Best LSD diff for M42 cars

[kwill22]

I got an open 4.10 in mine and it doesn't kill your mileage on the highway unless you're doing 90. If I do cruise at 80 I still get 30MPG's and my revs are at 3500-3600. That's on flat road though not hills. My city is mostly highway.

Really want a 4.10 LSD

[///digitalme]

what is the stock open diff on my '91 318i 4 door 5spd?

i believe it should be 4.10

[freeride53]

what is the stock open diff on my '91 318i 4 door 5spd?

[///digitalme]

3.91 is perfect as a daily, gears are not as short can drive on the freeway on 4th. I chose that particular diff because the 3.73 seems too low. The 4.10 was good but not for me I do a lot of freeway driving and 3.91 gives me better gas mileage. Unless you are making.serious power I don't see going lower than the 3.73. I am really happy with the 3.91 its a vlsd but dont feel any difference than a lsd

[decay]

u are going to need more than the differential if you go with the 3.91 out of IX cause its a different size case.

WRONG.

stop talking.

[MattBimmer]

^granted for that time and what they were shooting for with the 318 410 and m42 was not a mistake. I just wish I got better gas mileage!!! :( I always want a sixth gear for highway driving

[MattBimmer]

^E36 interiors M42 vacuum lines.... And um FWD cars now.

[getouth]

BMW doesn't make many mistakes and the 4.10 diff and the M42 isn't one of them!

[I8UR911]

I have a 3.73 and my only power mod is a chip. I think its great, but I also drive highway a little.

Sent from my XT907 using Tapatalk 2

[vert_this]

u are going to need more than the differential if you go with the 3.91 out of IX cause its a different size case. If you like decent fuel mileage I wouldn't do anything that starts with a 4. It will keep your R's up to high for the hwy unless u like racing home each day. The 3.73 is probably where you would want to be if your wanting the best of both worlds. If you wanted even better mpg and didn't care so much about 0-60 time go with a 3.25.

[MattBimmer]

Yeah I would like to know about this 391 diff. Sounds like the perfect gearing for a dd with not a lot of compromise for spirited driving

[freeride53]

i have a 3.91 from an ix and love it...the 4.10 wasnt for me...

why is that? differences in gearing and/or power?

[irish44j]

3.91 LSD small-case. Came stock in my car (which used to have an M10).

[///digitalme]

i have a 3.91 from an ix and love it...the 4.10 wasnt for me...

[timofeylbelarus]

i have 3.25 lsd and its slow lol i would go with 3.73 tho