Prothane bushing question

[robdp44]

I read on RRE website not to install the prothane bushing located directly beneath the shock because it increases shock wear and noise. The noise i wouldnt mind, but I dont want to prematurely damage parts if I can prevent it. Has anybody isntalled this bushing and had any adverse effects to their shocks? Picture of lower suspension located below.

**EDIT** This is all related to the front suspension and not the rear.

http://www.roadraceengineering.com/parts/prothane/front_suspension_lower_arm_assembly.jpg

 

[wret]

The Energy Suspension kits don't even include those bushings anymore. Apparently they placed excessive side forces on the shocks. Your best options are either to leave the stock bushings or look into spherical bearings.

 

[logic]

I answered this question on the chicagodsm mailing list for you as well, but I'll answer here in case someone grabs this from the archives at some point:

They're right, don't install that one. There's a decent explanation of what's going on down there from Dennis Grant here:

http://www.wincom.net/trog/a-arm.html

DG's solution is the correct way to go, if you want to properly remove the rubber from that pivot point. If you want to see the properties he's talking about in action, jack the front of the car up, take off a wheel, and watch that location as a friend turns the steering wheel back and forth through it's entire range of motion. It's quite enlightening.

(Note that I shameless stole that bit of advice from DG as well. )

 

[wret]

Actually, next time you have both front wheels off the ground, grab a wheel and push it back and forth. Lay underneath and watch the suspension pivots and bushings. "Wow, those things move that much?" Yup.

 

[LONEWOLF01]

thats a real good explanation on the website it gos to show that prothane doesn't think what parts would work on the cars but this is a great option for the car. but how would it fair for street use? is their any way i could get this done?

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[logic]

but how would it fair for street use? is their any way i could get this done?

Let's put it this way: your girlfriend will probably not like riding in the car after you do this. Any time you remove rubber from the suspension and replace it with something stiffer (poly, aluminum, etc), you're generally going to improve feel and responsiveness, but that rubber is there to isolate the harshness of the road from your backside.

If you know a local machinist, talk to them about it; most competant machine shops ought to be able do this for you relatively cheaply, plus the cost of the spherical bearings and standoffs. In his case, he also opted for a new set of a-arms as well.

(Your comment about Prothane not thinking about the application is a good one for people to keep in mind too: never blindly trust the vendor. When replacing parts that the Mitsubishi engineers put on your car, think through the implications of it: what might have been the original motivation for putting the sub-par part in there in the first place, and what side-effects might the replacement part cause? In the case of the Prothane kits, they took a look under the car, and made a replacement for everything that looked rubber, without giving it a whole lot of thought, and in this particular case, they missed the fact that this particular point needs that pivoting action that rubber's softness allows. Whoops.)

 

[LONEWOLF01]

I think the energy suspension kit doesn't even come with that part. I might just order the energy suspension master kit do you know anybody that sells everthing I need?