How critical is a poly differential bushing?

[bmwpower]

I'm installing AKG stuff on the rear of my car - subframe bushings and RTABs. How important is installing a AKG poly diff bushing for a dedicated HDPE/track car?

[Mike The Bavarian]

important.

[TheFightingCPA]

You might as well do it since you're going poly everywhere else. And do it now while it's easy (er) to get to.

[nando]

eh. IMO the diff is one place poly doesn't belong. a bushing from an M3 or M coupe is plenty stiff. hell since you're tracking you should be looking for an M coupe diff cover anyway. :)

[F34R]

eh. IMO the diff is one place poly doesn't belong. a bushing from an M3 or M coupe is plenty stiff. hell since you're tracking you should be looking for an M coupe diff cover anyway. :)

1+ this is the same route I am doing.

[bmwpower]

I've been looking for a diff cover, but haven't found one yet. I could just replace the bushing with an M bushing.

OT, but what's the drop in temp when using an M diff cover?

[AlarmedBread]

The poly isn't a big deal on anything but hard launches. It just adds a LOT of gear noise into the cockpit. Especially if your diff is a little long in the tooth.