side). That race side of the shop did shock rebuilds for top level SCCA, NASCAR, Indycar etc. What was weird was sometimes drivers for the same team, same car same everything, had wildly different suspension preferences. And they'd get shocks tuned to that, not something objective. These were top tier teams, not back markers. Last edited by ajsalida; 01-18-2017 at 11:49 AM.. |
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01-18-2017, 02:05 PM | #29 | |
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All I know is I'm not wanting any additional front bar on the e91 with my setup and I'm running an adjustable rear bar on the lowest setting. It's almost ideal. As you mention, were running different rate springs and that makes all the difference in the world (as does the amount of grip he has given tire size and spec). You're right about the amount of rubber in these cars, compared to my Pro3 car these things are ridiculous. The polish bushings are the direction I went, and I went with a mix of the red and yellows. I used the red in the subframes, shock mounts, etc. and yellow in most other places. If I were to do it again I may just go with the red throughout. It's not at all obnoxious or annoying on the street and it's still a bit tender on track with the compression and rebound dialed up for the beter grip and corner loading I have with the bigger slick rubber.
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Last edited by NiNeTyOne; 01-18-2017 at 02:13 PM.. |
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01-18-2017, 02:34 PM | #30 | |
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Have you heard of anybody using these through northeast winters and getting squeak issues? Sounds like a great upgrade, but I'm reluctant if they need to be removed and relubed after every winter. Any idea if they can be removed non-destructively for lubing purposes? |
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01-18-2017, 02:58 PM | #31 | ||
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Poly sway bar bushings will help a little but the UUC bar is very noticeably much stiffer. Bar torsional stiffness goes like diameter to the 4th power, so a little bit more is a lot of stiffness. again I want a neutral car, slight rear bias, with soft springs. If you like lots of oversteer and have the reflexes to catch it, knock yourself out. Your DSC will probably be on almost continuously. Quote:
http://www.strongflex.eu/en/45-e90-e91-e92-xi-4x4-05-11 As far as lubing, I haven't needed to. But it would be easy to do without removing the bushings from the arms, or removing the arms completely from the car. The part that pivots and needs lube is actually that metal sleeve inside the bushing. The big outer part of the bushing stays locked in the control arm and does not move, or rather it rotates around that metal sleeve if that makes sense. The sleeve pops out easily if you care to relube. You just remove the bolt, press the sleeve out by hand, lube, re-insert. I've inspected mine several times since install, they look good and no noise in harsh rocky mountain winters (40 ft of snow annual average at the local ski area, Wolf Creek). But, they do not use salt on roads here. Stronflex supplies a graphite-based super sticky lube with the bushings. The other front control arm on XI's, the smaller one, already has a monoball type spherical bushing OEM so you don't need to mess with it. Here's a thread on the bushing install should you want to look, with some discussion of those synchrodesign sphericals: http://www.e90post.com/forums/showthread.php?t=1108425 Last edited by ajsalida; 01-18-2017 at 03:48 PM.. |
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01-18-2017, 03:03 PM | #32 | |
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01-18-2017, 03:06 PM | #33 | |
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Last edited by ajsalida; 01-18-2017 at 03:18 PM.. |
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01-18-2017, 04:11 PM | #35 | |
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I used to use Powerflex on other cars, can't keep colors straight between them :/ As for the Ohlins, PSI can build them up for just about anything. They work with customers to dial in the valving on EVERY set that leaves the shop to the selected spring rate. Again, these guys really know their stuff. The shop is actually on site at Infineon/Sonoma/Sears Point or whatever it's called this week If you fall right into one of the Ohlins factory valving options they discount it an additional 10% which knocks another $200 off the price. Their kit comes complete with custom re-valved dampers, bump stops, Eibach ERS springs, mounting hardware, etc. Pretty much everything required to do the job correctly.
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01-18-2017, 04:35 PM | #37 | |
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Great coil overs are another realm entirely, JRZ Moton etc. 5k up to over 10k |
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01-18-2017, 04:39 PM | #38 | ||
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Oh, and what personal experience do you have with all of those coilovers on this platform? Do you have shock dynos you would like to show us? Spring frequency? What about wheel motion ratios? What about information on long term durability or how the valving holds up over time? Oh. You know names and parrot stupid shit your read on the internet. My bad. |
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01-18-2017, 08:30 PM | #39 | |
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01-18-2017, 08:57 PM | #40 | |
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01-18-2017, 09:12 PM | #41 | |
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01-19-2017, 06:10 AM | #42 | |
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For others who aren't being such giant dicks, if you want to slap a 1k set of cheap coil overs on your track car, be my guest. You won't be able to tune anything but ride height. My admittedly subjective criteria are they are at least single adjustable, rebuildable, name brand or race shop with good rep for quality (TCK), and low rate of reported failures here and elsewhere. And this is key...available for XI. I'm not sure anyone has shock dyno plots of these (and few know how to use them even if they were available), springs rates and damping curves are things you want to tune (see that adjustable part), and motion ratios are fixed by suspension geometry so play no role. Oh by the way I have run a shock dyno myself, quite a few times. When Bilstein first came out with sport shocks for E36 M3 I (personally) ran a set of comparison shock dyno curves for stock, sport and E30 M3 sport shocks, set up a website for it. This was circa 20 years ago. Guess what, nobody cared or even understood what it meant. That is probably still the case now, but I don't have access to a shock dyno anymore. The point is once you go coil overs for track purposes you're in (or should be in) the realm of user suspension tuning. By that I mean you are knowledgeable enough to want to start tweaking ride height, spring rates, damping curves and skillful enough to evaluate the difference. Also alignments (so camber plates would be nice), sway bars (so rear adjustable bar would be nice) etc. Ballpark price threshold I threw out there is one where you start to get most or all of that capability in a quality shock that doesn't start falling apart day 1. The base TCK Koni kit for XI for example is SA, comes with camber plates, your choice of springs, and a provision for custom shortened strut bodies that give you more travel in front, a key feature for XI's that need help with travel in front. These are based on the Koni Yellows. Most of these kits use true constant-diameter coil over springs (which you can swap out for tuning) and not goofy OEM type varying diameter progressive springs and OEM upper strut mounts, which only let you use the one fixed rate the manuf gives you (like the KW V1). KW V3 has most of this and double adjustable (3k or so), KW Clubsport has all of it (plus triple adjustable but over 5k) etc. Just be prepared to spend 3k on up to get that capability, not sure why anyone is getting pissed about that statement but then this is the internet. Like I said we're talking about real track-capable coil overs and IMHO you just don't get that for 1k. You start to get it all around 3k on up. It's just an opinion. Deal with it. Another opinion buried in here is CO aren't really appropriate unless you're getting to serious intermediate skills levels, and much more track focused car with all the compromises for street comfort that entails. Eg going to camber plates and CO's you're well along the road to removing compliance from the system, so the rest of the car to balance should have poly/spherical bushings etc. and that is going to be no fun to drive on the street. So hoping the 3k numbers scare some people off if they don't want to commit to all that, or feel they aren't really yet. As I said a basic K/E or K/ZSP package is a great place to start, and a 1k CO kit doesn't give you much over it. Except for ride height, which may be valuable for some but you lose SA feature at least on V1, H&R and similar. I actually DO recommend V1 type CO's for people having trouble getting ride height and rake right on street cars as it is so hard to do with the XI and conventional shocks springs. But I don't recommend these for track purposes as stated above. Hope this is clear. Last edited by ajsalida; 01-19-2017 at 06:53 AM.. |
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01-19-2017, 06:42 AM | #43 | |
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No objective measures tby which to define 'better' No first hand experience with said products No idea wtf you're talking about. |
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01-19-2017, 06:56 AM | #44 |
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Why are you being such an asshole about this? Provide the stuff you say I'm not or STFU. Jeez....some people. Probably has a financial interest in selling cheap coil overs to noobs.
Last edited by ajsalida; 01-19-2017 at 07:15 AM.. |
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