THSCC Forums

Does anyone here know what exactly the difference in performance and feel of delrin bushings as compared to poly ones. Ryan has some stock of delrin I could probably use to machine some bushings, but I don't want to do it if the ride will be horrible compared to what poly would give me. I know how to write machine code and have access to milling and lathe equipment so buying this stock and making my own will be way cheaper that buying aftermarket.

_________________
2006 Civic Si - #24 HS for 2015

2005 GMC Sierra
1991 318is Garage Ornament

Polyurethane bushings come in many different durometers, or hardnesses, although most vendors don't list them. In my personal experience, delrin is very hard, like solid nylon only tougher, while poly bushings seem to be made to allow some compliance...kinda in-between soft OEM rubber and delrin.

Personal experience...if you use delrin, you WILL feel a difference in street driving, and it may be unpleasantly harsh.

Hope this helps!

Jamie

I thought the only difference was that Delrin was self-lubricating, so they won't squeak at all. This might also help prevent the bushings from wearing out due to rubbing.

_________________
www.ncvw.org
1993 VW Corrado VR6 - DSP15 (RIP)
1986 MB 190E 2.3L 16v - STX (SOLD)
1997 BMW M3 3.2L - BS for now

I am not a "real" engineer (just a computer guy with engineer in his title), but seeing this discussion on several other boards, here's what I know:

>Delrin bushings on the street will be BRUTAL.
>Polyurethane hardness is measured on the durometer scale
>Delrin hardness is measured on the rockwell scale - metals are measured on the rockwell scale, if I'm not mistaken.

Working on a friend's car earlier this year, we installed a complete set of poly bushings. The difference from 50K oem rubber bushings and "soft" poly bushings from Energy was DRAMATIC. The car was much more responsive, but definitely transmitted a lot more NVH. Hitting a small pothole sounded like a shot going off. Larger bumps - no problem, but small sharp stuff (high frequency) was nasty.

Delrin can be done on a street car, but it will be a major compromise on comfort.

_________________
Tom Freeman
'98 M3/4/5 | '93 Spec3 325i | '12 TSX sport wagon | '03 Tahoe
Team Silver Bullets '91 240SX

I currently have delrin control-arm bushings on my GTi, and it did in fact, make a huge difference in both handling and ride... none to pleasant over rough surfaces, but it could be worse (spherical bushings anyone?)

Ihad all three on the 84GTi when it was a street and DSP car then
later an pure ITB race car.

From an engineering standpoint Delrin is far superior than Poly. In fact for most cars, I would keep stock rubber busings before switching to polly
I believe they are that bad.

Polyurthene compresses and expands under load , slightly less than
rubber bushings, but they swell and bind up the suspension when it compresses while Rubber does not when it swells up. So Ok, you end
up with less camber loss, that's cool, but you also end up with the wheel rates jumping to some astronomical value when the suspension binds up.
The car starts to push but won't respond to lower spring rate changes.

You end up chasing your tail. At first, I did not believe this, but I fould it to
be true. You can read what Dick Shine has to say about Polly
busings on his web site: SHINERACING.com I belive the word "EVIL"
is used but not for reasons that has to do with ride quality.

My car qlways understeered like a pig until I switched to Drelin LCA busings. No other changes, and I was finally able to start increasing front spring rates and able to gain grip ( with strut suspension).

Drelin was cheep but did not last long so it was more cost effective,
in the long run, to switch to sperical busings. Even less understeer
with Sperical and thus far I have not had to change them in 4 seasons
so they have paid for themselves. But they are pricey: the VW was
$400 for the LCA's, The rear of the Corvette was close to
a $800 but to me worth every penny.

On the street the Drelin or Sperical busings are not that bad. I actually
liked the way the feel. I replaced all 5 links in the back of the Corvette
with Sperical and I just love "the hooked up" feel of the car . I drove
several VW's with sperical lower controll arms with the stock rubber
strut bushings and they were no worse than pollyurthane comfort wise
but they did make more noise, espically on pavement seams.

We are not in Michagan where the roads have wide expansion joints.
For the driving we do here I would not have a problem with confort
but others may disagree. Spirical busings actually transmit more noise than harshness as drelin will dampen noise because it is a form or Nylon or plastic and has some dampening qualities.
Personally I like road feel I don't like a car that feels disconnected but other people are totally opposite. (which is why they sell Japanese cars!)

Sugest this: put 40-42 lbs in your tires and
drive for a day or two, thats very close to what it will feel like from a
ride/comfort prespective.

_________________
Mark Vitacco
THSCC TT Chairman
mvitacco@bellsouth.net

Thanks that was exactly what I was looking for Mark. I've decided I don't like FWD enough to put money into a Cavalier. I'm searching for an 88 Formula Fiero(a free one just narrowly slipped from my grasp. ) now but of course that will work great on that car.



I ride around at 51 right now in my current tires.

_________________
2006 Civic Si - #24 HS for 2015

2005 GMC Sierra
1991 318is Garage Ornament