Anyone running 318i open diff on m50 swap?

[EvilMorty]

Wondering if it will hold up, I have plans on supercharging the motor but I wanna get people’s opinions.

[twright]

I am not running that setup, but I would expect a lot of wheelspin at WOT with that configuration.

[AndrewBird]

Early model or late model? Late model had the same diff as 2.5 liter cars.

[TobyB]

a 168 diff?

It's not going to last- the spider gears are very small, and twright's wheelspin will chew them up in short order- IF the pinion can take it.

I use the 168s welded on a racey car, and even with a healthy M10, they don't last forever. So I can't 'magine that it'd withstand the torque very well at all.

fwiw,
t

[EvilMorty]

Later model 318i, the tag on the differential says 4.10. I’ve read some people have ran the open differential on a supercharged m42 and they hold up for quite some time but others say they would break in a mater of months with a naturally aspirated m50.
Just worried about putting in the motor and breaking my rear end.

[KIRIEIW]

I had a 4.10 open diff on my S50 swap with the stock ZF transmission from a 1995 M3. Mind you it wasn't a small case diff cause the car's a 325i. Anyways the point I'm trying to make is if you do a lot of freeway driving I wish you best of luck, I found myself in the slow lane most days. 65MPH was just about 4,000 RPMS if I remember correctly.

Finally ended up finding a good 3.25LSD on Craigslist (e36 M3 stock uses a 3.23LSD or 3.15LSD depending on the year. Basically using the e28 3.25 in a e30 is the perfect diff but a 3.46 would also be a great option.)

[PshlosE30]

Currently i have an 168mm small case with M50 swap... It's 3.45 ratio and with the G260, 205/55/R15 I have 105km with second gear at 7200rpm... I have this setup almost 2 years without problems..... I think for dailing you would be ok...

[EvilMorty]

Thanks everyone, the engine goes in this week. Will report back after I see how it drives. A lsd is definitely is in my future but it seems like there isn’t anyone selling one locally in my area. Nearest one is 4 hours away but it might be worth it to make the drive.

[TobyB]

If you're not too hard on it, (no 1st gear clutch dumps) it'll be ok for testing and regular use. It's when you start lighting up the rear tires that you'll have trouble.

Put good oil in it- I use Redline, but others swear by Swepco for their heavily loaded diffs.

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