GB: DRM Coilovers - ZR-1 Net Registry Forums

Aurora40 · 12-26-2012

There are a few things that we did/need to do that I thought I'd clarify.

One is, Pantera, we did not follow your suggestion for cutting the bushing. Cutting the bottom one seemed like a bad idea, as it is not that thick to begin with, and cutting 1/2 of it off would have left almost nothing. I do appreciate the help though.

The bottom bushing is taking all the force of the car slamming into bumps, while the top bushing would only take the unsprung weight, and only ever 1g worth of acceleration on it. So cutting the top bushing seemed more prudent. We also only cut about 1/4 off of it, not in half. This was enough to assemble the shock around Carter's plate. And we did not reuse the black flat washer, just the gold top one.

Additionally, Mike was of the impression that you only have to cut the frame where you can see through Carter's plate. I don't know if that was in a write-up or Carter said that, or where it came from. But it is not true.

If you look at the crude drawing I posted, bolting the plate in place and cutting the overlap will only make a hole big enough for the center section of the bushing assembly. The top is quite a bit wider than that, though. So that will not be enough material removal to insert the shock into the frame, and slide it forward to bolt it in place. It will not be able to slide forward because the bushing will not fit in the notched out area.

Mike has been grinding this out a bit more, but it seems that the plate doesn't address the concern of "how close to the bolt hole can you grind the opening before the remaining material isn't strong enough?" You still have to guess, test-fit, and hope you don't make a mistake.

I do wonder if the stock rubber bushing would let you trim less, as it is much more rounded in shape, and may slide over some small amount of the frame when pushed forwards. I don't know why a poly bushing is included with the stock kit, if this is "needed" to address some engineering/stress concern, or if it's just assumed most people think poly is better, so they toss it in as a nice gesture (or to offset the lack of any instructions)?

12-26-2012	#22
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,704	Re: GB: DRM Coilovers There are a few things that we did/need to do that I thought I'd clarify. One is, Pantera, we did not follow your suggestion for cutting the bushing. Cutting the bottom one seemed like a bad idea, as it is not that thick to begin with, and cutting 1/2 of it off would have left almost nothing. I do appreciate the help though. The bottom bushing is taking all the force of the car slamming into bumps, while the top bushing would only take the unsprung weight, and only ever 1g worth of acceleration on it. So cutting the top bushing seemed more prudent. We also only cut about 1/4 off of it, not in half. This was enough to assemble the shock around Carter's plate. And we did not reuse the black flat washer, just the gold top one. Additionally, Mike was of the impression that you only have to cut the frame where you can see through Carter's plate. I don't know if that was in a write-up or Carter said that, or where it came from. But it is not true. If you look at the crude drawing I posted, bolting the plate in place and cutting the overlap will only make a hole big enough for the center section of the bushing assembly. The top is quite a bit wider than that, though. So that will not be enough material removal to insert the shock into the frame, and slide it forward to bolt it in place. It will not be able to slide forward because the bushing will not fit in the notched out area. Mike has been grinding this out a bit more, but it seems that the plate doesn't address the concern of "how close to the bolt hole can you grind the opening before the remaining material isn't strong enough?" You still have to guess, test-fit, and hope you don't make a mistake. I do wonder if the stock rubber bushing would let you trim less, as it is much more rounded in shape, and may slide over some small amount of the frame when pushed forwards. I don't know why a poly bushing is included with the stock kit, if this is "needed" to address some engineering/stress concern, or if it's just assumed most people think poly is better, so they toss it in as a nice gesture (or to offset the lack of any instructions)? Last edited by Aurora40; 12-26-2012 at 01:01 PM.