Ride height changed after CMP/Vincebar

[Cubieman]

I had the same issue when I used PSM subframe bushings/risers. They bring the control arm with spring perch closer to the body of the car which effectively reduces the height of the area where the spring sits. Using the same height setting as before will result in a higher sitting car.

That's disappointing news as my BC springs are already set at their lowest position, I really likes the rear wheels almost up into the wheel wells for the looks.

I have adjustable shocks but that can't do much as the springs set ride height..

So it would seem with the CMP bushes one can't have small wheel well gaps unless you went to a stupid low (and stiff) rear spring.

[Tbonem3]

The CMP bushings simply undo the increase in height that welded-in plates add.

Unless you're running CMP bushings with no plates added in?

So if you're running CMP bushings WITH plates, then you're the same as a stock, un touched m3, and can certainly get a nice drop without using really short and stiff rear springs.

Perhaps something else is amiss. The CMP bushings only raise subframe a small amount (again, just putting you back at stock if you have plates added in)

[DoubleSidedTape]

The CMP bushings raise the subframe something like 8mm, plates are 2-3mm

[Cubieman]

The CMP bushings simply undo the increase in height that welded-in plates add.

Unless you're running CMP bushings with no plates added in?

So if you're running CMP bushings WITH plates, then you're the same as a stock, un touched m3, and can certainly get a nice drop without using really short and stiff rear springs.

Perhaps something else is amiss. The CMP bushings only raise subframe a small amount (again, just putting you back at stock if you have plates added in)

I have plates welded underneath, done by the PO, unsure of what brand they are, but I'm sure they are all about the same..

[Tbonem3]

The CMP bushings raise the subframe something like 8mm, plates are 2-3mm

Is this new? AFAIK, the whole point of the CMP bushings was to account for the thickness (1/8") of added plates. Not raise it even higher than stock.

An extra 5mm would be something to take into consideration.

[oceansize]

I installed CMP bushings and redish plates and didn't have any issues like this. I'm running GC coilovers with a 6 inch spring at 600lbs on the rear so nothing super super stiff and I have plenty of room for adjustment whether up or down.

Edit: if you still haven't moved the car back and forth quite a bit it will sit up very high until you do.

[Cubieman]

I installed CMP bushings and redish plates and didn't have any issues like this. I'm running GC coilovers with a 6 inch spring at 600lbs on the rear so nothing super super stiff and I have plenty of room for adjustment whether up or down.

Edit: if you still haven't moved the car back and forth quite a bit it will sit up very high until you do.

That's re-assuring, I hope that's the case as my BC springs are bottomed out, I want my fender gaps back!

[D-O]

I would not worry until you drive it around the block a few times. After coming down off the quickjack mine always settles after a bit of a drive.

[eacmen]

I’ve never had to roll it.

I make sure car is in neutral, no ebrake on. Push down on each corner hard 2-3 times. Have never seen the ride height change more than a 1/16” after driving it.

Maybe swaybar is binding?

[DoubleSidedTape]

Is this new? AFAIK, the whole point of the CMP bushings was to account for the thickness (1/8") of added plates. Not raise it even higher than stock.

An extra 5mm would be something to take into consideration.

I believe the point is to correct the geometry change that occurs both from the plates pushing the subframe away from the chassis as well as from lowering the car. I don’t see a measurement indicated but next time I’m under my car I can measure the difference in height. It’s a big deal because it makes it very hard to get a socket on the front diff bolt if the front brace is installed. When I put mine in a few weeks ago I torqued that bolt first and then put the front brace in.

[Tbonem3]

I believe the point is to correct the geometry change that occurs both from the plates pushing the subframe away from the chassis as well as from lowering the car. I don’t see a measurement indicated but next time I’m under my car I can measure the difference in height. It’s a big deal because it makes it very hard to get a socket on the front diff bolt if the front brace is installed. When I put mine in a few weeks ago I torqued that bolt first and then put the front brace in.

Interesting. So Cayn went ahead and assumed people are lowered by X amount, to further correct roll for those clients? I wonder what decrease in height he calculated for.

[Cubieman]

I’ve never had to roll it.

I make sure car is in neutral, no ebrake on. Push down on each corner hard 2-3 times. Have never seen the ride height change more than a 1/16” after driving it.

Maybe swaybar is binding?

No sway bar on yet, or driveshaft.

[oceansize]

Interesting. So Cayn went ahead and assumed people are lowered by X amount, to further correct roll for those clients? I wonder what decrease in height he calculated for.

From here:

Concerning camber geometry:

If the car these bushings are fitted to has been lowered ~13mm, (1/2”) or more, you’ll find that the change in rear camber from both is equally opposite and you'll remain roughly in the same range of adjustment as before.

If the car is still at factory ride height, the resulting change in camber geometry limits negative camber adjustment to less than ideal for sporty driving. We'd like to imagine that if you've purchased these subframe bushes this likely isn't your first suspension modification however, if your car is still are factory ride height, adjustable camber arms are required to dial in more negative camber.


And Then concerning roll:

Fitting underside reinforcement plates to the subframe mounts increases the distance between the centre of gravity from the roll centre creating additional body roll and less rear wheel grip based on the theory above.
Our solid subframe bushings aren’t intended to counter just the change due to fitting reinforcement plates but further improve geometry for better stability and reduced body roll.

[oceansize]

No sway bar on yet, or driveshaft.

Unless there is something really odd about your car or setup you will be fine when back together and moved. When lowering my car after being suspended it looks 15 to 25mm higher, ride around for 10 seconds and I'm back to normal. I can't budge mine pushing on it.

[repoman89]

Unless there is something really odd about your car or setup you will be fine when back together and moved. When lowering my car after being suspended it looks 15 to 25mm higher, ride around for 10 seconds and I'm back to normal. I can't budge mine pushing on it.

Mine too. The tires don’t sit flat on the ground until the car rolls. They stick in as the car gets put down since the outside of the tires grabs the ground first. Then they deform and the car looks like it has a bunch of positive camber and high ride height until you drive or roll it. Pushing down on it is not enough to release the grip that the tires have on the ground and spring them outward laterally.