The great bushing debate

BikerSC

Registered User
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I have been doing some searching on the poly bushings vs. rubber bushings and have some questions. I am hoping Duffy will ring in here. I know that poly bushings will negatively affect the ride quality. And I know that some claim that the poly bushings don't help the handling enough to justify the cost, but do they help the handling? Is there any situation where the poly bushings have been proven to hurt the handling? I know I read somewhere about the poly bushings slipping out (of the control arm?) in hard cornering, can anyone ring in there?

I am wanting tight steering and tight handling, as close to BMW as I can per say. I am wondering if the "best" setup would be a good amount of poly with some of the bushings being rubber.

I am already planning on chassis stiffening as much as possible.

Thanks.

-Steve
 
People who race claim that the car performs best with rubber. Chassis stiffening (subframe connectors or STB's) will be a big plus. Ford used poly in the steering rack bushings on their race car. The diff should be supported with poly on both ends. Rear subframe should be made solid to the body. That is enough to keep you busy for a long time. ;)
 
XR7 Dave said:
People who race claim that the car performs best with rubber. Chassis stiffening (subframe connectors or STB's) will be a big plus. Ford used poly in the steering rack bushings on their race car. The diff should be supported with poly on both ends. Rear subframe should be made solid to the body. That is enough to keep you busy for a long time. ;)


so wich one should be a priority a rear STB or the front one?
 
Thanks Dave. That is kind of what I was leaning toward. I was thinking that wfor the suspension, rubber would be the best way to go (from what I have heard), but I want the poly steering bushings. I will go with the poly diff bushings. Should I just maching some solid spacers to bolt in inplace of the rear subframe connectors? I could do those out of aluminum, steel, or even plastic.

-Steve
 
Anything solid is fine. Don't bother with any kind of poly or plastic. Keep in mind that a special fixture is required to remove the stock IRS bushings.

As for STB, the front will make the biggest handling difference but the rear will help you avoid cracks in the floor of the car which is common when suspension modifications are performed (and even when they are not).
 
Bushings or Connectors?

BikerSC said:
Should I just maching some solid spacers to bolt in inplace of the rear subframe connectors? I could do those out of aluminum, steel, or even plastic.

Steve, are you talking about Rear Subframe Bushings, or subframe connectors?

I'd buy a set of solid alum. subframe bushings right now, if you can get'em made!!!!!!

68COUGAR
 
If someone has a of subframe connectors, I could make them out of just about anything. Alum is one consideration but what about a high durometer polyurathane material, just a very little compliance and much more durable than the stock rubber. Again if someone has a spare that I could reverse engineer, I will make some.

Super XR7
 
Bushings OR Connectors?

Super XR7 said:
If someone has a of subframe connectors, I could make them out of just about anything. Alum is one consideration but what about a high durometer polyurathane material, just a very little compliance and much more durable than the stock rubber. Again if someone has a spare that I could reverse engineer, I will make some.
Super XR7, are you talking about the rear subframe bushings or subframe connectors?

If you're talking about subframe bushings, I'll buy a set.

68COUGAR
 
68COUGAR said:
Super XR7, are you talking about the rear subframe bushings or subframe connectors?

If you're talking about subframe bushings, I'll buy a set.

68COUGAR
Do you have a rear subframe connector that I could reverse engineer?
 
Rear Subframe Isolators (Bushings)

The Upper & Lower Isolators are what I'm talking about.

Rear Subframe Bushing.jpg


The isolators are compression fit into the holes, so you can't simply create the same thing in poly.

68COUGAR
 
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Special Fixture?

XR7 Dave said:
Keep in mind that a special fixture is required to remove the stock IRS bushings.

What kind of special fixture is required to take the subframe bushings (Isolators) off?

68COUGAR
 
68COUGAR said:
The Upper & Lower Isolators are what I'm talking about.

Rear Subframe Bushing.jpg


The isolators are compression fit into the holes, so you can't simply create the same thing in poly.

68COUGAR
I had my subframe off the car last spring and noted that the bushing design allowed a great deal of movement within the rubber. I also noted that a bushing could be made into two pieces, with a center tube going thru both bushing and then be secured with a bolt and washer. Have you had yours apart? What are your thoughts on this? One of my other thoughts was to add two donut shaped pieces to each mount one on the top and the other on the bottom of the OEM bushing. They would fit around the protruding rods that come from the center of the OEM mounts and extend out to the ID of the frame. They would be just above the lower cap plate (cover) and into the above cone part (upper isolator). This would help stiffen up the existing bushing. I wished that had I taken the dimensions of the upper as I can measure the lower relatively easily.

Super XR7
 
Dave, what mount are you refering to is made of polly that mounts to the back of the diff? If you are refering to tbird88's diff mount I ordered it back in december during the group buy and still have not gotten it yet. I have KB aluminum bushings on the front of my diff so I'm good there.

Shane
 
Re: Poly Rear Diff Mount

quick35th said:
Dave, what mount are you refering to is made of polly that mounts to the back of the diff? If you are refering to tbird88's diff mount I ordered it back in december during the group buy and still have not gotten it yet.
Shane, Did you send Wynn (tbird88) your old rear diff. mount? I sent him mine when I ordered my poly. rear mount. I got my poly. mount back pretty quick. Have you contacted Wynn about it?

68COUGAR
 
68COUGAR said:
Shane, Did you send Wynn (tbird88) your old rear diff. mount? I sent him mine when I ordered my poly. rear mount. I got my poly. mount back pretty quick. Have you contacted Wynn about it?

68COUGAR

No I never sent him my old diff mount. He gave us an option to pay $10 extra if we were not sending in a core with our money. I paid that extra $10 and also sent in extra money for his intercooler gaskets too. I haven't got them either. I supose I should get ahold of him to find out where my mount is. I just figured that he was really buisy because I have seen updates and he wrote in his thread that he was working on mine. I guess I have been alittle to patient and need to find out what is up with it.

Do you have his phone # so I can get ahold of him?

Shane
 
Re: Phone #

quick35th said:
Do you have his phone # so I can get ahold of him?
I don't have his phone number anymore, but his E-ddress is: tbird88 AT datarecall DOT net

It may take him a couple of days to get back to you. I know he's Very Busy.

I hope this helps resolve your problem.

68COUGAR
 
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