LSD; What are my options?

xLibelle · Jun 1, 2004

I have problems with my rear diff and its time to go limited slip.
I dont want to spend tons of cash like companies like BMP ask so what can i do? Something like building the diff. is an option if there is a kit. If you have experience with going through diff. swap / purchase, let me know.

nadroj · Jun 2, 2004

you could get an e30 //m3 lsd, or an lsd from a 325iS

xLibelle · Jun 2, 2004

HOW do i get the LSD from an sport version.

also, what other kinds of limited slip differentials will fit under the e30?

equate · Jun 2, 2004

With money

http://www.roadfly.org/bmw/classifieds/general/detview.php?view=31736
http://www.roadfly.org/bmw/classifieds/general/detview.php?view=31099
http://www.roadfly.org/bmw/classifieds/general/detview.php?view=31741
http://www.roadfly.org/bmw/classifieds/general/detview.php?view=31373

I 99% pretty sure all e28 diffs fit on an e30, but dont quote me on that

http://www.davelength.net/car/diff_swap.html

xLibelle · Jun 3, 2004

JESUS! i called Korman to find out how much to send in my 4.10 open diff and rebuild it;
$1600 = 25%
$1850 = 50%
$3000+ = Quaif (sp)

if i buy a limited slip and send it in to be rebuilt, then its ~ $1400
and they said they wouldnt sell a kit without service... sooo, F them

nadroj · Jun 3, 2004

why dont you get a used 4.10 lsd?

xLibelle · Jun 3, 2004

thats probably my best bet

why you ask - because there is no garantee that the diff is even good. i have been ripped off twice and its not fun.

but also because it wont cost much more to have mine upgraded to LSD than it would the 50% lock up. (which is the way i want to go)

flashinthepan · Jun 3, 2004

Ummm...

Jail time, huge profits, death by O.D.

[joke]

xLibelle · Jun 3, 2004

some wonder why im crazy...

[joke]

nadroj · Jun 4, 2004

xLibelle said:

where are you going to get yours done b/c you said i cost like 1800 in earlier posts, and that is alot of cash, and also i am intersted in getting an lsd for my 318

xLibelle · Jun 4, 2004

i will just prpbably buy one for around $300 and forget about it. Otherwise more research will have to be done - obviously no one around here knows about these things.

You, on the other hand, might already have a LSD at 4.10 in your car. Your differential ratio would be at 4.10 and since its a sport version, it should be limited slip. Two ways you can tell; one, read the number on the diff and it should have an S at the end of the number. Two, jack the car up off both wheels and turn one. The other should turn in the same direction - opposite if its not limited slip.

nadroj · Jun 4, 2004

yea i have already checked and it turns out that on the 318iS it was an option to get the lsd and the previous owner didnt get it...

epj3 · Jun 4, 2004

Don't buy a 4.10 if you do a moderate amount of highway driving.

I have the 3.73 limited slip on my 325is, and it's great. Decent acceleration and the limited slip part is still awesome after 16 years.

Jordon... all e30 "is" models have a limited slip. It wasn't an option to NOT get it on the is models.

The IS models have the following that the regular "i" models didn't.

-Limited Slip DIfferential
-Additional lower body
-Sport front spoiler (has brake coolers and "sport" fog lights)
-Limited slip differential
-Stiffer suspension (from factory)
-Full leater interior with M shift knob and steering wheel. (I believe in the late E30's you could get an airbag which did not have the M steering wheel.)

wood_e · Jun 4, 2004

A quaife is the best diff you can buy, period. They're not cheap but they're covered even for racing under their warranty

xLibelle · Jun 4, 2004

And Quaife is $1000 more. Technically, its variable lock, which is like you said, the best of the best, but needs at least 5 lb/ft torque on both wheels, meaning that if one lifts off the ground, youll be spinning the inside wheel (but that isnt a problem with out cars)...... and i thought to ask you guys for suggestions, hehe.

Eric, actually, the 4.10 ratio is very much acceptable as a highway gear upgrade. I easily had it at 110 mph at 4 grand on the tach (which kinda has me scratching my head), very comfortable. Yes the 3.73 is the one to keep as a daily driver that doesnt intend to track/autox, otherwise, this is THE upgrade to do, hands down.

epj3 · Jun 4, 2004

xLibelle said:

Whaaat? I assume our gear ratio's (tranny) are the same?

In 5th gear, at 4k rpm would be about 90 mph (93.85 theoretical speed) on my car in 5th, and I have the 3.73. There is NO WAY you'd be going 110 at 4k rpm unless you have an automatic or the gearing is different.

4.10 is NOT 'the' upgrade to have. If you plan on taking it to a track, a lower gear ratio is ideal. You need to go faster than 115 if you SERIOUSLY track your car.

xLibelle · Jun 5, 2004

I agree, there is something considerably wrong with the equation....

i swear, i could have pushed 125 out of the car easily and i know for a fact that i have a 4.10 diff.

I will update you when i have final word on whats going on here, i promise. (it will be a couple weeks before i know) (it is a possibility that the gear ratio is different in my tranny - i have no clue what it is)

epj3 · Jun 5, 2004

xLibelle said:

Absolutely impossible with a 4.10 unless you remove the rev limiter with a chip. Remember, your fuel cutoff at 133 is figured by RPM's, not MPH.

xLibelle · Jun 6, 2004

i do have a chip but i am saying that i havent even made it past 4500 rpm in fifth and was doing 110 mph easily!

like i said, my diff says 410 on it BUT i dont know the gearing of my tranny.
1st seems unusually short, 2nd feels tall, and 5th is giving me this weird top speed. Then again, i havent driven a Getrag 260 before.

nadroj · Jun 6, 2004

epj3 said:

i dont have an lsd on my 318iS i was an option on the 318iS

http://bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00127&Section=14

read in like the middle of that, and i know i dont have an lsd b/c i jacked up the back end and spun one wheel and the other spun in the opposite direction.

LSD; What are my options?

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