M3 or Adjustable Rear Links

[Seems Legit Garage]

Good Morning,

I'm currently running stock suspension with KW V2 coilovers and am looking to improve on my current setup. I'm looking for -2.5 F & -2 R for camber and 1/8 toe front and rear. I'm have ordered Ground Control camber plates, to help with the front. My question in the rear is......

M3 arms and adjustable toe link
Adjustable Camber link and stock toe link
Both adjustable camber links and adjustable toe
All 135i arms and upgrade bushings

The car is a DD / time attack but ignore the DD part of it, Michigan roads are so bad I dont care about road noise or harshness.

[justpete]

Originally Posted by Seems Legit Garage

Good Morning,

I'm currently running stock suspension with KW V2 coilovers and am looking to improve on my current setup. I'm looking for -2.5 F & -2 R for camber and 1/8 toe front and rear. I'm have ordered Ground Control camber plates, to help with the front. My question in the rear is......

M3 arms and adjustable toe link
Adjustable Camber link and stock toe link
Both adjustable camber links and adjustable toe
All 135i arms and upgrade bushings

The car is a DD / time attack but ignore the DD part of it, Michigan roads are so bad I dont care about road noise or harshness.

M3 arms have the same bushings/bearings as stock so they offer no improvement at all.

Adjustable arms need to use the best ballends possible and Seals-It seals for road use. But they aren't as strong as stock arms and really bad roads can cause catastrophic failure or at the very least ballend failure.

135i arms offer no improvement either.

I'm running all adjustable links in the rear with M3 lower camber arms and stock trailing arms, all with spherical bearings and Seals-it seals on the toe arms, upper camber arm, and wishbone. The spherical bearings in the trailing arm are a sealed type as are the welded-in bearings in the subframe for the lower camber arms. Not the best option for the street but it's fine although the roads here aren't in bad condition.

[Seems Legit Garage]

Any recomendations for adjustable link brands?

[ShocknAwe]

Keep in mind going to all spherical/bearing joinings will decrease effective spring rate in the rear. Dunno how much. This is important as many of the ratios for common suspension kits are already front heavy.

M3 guide rod is different from 135i version. I refer you to the bible of suspension components written by fe1rx (stickied). Also worth keeping in mind all the M3 arms are lighter by a non-insignificant margin. I think the full TRW kit is a great value for a dual duty daily driver.

[Cavpilot2k]

Originally Posted by ShocknAwe

M3 guide rod is different from 135i version. I refer you to the bible of suspension components written by fe1rx (stickied). Also worth keeping in mind all the M3 arms are lighter by a non-insignificant margin. I think the full TRW kit is a great value for a dual duty daily driver.

I am having installed the BMW PS plus M3 front control arms. I am considering M3 RSFBs, but I already have the Whiteline inserts, so I'm not sure if it's worth the parts & labor to upgrade from inserts to full bushings, from a "what will I feel?" perspective.

In talking with the shop (Turner motorsports, a known BMW specialist), they are suggesting the rear guide rods and upper link arms while I'm at it.

My car is my DD and only used for frequent daily spirited driving - I don't track it.

I'd be interested to hear your opinion on both the RSFB (if I already have inserts, is it worth it - bear in mind that my inserts have close to 50k miles - don't know if they wear...) and rear rods and arms (are they going to be felt and or worthwhile on a non-track car?).

[bbnks2]

Originally Posted by Cavpilot2k

I am having installed the BMW PS plus M3 front control arms. I am considering M3 RSFBs, but I already have the Whiteline inserts, so I'm not sure if it's worth the parts & labor to upgrade from inserts to full bushings, from a "what will I feel?" perspective.

In talking with the shop (Turner motorsports, a known BMW specialist), they are suggesting the rear guide rods and upper link arms while I'm at it.

My car is my DD and only used for frequent daily spirited driving - I don't track it.

I'd be interested to hear your opinion on both the RSFB (if I already have inserts, is it worth it - bear in mind that my inserts have close to 50k miles - don't know if they wear...) and rear rods and arms (are they going to be felt and or worthwhile on a non-track car?).

Rear arms can absolutely be felt in the way the car puts down power. They take a lot of slop and bushing "wind-up" out of the suspension that cause dynamic alignment changes resulting in wheel hop and bump steer (car rubberbands sideways in bumpy turns).

I have 2 rear upper M3 wishbones (camber arms) for sale if you are interested. I would also pick up a set of guide rods, as Turner suggested. Get an adjustable toe arm since you can't use the M3 one.

I swapped out the M3 rear upper camber arms for adjustable arms but it was pointless. Stock eccentrics have plenty of adjustment for a street/track alignment. 2* camber and .15* toe-in is where I have mine set. The adjustable arms I put into the wishbone spot are heavier and were not needed at all to obtain the alignment I wanted.

[ShocknAwe]

Big +1 to the above, but ill add that if you already have inserts don't bother with the m3 bushings. Go straight to full poly/delrin/aluminum rsfb.

I'm considering just ripping out the 135i subframe and swapping in the rest of the M3 parts back there now actually.

[Suprgnat]

Originally Posted by ShocknAwe

Big +1 to the above, but ill add that if you already have inserts don't bother with the m3 bushings. Go straight to full poly/delrin/aluminum rsfb.

I'm considering just ripping out the 135i subframe and swapping in the rest of the M3 parts back there now actually.

+1.5. Don't bother with any elastomeric RSFBs. Just get solid.

[Cavpilot2k]

Originally Posted by ShocknAwe

Big +1 to the above, but ill add that if you already have inserts don't bother with the m3 bushings. Go straight to full poly/delrin/aluminum rsfb.

I'm considering just ripping out the 135i subframe and swapping in the rest of the M3 parts back there now actually.

Originally Posted by Suprgnat

+1.5. Don't bother with any elastomeric RSFBs. Just get solid.

I appreciate the input, but this is a daily driver and the roads here in New England are crap. I think solid bushings would just transfer too much vibration.

[Suprgnat]

Originally Posted by Cavpilot2k

I appreciate the input, but this is a daily driver and the roads here in New England are crap. I think solid bushings would just transfer too much vibration.

I'm only referring to the sub frame bushings. Appropriate springs and dampers should be able to handle NE roads without causing additional NVH. You'd probably want to steer clear of poly or spherical bushings for the pivoting bits that are supposed to move, though.