Diff replacement ?s

[nsk040]

Given drivetrain noises that eluded diagnosis so far from multiple shops, I was thinking a new (used) diff might solve the problem. It looks like a few hundred on ebay will buy one. I'm thinking install is about 2 hours?

May as well take this opportunity to shorten of the final drive ratio a bit. I've seen some threads about complications about with non-M e46 diffs relating to drive shaft length, 4 vs. 6 bolt flanges, etc. What e46 diffs are shorter ratio vs. my stock ZHP and truly plug and play?

[Vas]

3.38 direct bolt in
3.46 will require to swap flanges

[ZHPizza]

yo I got a 3.46 in the garage that I'm not gonna use if you feel brave enough to swap input flanges

[nsk040]

Very tempting. How easy/complex is the flange swap?

Install time ~2 hours for 3.38 swap?

[pedro2u]

50sKid did a great video on this. Look starting at 22:30 in the video

https://www.youtube.com/watch?v=k0W5YOQTT2o

[nsk040]

So do I have this right?
-ZHP w/ 6 speed: 3.07
-ZHP w/ automatic: 3.64
-e46 330 (non-ZHP) w/ automatic: 3.38
-e46 323 and 325 w/ automatic: 3.46

[ZHPizza]

50sKid did a great video on this. Look starting at 22:30 in the video

https://www.youtube.com/watch?v=k0W5YOQTT2o

yeah output flanges are cake. input flanges require some care and precision.


So do I have this right?
-ZHP w/ 6 speed: 3.07
-ZHP w/ automatic: 3.64
-e46 330 (non-ZHP) w/ automatic: 3.38
-e46 323 and 325 w/ automatic: 3.46

u got it homie

http://www.bokchoys.com/differential/e46_gear_ratio_calculator.htm

[Reasoned1]

I just installed a 3.38 MFactory limited slip diff, and I LOVE it! I had a 3.38 open diff on before, and that was great but now, even with traction control on, the e-nanny isn't kicking on, and I have excellent traction control using the throttle and clutch instead. It makes for a much more pleasant (i.e., FUN!) driving experience, and I'm no racer. I'm also delighted to report no clunks.

[nsk040]

Reasoned - I'm tempted by the MFactory option, but as the car already has a lot of grip relative to how much power it has I'm not sure how much I'd notice it. I also don't live where it snows, which may have been a consideration for you.

As it sounds like you had the 3.38 before putting the LSD in, I'd be curious to hear a little more about the benefits you see in the LSD irrespective of the ratio change. I'm guessing a lot of people do LSD and ratio change at the same time and so it's tough to parse through their reviews to figure out how much they like the new ratio vs. how much they like the LSD.

Thanks

[Reasoned1]

I LOVE the 3.38 on my car. To me, it seems to make every gear better and more flexible (given the extra torque). The only possible reason BMW doesn't sell the cars this way is to hit some mpg target--it sure ain't road performance. In fact, I would've gone even shorter, but that wasn't feasible for MFactory. Having said that, 3.38 (or 3.46) is probably the best "compromise".

As for the LSD part of the equation, I was sick to death of having the traction control kill my power at every moderately aggressive launch at a turn--so much so that I actually preferred the ground grabbing behavior of my xi to my ZHP (sacrilege, I know). It doesn't do that now and, even though the light will still come on sometimes, it doesn't kill the power like it did, and I can reliably keep the tires on the verge of slipping during launches--CHIRP, CHIRP, CHIRP... DAMN, THAT's FUN!

I'd say the shorter ratio is 2/3 of the benefit at 1/6 the cost of the LSD but, if you can spare the cash, the LSD completes the differential performance picture wonderfully.

[ELCID86]

To me 1st is too short and I can almost start in 2nd (and do sometime when I’m stop and go traffic or a “rolling stop”. 3rd and 4th are great. 6 is awesome on the highway as I very seldom have to downshift when needing to pass or traffic slows to the 50s. I have a 3.38.

[Reasoned1]

Shawn, Is your experience with the traction control similar to mine?

Also, "more flexible" isn't technically true. Like Shawn said, 1st is 10% shorter--like every other gear--but most of my driving is done in 3rd (around town), 4th (tackling back roads), 5th (cruising back roads or tackling highway) , and 6th (cruising the highway), and each just feels perfect in its role with oomph on tap. As Shawn said, for example, he doesn't have to shift so much on Interstate, but I think the same can be said for the other gears--even 2nd (I can easily start in 2nd). As for 1st, you have to shift a bit quicker, but that's no biggie to me.

I do love it and am pretty enthusiastic about it, but I don't want to over-sell it. All it is is 10% more torque at the wheels, but that 10% makes the gears hit their sweet spots--at least for my driving.

[Sockethead]

The traction control still kicks in a lot on my car. I have a clutch pack LSD and 3.15:1. It's very annoying when it kills the throttle and the car falls flat on its face. I'm going to code in M3 settings one of these days...

[slater]

The traction control still kicks in a lot on my car. I have a clutch pack LSD and 3.15:1. It's very annoying when it kills the throttle and the car falls flat on its face. I'm going to code in M3 settings one of these days...

ha, me too!! mine is a 3.46 helical and it kicks in often enough that i find myself turning it all off anyway. the M3 DSC settings should be a nice compromise (i hope, anyway :)).

[Sockethead]

Yes everyone says M3 coding is much more forgiving

[Smolck]

My ZHP was amazing with 3.46 gears. I have a 3.64 for sale if you want it (Cheap) that already has the right flanges and would be plug and play. In my mind, the 3.64 is the best diff for performance because it allows you to utilize 3rd and 4th gears more. But the 3.46 was good too. My YouTube channel has videos of my ZHP with gears.

[Reasoned1]

What do you want for the 3.64, and how many miles?... mouth watering... thinking about the higher mileage yet cherry 330i I hope to find someday.

[Driver08]

Older thread here and forgive me if I'm stating the obvious but regarding the annoying TC interference mentioned above- if you hold your DSC button once (DSC light comes on) and then long hold it a second time until the "brake" light illuminates you can eliminate the annoying TC interference. It's no LSD but at least it allows for a bit more enjoyment. Why oh why didn't these cars come with a limited slip?
Sockethead, it must be seriously frustrating to go the trouble of putting in an LSD and still have TC spoiling the effect. Curious if you found a solution.

[Sockethead]

well, the real solution is to hold the DSC button in for a while :) sadly, this is the best solution in the M2 as well

[Newjack]

well, the real solution is to hold the DSC button in for a while :) sadly, this is the best solution in the M2 as wellIf I punch first gear it cuts power at 4k rpms everytime. I literally have to turn DSC in grandma mode to get on it. The LSD holds the grip just fine, it's the computer that gets all pissy the second there is a tiny bit of slip.

For the record I rarely push first gear hard. There's just no reason to

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[Sockethead]

In every other gear in that car, the DSC doesn't interfere that bad at all... your experience too?

[Newjack]

In every other gear in that car, the DSC doesn't interfere that bad at all... your experience too?The other gears are fine, first gear is just such a nuclear option on that car that the computer has a meltdown.

It interferes a little on second in cooler weather while turning. But on a warm day with warm tires it holds no problem.

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