The great suspension bushing debate- rubber or poly...
#41
Will do after my next race. What pushed me over the edge was killing a $150 AIM oil pressure sensor due to vibration. I was not going to do that twice. The other big reason was not being able to see out my rear view mirror when it hit a certain RPM. It's hard enough watching your mirrors without objects being so blurry. I could not tell what kind of car they were most times.
Last edited by k24madness; 05-03-2013 at 11:55 AM.
#43
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Bump- Just an update to say I replaced the diff. bushings with the ES units. I followed the "no need to remove diff" method and it worked like a charm. The air hammer made it super easy. The one thing we did differently was to remove the rubber from the "caps" under the mounts, we used an air chisel to scrape the rubber off, followed with a quick hit of a grinder. Was super easy and fast, no need to burn anything.
Impression- Noticeable difference right away when engaging the clutch. Much less clutch/drive line shudder*. NVH is minimal- the Beatrush PPF braces was more noticeable when installed. Would recommend. When we got all the bracing and exhaust off, I could actually see where the OE bushings had been moving withing the carrier as displayed by a smooth/shiny ring seen at the bottom of the bushing...kinda like the area next to the rear sway bar by the mounts where you can tell there is some side to side movement. Now that I removed and replace the exhaust, it's rubbing somewhere, no biggie though.
*I suspect the engine mounts I changed back in Jan are already toast as a side-effect of the bad diff. bushings. Will replace soon. I'll be looking into the information posted that the 90-93 engine mounts are stiffer than any of the others. I'd like to go with the stiffest rubber ( ) or the AWR mounts (go big or go home if using poly, right?)
Impression- Noticeable difference right away when engaging the clutch. Much less clutch/drive line shudder*. NVH is minimal- the Beatrush PPF braces was more noticeable when installed. Would recommend. When we got all the bracing and exhaust off, I could actually see where the OE bushings had been moving withing the carrier as displayed by a smooth/shiny ring seen at the bottom of the bushing...kinda like the area next to the rear sway bar by the mounts where you can tell there is some side to side movement. Now that I removed and replace the exhaust, it's rubbing somewhere, no biggie though.
*I suspect the engine mounts I changed back in Jan are already toast as a side-effect of the bad diff. bushings. Will replace soon. I'll be looking into the information posted that the 90-93 engine mounts are stiffer than any of the others. I'd like to go with the stiffest rubber ( ) or the AWR mounts (go big or go home if using poly, right?)
#44
*I suspect the engine mounts I changed back in Jan are already toast as a side-effect of the bad diff. bushings. Will replace soon. I'll be looking into the information posted that the 90-93 engine mounts are stiffer than any of the others. I'd like to go with the stiffest rubber ( ) or the AWR mounts (go big or go home if using poly, right?)
#47
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See- I REALLY wonder if there is a hard(ish...ist?) rubber bushing that can be used as opposed to the poly in the AWR mounts and if it would make a difference and will hold up.
#51
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My car is a rattletrap driving down dirt roads. On a paved road, with mazdacomp motor moutns and brand new OEM diff mounts this **** is butter. No buzzing from the chassis, just the exhaust which isn't even that loud anymore.
#55
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I'm not following? MazdaComp (aka Mazdaspeed) and Mazdaspeed Miata (MSM) are different. Well, I was implying between those two, the comparison to the 'harder' NA mount.
I figure, I just seek the knowledge to know the difference and how they may compare.
I figure, I just seek the knowledge to know the difference and how they may compare.
#56
I have never had a brand new set of MSM mounts in my hand to compare durometer so I don't know. Different part number though.
NB mount - softest. I forget the actual durometer measurement.
NA mount 55 durometer
Comp mount 70 durometer
My guess is the MSM mount is somewhere between the NA and Comp mount
NB mount - softest. I forget the actual durometer measurement.
NA mount 55 durometer
Comp mount 70 durometer
My guess is the MSM mount is somewhere between the NA and Comp mount
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#59
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...and after getting my engine mounts out, I see that I indeed used MC and not MSM like I had been thinking. I also found that the MCs are notably stiffer than the ILs. So I left the MCs in. Did some other tinkering on the car too...car is feeling much better to drive again.