Garagistic rear suspension mods?

[Qfbohc83]

I'm having some issues with rear suspension geometry. Seems there's a different amount of toe in side to side. Plus there's the camber issue from a lowered car.

The alignment guy at the BMW specialist recommended looking into Garagistic toe and camber mods.

They seem reasonable, any insight from the groups expertise and experience?

I have a 1978 320i that has a 323 rear end, disk brakes, LSD, sway bar with Ground Control coilovers.

Thanks
Dave

[82eye]

I'm having some issues with rear suspension geometry. Seems there's a different amount of toe in side to side. Plus there's the camber issue from a lowered car.

The alignment guy at the BMW specialist recommended looking into Garagistic toe and camber mods.

They seem reasonable, any insight from the groups expertise and experience?

I have a 1978 320i that has a 323 rear end, disk brakes, LSD, sway bar with Ground Control coilovers.

Thanks
Dave

it's actually for e30, but it might work with an e21 sub. i'd make sure of the measurements first to confirm the eccentric bolts will fit.

[Qfbohc83]

Thanks. Yeah, all the references are to an E30 but it lists a few models it fits including the E21.

[autox320]

I'm having some issues with rear suspension geometry. Seems there's a different amount of toe in side to side. Plus there's the camber issue from a lowered car.

The alignment guy at the BMW specialist recommended looking into Garagistic toe and camber mods.

They seem reasonable, any insight from the groups expertise and experience?

I have a 1978 320i that has a 323 rear end, disk brakes, LSD, sway bar with Ground Control coilovers.

Thanks
Dave

In a nut shell yes they work on an E21, but I'd not use them. They'll only stay in place once adjusted and welded. Even then can bind and break welds. Issue is the trail arm legs want to be in the same plane. They will fight to do so over time. Locking versions with teeth from IE used to be decent to hold but any way you look at it these are all a pain to adjust and setup. Even then the arms want to be in plane so instead of moving the bushes will wear at angles till they are back in plane

Diving deeper.
Difference in rear toe can be due to ride height. The trail arms travel through an arc. So depending on where the car sits can be anywhere in the arc, this is normal for street setup cars. Middle of the arc is usually zero toe while either side can be in or out. Ideally want some toe in on both sides of about 2mm IN for 200hp or less. So if one side is 2mm for example and the other is 1mm or 3mm I'd not even worry about it. If one side is 2mm in and the other 2mm out then there's an issue which is usually bent trail arm or bent subframe tabs.

Ride height plays the main role in static camber. If the car is dumped on the suspension I'd highly advise to at least put a bubble level on the axles. You want them at most parallel to the ground, ideally just a slight angle up to the diff. That's as low as you can go no matter how much shock travel is left. Especially if want the CV's to last. But worst is if dump below plane it will make the car push/understeer for handling plus won't get the power down as good for forward traction.

Usually camber will be huge when get the axles level. Another method is cut off and move the trail arm mount tabs but that's not easily done due to other changes in geometry it will make. Hence the eccentric adjusters is about all there is for a bolt on solution. Ultimate is make your own trail arms with adjustment on the outer leg (closest to subframe bushing). Then can change the camber at ride height.

If want better bushes I'd recommend AKG or Powerflex. Much better material than Garagistic and many others (condor) ebay etc brands. Not all are created equal. Just swapped some on an e30 last week. AKG are on backorder so put in the powerflex.

Note:
Secret to setting up trail bushes is shaving several thousandths off one bushing for each arm till the sleeve protrudes. If not they will bind for sure. This is cause when clamped down the trail arms ride on the sleeve not the bolt. The ears of the subframe are clamped with the sleeve to make a pivot pin which doesn't move. So what happens if just install the bushes as they come out of the box they will bind on the tabs cause the sleeve is too far inside. Worse case this breaks off mount tabs from the subframe

Made my own dtm trail arms due to this reason for getting the most out of the rearend. Traction is best with camber 2deg or below with other geometry changes while at it.

[Qfbohc83]

Thanks for the info.