Bushing Help Please

#1

I’m new here, not a Spec E30 racer but rather a future one (if you raced at the championship this year I saw you). I’m researching suspension components right now and plan to do the first stage of my build this winter.
What bushings do you guys use? I was thinking of using AKG 75D urethane for RTAB, CAB (offset) and AKG aluminum for motor, tranny, subframe, and diff. Do I need to worry about increased vibrations breaking anything?

Should I also do spherical bearings on my rear shock mounts (planning on GC plates up front)?

I thought about turning my own out of Delrin or Nylatron (nylon impregnated with MoS2), but I need dimensions. I could tear it apart and measure, but that would increase the amount of time my car was apart. Does anyone have dimensions or drawings?

Thanks.

#2

In my opinion…

AKG 75D poly bolt through motor and transmission mounts
AKG Aluminum differential and subframe bushings
AKG 75D poly trailing arm bushings
AKG 75D offset control arm bushings
Rouge Engineering rear shock mounts with race bushings

I’d be concerned that aluminum motor and transmission mounts might change the vibrational characteristics of the engine in a harmful way.

And while doing this, add weld in rear camber/toe adjusters.

#3

Thanks. I had planned welding in adjusters. I know they’re just tabs of metal, but are any better designed than others? I’ve read that people with stiff bushings sometimes have them slip out of adjustment on the track.

#4

9.3.1.8.1. Alternate, [color=#ff0000]non-metal[/color], motor mounts, providing the same height as original, are
permitted.

9.3.12.5. Alternate, [color=#ff0000]non-metal[/color], transmission mounts, providing the same height as original, are
permitted.

#5

Sorry, I know I need to RTFM, I just had read the suspension section where it says you can swap materials…should have checked drive train.

#6

The new IE serrated plate adjusters look like they may hold their setting better, though I suspect they will be a pain to adjust. I made “jack screw locks” for the common adjusters to eliminate this problem.

#7

I have the IE serrated adjusters. They are not that bad to adjust. I mark them when set and if need to adjust just reference the marks. Take care in that you place them correctly so you get the max adjustment in the directions you want. At Nationals I was hit and got a bent trailing arm. Ended up with 3/4" of toe out all on the right side. I adjusted both sides to as far in as I could and got to 1/16" toe out which was manageable. Of course the rear wheels were no longer in line with the front.

#8

The new IE serrated plate adjusters look like they may hold their setting better, though I suspect they will be a pain to adjust. I made “jack screw locks” for the common adjusters to eliminate this problem.[/quote]

Can you explain what you mean by “jack screw locks?” I’m having a little trouble visualizing that.

#9

[quote=“jlevie” post=68901]In my opinion…

AKG 75D poly bolt through motor and transmission mounts
AKG Aluminum differential and subframe bushings
AKG 75D poly trailing arm bushings
AKG 75D offset control arm bushings
Rouge Engineering rear shock mounts with race bushings

I’d be concerned that aluminum motor and transmission mounts might change the vibrational characteristics of the engine in a harmful way.

And while doing this, add weld in rear camber/toe adjusters.[/quote]

A few quick questions.

  1. Do we use the 10mm rear shock mount?
  2. By race bushing you mean the rear shock mount with the spherical bushing?
  3. Is there any reason to buy the stainless steel rear trailing arm bushings vs the aluminum ones? The stainless steel ones are $110 more.
  4. Will this suck to drive on the street? I realize it’s going to be a bit stiffer but I’m curious as to how bad it’ll actually be.

I totaled up the above parts and came up with $785.00 (aluminum trailing arm bushings + aluminum transmission mount cups).

#10

FWIW mine doubles as a DD although I don’t have the rear subframe hard mounted yet. The spec suspension itself is rather soft and offers no real discomfort on the street. All those solid bushings however will transmit noise like no-one’s business. It becomes a cacophony in the cabin. Fortunately I’m nearly stone deaf :wink:

#11

It’ll suck on the street.

#12

Yep!

#13

Hmmm. I guess I’ll have to give it some thought. The bushings on my car now are pretty much dead so I need to replace them with something. Maybe 75D all around would be best. Currently the suspension feels like it’s made of fruit.

#14

[quote]
It’ll suck on the street.[/quote]

Kyle normally pilots some kind of large ocean going vessel that has street mods and a Lay-Z-Boy interior conversion. At least that’s all I’ve ever seen him in. :wink:

I’ve got almost 1000 DD miles on the “racecar”.

#15

I have to say, I’m surprised no one turns their own. Maybe they just haven’t chimed in yet.

#16

[quote=“RRhodes” post=68960][quote]
It’ll suck on the street.[/quote]

Kyle normally pilots some kind of large ocean going vessel that has street mods and a Lay-Z-Boy interior conversion. At least that’s all I’ve ever seen him in. :wink:
[/quote]
If he could qualify on pole with that thing then maybe he’d be able to win by virtue of taking up the entire track.

#17

I offer a full set of bushings & motor mounts, all made from UHMW. We fabricate them all in house… No Chinese junk like some of the other bigger brands. My pricing is very competitive, and I keep everything in stock. I’ve tested all my parts on the track. Please check out my site, and if you have any questions about anything I’ll be happy to answer them.
Carlos
www.condorspeedshop.com