Re: [DMCForum] DMCH performance suspension

["Walter Coe" <Whalt@xxxxxxx>]

> Any thoughts on the DMCH Eibach setup?

DMC Eibach is the way to go if you are not worried about spending money.  You get shocks & springs that were purpose-built for the DeLorean and balanced front & rear.  But if you dont want to spend a fortune on new parts that you really dont need, you can keep the original rear springs just fine.  Some people will be correcting the cut & swap lowering blunder that was popular before custom springs were available.  Then they will need new rear springs because they will have been cut and put on the front.  And their too tall front springs will be on the rear making the rear probably too low.

If you buy any lowering kit that is not sold by DMCH, then you may only get a new pair of front springs.  The rear springs are quite fine as they came from the factory with the exception that replacement shock absorbers are hard to make fit.  Various adapter kits are available, but when you are messing with critical things like a car's suspension, you dont want anything to suddenly break.  So make sure that whatever alternative that you come up with will actually stand up to the job.  It holds a lot of weight.

As for springs, the PJ Grady ones are fine and priced fair.  I drove my car too many miles with a PJ Grady spring on my front right and an older DMCH spring on my front left.  I couldn't feel nor measure any effect between these mix-matched springs.  This tells me that all the new front springs are probably made to the same criteria: Length and Spring Constant the same.  

Of note about the PJ Grady springs is that they have more coils per spring.  This spaces the coils closer together and makes fitting compression tools on them more of a challenge.  Question your mechanic aptidude before you have a spring slip & kill you.  I kid you not -- I wore a full motorcycle helmet the last time I did front springs on a DeLorean.

The DMCH springs that I tested were the older generation pre-Eibach ones.  The springs they are selling now look very different.  The 'wire' is thinner.  And the springs weigh much less.  The first time I picked one up I nearly threw it over my head; it was so light.  Okay, I'm exaggerating a little.  I cant say that thinner, lighter & pretty metal flake paint makes a better spring.  But they look really cool anyway.  I wanna try a set of those next.

There are still issues with all the vendors shocks & bushings:

All front shocks, OEM & aftermarket the same, they bind on the lower control arm when the suspension is relaxed.  You will see this as missing paint on the side of the shock absorber.  It aint bad, but it aint so good either.

All non-OEM shocks have issues with the shank (upper) bushings.  The OEM ones were steel sleeved, per se, to protect them from the frame's tendency to cut the rubber.  Aftermarket shank bushings do not come with protective sleeves.  Therefore, they may cut & slip.  Then you have a metal shank slopping in a steel frame which you will notice as another clunk as you drive over uneven surfaces.  

I have had success with using a lathe to cut down aftermarket polyurethane bushings to fit.  Polyurethane holds up better than the soft rubber variety, but to do the job right, someone needs to make a smooth saddle for the bushing.  If I get a good lathe then I'll see if I can turn out a few.

Another problem with all aftermarket shocks (including DMCH's) is that the shanks are too long.  The threaded portion does not go low enough.  This causes the retaining nut to bottom-out before the bushing can be properly compressed to 20 ft-lbs.  The way I fix it is to stack a pair of washers under the nut.  That gives an extra 2 or 3mm of room to tighten.  This is the case with most shocks front and rear.  It is much worse on the rear due to suspension geometery.

The lower front bushings work satisfactorily because they are not bearing any weight.  The lower rear bushings are another story.  Due to poor design, this bushing is being crushed unevenly by the car's weight.  This is because the lower body of the shock absorber is holding the spring which is holding the car's weight.  Generic shock absorbers are not intended to carry that much weight.  If you try this then make sure the metal thickness is appropriate and that the welds look good.  I have seen aftermarket ones sold with custom lathe-turned bushings.  Many generic shocks wont have bushings strong enough to handle the abuse that a DeLorean would put on it.

Another issue with the lower rear bushing is with suspension geometry.  With the car stable, this bushing has a bolt shank going thru it at an angle.  This does not make good use of the bushing's properties.  With such a pre-load, it is more apt to tear or crack.

The best solution, I think, is to make a new rear hub carrier.  Have the carrier hold the spring directly.  Let the shock absorber alone and let it only be a shock absorber and not a support for the car's weight.  And while we are changing the hub carrier, maybe we could make it take a better bearing.  And maybe a better hub, too.  Like a 5 bolt pattern.  And while we are in there, how about a better caliper & rotor, too.  Oh shit, we got a lathe & a mill, let's just make a whole new car from scratch.  We'll just reuse the original stainless steel panels.  It's too much work to make the dies for that.  And it is about the only part of the car -- the style -- that they got right the first time.  The rest of the car needs to be totally re-engineered.

What a mess we have got ourselves into!
Walt

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