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Old 09-21-2010, 04:34 PM   #1
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Default FCM bilstein ride height question

gear: FCM revalve bilstein setup w/ 450 6" Eibach fronts and 300 7" QA1 rears
ride height: 12 3/4 front and back
weld seam ride height (w/ driver in car):
lr 5 1/16"
rf 5 1/16"
lr 5 1/16"
rr 5"

i'm curious about what ride height's ppl are at. i'm struggling with ride height on mine. i'm 12 3/4 on front and 12 3/4 rear if car is setup flat rake. if i go any lower i'm on the bump stops.

responses i got in another thread:

Quote:
Originally Posted by FatKao
That's strange. Same one, Bilsteins with collars. I'm 12.25f 12.50r hub to fender. What rate springs are you on? Have you sent a note to
Shaikh? He helped me out with some alignment specs when I first
ordered.
450f/300r which is quite a bit softer than yours.

Quote:
Originally Posted by webby459
On the stops at static ride height, or when in compression? If at static, your stops
are way too long. I'm at 12.25/12.5 like the OP, but I'm on
550/350s. They are too light for autocross, I was on the stops badly
in back. I did different tophats, which has kept me off the stops and
more stable.
on the stops static. my static gaps (measured from top of shock to bump stop)
rf 1/2" gap
lr 1" gap
rr 1/4" gap
lr 3/4" gap

i'm right rear limited. i'm also camber limited to -2.3* because of right rear. i must have something bent somewhere.

Last edited by jasonb; 09-22-2010 at 05:51 PM. Reason: updated weld seam heights
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Old 09-22-2010, 05:39 AM   #2
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I am waiting for my FCM re-valved Bilsteins to be shipped to me.

In the mean time, I am using the OTS Bilsteins HD with the FCM mounts, 36mm bump stops and FCM perches running 400/300. My ride height is 12.75"F and 13.25"R and I have quite a fair bit of shock travel before engaging the bump stops (not measured but definitely more than 1").
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Old 09-22-2010, 09:36 AM   #3
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Try this thread for more info:
https://www.miataturbo.net/showthrea...ht=ride+height

Also, how tall are your bump stops?
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Old 09-22-2010, 10:01 AM   #4
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Old 09-22-2010, 04:49 PM   #5
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I have/had a non revalved FCM setup on my 95 and also had issues at height.

I originally had 400/300 7" springs all front/back and it seemed no matter what ride height below 13" I was either feeling too much sway, or jarring impact of the bumpstops.

I recently installed installed 7" 550 springs up front and isc tophats in the rear. I was also forced to lower my car more because of the isc hats(coil bind), and I'm now a hair above 12" all around while not feeling impact... just a progressive stiffening(which was a bitch with the 7" 550 up front).

I think that the added travel in the rear really softened things up and even though I thought the front travel was a problem too, it seems the rear was the jarring issue.

Also, I am using 46mm stops that are trimmed down a bit.(maybe 1/4 - 1/3 chopped off)

The car feels much more predictable now although I would like to raise it a 1/4" to have a little more clearance. I will need to use a spacer on top of the rear isc hat between the hat and car, or buy a longer rear spring.
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Old 09-22-2010, 05:04 PM   #6
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lol @ door handle scratching bumb-stop riders...I'll go fast on my 700lb springs with confidence.
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Old 09-22-2010, 05:31 PM   #7
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Quote:
Originally Posted by hustler View Post
lol @ door handle scratching bumb-stop riders...I'll go fast on my 700lb springs with confidence.
god damn ain't that the truth. the car sucks and i'm going broke (> $600 to kraus so far for cw and align).

you and me both need to find a friend with scales. badly.


@brain/curly thanks for the links. i'm going to run the numbers in brains link and see for my weight (1315 front/ 1148 rear) and see how much movement i'm seeing. i'll take a measurement on my bump stops, don't have the # handy.

@chapman, thanks for the datapoints. what were your static gaps when all said and done? i'm surprised to hear you had trouble with coil bind. was it coil <-> coil or coil <-> isc hat?

i'd appreciate any input why i shouldn't throw the whole mess and start over with a proper length damper. do koni 8611's come in the right length for us?

Last edited by jasonb; 09-22-2010 at 05:47 PM.
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Old 09-22-2010, 05:59 PM   #8
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Quote:
Originally Posted by owm View Post
I am waiting for my FCM re-valved Bilsteins to be shipped to me.

In the mean time, I am using the OTS Bilsteins HD with the FCM mounts, 36mm bump stops and FCM perches running 400/300. My ride height is 12.75"F and 13.25"R and I have quite a fair bit of shock travel before engaging the bump stops (not measured but definitely more than 1").
there isn't a huge difference, maybe 1/2", but it appears teh whole right side of my car is a little fucked.
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Old 09-22-2010, 05:59 PM   #9
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Quote:
Originally Posted by hustler View Post
lol @ door handle scratching bumb-stop riders...I'll go fast on my 700lb springs with confidence.
I've been surprised at how comfy my new 670/350 setup is even on our terrible MS road surfaces. It's not plush by any means, but it's controlled and not jittery or harsh.
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Old 09-22-2010, 06:17 PM   #10
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Quote:
Originally Posted by jasonb View Post
god damn ain't that the truth. the car sucks and i'm going broke (> $600 to kraus so far for cw and align).

you and me both need to find a friend with scales. badly.
I don't, I'm pretty happy with the tire temps and wear, its damn good.
Quote:
Originally Posted by mgeoffriau View Post
I've been surprised at how comfy my new 670/350 setup is even on our terrible MS road surfaces. It's not plush by any means, but it's controlled and not jittery or harsh.
I'm on 700/400 and could easily take another 100lb on each side.


It looks like the theory of soft springs and bump stops are falling short in the results department.
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Old 09-22-2010, 06:24 PM   #11
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@Hustler...I wish I could spend the money you do. I'm not worthy I guess

I got the rears mixed up but these are the before modifications
Rear at 12.5"
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Front(I think) I forgot which pic was which. These are from a long time ago. Was at 12.25"
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I had raised it after I took those pics though to get some more travel.

I'll have to get some pics of how it is now.
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Old 09-22-2010, 06:25 PM   #12
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Did either of you guys call FCM to ask about this?
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Old 09-22-2010, 06:28 PM   #13
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Quote:
Originally Posted by hustler View Post
It looks like the theory of soft springs and bump stops are falling short in the results department.
QFT!
My car is pretty damn smooth right now 550/300, a lot better than 400/300. I need to have my billies revalved badly though.

The stiffness of the heavier spring is nothing compared to slamming bumpstops to shock bodies.

Quote:
Did either of you guys call FCM to ask about this?
I did way back when I had the problem, but he told me to raise the car to about 13-13.5". I didn't want to do that, and at the taller heights, my car was swaying a lot more than I wanted it to. Too soft.
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Old 09-22-2010, 06:54 PM   #14
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You can get Swift springs for $90/pair and Hyperco from 949 at $150/pair. Both of those will reduce blocking which looks like its a potential issue with those and either Hyperco or Swift will have fewer coils and thinner wire (the Swifts are crazy light). I'll snap pics of my suspension at rest to compare.
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Old 09-23-2010, 03:50 AM   #15
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@hustler id like to see pics, tho my only chance for baller like that is if i can find used koni 2812's someplace (or possibly 8212)

my bump stops are 45mm with a 3mm plastic washer. now i need to run the #'s to see if cutting them will make any difference
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Old 09-23-2010, 10:06 AM   #16
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I must admit that I was surprised to see so little travel available in the rar, but the experience from the driver's seat doesn't lie:
Front

rear:


I don't know the ratio of wheel-spring movement (forget the term for that) but judging from my track pics I'm not moving the suspension more than an inch on low-speed and the car feels great with high-speed curb eating.
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Old 09-23-2010, 10:21 AM   #17
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looks like you have about an inch before you hit the bump, and they probably compress a good .5-1.0" before they get solid.

so around 2-2.75" of wheel travel. (* 1.52 for the front, 1.36 for the rear)

Last edited by Braineack; 09-23-2010 at 11:20 AM.
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Old 09-23-2010, 10:59 AM   #18
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@Hustler, that doesn't look too bad, even in back. That's a pretty long stop, so you have a good amount of movement before the stop, then a lot of bump stop.

Where are you finding the Swift springs @90/pr? I'd probably do them if I could find them at that price and size I'd be needing.
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Old 09-23-2010, 11:09 AM   #19
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Quote:
Originally Posted by webby459 View Post
@Hustler, that doesn't look too bad, even in back. That's a pretty long stop, so you have a good amount of movement before the stop, then a lot of bump stop.

Where are you finding the Swift springs @90/pr? I'd probably do them if I could find them at that price and size I'd be needing.
I searched on google. Maybe call Vorschlag, AST, or Cobb in Dallas.
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Old 09-23-2010, 04:07 PM   #20
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What bump stops and tophats are you on? I'm at something like 11.5 front 11.25 rear using the FCM stuff on FCM hats (basically stock NB hats with new bushigns) and the shorter FCM stops. My adjusters are pretty much bottomed out using 7"/8" springs. Never hit the stops. 550/350 (or 325?) rates. Too soft for the track, fairly plush on the streets. Too much oversteer even with a 1 1/8" hollow bar up front and no rear bar

When it's time for a revalve I'll go for 800-900/350 in 6"/7" or 6"/6" and ISC hats. Travel is over-rated
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