RotaryRevolution

so why is it so hard to find a suspension bushing kit for the FD, all i can find are kits for the first, and second generation.... why arent FD kits more popular? where can i find one of these top seceret, hidden in the dark kits?

bartlette84

not sure but i am also on a mad goose chase trying to find this kit..

RotaryRevolution

actually i found that there is a group buy going on at the rx7 club for a Full delrin(similar to urethane) bushing kit for the FD

bartlette84

can you link me to the thread? also how much are they going for?

eyecandy

What kind of bushing kit are you looking for?

treceb

delrin is similar to polyurethane which is not urethane. i think....

polyurethane = no flex, urethane = flex???

eyecandy

This can get very complicated, but I will try to explain simply. Polyurethane = urethane (there are many groups of urethane; polyurethane contains many) Delrin is not similar to Polyurethane.



Delrin has many different grades ranging from self-lubricating, to non self-lubricating, tensile strength (8500-12000psi), shatter strength, flex strength, no shock absorption (on all), varying coefficent of frictions, each designed for a different application, think of it as a synthetic rock.



Polyurethane (urethane) on the other hand is essentially one grade, with a VERY broad range of hardness (durometer) it can be soft and flexible as a rubber band or as hard as skateboard wheels (or harder, harder than Delrin). Polyurethane is very tough, its abrasive and tear resistant, crack/shatter resistant, shock absorption, low coeffiecent of friction, broad temperature range, and LONG service life. Polyurethane is one of the best materials known to man.



To give you an idea the OEM bushings are in the ***-60 duro range, Mazdaspeed is in the A60-70 range, and Autoexe bushings are in the A70-75. A good rule of thumb is for every 5 duro increase, the stiffness increases 50%.



There are different scale ratings for material hardness, polyurethane is in the A "softer" and D "harder" Shore scale, Delrin, Nylons, Torlon (harder plastics) are in the M or R Rockwell scale, and sometimes they are shown in the D scale. Here is a good link that may help http://www.matweb.com/reference/shore-hardness.asp Delrin is in the range of R115-125, which is about 83-88 on the D scale. To give you an idea 60A polyurethane would be about 10-15 on the D scale.



The reason for the multple scales is like the same reason we have, inches, feet, yards, etc.



I hope you were all able to follow, if not let me know.

treceb

so the autoexe bushings are bout 200% stiffer that stock, yet not solid like jimlabs or delrin?

bartlette84

where can we order these from???