So I am considering getting BC coilovers. Now the kit they make is specifically for the M37 with spring rates of 10K in the front and 8K in the rear. Since I will be getting the Swift Springs upgrade I can choose my own spring rates. Should I stick with 10k/8k or go higher in the front top compensate for the 230lbs heavier M56?

The M37X uses 12k/8k presumably to compensate for the heavier AWD equipment. The M37X is actually 30lbs heavier then the M56 so maybe 12k/8k is the way to go. Or maybe sprlit the difference at 11k/8k?

If your M56 is currently on BC's what spring rates are you running?

I have a m37x and got BC w/ Swift spring upgrade...I went with 8k front and rear...rides wonderful...jus like stock for the most part...

M37xNY2ATL wrote:I have a m37x and got BC w/ Swift spring upgrade...I went with 8k front and rear...rides wonderful...jus like stock for the most part...

So you actually went softer then what they offer in their M37X kit. Does your front end bottom out at all on dips or driveways?

There is no M56/x kit? What is Tunerz Store selling then (looks like the V-16 kit per their site)? Or all those folks on Ebay? Guess the same kit can be used on the V6 or V8 variant?

No bottoming out at all on the stock 20x9s. i would go stiffer if your going with a more aggressive setup. @IlyaKol The suspension is the same on 37x/56x variant.

Well I ordered and received BC's with Swift 10k/8K springs. They are very pretty.

What's the benefit of the spring rates? Is it going to be noticeably softer? And how much extra did it cost you?

IlyaKol wrote:What's the benefit of the spring rates? Is it going to be noticeably softer? And how much extra did it cost you?

The softer rate (lower number) will generate a smoother ride while the stiffer spring (higher number) will result in a firmer ride. For race or super low applications higher rates are usually used to keep the car from bottoming out. This also results in a rough, jarring ride.

For street use lower rates are usually used which are more forgiving of potholes and general public road conditions. The weight of the car plays a big roll too. Since I do not plan on going super low, just eliminating the tire to fender gap, and want an enjoyable ride I choose the recommended rates of 10k/8k.

The Swift springs offer several upgrades from the standard BC springs. Here is a list from The Best Coilover Guiide: Swift Springs. Worth it? which is a GREAT read for someone considering coilovers. If anyone is I highly suggest they check it out.

Best Coilover Guiide wrote: -
Swift Springs offer solutions to the problems we didn’t know we had:
-

• >The spring rate is consistent throughout the stroke: they are more predictable and more comfortable.
  >The largest amount of stroke: they are thinner and stronger, allowing for less coils, which allows for a greater amount of room for compression.
  >They are more durable against loss of spring height. Cold wound springs break in, then wear out, eventually their uncompressed height become less, due to having constant weight on them. They just wear out faster due to being made of an inferior material.
  >They weigh less than cold wound springs. If you’re not driving a race car you might not care too much about this one, but in truth, less unsprung weight makes a huge difference in both ride quality and performance.

I paid an extra $325 for the Swift springs and got free rear knob extenders too.

Best Coilover Guiide wrote: -
Swift Springs Summary
-
Common springs are made out of a silicone chrome material, because Swift Springs are stronger they can be made thinner and could be wound with fewer coils, greatly reducing weight and allowing for a larger and far more consistent stroke.
The results speak for themselves. If Swift Springs are available, they are worth the extra dollar...

YES, Swift Springs are Worth your Money.

Good stuff, thanks. So even if I choose to stay with the stock spring rates, I'll be better served dropping an extra couple hundred on those. Good to know. Our roads here (because I live in crappy NY and it's stupid winters) are pretty terrible for the first part of summer and during the winter (they are only good for about 2-3 months after they've been repaired lol)...so I need something that can be as comfortable while stronger/better in function.

I had the knob extenders on my old BC's...I mean, I got them. Didn't install them as I couldn't figure it out. Do they go inside the trunk somehow? I ended up setting all four corners of my 07 M BC's on the softest possible settings (again, I also lower just for looks and not performance/etc.) and just forgot about adjusting.

I don't know about the othe M chassis cars but on the Y51 the top of the strut is only accessble with the rear seat removed. Here are some pics a member on another forum (Deecarp1) posted of the installed extenders.





Final product. Trimmed to fit flush against rear deck.

Ahh, nice!

that rear extender is nice with a flush final install. I wish the older M's could the same.

IlyaKol wrote:There is no M56/x kit? What is Tunerz Store selling then (looks like the V-16 kit per their site)? Or all those folks on Ebay? Guess the same kit can be used on the V6 or V8 variant?

There is a kit specifically for AWD and one for RWD.

RED_DET wrote:

IlyaKol wrote:There is no M56/x kit? What is Tunerz Store selling then (looks like the V-16 kit per their site)? Or all those folks on Ebay? Guess the same kit can be used on the V6 or V8 variant?

There is a kit specifically for AWD and one for RWD.

Thanks

Yeah i went 8/8 because there recommended 10/8 is for more of a race feel..i wanted to keep my stock feel & jus add handling/eliminate body roll...

Swift Springs allows you to buy custom springs from them.

http://www.swiftsprings.net/products/un ... rings.html

Anybody know what dimensions and spring rates our cars have to match what Swift offers? I'd love to get something 0.75 lower than my Sport suspension now.

Those are coilover sprngs... same swift spring upgrade offered by BC Racing to use with there coilovers.

Thing is, I remember someone suggesting if you could get the right coils, they could replace any matching OEM spring.

@debonair, I'm about to buy some coils tomorrow. You've have your coils for sometime time now. Do you like the spring rate you chose or would you recommend the 11k/8k? I'm not slamming but may want the option later. Have you had any issues with the bc coils since purchase?

infinitedrift wrote:@debonair, I'm about to buy some coils tomorrow. You've have your coils for sometime time now. Do you like the spring rate you chose or would you recommend the 11k/8k? I'm not slamming but may want the option later. Have you had any issues with the bc coils since purchase?

Also, as I'm still going to be getting coilovers in the spring with the tax refund most likely, did you install the extenders? How did you 'cut them down' to fit flush?

@llya, the extenders are cut by a dremal tool or something similar of that type tool. The knob on the top had a set screw. Undo the set screw, take the knob off, cut extenders to length, put back knob, tighten set screw.

Oh okay, gotcha.

I chose the swift spring with 12K front and 8K rear. Feels really good, not bouncy and actually seems like I get better steering feel(could be my imagination though)

Another option for the rear adjuster knob; instead of going through the rear deck, I have access the knob through the child seat anchor window. It is the opening pictured below to the right. The cover swivels up to open and down to close. I had the installer cut the length so that the knob head surfaces when the flap is opened and pushed down when closed.

Debonair wrote:

infinitedrift wrote:@debonair, I'm about to buy some coils tomorrow. You've have your coils for sometime time now. Do you like the spring rate you chose or would you recommend the 11k/8k? I'm not slamming but may want the option later. Have you had any issues with the bc coils since purchase?

I am happy with the spring rate I got. There is some stiffness bounce but this is unavoidable since the suspension travel has been significantly shortened. It can get uncomfortable on extreme washboard roads so I remember where those are and avoid them. I also subconsciously change lanes on the freeways to avoid know bumps and drops now.

IlyaKol wrote:Also, as I'm still going to be getting coilovers in the spring with the tax refund most likely, did you install the extenders? How did you 'cut them down' to fit flush?

infinitedrift wrote:@llya, the extenders are cut by a dremal tool or something similar of that type tool. The knob on the top had a set screw. Undo the set screw, take the knob off, cut extenders to length, put back knob, tighten set screw.

Correct, a Dremel cutoff wheel does the job best.

Remove the knob by loosening the set screw. Measure the length of the inner rod that is exposed at the top. Trim the outer sleeve (it just slips off once the knob is removed) to the necessary length. Then trim the inner rod making sure to leave the same length exposed at the top so you can remount the knob.

Those original pics with the extenders uncut were from another member. This is from my car a few days ago. The pic below is is also from my car and was posted in my wheels thread.

How hard is it to remove seats in this car? I'm the kind of guy who will set them at their softest setting and forget it/never touch them again.

Also, being that I ran my BC's on their softest setting on my 07 and plan to do it on the '11, what spring rate would you recommend?

IlyaKol wrote:How hard is it to remove seats in this car? I'm the kind of guy who will set them at their softest setting and forget it/never touch them again.

Also, being that I ran my BC's on their softest setting on my 07 and plan to do it on the '11, what spring rate would you recommend?

SUPER easy. Bottom cushion has two release latches in the front. Upper cushion / seat back is held on by 4 nuts at the bottom. Once they're off you lift it up and forward off some hooks. That's it.

No yanking or popping clips like other cars, which always makes me feel like I am about to break something.

I got 10K/8K and am happy.

Think I'm going to split it between debonair and iwk2much and go with 11k/8k. I'm probably going to go with Scale Suspension and be the test dummy.

@debonair and @iwk2much are you guys still hearing the clunking sound at slow speeds everyone complains of with BC'S?

No clunks or rattles ever. I thought there was during the initial test drive but it was the seat belt against the floor pan (seats were still out).

Ahhh, now you made this decision so much harder. That was kinda swaying me away from bc.

Debonair wrote:

IlyaKol wrote:How hard is it to remove seats in this car? I'm the kind of guy who will set them at their softest setting and forget it/never touch them again.

Also, being that I ran my BC's on their softest setting on my 07 and plan to do it on the '11, what spring rate would you recommend?

SUPER easy. Bottom cushion has two release latches in the front. Upper cushion / seat back is held on by 4 nuts at the bottom. Once they're off you lift it up and forward off some hooks. That's it.

No yanking or popping clips like other cars, which always makes me feel like I am about to break something.

I got 10K/8K and am happy.

Okay, so it's exactly how my old 99 Maxima was. Nice.

I won't bother with the extenders then.

I might go with 11k in the front due to being AWD. So, 11/8.

infinitedrift wrote:Think I'm going to split it between debonair and iwk2much and go with 11k/8k. I'm probably going to go with Scale Suspension and be the test dummy.

@debonair and @iwk2much are you guys still hearing the clunking sound at slow speeds everyone complains of with BC'S?

If your friend made them for the X, I'd give them a try. They look beautiful lol.