Its not that noticeable now to me. I think the gap is there just to allow some extra rear end squat. Very few people buying $50,000 cars in '90 wanted something firm.
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Its not that noticeable now to me. I think the gap is there just to allow some extra rear end squat. Very few people buying $50,000 cars in '90 wanted something firm.
The air gaps are there to allow the rear subframe to deflect fore-and-aft during harsh impacts from potholes and the like. The webs of the bushing are oriented side-to-side allowing the subframe to resist movement during lateral thrust from cornering.Quote:
Originally Posted by Jon K
Filling the gaps will make impact shocks more harsh and, IMO, add little to the handling of the car. That said, bushings do get soft with age so that's why the urethane fillers would seem to "stiffen up" the rear end. I'd just pop a new pair of bushings in and be done.
I would say they tighten up the rear, significantly reducing oversteer. I tracked my car with and without them, and existing corners with the delrin inserts made the car a lot more stable, is was noticably improved. The extra noise vechile harshness was minimal.Quote:
Originally Posted by Anthony (M5 in Calgary)
How old are your subframe bushings?Quote:
Originally Posted by BigKriss
the car is 17 years old, 225,000 kms and never have been replaced. I will replace them with solid polyurethane bushes, i'm just waiting for them to be made. I'm unsure though what polyurethane bushes would be like for the e34, as I've never heard of members on here running with them before.Quote:
Originally Posted by Anthony (M5 in Calgary)
Back in '98 I purchased a '90 535 with ~160,000km. The rear subframe bushings were so bad the subframe would bang upwards at launch then thump down at coast, not to mention awful handling. I temporarily shored them up by using a couple of muffler hanger donuts from some other car (~2"ID,~3/4" cross section) on each side, 1 above and 1 below on each side mounted co-axially with the chassis bolt. That firmed the thing up so much that I almost forgot about them. When I had new bushings installed a couple of months later the handling difference was night and day - much firmer and more exact. I suspect you would find the same thing with just a new pair of OE mounts.Quote:
Originally Posted by BigKriss
Everybody is entitled to try upgrades to their cars - we all do it. So go ahead and try the urethane bushings and report back. BMW had some pretty savvy people designing these things originally though. FWIW, the M5 uses the same subframe bushing as a 535 so I doubt it is a weak link for handling or BMW would have upgraded it for the M5.
Jacking up or supporting E34s by the rear subframe will tear bushings up pretty quick too. I always jack using a floor jack at the factory jack point then support the rear with a jackstand under the subframe mount.
I just got my shipment of Delrin insert plates today and will try to install them on the weekend. As Anthony (M5 in Calgary) pointed out, replacing worn rubber subframe mounts with new ones will tighten up the rear considerably. However, removing the old subframe mounts is not an easy task for DIYer without a car lift, a torch or a sawzall. The other option is to take it to the stealer so they can use their special BMW puller to pull it out.
For the price of Bruno's inserts, I figured it was well worth the try.
Best write up on the planet for these inserts - and I've looked everywhere! Great job Qube.
Hmmm cool!
....putting this on the ol' wish list
:)