Advan - M3 Sub Frame Bushings & Rear Arms

[TS135i]

A very long 30+ degrees day, but success in the end.

Before & After shots.
Peter pointed all four bushings towards the center for maximum rigidity. The coat hanger RSB remained.
Result is Night & day compared to stock, I'm still on stock suspension and won't be touching anything else, I also have the E92 FSB, perfect daily setup IMO.

[Walnut]

Great stuff! What are the 'night and day' differences? What sort of cost is involved? Thanks.

[TS135i]

^^ This car is almost brand new, I don't understand why BMW chose to put chewing gum for the rear bushings
I noticed this error in the rear suspension when I took the dealer's 135i for a test drive, I mentioned the car has a problem with the rear and he just looked at me expressionless.

The car now drives like it should have from Leipzig, the rear doesn't wobble/stretch like it did, just pissed that I had to correct BMW's new suspension at my own expense.

[John_01]

I also had Advan install the M3 bushings into the rear subframe of my 135i a few months ago. Funnily the pics of the rear subframe look almost exactly the same as mine! Anyway, it makes a very big difference to the handling. As a result the car feels a lot safer, more predictable and stable in hard cornering. The car seems to track a lot more precisely than it did before. It needs less steering corrections in pretty much all situations - which is even noticeable in normal suburban driving.

The problem now is that my 325i still has the stock subframe bushings, which has become a lot more noticeable now I've driven with the M3 bushings in the 135i. Anyway that's going to be fixed soon.

[MO3]

Do I still need an LSD if I had the M3 bushings installed to stop my car going sideways in third gear under hard acceleration?

In other words, would this improve acceleration, traction and stability to the extent that I won't need an LSD?

My aim is to improve my quarter mile time, eg crack 11s!

[TS135i]

As to whether you need an LSD for your application, I couldn't say.. But I couldn't imaging doing any performance mods without first replacing the rear chewing gum bushings in any case.

[John_01]

Last week I had the E90 3 series at Advan for a M3 subframe bushing upgrade and a log book service too. I thought I would take the chance to report the outcome.

2009 325i with stock M-sport suspension now has the following mods:
* Non-RFT tires. 235/45/17 Goodyear F1 all around.
* Drilled out front alignment pin for extra 0.5 degree negative camber.
* BMW performance front sway bar - I guess about 30% stiffer than stock.
* M3 rear subframe bushes.

Adding the front sway bar and rear M3 subframe bushes has made the car noticeably firmer than before and it now feels a lot more precise. When taking twisties on the open road the steering has a more solid and grippy feel on the road. The car has better steering overall, but will understeer when pushed, particularly as the body leans in turns. That aspect is different from before where the front of the car previously felt quite vague while the rear would wander around in the corners.

Now I had two cars modified with subframe bushes, I found a few consistent outcomes.
1) It makes a big difference to the steering precision. The car tracks a lot straighter in normal driving which is a great outcome in itself.
2) The car feels less nervous in corners. It doesn't wriggle around the corners in normal driving which applies to both 1 series and 3 series cars. In hard turns, the previously loose and unpredictable feeling that I hated in the 135i is completely gone. If no other suspension mods are made, the subframe bushing upgrade seems to result in a net understeer effect. The good news is the car is so much more predictable that it gives freedom to sharpen the handling in other areas. I think the understeer effect is less when firmer springs or sway bars are used.
3) Steering feel is improved. It may seem weird that the change of rear bushings affect the steering. However in both cars I found the steering feels more solid, more tactile and gives better road feel.

In the E90 I kept the stock pressed steel rear upper arms. That probably minimised the increase in vibration as the upper arms have soft rubber bushings. The rear suspension now feels firmer than before even though there was no change to springs or dampers. The stock dampers on the 2009 E90 are a bit firmer than what came stock on my 135i, so they are ok but not great. If I was focussed on sprited driving in the E90, I would probably change them to something firmer. Considering what I use the car for, the stock dampers will remain for the time being.

[froop]

Originally Posted by MO3

Do I still need an LSD if I had the M3 bushings installed to stop my car going sideways in third gear under hard acceleration?

In other words, would this improve acceleration, traction and stability to the extent that I won't need an LSD?

My aim is to improve my quarter mile time, eg crack 11s!

Pssst Moe!

http://www.turnermotorsport.com/p-14...m-e82-e9x.aspx

[Eddie135]

Hi TS135i

Can you PM me the total cost to change all the 4 rear sub-frame bushing to M3 ones as a guide.

I also hate the chewing gum feel in the rear.

Thanks.

[MO3]

Originally Posted by froop

Pssst Moe!

http://www.turnermotorsport.com/p-14...m-e82-e9x.aspx

Thanks Alex! So tempting!

[froop]

Originally Posted by MO3

Thanks Alex! So tempting!

I already gave into the temptation haha

[flinchy]

Originally Posted by froop

I already gave into the temptation haha

pity, wouldve been happy to combine shipping

[skidz]

Originally Posted by flinchy

pity, wouldve been happy to combine shipping

dont worry his girlfriend will find out soon and he will be forced to offload these AND his M3 rear end. dibbs on the m3 rear end

[froop]

Originally Posted by flinchy

pity, wouldve been happy to combine shipping

Pity indeed. I guess it was only $50. Next time maybe if I decide to do Delrin diff mounts haha

If you need something from ECS I'm putting in an order now. Getting E46 M3 trans bushings amongst other things.

[flinchy]

Originally Posted by skidz

dont worry his girlfriend will find out soon and he will be forced to offload these AND his M3 rear end. dibbs on the m3 rear end

NO DAMMIT \@ last bit

Originally Posted by froop

Pity indeed. I guess it was only $50. Next time maybe if I decide to do Delrin diff mounts haha

If you need something from ECS I'm putting in an order now. Getting E46 M3 trans bushings amongst other things.

i asked turner, they told me the Alu ones had no downsides vs the delrin, and the delrin are purely there for some race classes that can't have a 'solid' bushing... can't not believe them, when the delrin's are $150 more money for them haha

do the E46 trans bushings fit on the 1ers?

there's probably a ton i could use (some sweet schwaben tools) but .. can hold out for now haha

[froop]

Originally Posted by flinchy

NO DAMMIT \@ last bit

i asked turner, they told me the Alu ones had no downsides vs the delrin, and the delrin are purely there for some race classes that can't have a 'solid' bushing... can't not believe them, when the delrin's are $150 more money for them haha

do the E46 trans bushings fit on the 1ers?

there's probably a ton i could use (some sweet schwaben tools) but .. can hold out for now haha

Yeah they do. There's a DIY by wolfe somewhere. He tried UUC ones which are urethane and then the E46 M3 ones. I'm going the E46 M3 ones for less NVH but still greatly improved shifting feel. Only $15/mount.

As for Delrin, I think they are meant to be marginally less stiff than solid Aluminium. Not sure how much difference really though.

[flinchy]

Originally Posted by froop

Yeah they do. There's a DIY by wolfe somewhere. He tried UUC ones which are urethane and then the E46 M3 ones. I'm going the E46 M3 ones for less NVH but still greatly improved shifting feel. Only $15/mount.

As for Delrin, I think they are meant to be marginally less stiff than solid Aluminium. Not sure how much difference really though.

awesome, would love to hear impressions

i heard the UUC bushings are prone to split! well, read that recently anyway, which was disappointing

delrin appears to be.. 86 shore D, M 94 (120) rockwell - ... i assume we'd have to find out the actual alloy of the alum to compare, but it looks like alu is 90~ shore D?

[AP135]

Originally Posted by skidz

dont worry his girlfriend will find out soon and he will be forced to offload these AND his M3 rear end. dibbs on the m3 rear end

LOL! I wouldn't be so cruel! Sorry to dampen your hopes there skidz.

But we'll definitely be driving my car more often. Not looking forward to new feel of the car with the hard suspension settings, on top of the already really loud exhaust and constant grey smoke...

[DR-JEKL]

Originally Posted by flinchy

awesome, would love to hear impressions

i heard the UUC bushings are prone to split! well, read that recently anyway, which was disappointing

delrin appears to be.. 86 shore D, M 94 (120) rockwell - ... i assume we'd have to find out the actual alloy of the alum to compare, but it looks like alu is 90~ shore D?

The bushes are most likely 6061 grade (common Al grade used for automotive components)

As for the hardness differences something like the 6061 definately should have a higher rockwell rating & superior mechanical properties (bloody rockwell is the worst hardness test, but the yanks love it!!)

Would you guys be interested in some custom Al subframe bushes? These would be relatively easy to manufacture, and whilst i no longer program & machine, I know a few engineering co's who may do this for me as a 'favour' at mates rates (can I borrow your bushes for a few days Alex!?!? haha)

[DR-JEKL]

Originally Posted by AP135

LOL! I wouldn't be so cruel! Sorry to dampen your hopes there skidz.

But we'll definitely be driving my car more often. Not looking forward to new feel of the car with the hard suspension settings, on top of the already really loud exhaust and constant grey smoke...

Shit busted!!!

Glad my gal doesn't get online and check up on me, I would have a lot of explaining to do with all my 'mods' :P

[skidz]

Originally Posted by AP135

LOL! I wouldn't be so cruel! Sorry to dampen your hopes there skidz.

But we'll definitely be driving my car more often. Not looking forward to new feel of the car with the hard suspension settings, on top of the already really loud exhaust and constant grey smoke...

hang on what about the wedding/baby etc surely you can think of more important things than some silly m3 rear....

[flinchy]

@ above LOL - no hiding for me either from @bmwlady

Originally Posted by DR-JEKL

The bushes are most likely 6061 grade (common Al grade used for automotive components)

As for the hardness differences something like the 6061 definately should have a higher rockwell rating & superior mechanical properties (bloody rockwell is the worst hardness test, but the yanks love it!!)

Would you guys be interested in some custom Al subframe bushes? These would be relatively easy to manufacture, and whilst i no longer program & machine, I know a few engineering co's who may do this for me as a 'favour' at mates rates (can I borrow your bushes for a few days Alex!?!? haha)

How much approx would they be to get made up? When the bushings from turner are $300/set plus post?