Rear diff. bushings AKG vs RE vs Revshift vs Condor

[x X Cloud X x]

Planning on upgrading the rear differential bushings already done tons of reading across several M forums just seeing what brand everyone likes and dislikes before I order a set tmr.... your thoughts

AKG 95A vs Rogue Engineering 94A vs Revshift 95A vs Condor speed shop

[simonnim]

The shop I have gone to says he recommends AKG. I have revshift in subframe and diff. He did mention however that as long as it doesn't articulate like the trailing arms, it doesn't matter too much for whichever you go with.

I haven't swapped in and out any so I wouldn't be able to tell you if they 'feel' different.

[EthanolTurbo]

OEM. There is no need to upgrade the diff bushings.

[Notan_S54]

I ended up using Revshift solid 95A bushings for the subframe and differential then using 80A street performance bushings for the trailing arms. Car is great so far!
Edit: my mistake that’s the setup I’m running on my e36. The E46 M has the AKG bushings.

[old///MFanatic]

Planning on upgrading the rear differential bushings

Are your aftermarket poly choices really an “upgrade”?

[RC Fresh]

Got solid diff bushings and hate it. Going back to OEM soon so I hope the cabin noise and vibration goes away. Bought the car with it so brand used is unknown.

[Tbonem3]

OEM. There is no need to upgrade the diff bushings.

There's no NEED to upgrade anything. OEM headers, wheels, exhaust, etc...

Are your aftermarket poly choices really an “upgrade”?

Yes, upgraded responsiveness, and, theoretically at least, much longer life.

[9kracing]

The harder your diff bushings, the more gear whine you will hear.

[x X Cloud X x]

Posting this from E46fanatics im thinking of going the same route as described by this member no vibrations, no clunk, no whine =)

"Recently after I bought my e46 m3 I notice a vibration at 2k rpm (and only at 2k rpm) along with a slight clunk/thud under hard acceleration. Very common in these models and some people will even tell you this is the "M Clunk". Anyway, my first thought was to change the Guibo or Flex disc along with center support bracket etc. I did this and it helped but did not completely solve the vibration and clunk..

I went back to my local shop and asked them take photos of diff bushing for me, sure enough they were pretty worn! Still driveable but worn enough to cause the slight vibration and clunk but only under hard acceleration. NOW, onto the purpose of this background information: I ordered the Revshift 80a poly bushings which they describe as an OEM plus+ feel as they are slightly stiffer than OEM, but not as stiff as many of the other brands that use 95A or 75D.

the Revshift 80a bushing COMPLETELY got rid of the vibration and the slight clunk. Both are completely GONE. I have no diff whine whatsoever no vibrations no squeaking at all (I have now had the bushings in for a week). Everything in my drive line is completely stock besides the diff bushings. Maybe this is why I don't have any NVH? I dont know if you have any other poly or solid components in your driveline or suspension but just know that if you are completely stock down there and you add quality 80a diff bushings, you should see little to ZERO NVH considering your car is in good condition. Also this information is not outdated and no other weird variables playing into it - like is said my car was 100% stock and I added the 80a diff bushings and it was perfect. Couldn't be more happy with them. I could make in cabin video for you if you needed heck i would even let you drive my car for yourself if you are in the PNW.

Anyway, just wanted to make sure you had accurate information from someone that specifically has poly 80a diff bushing with no other driveline modifications."

[BMW_QAS]

My '03 has metal inserts, no idea what brand. The gear whine is very loud, however, I knew immediately when the bearings in the diff went. The tone changed from gear whine to metal screech. I rebuilt it with Racing Diffs internals and haven't had a problem since. I'm using smurf blood Motul for gear oil.

[Obioban]

For a car that sees any street use at all: new stock. Already extremely firm with little room for improvement.
(which is not to say e36 parts-- those are softer than stock, so a performance downgrade)

For a track only car where you don't area about noise: something solid.

Can't think of any use case where I'd want poly.

[Nate047]

I have poly in my car, they came with the car so I am used to it. I've also driven a freshly restored original car, and a couple of other original-ish cars of various wear stages.

It's all about perspective. Is your car stock and do you like things to be quiet? Or do you like some because racecar sounds?

[old///MFanatic]

Yes, upgraded responsiveness, and, theoretically at least, much longer life.

With a downgrade of NVH compared to new OE.

So the question of it being an upgrade or downgrade depends on what the person wants and is willing to give up.

[Tbonem3]

So the question of it being an upgrade or downgrade depends on what the person wants and is willing to give up.

Of course, like anything. Mind you, you've already chosen a much more hardcore experience than comfort simply by selecting the E46 M3 versus a lexus for example.

Also, the main "downgrade" is noise (whine) which I almost complete eradicated with some lightweight sound deadening foam under the rear bench. So I got my cake and got to eat it too.

[old///MFanatic]

Of course, like anything. Mind you, you've already chosen a much more hardcore experience than comfort simply by selecting the E46 M3 versus a lexus for example.
Also, the main "downgrade" is noise (whine) which I almost complete eradicated with some lightweight sound deadening foam under the rear bench.

Well these bushings were engineered by ///M division specifically for this M car. So imagine they already considered that sport compromise. When you examine these M bushings you’ll notice they have very little bonded rubber as their isolation compared to poly versions.
Sounds (pun intended) like you got most of the compromise fixed in your use. Curious which brand and durometer you used? Although there are many poly diff bushings on market, they vary greatly in design too. Some have a “top hat” design, some flush, some with aluminum inserts with “top hats” while others deep inset like stock. There’s even one with a square alumuminm insert inside a squared out round poly base.