BMW E36 differential ratio - (got screwed up)

D

Daddy_D

D1 street king
Tonight I received a very bad message from my tramp mechanic that made me extremely angry. The fucker conveniently lost the differential he was suppose to weld and kept lying to me in the past 2 weeks that he will bring it back. I'll be short, tomorrow I'm going to show him what I want so he can find it or pay for it, since he hasn't got a clue what ratio I gave him and how much sweat and work I had to put to cut it off with a HILTI angle grinder (I know :smokin: )

BMW E36 Differential Ratio (Europe)
Type 168 casing
316i manual 3.23 & 3.45
316i auto 4.44
318i manual 3.45
318i auto 4.44
318is manual 3.38
318is auto 4.44
320i both 3.46 < Mine
Type 188 casing
323i manual 2.93
323i auto 3.64
325i both 3.15
328i manual 2.93
328i auto 3.07

---I hope somebody appreciate this information as I spend hours trying to find it. As you can see I'm currently rolling on a open 3.46 ratio and I feel the car not so fast with the 150hp. My plan was to ask the 'gimp' to provide me with a 323i auto diff which I'm not sure if it will fit on mine (Type 188) or go for the 4.44 ratio as it can be easily aquired from car morques and Ebay.
---My question is what would the 4.44 be like welded? I know MJG was very pleased with his E28 running a 4.1 but mention that he didn't like in some cases the gearing when going into certain drifts. Bare in mind I only have 150hp so maybe it will help the car not to be so slugish. I love torque!
 
Don't get a 4.44, 320i is already fairly short geared, it will suck balls. Really your problem isn't the gearing but the massive flywheel lamped on the back of a not-very-powerful 2.0.

Get him to find a 323i auto diff, that'd be the ultimate really, it'll fit your car but you'll need to source a pair of 325i driveshafts, which will be dead easy to find. :)
 
BonBon you surprice me all the time how much you know about BMW's :nod:. Only problem is he might not be able to find 323i auto easy and judging from RealOEM only japanese/international version has the 3.64 ratio. Is this right? I'd love to do it but might have to offer him the easy option, if I don't want to wait another 6 months, and let him supply me with a 318i/320i manual diff.
Still I do want to ask couple more questions while on this subject.

How much of a difference is 3.45:1 than 3.46:1? Is that the number of teeth inside the diff? Also hypothetically what will actually happened if fit the 4.44 welded on my E36, something like this > http://www.youtube.com/watch?v=dNXzOj4X6gk? AE86 runs a 4.1-4.3 and produces 130bhp so thats where my original idea came from.

Sorry if I'm going on about this too much!
 
id go with the 4.44 if your running fifteens on it .take off then in second gear rather than first .you should have no problem in 3rd gear as you will only be able to do about 60ish in it and if you find yourself not going fast enough in 3rd , 4th is straight back and it would be about 80mph max...!
 
Well, think about what revs your car does now at 90mph, then imagine it with a ratio that much shorter. I dunno ,it MIGHT work, but it's not like the 2.0 is very revvy and enthusiastic to take advantage of short gearing. 4age is pretty "keen" and works well with short gearing.

M50B20 with a light flywheel and 4.44 would be OK I think.

My M3 was appauling with 4.44 gearing, but then it had the short ratio box with direct drive 5th too, so it'd to 110mph on the rev limiter in 5th at 8000rpm. lol
 
I've just got my 3.46 ratio diff welded by friend and I'm very pleased with his work. Now I have to see what it will be like on the car once the exhaust is fixed. I'd try to take some photos as soon as possible if I can borrow a good camera from somewhere. Also got some 75-90w oil designed for LSD's from oilman (aka opie oils), which should make some difference as it's thicker.
I do have one question, there is a few spits from the MIG welding so what do I need to do? Clean them or leave them?
 
Daddy_D said:
I've just got my 3.46 ratio diff welded by friend and I'm very pleased with his work. Now I have to see what it will be like on the car once the exhaust is fixed. I'd try to take some photos as soon as possible if I can borrow a good camera from somewhere. Also got some 75-90w oil designed for LSD's from oilman (aka opie oils), which should make some difference as it's thicker.
I do have one question, there is a few spits from the MIG welding so what do I need to do? Clean them or leave them?
Click to expand...

75W90 LSD oil in a welded diff? Thicker? Most BMW diffs use 75W140 oil which is far thicker than 75W90 at high temperatures.

And there is no need for an LSD oil in a welded diff.

Clean up any spatter and thoroughly flush the diff/casing/gears with brake cleaner so there's no bits of metal to grind your final drive gears.

Then fill with oil... I'd recommend a decent & cheap 85W140 GL-5 gear oil. And change it regularly. Redline 75W140 is the bollocks if you are loaded though.
 
I cleaned this morning the spat from weld and put headgasket sealer around the edges and drain/filler plugs. Differential is now on the car and seems to work fine when I drop it in gear, but the car is on axel stands so I won't know anything until I fix the rest. Also you were right, the numbers I gave you were from the top of my head but it was actually Castrol SAF-XJ 75w-140.
I've been waiting for a long time to get this done to my car so hopefully won't take too long before I try it. My BMW is a mess and just a bare shell to me at the moment.
 
sorry to drag up an old thread but i need answers asap.

i found a 320i diff, putting it in a 318is. ratios are not quiet right so will this make a noticable difference.


HELP NEEDED ASAPPP
 
Pat on the back for searching. You won't really notice the difference. It'd only be gay if you put a 328 diff on it haha.
 
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