E92 M3. BROKEN drive Axle. Pictures inside

[Tim B.]

Originally Posted by pbonsalb

I don't know. Need to read more from those who have done it. If I read the responses correctly, at least one person said his wife complained enough that he removed the delrin diff bushings and replaced them with poly.

Well, i'm the only one that rides in my car 95% of the time, so the wife complaining will not be an issue for me
I'm just not sure which way to go on this since there are a few different options to go with now. My car is a 6MT with 40K miles on it and I just added the VT2-585 kit to it, so it already feels a bit "squirrely". For every positive you hear about solid Delran or poly, you seem to hear a negative too

[thekurgan]

Originally Posted by sterile stork

As a long time user of powerflex components, I was greatly disappointed to see the lack of product offerings for the E9X M3. Thank you for making my day with this announcement. A foresee a big order in the near future!

I've been checking monthly and was also disappointed until a couple of months ago.

[exmowner]

Originally Posted by Tim B.

Well, i'm the only one that rides in my car 95% of the time, so the wife complaining will not be an issue for me
I'm just not sure which way to go on this since there are a few different options to go with now. My car is a 6MT with 40K miles on it and I just added the VT2-585 kit to it, so it already feels a bit "squirrely". For every positive you hear about solid Delran or poly, you seem to hear a negative too

I'm at 15K miles and I can tell you that "squirrely" feeling is related to suspension and or top mounts.

[uniter]

Lalit@AUTOcouture Carries the DEFIV kit... I think there's some detail here: http://www.m3post.com/forums/showthread.php?t=839960

[italyix]

Guys, I wrote a full review solid bushings a while back. Look for my thread, it even has pics of the old bushings and their conditions after 58k miles.

[Tim B.]

Originally Posted by italyix

Guys, I wrote a full review solid bushings a while back. Look for my thread, it even has pics of the old bushings and their conditions after 58k miles.

Pretty sure I read that when you posted it. Anything new to add? Pros? Cons? Thanks.

[roycemek]

Looking at Turners website there are a few subframe bushing options.
Delrin
http://www.turnermotorsport.com/p-15...1m-e9x-m3.aspx

and Solid AL
http://www.turnermotorsport.com/p-44...1m-e9x-m3.aspx

The solid AL pieces are $200 less than the Delrin pieces. Any reason to even consider the Delrin subframe bushings? Sounds like the consensus is that rigidly mounting the subframe to chassis is ok for NHV, and most of the increase in NHV is when you rigidly mount the diff to the subframe. Did I understand this correctly?

Thanks,
Royce M

[vinniechin]

Royce,

I emailed turner about this and they said to use the Delrin on the street but this contradicts what Malek says. I have the Delrin subframe bushings and it produced little to no VH, just slight noise transmission with them. I would tend to believe Malek on just going Aluminum because the Delrin definitely didn't add much NVH in my opinion.

Malek even recommends delrin diff bushings which I had and switched to poly. Definitely less noise, and the vibration and harshness only comes from downshifts and shifts to reverse on DCT. While driving its just noise from the whine in the diff but I have the Dinan diff and its LOUD on deceleration and coasting...even with the poly (just slightly better). The poly reduces the clunk from downshifting and going to reverse significantly though, which I guess its why some recommend with the stiffest stuff in the differential. Turner has aluminum diff bushings that are cheaper as well. I wish I just stayed with the Delrin because it is stiffer. The upshifts feel SO GOOD and solid/firm now, I'm happy with the results.

I think with the factory diff the whine is not as loud from what I hear.

Those that have this mod, I would love to hear what you guys are hearing and feeling on the drive and shifts going up and down the gears. I hope this helps and this is just my experience. Others may feel differently.

Vin

[vinniechin]

With the noise coming from the diff bushings likely through the frame...would something like Dynamat over the differential and axles help with the whine or because it is the harmonics in the metal that is causing the whine that this will not help the situation at all? Anyone try or have any thoughts on this? I may give that a try.

[sterile stork]

Originally Posted by vinniechin

Royce,

I emailed turner about this and they said to use the Delrin on the street but this contradicts what Malek says. I have the Delrin subframe bushings and it produced little to no VH, just slight noise transmission with them. I would tend to believe Malek on just going Aluminum because the Delrin definitely didn't add much NVH in my opinion.

Malek even recommends delrin diff bushings which I had and switched to poly. Definitely less noise, and the vibration and harshness only comes from downshifts and shifts to reverse on DCT. While driving its just noise from the whine in the diff but I have the Dinan diff and its LOUD on deceleration and coasting...even with the poly (just slightly better). The poly reduces the clunk from downshifting and going to reverse significantly though, which I guess its why some recommend with the stiffest stuff in the differential. Turner has aluminum diff bushings that are cheaper as well. I wish I just stayed with the Delrin because it is stiffer. The upshifts feel SO GOOD and solid/firm now, I'm happy with the results.

I think with the factory diff the whine is not as loud from what I hear.

Those that have this mod, I would love to hear what you guys are hearing and feeling on the drive and shifts going up and down the gears. I hope this helps and this is just my experience. Others may feel differently.

Vin

I'd really like to hear Malek's thoughts in response to the Turner remarks!

[vinniechin]

Look at post #11 for Malek's opinion on the subframe and diff bushings.

[PrometheusM3]

I'd like to hear more from Malek and others about the differential bushing options and their reviews. Malek implied we'll be hearing from a lot of people who have installed these, so I'd love to hear from them.

Turner lists a "review" for the Delrin diff bushings on their page which claims no NVH, but it actually is a review for the subframe bushings from this forum. (I think it's more of an oversight than anything disingenuous, but it's still not at all helpful.)

According to this thread our only option is installing diff bushings that create so much NVH that it is hard for vinniechin's wife to ride in the car. I don't think I'm alone in not wanting this type of experience. I find it hard to believe that the only option for us here is constant gear whine or a cracked drive axle.

The Powerflex site lists two poly differential bushing options as well. I assume both front and rear are recommended? Are these any better or worse? Any info from Malek or others regarding a review of the Powerflex bushings versus Delrin, in terms of both effectiveness and NVH, would be appreciated.

[vinniechin]

I have the AKG 95, as the 75 I think are close to the delrin hard. (I could be confused here - sorry)

Disclaimer is that I have the Dinan 3.45 diff. On a stock diff I think the whine isn't as bad as I had a brief ride in someone's car with solid aluminum bushings.

The poly stuff still allows for more solid, firmer and crisper upshifts. Whine is on deceleration or off/light throttle cruising between 2300 and 2900 rpm only which unfortunately for me is prime cruising range for me in 7th. This also solved 90% of my wheel hop issues as I have full bolt ons with gears. I'm debating adding the brace if I S/C but right now its solved my issues other than the wife but there's no cure for that.

The subframe bushings are a no brainer like Malek says...the rear just feels so much more solid and planted.

I would also like to hear other's opinions. I HOPE poly diff bushings are sufficient to avoid these issues in the future...

Any comments to open discussions would be welcomed.

[vinniechin]

Additionally, I also don't like the clunkiness on downshifts in S mode but in D mode it is still smooth as no clunkiness. Going into R also produces a harsh clunk. Odd but annoying. I hoping this is normal because of the limited play in the driveline now. Someone who has this mod, I would like to hear their feedback on this as well.

Thanks everyone for listening.

[sterile stork]

Originally Posted by vinniechin

Additionally, I also don't like the clunkiness on downshifts in S mode but in D mode it is still smooth as no clunkiness. Going into R also produces a harsh clunk. Odd but annoying. I hoping this is normal because of the limited play in the driveline now. Someone who has this mod, I would like to hear their feedback on this as well.

Thanks everyone for listening.

I know it's not convenient, but I'd wonder if something in the prop shaft, maybe the guibo is wearing? I'm very curious about your experience in any event.

[Someone?]

On the turner website it says "Solid mounts are suggested for track/racing use only" im interest in some kinda upgrade back there, but surely dont want a over stiff or noisy option.

[MSteve5036]

Welp, add one more thing to the list of things I find out about and am now paranoid as all hell about. Subscribed for more info and reviews

[vinniechin]

Originally Posted by sterile stork

I know it's not convenient, but I'd wonder if something in the prop shaft, maybe the guibo is wearing? I'm very curious about your experience in any event.

My car has just 3000 miles but I will check the shafts. Thanks

[Malek@MRF]

Hi everyone,

We were all out of town due to the MFEST VII show. I am responding from a mobile device, but I will address every one of your questions today when back in the shop.

Hope you all had a great holiday weekend.

Malek

[Malek@MRF]

Originally Posted by vinniechin

With the noise coming from the diff bushings likely through the frame...would something like Dynamat over the differential and axles help with the whine or because it is the harmonics in the metal that is causing the whine that this will not help the situation at all? Anyone try or have any thoughts on this? I may give that a try.

Placing any forum of dynamat there would not really alleviate the issue. Most importantly, you don't want to place anything over the rotating assemblies such as the axles as it will unbalance the unit and create massive amounts of harmonic vibration. If Dynamat is to be utilized, the best way of going about it would be to pull the interior panels that surround the corresponding area's around the sub-frame mounts and place dynamat there. The idea behind dynamat is that it will take sound/vibration energy and convert it to heat. The only place where the differential whine can transmit itself into the cabin would be through the differential mounts, which will then transfer to the rear axle carrier (typically referred to as sub-frame) which will then transfer to the axle carrier mounts and finally reaching the 4 unibody mount points.

Originally Posted by vinniechin

Royce,

I emailed turner about this and they said to use the Delrin on the street but this contradicts what Malek says. I have the Delrin subframe bushings and it produced little to no VH, just slight noise transmission with them. I would tend to believe Malek on just going Aluminum because the Delrin definitely didn't add much NVH in my opinion.

Malek even recommends delrin diff bushings which I had and switched to poly. Definitely less noise, and the vibration and harshness only comes from downshifts and shifts to reverse on DCT. While driving its just noise from the whine in the diff but I have the Dinan diff and its LOUD on deceleration and coasting...even with the poly (just slightly better). The poly reduces the clunk from downshifting and going to reverse significantly though, which I guess its why some recommend with the stiffest stuff in the differential. Turner has aluminum diff bushings that are cheaper as well. I wish I just stayed with the Delrin because it is stiffer. The upshifts feel SO GOOD and solid/firm now, I'm happy with the results.

I think with the factory diff the whine is not as loud from what I hear.

Those that have this mod, I would love to hear what you guys are hearing and feeling on the drive and shifts going up and down the gears. I hope this helps and this is just my experience. Others may feel differently.

Vin

Vin, that is correct, that factory differential would be more quiet than the Dinan diff. I have personally noticed the Dinan diff being a tad louder than the factory diff even with stock mounts and bushings.

The idea of going as stiff as possible, is to negate the movement and deflection in the rear end of the vehicle which results in prolonged reliability, response and sheer driving enjoyment. It is almost ridiculous how weakly mounted the rear end of this vehicle is, especially the differential. Taking an 18" pry bar, placing it against the diff and sub-frame, the unit can be moved alarming amounts with barely any arm pressure. With the amount of force, torque and shock this car is capable of producing, I am not in the least bit surprised of the rear end failures this car exhibits. The deflection is enough to change the pinion angle of the passenger side half shaft to create breakage as seen in the first post. The spring loaded "shock" effect is enough to throw the differential down and up violently enough to physically weaken and break the hardware and mounts. Let's think of it this way... we take a paper clip and consistently bend it. Over time, that portion of the metal will weaken, and finally break (one, because of constant bending, and two because of the heat generated when deflecting further weakening the metal and preparing for breakage).

-Malek

[vinniechin]

Originally Posted by Malek@MRF

Placing any forum of dynamat there would not really alleviate the issue. Most importantly, you don't want to place anything over the rotating assemblies such as the axles as it will unbalance the unit and create massive amounts of harmonic vibration. If Dynamat is to be utilized, the best way of going about it would be to pull the interior panels that surround the corresponding area's around the sub-frame mounts and place dynamat there. The idea behind dynamat is that it will take sound/vibration energy and convert it to heat. The only place where the differential whine can transmit itself into the cabin would be through the differential mounts, which will then transfer to the rear axle carrier (typically referred to as sub-frame) which will then transfer to the axle carrier mounts and finally reaching the 4 unibody mount points.



Vin, that is correct, that factory differential would be more quiet than the Dinan diff. I have personally noticed the Dinan diff being a tad louder than the factory diff even with stock mounts and bushings.

The idea of going as stiff as possible, is to negate the movement and deflection in the rear end of the vehicle which results in prolonged reliability, response and sheer driving enjoyment. It is almost ridiculous how weakly mounted the rear end of this vehicle is, especially the differential. Taking an 18" pry bar, placing it against the diff and sub-frame, the unit can be moved alarming amounts with barely any arm pressure. With the amount of force, torque and shock this car is capable of producing, I am not in the least bit surprised of the rear end failures this car exhibits. The deflection is enough to change the pinion angle of the passenger side half shaft to create breakage as seen in the first post. The spring loaded "shock" effect is enough to throw the differential down and up violently enough to physically weaken and break the hardware and mounts. Let's think of it this way... we take a paper clip and consistently bend it. Over time, that portion of the metal will weaken, and finally break (one, because of constant bending, and two because of the heat generated when deflecting further weakening the metal and preparing for breakage).

-Malek

Thanks Malek! Do you think the poly bushings although not as good as solid aluminum or delrin will still help alleviate some issue? My concern also is that when you stiffen something up, the next point of weakness begins to take on the additional stress so that at some point something else breaks (weakest link theory here).

If you really think I should just go back to the delrin and the 95 poly is not sufficient, then I will...if you think it will do for now, I have a set of delrin diff bushings to sell cheap to somebody!

[Malek@MRF]

Originally Posted by vinniechin

Thanks Malek! Do you think the poly bushings although not as good as solid aluminum or delrin will still help alleviate some issue? My concern also is that when you stiffen something up, the next point of weakness begins to take on the additional stress so that at some point something else breaks (weakest link theory here).

If you really think I should just go back to the delrin and the 95 poly is not sufficient, then I will...if you think it will do for now, I have a set of delrin diff bushings to sell cheap to somebody!

For now, keep your poly bushings and unitized your sub-frame with solid bushings.