on my road race rx8 i have removed the ppf, due to the fact that i have been using a bmw 5 speed gear box. i am contemplating using solid differential mounts, (by contemplating i mean i have already built the mount with solid aluminum bushings but im having second thoughts about it). anyone with real world experience care to share what they have seen with solid diff mounts in an rx8?

 

how did you support the front pinion nose end of the diff case?

if it’s a race care than likely no big deal, but would probably be harsh/noisy on the street. It’s a bit different for your situation, because with a PPF the entire drivetrain weight and loading is carried at the front by the motor mounts and at the rear by the diff mounts. So the diff now is only carrying it’s own weight and the drive torque loading without one. So if anything I’d think the effect on yours would be less than one with a PPF. Otherwise being Aluminum they will transfer more noise and vibration than a polymer like Delrin. Sort of surprised you would make them rather than buy the usual Delrin etc.
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the front of the diff is bolted solidly to a bracket i have welded to the rear cradle, using the top two bolt holes where the ppf would be bolted. i used aluminum as i had the right pieces in my scrap bin. its nothing too elaborate, two pieces of 3/16 plate cut out with a hole saw and then welded to the diff mount, with a piece of aluminum tube welded through the center where the bolt passes through