[joeybutts]

Some time this year I plan on overhauling the suspension; bushings, coilovers, alignment, etc. but it seems there are differing opinions on spring rates for the e90. Some guys say stick 1:3, some say go 1:2, few say 1:1, even fewer are approaching 1:4.

I’m 99% set on going with FA500’s. My car will probably never see the track, but I drive more spirited than I should on the street, approaching track classification. I want to close the fender gap a bit, which it seems all coilovers do enough for what I want.

Where should I go with my spring rates? Also, what’s the difference in springs that come with the kit by default and “Swift” springs?

Thanks for any insight and can’t wait to upgrade!

[Digitalize]

Swift springs are made differently to conventional springs, and in theory are of a higher quality.

I'd go at the very least for 1:2 for a road car, so 6k/12k would probably be a nice road rate.

I think whilst 1:3 might be more technically balanced, I'd be worried it might be too stiff on the rear for the road.

[zero2sixtyZ]

Let me know if you have any questions on the FAs. I have the 500s, all of their options, swift springs 8k/14k after some trial/error and learning some suspension math. Their stock rates don't work well on this chassis IMO. Had them for 2+ years now, 90% street, 8% backroad attack, 2% autoX.

I'd probably go 6k/14k from what I've learned now.

[joeybutts]

Thanks fellas!

026z- do you feel all the options were worth it? Can you describe your setup to what 6k/14k should feel like? I’m guessing 6k should be a little more supple....

Do you also have m3 bits on your car or sway bars? My vehicle has hotchkis sways, m3 front bits...

Thanks!

[zero2sixtyZ]

Originally Posted by joeybutts

Thanks fellas!

026z- do you feel all the options were worth it? Can you describe your setup to what 6k/14k should feel like? I’m guessing 6k should be a little more supple....

Do you also have m3 bits on your car or sway bars? My vehicle has hotchkis sways, m3 front bits...

Thanks!

Nothing really to compare it to, but I would option for the radial bearings and the swift springs again. Front with the 8ks is a little firm, but I don't mind it. Originally with the rear 12k, the rear end bounced via a pogo effect. 6k would be a bit softer and a better suit for the motion ratios front to rear.

M3 bits, I have the Front Strut Tower Brace (kinda necessary as the FA front adjustment knobs would hit the stock braces) and rear lower control arms (had FA spec my setup for M3 rear struts). The rest of the M arms are going in this Spring.

[feuer]

I have used FA500 with Swift springs if anyone is interested, 5/9k spring rates I think.

[joeybutts]

Can you elaborate a bit more on your experience feuer? 5/9 is way different than anything I have seen/heard other than being nearly 1:2....

026z- what strut brace are you using?

[feuer]

Originally Posted by joeybutts

Can you elaborate a bit more on your experience feuer? 5/9 is way different than anything I have seen/heard other than being nearly 1:2....

I don't have personal experience. They came on a car I'm parting out. Says Swift 050 that stands for 5k. Or at least that is what I've been told.

[joeybutts]

Oh... hahahahaha I read used as a verb, not a noun.

[zero2sixtyZ]

Originally Posted by joeybutts

026z- what strut brace are you using?

OEM M3 brace. Removed the studs, and threw in bolts to clear cowl.

[eetadik]

Zero, glad to read your feedback on the spring rates. I have a 09 328i xdrive and I am close to ordering the FA500's with Swift springs and all the extra goodies. After reading your feedback though, I may go lower on the front and higher on the rear But I'm not sure if it will work out the same from RWD to AWD. I've been doing suspension math for the last few days so my head is spinning...
It seems that an 8k/12k setup keeps the same relative spring ratio from front to rear the same, I just am worried its still going to be oversprung. I want as stiff as I can go before "pogo-ing".

[zero2sixtyZ]

@motiv7891 joeybutts

Take a look at this thread I made a while back. This was before revalving the rear struts to match for the 14k rear spring change. I posted some of the calcs and a lot of good info from other members.

Short travel coilovers (front) change motion ratio? http://www.e90post.com/forums/showthread.php?t=1359653

[joeybutts]

0260Z - does it matter that you are in an e92 and i an e90? HAve you made the switch to 6/14? Im hoping fall to do all inserts and coilovers, so have time.

[zero2sixtyZ]

Originally Posted by joeybutts

0260Z - does it matter that you are in an e92 and i an e90? HAve you made the switch to 6/14? Im hoping fall to do all inserts and coilovers, so have time.

Shouldn't really. Weights are close enough, unless you're in an X-drive.

Still 8k/14k at the moment. Might switch to 6k front later when I need to take apart the front setup.
After last auto-X (which was on a rough surface), I was happy with the handling/dive. Tire pressures should've been set a bit higher though...