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11-12-2016, 09:26 AM | #1 |
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BC Coilovers not low enough in the front for e84... options?
Installed my BCs with upgraded Swift springs and what a disappointment... Don't get me wrong, the car rides great once I figured my front/rear dampening settings, but the front ride height is still 40mm higher than I want it to be. Truly disappointing since I've had BCs on two other cars too (mini cooper s & e36 m3).
Seems like someone else had this problem on an earlier BMW e28. When you adjust the fronts all the way down, they will eventually hit the bottom of the strut housing. I even re-adjusted to minimal preload in the front to try to drop it down 5mm lower. Granted my front tire is 1" shorter than stock (from 26" to 25"), I didn't think the 1/2" delta from top of the tire to fender would be that huge of a difference. I emailed Vivid Racing (our board Sponsor) and BC tech support. Hopefully they can send me a shorter body threaded damper for the front. BTW, please spare negative comments about lower ride height. I already have an x5 4.8is for the family... I happily drive my x1 like a car and was going for the wagon-look. |
11-15-2016, 12:53 AM | #4 |
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I Had that problem with BC they sat higher in front than rear. H&R and stock shocks sat lower. Saving up for KW. Had to return BC and took 1 month to get my refund....
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11-15-2016, 09:08 AM | #6 |
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Is the issue the threaded strut body bottoming out in the lower sleeve? Or that the spring perch collar hits the lower sleeve before your desired ride height is achieved?
If the latter, can you just take a hack saw to the lower sleeve (or otherwise have shortened), removing about an inch or so?
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) |
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11-15-2016, 10:49 AM | #7 | |||||
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After zero response from BC or Vivid Racing (forum sponsor), I had to do come up with my own solution. I basically went from this ---> --->
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Luckily I found a youtube video of someone who has already done it. I believe he explains it perfectly. |
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11-15-2016, 01:46 PM | #8 |
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By sleeve I meant the sleeve that goes around the bottom of the threaded damper. Not cutting through the damper itself. By trimming the sleeve, I figured you could thread the collar down the damper further.
But yeah, the obvious answer is shorter springs. Also, don't discount the fact that you're a full 1" smaller on overall wheel diameter. It will look a good bit lower using "correct" wheels. This is particularly relevant given the HUGE (and ugly) wheel wells of these cars. Even 18" factory-sized wheels/tires look way too small.
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) |
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11-15-2016, 09:18 PM | #9 | ||
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Shorter springs won't help. Quote:
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11-16-2016, 08:37 AM | #10 | |
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I think we're having a miscommunication here. If you can't get the collars low enough with springs of your current length because you've bottomed out the collar on the sleeve, shorter springs will absolutely allow you to lower the car more. Spring length (and rate) dictate your ride height.
Edit: I just watched your video on helper springs. In the video, that strut assembly has plenty of threading to go lower before the lower spring perch or collar hits the sleeve (the cup that threads on the strut from the bottom). The problem is, his springs are too short, and as such, when the car is in droop the spring will be unloaded, which is dangerous. The solution is to keep some preload on the spring with the helper. The other option is to simply use a longer spring in the first place, allowing you to lower the collar without the spring going slack. In distinction, you described a situation where the spring's lower collar was bottoming out on the sleeve, or at least I thought that's what you were saying. You said: Quote:
So...what problem are you having? 1. Can you not go lower because you've threaded the collar all the way down to the sleeve, or 2. As shown in the video, can you not go lower because you've threaded the collar to the point that you remove the preload from the spring? If 1, you need a shorter spring or a trimmed sleeve. If 2, you can use a helper, or just a longer primary spring.
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) Last edited by PrematureApex; 11-16-2016 at 09:03 AM.. |
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11-16-2016, 10:56 AM | #11 | |
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I really like how the rear sits, but need the front to come down another 10mmm. I drove the car yesterday to work and already got 2 thumbs up on the highway. [/URL] |
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11-16-2016, 11:03 AM | #12 |
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The design of that setup will not allow you to go any lower. You need a shorter strut housing and strut body if I'm looking at it correctly. A shorter spring will only preload the shock more and a longer spring or a helper will keep you at the same height. Also depending on your spring rate it could turn out into one bouncy ride.
On another note, I think that height looks spot on! |
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11-16-2016, 11:50 AM | #13 | |
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but you gettinOld!!! LOL. |
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11-16-2016, 11:52 AM | #14 | |
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Pick from these options: 1. You threaded to lower spring perch (the green one in the pic, no one cares about the lower red collar) all the way down until it hit the sleeve (or the red collar just above the sleeve), AND that position just happens to also be the minimum preload? If that is the case, use a shorter spring plus a helper. 2. Or does yours look like the pic you posted. AKA you threaded the spring perch down to the minimum preload, SO you can't thread it any lower (but there is in fact room to physically thread it lower...as there is in the pic)? If that is the case, try just a helper (if not a longer primary spring).
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) Last edited by PrematureApex; 11-16-2016 at 12:04 PM.. |
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11-16-2016, 11:55 AM | #15 |
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There's nothing necessarily wrong with "preloading" the strut more, sans a decrease in stroke.
If your lower perch is at max travel downward, and you still can't achieve your desired drop, one option is always to use a shorter spring (perhaps at a bit higher rate). For the same lower perch location, a shorter spring means a lower ride height. If the shorter spring gives him a spring preload issue (aka no preload), than you use a helper with the shorter spring. ? No it won't. You add the helper so you can lower the perch further down without the spring going slack, thus lowering the ride height. If you added the helper, and left the perch alone, the ride height would marginally increase, by an amount reflecting the slightly increased combined spring rate, as well as the compressed height of the helper. The helper is simply to keep some preload on the spring when the car is in full droop. Technically speaking, he could thread the collar 10mm further downward, and be careful never to get airborn when he drives around, and the spring would remain preloaded at all times under the weight of the car. Where do you people come up with this stuff?
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) Last edited by PrematureApex; 11-16-2016 at 01:02 PM.. |
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11-16-2016, 12:26 PM | #16 | |
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No. Sorry PrematureApex... I know you know your stuff, so let's chalk this up to my ESL days in High School... haha. For simplicity sake, perch 1 and 2 set preload. These perches have nothing to do with height adjustment. According to BC, preload should be hand tighten and then add 4mm of compression so the spring stays in place. Perch 3 is what is used to set/lock the height. Raise perch 3 to lower the car. Lower perch 3 to raise the car. In my case, the threaded damper is spun all the way down till it hits contact with the strut housing. Perch 3 at this point only locks it into place. This video explains it way better. |
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11-16-2016, 12:52 PM | #17 |
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Ahhh, that is where the miscommunication is. That's my fault, not yours.
I was talking about adjusting them like all other coilovers I've owned RCE/KW/GC/etc., that adjust ride height only via the lower spring perch (your "preload" perch). Didn't realize you were referring to the lower sleeve position for ride-height dictation. Hence, you mentioned cutting the strut housing to shorten it, and I was confused. Makes sense now. I'm an idiot. With that being said, I don't see any good reason why you couldn't simply use the top perch(s), your "preload" perches, to adjust ride height, as done on many, many coilovers. A helper and lowering the perload perch farther would get you there, with the helper allowing you to change ride height without significantly preloading the main spring and losing any stroke. Which is what the design of your coilovers are meant to acheive. Set the height max low on the bottom, and do whatever other height adjustments you need with the upper spring perch. http://www.superstreetonline.com/how...oilover-works/ Go to the preload section. You'd essentially be adjusting your coilovers like you would slip-fit types, or other types that don't have separate adjustments. Not a big deal for the street, at all, imho...particularly if you use a helper.
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'02 S54 M3 (500/500 GC/Koni)
'08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat) Last edited by PrematureApex; 11-16-2016 at 01:09 PM.. |
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11-16-2016, 01:07 PM | #18 | |
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