# I've had enough of this open diff



## Mystikal (Dec 20, 2001)

Honestly, I had no idea the stability and control an LSD could provide on a RWD car. Since it's been raining a lot recently and I found an insanely twisty backroad near my house, I've been exploring the limits of my car. After a week of thrashing the E30 and E46, I realize that the LSD absolutely makes or breaks the experience. I can consistently hang the 325is' tail out mildly out of every turn with confidence. Even running on 195/65/14 all-seasons, the car inspires a lot more confidence than the E46. The E46 so far is the only one that I have completely lost control of. On a 6-lane wide industrial side road this week, I decided to try and drive the car hard in the rain like I always do in the E30. I simply could not predict what the car was going to do as I set up for the corner. Frequently, the inside tire would spin with so little grip that the car would be bouncing off the rev-limiter doing 40km/h in 2nd. WTF?! This is just sad. On the same road 30 mins earlier in the E30, I was getting the power down efficiently, despite 60mm less contact patch on the road and similar power ratings. I actually skidded sideways to an almost complete halt about 4 times that night in the E46. Meanwhile, I had some excellent opposite-lock full-throttle slides in the E30. This is of course intentional, when I'm actually trying to get somewhere fast the E30 simply does it with a lot less drama.

I think spending any money on a mod other than an LSD would be wasteful. Nothing would improve the car as much as a good 25%+ differential. I hate you BMW!


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## nate (Dec 24, 2001)

You are lucky that your dad's 325 has the optional LSD, most didn't.

The Sports Package should come with a limited slip and lower ratio, like the 540 SP


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## Mystikal (Dec 20, 2001)

nate328Ci said:


> *You are lucky that your dad's 325 has the optional LSD, most didn't.
> 
> The Sports Package should come with a limited slip and lower ratio, like the 540 SP *


The LSD was part of the sport package up here (all "is" models had the sport package). :thumbup:


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## nate (Dec 24, 2001)

Mystikal said:


> *
> 
> The LSD was part of the sport package up here (all "is" models had the sport package). :thumbup: *


I was talking about the E46


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## Nick325xiT 5spd (Dec 24, 2001)

nate328Ci said:


> *
> 
> I was talking about the E46 *


Surely you mean E30?


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## Jspeed (Dec 23, 2001)

HOIP makes a Torsen-style LSD for the E46. It costs US$1200.

http://www.hioprace-tec.com/


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## Matthew330Ci (Sep 9, 2002)

actually it amazed me when i first found out that the e46 so often praised for its performance and handling comes only with an open differential... :eeps:


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## Bob330Ci (Oct 15, 2002)

Jspeed said:


> *HOIP makes a Torsen-style LSD for the E46. It costs US$1200.
> 
> http://www.hioprace-tec.com/ *


...as does Dinan. I'd be curious to compare the two, especially since I was planning on getting the Dinan (and had never heard of the HOIP.) Anyone out there with first hand experience? The pricing is comparable.

B.


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## JawKnee (Dec 20, 2001)

Bob330Ci said:


> *
> 
> ...as does Dinan. I'd be curious to compare the two, especially since I was planning on getting the Dinan (and had never heard of the HOIP.) Anyone out there with first hand experience? The pricing is comparable.
> 
> B. *


Actually, the Dinan diffs for the e46 are open units as well. If you're still interested, my Dinan 3.15 is for sale in the classifieds


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## webguy330i (Jan 9, 2002)

Nick325xiT 5spd said:


> *
> 
> Surely you mean E30? *


Nate was saying "the e46 sport package should come with... blah blah... like the 540" while Mystikal was saying "back in the e30 days the e30 sport package brought with it an LSD".


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## Jetfire (Jun 20, 2002)

Some sort of LSD is a NECESSITY for truly sporty driving, IMO. One can learn to drive well with an open diff, but the traction issues can really ruin your day.  And no matter what BMW says, their DSC/ASC/T selective braking systems don't come close to the same level of functionality during aggressive driving maneuvers.


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## Mashuri (Aug 14, 2002)

This really irks me too. Thanks for the link JSpeed. I was losing hope that anyone made a LSD for E46. Question: Has anyone installed or attempted to install the M3's LSD onto their 323/325/328/330? I'm wondering if it's feasable and how much it would cost.


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## webguy330i (Jan 9, 2002)

Mashuri said:


> *This really irks me too. Thanks for the link Bob. I was losing hope that anyone made a LSD for E46. Question: Has anyone installed or attempted to install the M3's LSD onto their 323/325/328/330? I'm wondering if it's feasable and how much it would cost. *


IIRC it's electronically controlled, so I doubt it's even remotely possible without thousands of $$$ to throw away. =)


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## Mashuri (Aug 14, 2002)

Jspeed said:


> *HOIP makes a Torsen-style LSD for the E46. It costs US$1200.
> 
> http://www.hioprace-tec.com/ *


I just called them and was quoted $1,350. Is someone yanking my chain or is there something I'm missing?


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## JawKnee (Dec 20, 2001)

Mashuri said:


> *This really irks me too. Thanks for the link JSpeed. I was losing hope that anyone made a LSD for E46. Question: Has anyone installed or attempted to install the M3's LSD onto their 323/325/328/330? I'm wondering if it's feasable and how much it would cost. *


I'm assuming you're referring to the e46 M3 diff. If you are, it requires custom work to the subframe I believe. Contact Tony at http://www.vacmotorsports.com


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## JawKnee (Dec 20, 2001)

Mashuri said:


> *
> 
> I just called them and was quoted $1,350. Is someone yanking my chain or is there something I'm missing? *


Yanking your chain? I'm assuming you said this because it's more than you thought. However, I think it's in the ball park with other LSDs. Do note that the HIOP is just a worm gear so you install it in your current diff or whatever diff (i.e. ratio) you want.


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## Mashuri (Aug 14, 2002)

JawKnee said:


> *
> 
> Yanking your chain? I'm assuming you said this because it's more than you thought. However, I think it's in the ball park with other LSDs. Do note that the HIOP is just a worm gear so you install it in your current diff or whatever diff (i.e. ratio) you want. *


I realize it's in the ballpark, it's just that JSpeed said it was US $1,200 and I wanted to confirm.

I'm fine with simply installing the wormgear in my existing case as long as it works well. I know it won't be as high tech as the M3's diff. but it should greatly improve over the stock open diff. :thumbup:


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## Mashuri (Aug 14, 2002)

JawKnee said:


> *
> 
> I'm assuming you're referring to the e46 M3 diff. If you are, it requires custom work to the subframe I believe. Contact Tony at http://www.vacmotorsports.com *


Sounds like a cool mod but I'm almost afraid to find out the cost.


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## ruteger (Dec 31, 2001)

Mashuri said:


> *Sounds like a cool mod but I'm almost afraid to find out the cost.  *


Since you've got an '03 330Ci on order, if you're truly interested in the LSD, you might as well just cancel the 330Ci and pony up the extra cash for an M3. I would wager that the price of having the M3 LSD installed in a garden-variety 330Ci will be a large chunk of the price difference between the two, anyway.

If I had known that an LSD could not be had in any 3-series other than the M3, I might have paid the difference and went with the M3, too.


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## Mashuri (Aug 14, 2002)

ruteger said:


> *Since you've got an '03 330Ci on order, if you're truly interested in the LSD, you might as well just cancel the 330Ci and pony up the extra cash for an M3. I would wager that the price of having the M3 LSD installed in a garden-variety 330Ci will be a large chunk of the price difference between the two, anyway.
> 
> If I had known that an LSD could not be had in any 3-series other than the M3, I might have paid the difference and went with the M3, too. *


I would consider buying the M3 if it cost me a few thousand or more to put a LSD on my 330. Since http://www.hioprace-tec.com/  offers one that looks to be up to the task for $1,350, I think that'll be the way for me to go.


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## ruteger (Dec 31, 2001)

Mashuri said:


> *I would consider buying the M3 if it cost me a few thousand or more to put a LSD on my 330. Since http://www.hioprace-tec.com/  offers one that looks to be up to the task for $1,350, I think that'll be the way for me to go. *


I agree _if_ $1350 were the _installed_ price.

But I'm almost certain that $1350 is just the price of the LSD itself. The proper installation is very likely going to cost quite a bit more on top of that.


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## Mashuri (Aug 14, 2002)

ruteger said:


> *I agree if $1350 were the installed price.
> 
> But I'm almost certain that $1350 is just the price of the LSD itself. The proper installation is very likely going to cost quite a bit more on top of that. *


I'll call some tuners around here when I have time. I can't imagine it costing more than a few hundred in labor though. It's not that hard to install a diff. If they're too exhorbitant I'll do it myself. :eeps:


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## Nick325xiT 5spd (Dec 24, 2001)

It's not a diff. They have to remove your current diff and totally rebuild it with the new component(s).


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## blackdawg (Jan 4, 2002)

*yeah.*

once again reaffirming the notion that the E46 is tracking further and further away from the concept of "sport".

even though porsche has chosen to eschew a mechanical LSD, the PSM works quite well (on the 996s i've driven hard in the rain) as a sort of ABD VW-type thing, but at speeds higher than 25mph.


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## Mashuri (Aug 14, 2002)

Nick325xiT 5spd said:


> *It's not a diff. They have to remove your current diff and totally rebuild it with the new component(s). *


I called the guys at Hiop Race Tech in AZ and they said it uses the existing differential case. I just have to replace the old diff with the new one. Sounds pretty simple to me. BTW, I have experience working on cars. Just don't have the time like I used to.


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## ruteger (Dec 31, 2001)

Mashuri said:


> *I called the guys at Hiop Race Tech in AZ and they said it uses the existing differential case. I just have to replace the old diff with the new one. Sounds pretty simple to me. BTW, I have experience working on cars. Just don't have the time like I used to. *


If you go the DIY route, please consider taking pics and posting the procedure. I'm sure there are lots of folks who would like to know how to install some sort of LSD in their non-M 3-series at a reasonable cost (present company included).


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## JawKnee (Dec 20, 2001)

Would you guys be interested in a group buy for the Hiop worm gear?


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## Mashuri (Aug 14, 2002)

ruteger said:


> *If you go the DIY route, please consider taking pics and posting the procedure. I'm sure there are lots of folks who would like to know how to install some sort of LSD in their non-M 3-series at a reasonable cost (present company included). *


I would be happy to post pics. It's just hard for me to find the time...plus I would need to mooch a lift (not unheard of...) I may have a guy locally that can do it for a pretty reasonable price. He did work on my C5 Corvette for low $$$ and would let me hang around snapping photos.



JawKnee said:


> *Would you guys be interested in a group buy for the Hiop worm gear? *


I would be EXTREMELY interested. I'm curious if they use a Torsen I or Torsen II (a la Quaife) design. Keep in mind that the Torsen design is smoother than a clutch-plate LSD BUT it generates a lot of heat. Use synthetic gear oil and, if you plan to do extended track stints (autocrosses don't count,) consider adding a differential oil cooler.

BTW, if we can't generate much interest in a group purchase here, I bet that the mod-crazy people on Bimmerforums would be happy to participate. Just make sure to link it here as well. :thumbup:


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## nate (Dec 24, 2001)

JawKnee said:


> *Would you guys be interested in a group buy for the Hiop worm gear? *


Depends on the price and install costs


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## ruteger (Dec 31, 2001)

Mashuri said:


> *I would be EXTREMELY interested. I'm curious if they use a Torsen I or Torsen II (a la Quaife) design. Keep in mind that the Torsen design is smoother than a clutch-plate LSD BUT it generates a lot of heat. Use synthetic gear oil and, if you plan to do extended track stints (autocrosses don't count,) consider adding a differential oil cooler.
> 
> BTW, if we can't generate much interest in a group purchase here, I bet that the mod-crazy people on Bimmerforums would be happy to participate. Just make sure to link it here as well. :thumbup: *


Seems like I read where one of the new types of LSDs can wear out after a while. Any idea how long these things last?

Also, I did some checking over at rennsport. Here's some links that might be worth checking out:

Look under 'Quaife' and 'Technik'

rennsport LSD forum discussion

The Quaife runs the aforementioned $1200 (maybe that's where that number came from) but it's not listed for the E46.

There's a Technik Torsen for the E46, but it appears to be the much pricier entire assembly, which includes a choice of gears.

Interestingly, there's nothing under the hiop section for differentials.

Frankly, I might be more interested in just popping for the entire assembly with new gears (although I'm not crazy about spending $2300 for it). I would think it'd be a lot easier to install (in the discussion they say it's 'plug and play') and I'd love to go from a 2.93 final drive ratio to 3.46. I'm just not sure how a gear ratio change affects the ECM, i.e., if it would have to be reflashed or something more in depth.

Not to mention how it might affect warranty work. I hear some BMW dealers can get quite anal if mods have been performed and this would seem to fall under the category of a 'serious' mod.

And you're correct about checking out some of the other boards. I'm sure there's enough 'mod-happy' guys out there on the other forums for this sort of thing.


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## JT - '02 330i (Dec 29, 2001)

Assuming he didn't tear the diff apart. Would a dealer be able to tell you had the hiop unit installed? 

I've got one of those dealers that complained about my uuc sways. Perish the thought of me rolling in there with a set of PSS9's and camber plates for autox....

Also, will any of the z3 diffs fit the car? I thought a few of them were LSDs.


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## Jetfire (Jun 20, 2002)

JT - '02 330i said:


> *I've got one of those dealers that complained about my uuc sways. Perish the thought of me rolling in there with a set of PSS9's and camber plates for autox.... *


My dealer actually carries and installs UUC parts. Go figure! 

Anyway, back to diffs. Any LSD that uses clutch packs will, in theory, wear out over time. I don't know what a reasonable number of miles is before that happens. I'm guessing it's a fair amount of time, but I've never seen an estimate listed anywhere. Gear-based LSDs, like Quaife units, should last forever.


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## ruteger (Dec 31, 2001)

*That's it*



Jetfire said:


> *Anyway, back to diffs. Any LSD that uses clutch packs will, in theory, wear out over time. I don't know what a reasonable number of miles is before that happens. I'm guessing it's a fair amount of time, but I've never seen an estimate listed anywhere. Gear-based LSDs, like Quaife units, should last forever. *


I couldn't remember which wore out faster. I think the clutch packs are better in the short term in that they slip less, but because of that, will also wear out eventually.

FWIW, here's the same conversation currently going on over at dtmpower where a group purchase is also being discussed:

dtmpower LSD discussion

Here's an older one about gearing:

dtmpower gearing discussion

Maybe going to a 3.46 (or even 3.38) isn't such a hot idea, after all...


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## JawKnee (Dec 20, 2001)

JT - '02 330i said:


> *
> Also, will any of the z3 diffs fit the car? I thought a few of them were LSDs. *


The z3 3.0 comes with torsen LSDs. However, the Z3 diffs are based on the old e30 geometry and consequently, has a different mounting system than the e46.

For example, notice the different mounts...









​


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## Mashuri (Aug 14, 2002)

ruteger said:


> *Seems like I read where one of the new types of LSDs can wear out after a while. Any idea how long these things last?
> 
> Also, I did some checking over at rennsport. Here's some links that might be worth checking out:
> 
> ...


Rennsport sells the worm gear seperately for $1,195. I wonder if the Technik units are really Hiops or not. Perhaps we can talk to them about a group purchase as well. Quaife does not make a differential for the E46 and they had no plans to last time I called them.  I personally don't want to lower my gear ratio. I just want to maximize my traction.


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## Mashuri (Aug 14, 2002)

JT - '02 330i said:


> *Assuming he didn't tear the diff apart. Would a dealer be able to tell you had the hiop unit installed? *


They would have a very difficult time if you didn't change gear ratios. They would have to do a burnout in your car to see the difference. Then they'd have some REAL explaining to do.


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## Jspeed (Dec 23, 2001)

Mashuri:
The US$1,200 figure is indeed from RENNsport, and it is for the HIOP Torsen-style LSD. Talk to Samir (technik) for more info. I believe he owns RENNsport.


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## ruteger (Dec 31, 2001)

Mashuri said:


> *They would have a very difficult time if you didn't change gear ratios. They would have to do a burnout in your car to see the difference. Then they'd have some REAL explaining to do.  *


Well, the simple way to check for an old-style, clutch-pack LSD was to get the car in the air and turn one rear wheel. If the opposing wheel spun in the opposite direction, it was an open diff. If both wheels spun in the same direction, it was an LSD.

I don't know if this type of test works with the Torsen-style and, frankly, I can't imagine any dealer going to this length to void a warranty.


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## Mashuri (Aug 14, 2002)

Ok...been talking to my shop guy. He said it depends if they have to remove any cross-bracing and drop the exhaust like on the M3. Has anyone seen the underside of their 3-series? This will make a difference of ~$300 or so... :yikes:


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## Bob330Ci (Oct 15, 2002)

Hmmm...seems like both types have downsides. The clutch pack style wears out, and the torsen generates a lot of heat. :dunno: I think I'd lean towards torsen given the choice.

Still...seems like something that would drastically help my car out in rain or the normal 6" snow we see here every so often. I could be interested in the group buy depending on how much I could get it installed for. (I have nowhere near the mechanical skill to do it myself...)

My old Trans Am (OK, ancient..) had a limited slip. I did better off road than a lot of my friends with 4WD...they had two open diffs, sending the torque half to the front tire with less traction, half to the rear with less traction, while I always had near 50/50 to the rears. (Yes, that WAS high school.) Pretty entertaining.

JawKnee...you just blew away 95% of the reason I wanted the Dinan diff. That'll teach me to listen to the salesman and not check the website. :banghead: 

B.


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## JawKnee (Dec 20, 2001)

Bob330Ci said:


> *
> JawKnee...you just blew away 95% of the reason I wanted the Dinan diff. That'll teach me to listen to the salesman and not check the website. :banghead:
> 
> B. *


Well, you could buy my used Dinan 3.15  It's still the best bank for the buck in terms of butt dyno (i.e. shorter gearing) out of the basic bolt-ons (e.g. CAI, software, exhaust). And $7xx is a lot cheaper too 

Oh, my race shop installed my diff for $150


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