Adjustable trailing arm mounts hit fuel tank?

[Jswheeler1990]

Hi all,

I am looking to reduce the total amount of rear camber from approximately 3.5 degrees (according to my last wheel alignment) to 1.5 ish to align nicely with my front end. With some basic measurements and calculation I believe i will need approximately 14-16mm of movement on the inner trailing arm mounting point to give me the camber i am after.

I know there is generally a lot of talk on this subject, with people raising the subframe into the body on offset revshift bushes etc but i have a few question outstanding I hope people can help with.

1. how much difference do the 12mm refshift bushes actually make to the camber in degrees?
2. have people here installed the posi-lock shim system?
3. much movement vertical movement can be expected in the sub frame when driving along the road
4. and this is the one that is keeping me up at night - Even as standard I can only see a 15 - 20 mm gap between the top of the inside, driver-side trailing arm and the fuel tank (This may be because my subframe bushes are warn and allowing vertical movement but either way i do not want anything to hit the fuel tank). What gaps are people finding between the fuel tank and the trailing arm pivot points after the revshift bushes or adjustable bolt holes.

any help would be appreciated, thanks.

 

[the Nefyn cat]

Well, just been out and had a poke under mine, recent new polybushes and Whiteline eccentric swing-arm bushes, and there's a good inch between the top of the swing-arm pivots and the fuel tank. Unless the bushes are completely and utterly knackered they shouldn't get anywhere near each other. Not saying they won't ever, but things would have to be really bad.

 

[Jswheeler1990]

Thanks for getting out and having a look. How do you have your eccentric bushes set up, to reduced or increase camber?

Its interesting that you are finding so much room even with the eccentric bushes and i am finding so little stock. I might have a little but more of poke around in my lunch hour and see if there are any obvious signs that the bush is allowing vertical movement of the entire sub-frame.

 

[the Nefyn cat]

Mine are set up to reduce camber, don't feel I need as much as it had for road use. Maybe if I was to take it on a track day or two it might be different, but that ain't likely to happen. Have a good look at the bushes at each end of the transverse beam, if they're really bu55ered they'll let the swing-arms move in ways they're not meant to. If you look at the way the back end is laid out you'll see that the swing-arms can pivot about the spring,making the beam move in ways it ain't meant to.

That's the one I mean, if it allows the beam to bounce around that can/will cause problems. To test, jack the back end up to take the weight off the bush and try to lever the beam up and down. Any more than a bit of movement is a bad thing.

 

[Jswheeler1990]

Thanks,

Any chance you can get a photo of the more ‘car central’ trailing arm bush on that same trailing arm. That is literally the one I have concerns with and the one with the least vertical clearance.

My friend has done the Revshift bushes and we are planning to climb under and have a look tomorrow baring in mind that his will be 12mm higher than the polyflex bushes.

Nice job above by the way, the purple looks cool

 

[5harp3y]

I have the Revshift 12mm raised bushes fitted to mine. Absolutely no problems with the beam hitting the tank .

Massive difference in camber (not had it measured yet) but it's visibly different

 

[Antm72]

As above i have the Revshift kit fitted and the rear camber has decreased alot the car is low so rear camber was quite pronounced it is alot better after fitting the bush kit.

 

[the Nefyn cat]

Not a day for laying under the car, normal Welsh weather has resumed.I've got the Whiteline eccentric bushes on mine, no idea how much they've taken out of the camber but it's definitely a lot. Bear in mind that the swing-arm pivots on the bushes on the beam, there's no up and down movement there. I'll try to get under there once the rain stops. See, an optimist.

 

[g8jka]

Any links to the bush kit @Sharpy or @Antm72?

 

[5harp3y]

Any links to the bush kit @Sharpy or @Antm72?

Got mine from hack engineering as a supplier but here's the link to the manufacturer

http://www.revshift.com/product-p/psb-318ti.htm

 

[Jswheeler1990]

So I have been under mine and my friends z3s this weekend and found... with new revshift bushes my frends sits with an approximate 15mm gap between the top of the trailing arm braket and the fuel tank and a 8 mm gap between the top of the trailing arm and the fuel tank.