lowball is right, the factory bushings are extemely soft. when i was installing the Kartboy shifter bushings in my car, i ripped the stock shift bushing taking it out. ditto the steering rack bushings. the stock rubber bushings are designed for old grandmothers that don't want to rattle their delicate little bodies.

stiffer bushings will make the car feel more responsive and more communicative. whether or not that is a good thing depends on you, and what you intend to do with the car. if you're running stiffer than stock springs, or coilvers, you probably won't mind the little bit of NVH that they cause. the other upside is that they'll last longer than the stock rubber pieces, since urethane is a more durable material, and less prone to rotting like rubber.

 

Very thorough! Thank you very much. That answers a lot. (I dont think thats very much for such a wide variety upgrade.)

If you ride in a car that vibrates like a crazy even at idle, its a good chance the bushings are worn out. Correct assessment?

It means having to uproot every part conncecting to more or less the "hull" of the car. Thats a lot of work. I figure that will take a few days to install (estimate) every bushing on the car. Labor costs must be huge for that type of work or physically sucky if you do it on your own =P

 

if you were to install every bushing on the car yourself it would be a hell of a lot of work. i know of at least four to six bushings that have to be pressed in, so unless you have an arbor press in your garage (unlikely) you'd have to find a shop to press them in. once that was done, you'd need to get the car realigned front and rear since there is virtually no way you're going to be able to get the front control arms, rear lateral links, and rear trailing arms off and back on without hosing the alignment. i figure a good home mechanic with a press could do it in a weekend, as long as his/her significant other didn't mind not seeing much of them that weekend.

 

on the 1.8 the sti pitch stop is stock so if you want one i have it just laying someplace

 

subarus equiped with the 1.8L ej engine
93-96 imprezas
legacy too but dont know years except that my mom's 95 has one

 

Will the polyurethane bushings squeak as the suspension moves?
Which brand of bushings should be used? Energy, SuperPro. Which are best?

 

They can squeak if they're not lubricated. Brand doesn't matter very much, they all work fine.

 

We are very fortunate because Subaru, unlike most all other car makers, offers a high stiffness version of every suspension bushing on the Impreza in the most silent and extraordinarily durable material - RUBBER. I wouldn't even consider using poly crap when the real deal Group N bushings are available right from the dealer.

 

Rubber is organic for one and need to be replaced over time. Rubber has different properties than poly material. Rubber compresses and poly doesnt really compress it just flows. Both are nice but you will handle better with the poly stuff because it is stiffer. Cheaper too compared to dealer prices.

 

That's right, it's a natural product from trees.

Yes, rubber is subject to ozone degradation and will dry out over a period of say 30 years.

True, if they were the same then we wouldn't be having this discussion.

Okay, here's where you start to go astray. The Poissons ratio of rubber is 0.49, one of the highest of all materials. Steel for example is only 0.3. This means that rubber is less compressible than steel!


My ex-wife is nice. That doesn't mean much.

Rubber and poly materials are both moldable in a range of stiffness. One is not fundamentally stiffer than the other.

Stiffer suspension bushings certainly do not universally provide improved handling.

This is true, and for good reason. Rubber parts are much more durable and quiet. Because rubber is so very elastic, it can provide all the articulation requried in a suspension bushings through shear motion without any sliding motion required. This makes rubber suspension bushings fundamentally quieter, more durable and maintainance free.

 

If its just left on the shelf. In a automotive aplication 2-5 years it the life before a noticeable difference in handling results. Remember salt and oil accelerate degradation alot. If you think different there are many people that have replaced all the bushings with new on a 10 year old car and it was a huge difference.



Ah a engineer. Ok you got me. Did alittle research I had it *** backward. Well someone else did because that was how it was explained to me. Though I guess in a correctly designed bushing it wouldnt matter because hardness it much more important.



Both are nice in the respect that one would assume they are the same hardness in a comparison. A stiffer bushing will always handle better. You are able to keep static alignment as well as dynamic alignments closer to what you have it set to. Now granted with the harder bushings you might have to change the hardnesses of different bushings when you have side load issues.


I wouldnt say quiet. I have rubber bushings that need to be lubed just like urethane. Every few months they need to be sprayed(front swaybar bushings). They are also getting very soft. The spray to keep them lubed is making them break down alot faster. They are not maintainance free. The thing is the bushings on newer cars are vulcanized to a center bushing and pressing in to a control arm or what ever it goes into. Thats why you have alot less problems. They dont have to rotate on metal(unlike swaybar bushings which are metal on rubber moving all the time). Thats normaly why your urethanes squeak. For the most part you just put them in some without the need for a press. They are rotating on metal. Though they do transmit more noise because they are normaly harder but rubber has the same problem.

 

Yes rubber bushings get old, but poly ones get old faster. And they tend to get brittle over time and cumble.

Yah, rubber sway bar bushings can be noisy like poly control arm bushings since unless they are bonded to the bar, they must allow atleast some rotational slipping.