Has anyone installed the M3 Diff?

[jonnyd330]

So I saw someone selling a full M3 diff swap for non-M cars. Anyone on here done it?

http://forum.e46fanatics.com/showthread.php?t=1048147

Just wondering what this entails an how much I can expect to spend on extra parts. I would want to do a bushing refresh while everything was out. What else would I need to do for maintenance?

[slater]

lots of folks have done it. but, at that price - which is $1200 really, as you need the driveshaft (he offers them) - i'd go for the MFactory diff. then you get a NEW diff, for not much more money, and it's compatible with everything you've already got.

[NoVAphotog]

lots of folks have done it. but, at that price - which is $1200 really, as you need the driveshaft (he offers them) - i'd go for the MFactory diff. then you get a NEW diff, for not much more money, and it's compatible with everything you've already got.

+1

Same thought process I had...considered M3 rear end...went with brand new Mfactory diff. Happy Camper, significantly less work, brand new diff, OEM+ car still instead of M3-ish frankencar.

[jonnyd330]

I see both of you run the 3.46 LSD. Is that is the popular ratio to run?

[wertyu78]

Go with Diffsonline. Race proven, 100% Made and Warrantied in the USA, and 100% awesome. As close to OEM as you can get and a quality warranty standing behind it.

www.diffsonline.com

[ELCID86]

+1

Same thought process I had...considered M3 rear end...went with brand new Mfactory diff. Happy Camper, significantly less work, brand new diff, OEM+ car still instead of M3-ish frankencar.

+2

3.38 FTW


---
"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - an e46fanatic

[slater]

I see both of you run the 3.46 LSD. Is that is the popular ratio to run?

the gearing is enough of a difference over the 3.07 to be noticeable, without sacrificing highway driveability.

the added grip is nice, too. :)

[jonnyd330]

One of the reasons I was looking at doing the M3 diff was allegedly that setup would change the offset for our rear wheels. So this meant I could potentially run M3 rear wheel sizes. I would really like to run some Volk TE-37's and it seems like they are more commonly available in M3 sizes.

[wertyu78]

One of the reasons I was looking at doing the M3 diff was allegedly that setup would change the offset for our rear wheels. So this meant I could potentially run M3 rear wheel sizes. I would really like to run some Volk TE-37's and it seems like they are more commonly available in M3 sizes.

This is true, but you could also order the wheels in the offset you are looking for, fitment wise. If the wheel manufacturer is limited on offset availability, you can always have a machine shop touch up on them for you.

The viscous limited slip unit in E46 ///M diffs is nothing to brag about. You'd be a lot happier with a true mechanical clutch type diff (just like the E36 M, E30 M, and several other cars.

IMO, the real benefit in an E46 M subframe and diff is in how the diff is mounted, with two ears on the most rear facing part of the diff, and more options for fluid cooling.

[slater]

One of the reasons I was looking at doing the M3 diff was allegedly that setup would change the offset for our rear wheels. So this meant I could potentially run M3 rear wheel sizes. I would really like to run some Volk TE-37's and it seems like they are more commonly available in M3 sizes.

well, the M3 also has much larger-flared wheel arches - so you'd be in for a guessing game at that point.



The viscous limited slip unit in E46 ///M diffs is nothing to brag about. You'd be a lot happier with a true mechanical clutch type diff (just like the E36 M, E30 M, and several other cars.

IMO, the real benefit in an E46 M subframe and diff is in how the diff is mounted, with two ears on the most rear facing part of the diff, and more options for fluid cooling.

these are excellent points, wyatt - i didn't even think of the mounting. nice.

still though - you're right about the diff. there are better options out there.

[terraphantm]

This is true, but you could also order the wheels in the offset you are looking for, fitment wise. If the wheel manufacturer is limited on offset availability, you can always have a machine shop touch up on them for you.

The viscous limited slip unit in E46 ///M diffs is nothing to brag about. You'd be a lot happier with a true mechanical clutch type diff (just like the E36 M, E30 M, and several other cars.

IMO, the real benefit in an E46 M subframe and diff is in how the diff is mounted, with two ears on the most rear facing part of the diff, and more options for fluid cooling.

M3 unit isn't viscous. It uses multiple clutches to lock up. What it does have in addition is a sheer pump which can vary the lock up to 100%. http://www.autos.ca/auto-tech/auto-tech-bmw-variable-m-differential-lock/

[NoVAphotog]

there are better options out there.

Which like with anything becomes a matter of deciding your personal uses and budget.

There is a spectrum IMO that I figured when shopping around:

Race-spec, solid, Made in USA, proven quality, priciest of all options, pay to play, get brand new diff - Diffsonline ($3500+/-)

Middle ground price wise, couldn't find a negative review, new to BMW world, race proven in JDM world, some people don't like foreign built products, personal experience, no issues at all, works well, built in Taiwan, assembled in USA, get brand new diff - Mfactory ($1375+/-)

OEM, changes car, bigger rear brakes, can be found for cheap, "easy" install, not as easy as other two options, can replace other subframe and suspension components with new parts while it is off car easily before install, used diff, untold story (abuse, fluid change interval unknown, etc) - M3 Rear End ($800-2000+/-)

There are others out there and several threads on the matter both myself and others have put together. Quaife, Koala, etc...definitely other options, but these are the main ones I think are worth considering. All I know is...avoid the OS Giken!! :p

[wertyu78]

M3 unit isn't viscous. It uses multiple clutches to lock up. What it does have in addition is a sheer pump which can vary the lock up to 100%. http://www.autos.ca/auto-tech/auto-tech-bmw-variable-m-differential-lock/

Exactly right. Most folks aren't able to determine the difference (pun intended), hence the E46M diff often being referenced as a viscous diff. In reality, it's a hybrid of a true mechanical clutch diff and a viscous unit (by using hydrodynamic fluid flow) via the sheer pump to create additional lock.

The problem lies within the sheer pump failing or weakening, resulting in very poor locking performance. The pump loses it's ability to apply additional pressure to the clutch discs. They work great when they are new, but when they age and rack up mileage, they just don't work and are expensive to make proper again.

True mechanical clutch-type only diffs are tried and proven. By going with an aftermarket unit, you are able to choose from a wide selection of ramp angles and static lock, based on the consumers preference. They last a long time, work every time, and are super simple. They are cheap and easy to maintain, too.

[wertyu78]

Which like with anything becomes a matter of deciding your personal uses and budget.

There is a spectrum IMO that I figured when shopping around:

Race-spec, solid, Made in USA, proven quality, priciest of all options, pay to play, get brand new diff - Diffsonline ($3500+/-)

Middle ground price wise, couldn't find a negative review, new to BMW world, race proven in JDM world, some people don't like foreign built products, personal experience, no issues at all, works well, built in Taiwan, assembled in USA, get brand new diff - Mfactory ($1375+/-)

OEM, changes car, bigger rear brakes, can be found for cheap, "easy" install, not as easy as other two options, can replace other subframe and suspension components with new parts while it is off car easily before install, used diff, untold story (abuse, fluid change interval unknown, etc) - M3 Rear End ($800-2000+/-)

There are others out there and several threads on the matter both myself and others have put together. Quaife, Koala, etc...definitely other options, but these are the main ones I think are worth considering. All I know is...avoid the OS Giken!! :p

Race-spec and like OE drive-ability! Seriously, it looks and drives like an OE BMW part. Per their site, a non-m 3.46 2 clutch setup would run you around $2,200 out the door, add $300 if you want a 3 clutch carrier. That's essentially a brand new diff, with OEM or better than OEM parts. I paid just under $3k for a 3 clutch setup and 3.64 gears, 45/45 angles.

There are a ton of options, go with your gut and budget. For me, I'll pay a premium to support a US based business with an exceptional product. One thing is for sure, avoid the OS Giken stuff like the plague!

[terraphantm]

Exactly right. Most folks aren't able to determine the difference (pun intended), hence the E46M diff often being referenced as a viscous diff. In reality, it's a hybrid of a true mechanical clutch diff and a viscous unit (by using hydrodynamic fluid flow) via the sheer pump to create additional lock.

The problem lies within the sheer pump failing or weakening, resulting in very poor locking performance. The pump loses it's ability to apply additional pressure to the clutch discs. They work great when they are new, but when they age and rack up mileage, they just don't work and are expensive to make proper again.

True mechanical clutch-type only diffs are tried and proven. By going with an aftermarket unit, you are able to choose from a wide selection of ramp angles and static lock, based on the consumers preference. They last a long time, work every time, and are super simple. They are cheap and easy to maintain, too.

If ice performance is anything to go by, mine still works great 11 years and 142k miles later.

The good aftermarket LSDs are quite expensive too. If you want something US or European made, you're usually in for at least $3k

[wertyu78]

If ice performance is anything to go by, mine still works great 11 years and 142k miles later.

The good aftermarket LSDs are quite expensive too. If you want something US or European made, you're usually in for at least $3k

Ditto, I'm in my LSD for just under $3k. Totally worth it, but that's a matter of opinion, I guess. Glad to hear your diff is still in good working order. PO must have taken great care of the car.

[terraphantm]

Ditto, I'm in my LSD for just under $3k. Totally worth it, but that's a matter of opinion, I guess. Glad to hear your diff is still in good working order. PO must have taken great care of the car.

I've owned it for the last 70k, I'd like to think at least some of that care is me :P

[wertyu78]

I've owned it for the last 70k, I'd like to think at least some of that care is me :P

Ditto! How's the ZHP coming along?

[jonnyd330]

This is true, but you could also order the wheels in the offset you are looking for, fitment wise. If the wheel manufacturer is limited on offset availability, you can always have a machine shop touch up on them for you.

The viscous limited slip unit in E46 ///M diffs is nothing to brag about. You'd be a lot happier with a true mechanical clutch type diff (just like the E36 M, E30 M, and several other cars.

IMO, the real benefit in an E46 M subframe and diff is in how the diff is mounted, with two ears on the most rear facing part of the diff, and more options for fluid cooling.

Volk TE37's are typically 18x10.5 et22 in the rear. They don't offer other sizes for a staggered setup only solution is to go square with 8.5 all around.

[terraphantm]

Ditto! How's the ZHP coming along?

It's running well, basically been using it as a daily driver the past month. Just need to take care of a few things here and there before I start school and bring it with me.

[ELCID86]

It's running well, basically been using it as a daily driver the past month. Just need to take care of a few things here and there before I start school and bring it with me.

Where are you going?


---
"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - an e46fanatic

[terraphantm]

Where are you going?

I'll be in Philly for medical school

[Sockethead]

Damn were leaving Philly for SC in a few weeks. Would of been nice to meet you

[Sockethead]

I have a diffsonline 3 clutch, polished gears, 90% lockup (I forget what the ramps are) a finned Z4 diff cover and 3.15 gears.
I bought it used from another member here and have been very happy with it

[terraphantm]

Are there any options for a car that will never see anything beyond street duty for less than say... $1500?

[NickZHP]

I have a diffsonline 3 clutch, polished gears, 90% lockup (I forget what the ramps are) a finned Z4 diff cover and 3.15 gears.
I bought it used from another member here and have been very happy with it

That's great, I would love to pick up a used one but I don't think LSD's pop up on the classifieds too often :(


Are there any options for a car that will never see anything beyond street duty for less than say... $1500?

You can get the M3 Diff and Subframe for less than $1500 and also MFactory sells LSDs for $1350 http://www.zhpmafia.com/forums/showthread.php?15863-MFactory-Helical-LSD-s-Lifetime-Warranty-30-Day-Money-Back-Guarantee!

[slater]

Are there any options for a car that will never see anything beyond street duty for less than say... $1500?

MFactory.

[ELCID86]

I'll be in Philly for medical school

Awesome!


---
"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - an e46fanatic

[ELCID86]

MFactory.

+1


---
"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - an e46fanatic

[NoVAphotog]

Are there any options for a car that will never see anything beyond street duty for less than say... $1500?

+3

MFactory.

[terraphantm]

You can get the M3 Diff and Subframe for less than $1500 and also MFactory sells LSDs for $1350 http://www.zhpmafia.com/forums/showthread.php?15863-MFactory-Helical-LSD-s-Lifetime-Warranty-30-Day-Money-Back-Guarantee!

Yeah I thought about the M3 diff and subframe, but I don't really want to go that route. 3.62 is too short for this car IMO, so then I'd want to grab a 3.15 R&P from an E39 M5. I also would like to avoid having to run the M3 rear brakes if I can.

I'll have to research M-factory.

[NickZHP]

Yeah I thought about the M3 diff and subframe, but I don't really want to go that route. 3.62 is too short for this car IMO, so then I'd want to grab a 3.15 R&P from an E39 M5. I also would like to avoid having to run the M3 rear brakes if I can.

I'll have to research M-factory.

MFactory seems to get a good response from other members of the forum so definitely a good route to go. Here's a good resource on the differentials in our cars and how different ratios affect it. http://www.bokchoys.com/differential/Speed.htm

[Vas]

I am doing the M-Factory diff eventually down the road.

[terraphantm]

Yeah I'm aware of how the ratios will impact the cruising revs. I like the stock 3.07 since the revs are pretty low even at high speeds. I have the M3 for when I have the urge to have more response, so I have no desire for a 3.46 or 3.62