Who's all running a true coilover in the back?

[Lienrocs]

Hey everyone,

I'm in the process of going to a true C/O on my M4 and am just wondering how many have done it and if anyone has noticed anything bad happening. I haven't seen anything saying reinforcement around the towers is needed but if anyone's been running like that for a while on street and track it'd be great to know some info:

Total miles on c/o set up
Spring rates
Usage of car (street, track, street/track)

Thanks for helping out everyone!

[SYT_Shadow]

I have two seasons on real coilover rears with MCS. Spring rate is 700 in the rear. MCS 3WR

I have over 10k miles on the setup and have dismounted and remounted several times doing R&D. It's easy to see where the issue would occur by going with the full C/O and so far zero, zilch, nada.

The car is dedicated to the track but still driven to/from the track, so there's quite a bit of driving on the street.

[rborane]

I almost went true coilover rear with my AST 5100 coils, but stuck with divorced rear as I have heard some having issues with the spring rubbing against the rear sway bar / endlinks. Maybe keep that in mind.

[Lienrocs]

Originally Posted by SYT_Shadow

I have two seasons on real coilover rears with MCS. Spring rate is 700 in the rear. MCS 3WR

I have over 10k miles on the setup and have dismounted and remounted several times doing R&D. It's easy to see where the issue would occur by going with the full C/O and so far zero, zilch, nada.

The car is dedicated to the track but still driven to/from the track, so there's quite a bit of driving on the street.

Awesome! Good to hear.

[Lienrocs]

Originally Posted by rborane

I almost went true coilover rear with my AST 5100 coils, but stuck with divorced rear as I have heard some having issues with the spring rubbing against the rear sway bar / endlinks. Maybe keep that in mind.

I'll keep that in mind. Thanks for the heads up.

[SYT_Shadow]

Ah yes, good point with the sways. I run hotchins sways front and rear and it clears ok, but the rear sway cannot use all 3 positions -- which is fine by me, I only use one

[Lienrocs]

Originally Posted by SYT_Shadow

Ah yes, good point with the sways. I run hotchins sways front and rear and it clears ok, but the rear sway cannot use all 3 positions -- which is fine by me, I only use one

How much additional clearance is needed for the full adjustment range? Are we talking a few mm or an inch?

[SYT_Shadow]

Originally Posted by Lienrocs

How much additional clearance is needed for the full adjustment range? Are we talking a few mm or an inch?

It's adjusted where it's supposed to go. But it's close to making contact. If you tried putting the rear bar on full stiff it would contact.

[Lienrocs]

Originally Posted by SYT_Shadow

It's adjusted where it's supposed to go. But it's close to making contact. If you tried putting the rear bar on full stiff it would contact.

Gotcha. If you wanted full adjustability though could you do it with a few more mm of clearance or is it a matter of inches?

[SYT_Shadow]

Originally Posted by Lienrocs

Gotcha. If you wanted full adjustability though could you do it with a few more mm of clearance or is it a matter of inches?

It's not inches, more like mm. It might get solved with different sway bar end links vs the stock ones I'm using.

One day someone will release a rear sway that fits perfectly

[aswy6]

Originally Posted by SYT_Shadow

I have two seasons on real coilover rears with MCS. Spring rate is 700 in the rear. MCS 3WR

I have over 10k miles on the setup and have dismounted and remounted several times doing R&D. It's easy to see where the issue would occur by going with the full C/O and so far zero, zilch, nada.

The car is dedicated to the track but still driven to/from the track, so there's quite a bit of driving on the street.

Is MCS 1 way non remote a true coilover in the rear? And what issues one can be potentially facing by going true coilover in the rear?

[SYT_Shadow]

Originally Posted by aswy6

Is MCS 1 way non remote a true coilover in the rear? And what issues one can be potentially facing by going true coilover in the rear?

It is not, although I wouldn't be surprised if you could order it in true coilover configuration.

The difference is small, I'd say unnoticeable. On the CS track car we have full coilover, on the E90 stroker track car we have remote rear setup. Both cars put down the same laptimes and both feel the same. You don't go over a bump with the E90 and think "ugh the CS took that rumble strip so much better".

It's a tiny, tiny difference.

When you do a full coilover rear you are moving the spring forces to the same place that was designed for just shock forces. People have been doing that for a long time, but it is not recommended prior to the F8X series without a cage tied into those points.
In the F8X, there is a massive plate distributing forces where you attach the shock, so zero concerns about extra forces going through there.

[JustAnothaM4]

What is the correct spring length to use when running a rear coilover? 7" or 8"? Is a tender or helper also required in the rear?

I assume everyone runs a short 5" front spring with a helper/tender to help with wheel clearance?

[rborane]

I decided to get into a set of MCS 1 ways with coilover rear and ordered through bimmerworld. Here are my specs:

Front: Eibach 6" spring - 600lb - hyperco helper spring

Rear: Eibach 6" spring - 500lb - hyperco helper spring

Those rates and length were recommended from Bimmerworld to keep it as a daily and capable for track, and it sounds like they worked with MCS directly for the F8X.

They told me to run the rear coilover non-inverted with the spring towards the top. A lot of MCS guys run it inverted but I believe that is more with the multi way remote setups.

Also was told a 6" rear spring was necessary to prevent rubbing on the rear sway. Having them installed this coming week.

[Lienrocs]

Originally Posted by rborane

I decided to get into a set of MCS 1 ways with coilover rear and ordered through bimmerworld. Here are my specs:

Front: Eibach 6" spring - 600lb - hyperco helper spring

Rear: Eibach 6" spring - 500lb - hyperco helper spring

Those rates and length were recommended from Bimmerworld to keep it as a daily and capable for track, and it sounds like they worked with MCS directly for the F8X.

They told me to run the rear coilover non-inverted with the spring towards the top. A lot of MCS guys run it inverted but I believe that is more with the multi way remote setups.

Also was told a 6" rear spring was necessary to prevent rubbing on the rear sway. Having them installed this coming week.

I'm running my ohlins set up with the spring at the top as well. It's a 2.25 ID spring and I haven't had any rubbing issues at all.

Awesome set up! MCS makes some great stuff and BimmerWorld's recommendations are top notch as well.

[rborane]

Originally Posted by Lienrocs

I'm running my ohlins set up with the spring at the top as well. It's a 2.25 ID spring and I haven't had any rubbing issues at all.

Awesome set up! MCS makes some great stuff and BimmerWorld's recommendations are top notch as well.

Thanks! Any idea what length spring your Ohlins setup uses now that you are coilover rear?

[Lienrocs]

Originally Posted by rborane

Thanks! Any idea what length spring your Ohlins setup uses now that you are coilover rear?

That's a great question. I'd have to take a look. I'm not sure how relevant it would be though. I'm running an 800 pound rear so it's going to compress a lot less.