Offset rear sub-frame and diff 12mm?

[Mafiaracers]

I'm invisioning this....so the subframe bushing has the 12mm spacer on the bottom to raise the frame up. Therefore, the offset diff bushing should then be installed in such a way (offset hole in the 'up' position) to push the diff down to where it "was" prior to raising the frame....

Do we agree on this?

I'm forgetting that the diff is bolted to the subframe, not just the trunk, so diff height is directly at the mercy of the subframe. so the the offset diff bushing will have to be installed with offset mounting hole aiming down to raise the diff "with" the subframe...

I think I'm making more out of this than needed, I'll find out when I install

[Wh33lhop]

What he said.

EDIT..
Well, raising the subframe puts rear wheel in a different spot of the toe curve, and it is just that, a curve not linear. In other words toe change per amount of suspension travel is less. Which is nice.
Camber change again, is linear.

I did it solely for a better toe curve, but if you don't have adjusters it will get rid of a half degree of camber and some toe.

I'm forgetting that the diff is bolted to the subframe, not just the trunk, so diff height is directly at the mercy of the subframe. so the the offset diff bushing will have to be installed with offset mounting hole aiming down to raise the diff "with" the subframe...

Yes.

[Massimo]

Basically you have two options

1. Use the diff offset bush with the stock sub-frame to diff bolts. This will raise the diff with sub-frame.

2. Use a standard diff bush and space the diff down from the sub frame 12mm using 40mm bolts. This will keep the diff in the stock location.

[Wh33lhop]

Another issue I noticed--the exhaust hanger that bolts up to the subframe doesn't work with the subframe raised 12mm. I just didn't reinstall mine. Should be fine.

[Massimo]

Another issue I noticed--the exhaust hanger that bolts up to the subframe doesn't work with the subframe raised 12mm. I just didn't reinstall mine. Should be fine.

Hehe mine has another issue involving the muffler. My solution cut muffler off. But yours sounds so much more fun.

[Wh33lhop]

Hehe mine has another issue involving the muffler. My solution cut muffler off. But yours sounds so much more fun.

What was the issue? It was too quiet? ;)

[Massimo]

What was the issue? It was too quiet? ;)

No someone previous welded the mounting brackets onto the muffler instead of using the clip on things. So I am not sure if you can see what the problem is but lets say that it is imposable to remove or install the muffler on to it rubber mounts with welded hangers.

Anyways I need a new exhaust system so i am just going to cut it behind the muffler for the time being while I draw up plans for a new system from the headers back.

[FLG]

Basically you have two options

1. Use the diff offset bush with the stock sub-frame to diff bolts. This will raise the diff with sub-frame.

2. Use a standard diff bush and space the diff down from the sub frame 12mm using 40mm bolts. This will keep the diff in the stock location.

IMO, option 2 is a better one...dosnt change driveshaft angle.

Can someone tell me the size/thread pitch on the diff bolts?

[AndrewBird]

RealOEM says M12x1.5, 25mm long.

http://www.realoem.com/bmw/showparts...24&hg=33&fg=10

[Eric]

damn, I just replaced my subframe bushings last year, now it's more things to spend money on!

[Mafiaracers]

So here's what I found this evening after installing my akg 12mm setup.

The whole subframe assembly is raised to a point that it appeared the driveshaft would make contact with the gas tank. I did not install my drive shaft tonight, but it sure looked like a potential problem.

The main issue I ran into was the diff making contact with the swaybar. I have the Ireland 19mm rear with IE trunk mounts. With the diff raised an extra 12mm, I noticed the swaybar was binding on something...inspection revealed the top of the diff pressed right up against the bar.

Placing the 12mm aluminum spacers on TOP of the subframe bushings to, in effect, lower the frame is a simple enough task, but spinning the diff bushing 180*, to place the offset hole in the UP position, will not be an option as it'll be out of alignment. I'm a fan of DIY and figure I can save $60 on a new bushing and just press out the liner, re-drill the hole in the center, press in the liner and press in a (metal of choice) plug for the offset hole....voila.

[Wh33lhop]

After installing the 12mm offset subframe bushings WITH the washers (spacing it down about 3mm), the driveshaft rubs on hard accel, and my CSB was quickly chewed up. AKG has offered to ship me another pair of washers to space the subframe down a bit more which should alleviate the issue, although I am still a bit curious about the CSB as it was fairly new.

[FLG]

Just unbolt the differential and space it 12mm back down, might need longer bolts but it will put the driveshaft right back where its supposed to be, along with the diff bushing mounting point.

[Wh33lhop]

Just unbolt the differential and space it 12mm back down, might need longer bolts

As well as a different diff bushing and the spacers themselves. Not to mention, bolting up new diffs will be a bitch because you'll have to line up the spacers.

AKG's shipped me another set of washers, if this doesn't work I will space the diff down.

[FLG]

IMO its worth spacing the diff down regardless. By keeping it where it is your changing your drive shaft angle. I cant tell you if your going to have negative effects, as it might still be OK but if its not your going to get vibrations and/or u-joint failure.