forsolo2

I have a C4 and the suspension bushings are shot. I'm going to change them and everyone I talk with says go with poly but I'm under the impression this will take the car out of stock class in SCCA autocross. Is this true and if so where can OEM rubber bushings be found? My local Chevy dealer was telling me he could get me poly-graphite.

Thanks for any help.

acrace

Yes, poly (if the originals were rubber) do take you out of the Stock category.

Which bushings are shot? Some of them are not available as service parts individually (like the front suspension control arm bushings).

BrianCunningham

GM won't sell you just the bushings. It's cheaper to get the poly.

Unless you going to the nationals I won't worry about it.

forsolo2

"Which bushings are shot? Some of them are not available as service parts individually"

Rear spindle support rod and rear upper and lower control arms. The rear feels, with any bump in the road or change of power, as if it wants to go anyway but straight.

Does this mean I'd have to buy new rear upper and lower control arms and rods to get bushings?

RX7 KLR

Far as I know the bushings were never available alone, you have to buy the complete component, control arm, support rod etc... The bad news is many of those items were discontinued years ago and best case is you will find a decent used set.

90pololt4

Jason,
If he cannot buy new ones, what is the current provision for aftermarket in stock class? Is it time to write the SEB about some of the older cars and ask for help?
Rod

forsolo2

That's a good question. GM Parts doesn't have upper and lower control arms. So, no bushings, even if I was willing to buy the arms just for the bushings. Rods are a special order item, but available.

So, yes maybe it's time to write the SEB about some of the older cars.

RX7 KLR

There is no provision or allowance for an old car to upgrade. If you can not find NOS or good used parts you could try to have some rubber ones made. There are older cars than C4s in stock classes and to date no allowances have been made just because the only replacement part is an upgrade. You have about as much chance of getting poly allowed in stock as you do getting GM to replace the old part number with a poly one.

The C4 is a perfect example of how you could really upset the stock classing structure if you were to allow them to upgrade to poly bushings. Already the C4 is one of if not the most dominate car in AS. Now if you allow them to replace all of the rubber bushings on those old C4s that are already the top dog in the class what happens to all the other cars in the class.... They fall further behind. On the other hand it would also kill the C4 if you were to say you can upgrade to poly but so we don't wreck AS you have to move to SS.

So then if you allow poly in every stock class you just made it a must have item for every car out there and drive the cost up for everyone so a few old cars can hold on to life for a few more years. It is a lose lose situation.


I got my last good used set from these guys: http://www.ikerds.com/ They sell re-manufactured control arms with new ball joints and poly bushings. I just called and asked for a set with new ball joints and decent used bushings, the set they sent me were in great shape.

BrianCunningham

Did GM make them or where they supplied by an outside vendor?

If it was an outside vendor, phonecalls could be made.

I've said it in the C4 Tech section as our cars get older, we're just going to have to learn to be more self efficient.

rhneff

RX7 KLR has quite clearly explained both the rules and the rationale behind not allowing poly bushings, and in that context your comment above is IMO very bad advise to the person originally asking the question.

Poly bushings are illegal for Stock class use, period. Suggesting that's only important at Nationals implies it's okay to cheat at local events. IMO it's not okay to cheat at any level, because in doing so you're only cheating yourself. Auto-x is, after all, an amateur sport with for the most part only trophies and bragging rights available for winning - so if you cheat to win, how are you going to feel about your victory?

And by the way, those of us who have spent literally thousands of dollars on factory parts to abide by the Stock rules will not feel at all remiss in taking that win away through protest.

BrianCunningham

I didn't suggest that it was OK to cheat, I suggested that most local clubs won't care unless he's winning.

What are you going to do now that GM is no longer suppling them then?

RX7 KLR

Well you can buy new rubber bushings for a C3... Maybe one day if the C4 is worth restoring someone will make them.

See if you can find someone to custom build a dozen or so sets of rubber bushings, I am sure there will be a market for a few sets some day. Someplace on the net I even saw the specs for the rubber hardness of base and Z51 bushings, I bet Hib knows.

The one good thing you have going for you is that Howard Duncan, SCCA program development manager, has my C4 now. In a few years he may need new bushings and will feel sorry for ya.

RAFTRACER

I may know where a relativley large supply of used upper and lower front control arms are w/Z51 bushings......PM me and I'll se if I cant acquire some.....