Question about adj. aluminum differential mounts

[BrandC]

I'm looking into aluminum subframe bushings and differential mounts for my track rat. What are the benefits of having an adjustable differential mount?

[325is///M-tech]

about the only thing I can think of is it allows you to get your pinoin angle lined up with you drive shaft better. From the cars I have built I have always used poly subframe bushings and a rubber diff bushing. Aluminum may put alot of extra stress on the mounts. I havent used them so i cant say if this it so.

[Elephant]

Use of solid bushings (delrin, aluminum) is not typically a problem if done properly. Sometimes this means reinforcements but generally the main thing is to make sure like bushing hardnesses are installed together. Using a rubber bushings in one location and solid bushings in another will generally accelerate the wear on the rubber bushing. Use of solid mounts throughout is better than rubber actually. The problems typically arise from mixing and matching then once the rubber bushings wear and are not replaced the forces on the hard points are much great. These forces are nonlinear as well so as the rubber wears the forces transmitted to the hard points is worse. Using solid mounts/bushings sends those forces throughout the chassis, not just the hard points. Most people do not understand this and feel that solid mounts are bad. It's all about how it's done.

Course for a street car solid mounts are generally not desirable because they offer no isolation from road and engine inputs. Regular road driving is typicall a bit worse for a car depending on road conditions as well, race tracks are generally much smoother so there are no harsh impacts/inputs.

Cheers.

[BrandC]

Thanks for the responses guys. I will be going with delrin RTAB's, and aluminum subframe bushings/differential mounts. I have heard about using similar materials so they do an equal amount of load sharing. I was just wondering if there was a benefit to using an adjustable diff. mount vs. fixed mount.

[Elephant]

Thanks for the responses guys. I will be going with delrin RTAB's, and aluminum subframe bushings/differential mounts. I have heard about using similar materials so they do an equal amount of load sharing. I was just wondering if there was a benefit to using an adjustable diff. mount vs. fixed mount.

Sorry, to answer your question, if you are speaking of the slotted variety vs fixed round hole then yes, I'd do that.

Cheers.

[BrandC]

I'm debating whether to get slotted or fixed, that's the dilemma lol. I'm not even sure how the slotted differential will benefit me.

[Elephant]

I would do the slotted because once you install all those solid bushings the hole/bolt may not line up properly. If you force it in there you've created a load on it in the static condition, best to avoid that. If you're going to use a urethane diff mount then I wouldn't be so worried about it, there is still some flex in there. But for aluminum and probably even delrin I'd opt for slotted. I have a slotted aluminum version in my race car which currently has delrin subframe and trailing arm bushings. I have another subframe which has the new aluminum subframe bushings already in. For the trailing arms I will install adjustable urethane bushings or I may have the tabs welded in so I can use eccentric bolts for the adjustment.

Cheers.