3.64 lsd or 3.73 lsd?

[Stir Fry A Lot]

535im. Discuss.

[SC David]

^ This here is Max everyone, I recruited him from off the streets :D. Welcome to the bimmerforums.

Do you have parted LSD's to choose from, or something? What's on your car now?

[screwbiedoo15]

I'll be putting a 3.64 lsd on my car over the summer that's off my parts car. I've never had either but I'd imagine the 3.64 if you're on the freeway more. If you're just going around town, then the 3.73 would probably be more fun

[Stir Fry A Lot]

Thanks David, sorry about not introducing myself. I'm leaning toward the 3.64 so that I'm not constantly shifting around town. I had an e30 with an upgraded diff and it gets tiring after a while.

[screwbiedoo15]

I won't be getting my 3.64 on till the summer most likely, but if you're undecided still then I'll tell you how it is. I imagine it'll be just the perfect little jump

[Stir Fry A Lot]

that's what i'm thinking.

[HausBimmer]

I'm running a 3.73 LSD in my 89 535iM - I like it! I drive mostly in town. Just checked the rpms at 80 last night after someone else on the board asked and they were 3250. I also put a 3.73 in my 635csi Euro and it ran great. No lag at low rpms anymore. I'm not sure that the 3.64 would be a very noticable change (3.64/3.46 is only a 5% change - like having an extra 10 hp (208 x 1.05 = 218) - but probably would be a bit better for highway cruising.

[Stir Fry A Lot]

Within a one block stretch in normal driving will you usually be in third gear by the end of the block or second? I tend to do a lot of inner neighborhood (zig zaging through the city) driving and my concern is that if I'm in third I'm going to need to drop it into second to bend the next block. That's shifting two more times than i need to. Also how much of a first gear do you have? Is it still usable?

[screwbiedoo15]

I'm running a 3.73 LSD in my 89 535iM - I like it! I drive mostly in town. Just checked the rpms at 80 last night after someone else on the board asked and they were 3250. I also put a 3.73 in my 635csi Euro and it ran great. No lag at low rpms anymore. I'm not sure that the 3.64 would be a very noticable change (3.64/3.46 is only a 5% change - like having an extra 10 hp (208 x 1.05 = 218) - but probably would be a bit better for highway cruising.


Thanks very much, I think it was me who asked. Hmmm so I guess I'll guestimate the 3.64 will be around 3150 rpm while cruising at 80mph in 5th. that's true that it is a very small change, but it is on the parts car that I have so I might as well throw it on my car for something. As long as it helps me pull a bit better in 3rd I'll be happy since below 3000rpm in 3rd you just don't get anywhere quickly.

[Stir Fry A Lot]

I still think that I'm going to go with the 3.64. I often travel to L.A. which is quite a distance from the homestead. e34's aren't exactly meant to be high strung either, at least for what I'm envisioning mine as. Thanks for all the input.

[Stir Fry A Lot]

Hey Screw, tell me what you think of the 3.64 after all is said and done. I'll let you know if I do mine'z first.

[clevertd]

3.91 or bust:shifty

[Stir Fry A Lot]

Uhhhhhhhhh... no.

[clevertd]

It's a joke. Really, the 3.46 is perfect.

[Stir Fry A Lot]

Screw, If you want more mid-range power get rid of the Dinan chip and get an EAT chip. Dinan tunes their chips only at WOT. All others start mapping at partial. Where in the Bay are you? We should compare rides some time.

[Stir Fry A Lot]

Says in your sig that you have a 3.91. Discuss.

[screwbiedoo15]

Screw, If you want more mid-range power get rid of the Dinan chip and get an EAT chip. Dinan tunes their chips only at WOT. All others start mapping at partial. Where in the Bay are you? We should compare rides some time.


It's basically gone right now, I just haven't updated my sig. Right now I'm doing the Miller MAF conversion. Well, I was doing it till I somehow tweaked one of the wires in the wiring harness when trying to move a pin and now a shop had to swap out the whole wiring harness for me. I feel like a dumbass for making this much of a problem from I guess was a little mistake by me. But... once the Miller MAF is working and all it should be the best thing for midrange power. I'm in Lafayette btw, but currently off at school in SoCal

[blanko]

I know I don't have an E34, but I do have a 3.91 LSD in my e36. It is a bit overkill IMO since the stock diff is a 2.93. Its a huge huge difference in low end, but the car revvs pretty damn high at highway speeds. Most of my driving is done on the streets, so it doesn't bother me most of the time, and being able to launch a RWD car as fast as a lot of AWD cars is worth it. I don't think you will be satisfied with the 3.64 if you are looking for a noticeable gain, as it really isn't that big of a difference in your car.

[screwbiedoo15]

I know I don't have an E34, but I do have a 3.91 LSD in my e36. It is a bit overkill IMO since the stock diff is a 2.93. Its a huge huge difference in low end, but the car revvs pretty damn high at highway speeds. Most of my driving is done on the streets, so it doesn't bother me most of the time, and being able to launch a RWD car as fast as a lot of AWD cars is worth it. I don't think you will be satisfied with the 3.64 if you are looking for a noticeable gain, as it really isn't that big of a difference in your car.

That's true that it isn't much of a gain. guess I'll just have to see. I have it already so might as well try it out and hope for something. I'll be doing the Miller MAF conversion and a set of headers so I'm not hoping for record breaking power but maybe just a little more oomph behind the pedal. So guess I'll be conservative with how much quicker the car will be

[Stir Fry A Lot]

my e36.

nuff said.

[psyctrance]

I've had both recently, 3.64 was stock. The rebuilt one I just received is 3.73; I like the acceleration better, but still have low revs on the freeway doing 80. Very similar gearing to my WRX, just heavier and more family oriented ;-)

[screwbiedoo15]

I've had both recently, 3.64 was stock. The rebuilt one I just received is 3.73; I like the acceleration better, but still have low revs on the freeway doing 80. Very similar gearing to my WRX, just heavier and more family oriented ;-)


Is your car a manual? I thought the diff was always 3.46 on manual 535is

[HausBimmer]

Within a one block stretch in normal driving will you usually be in third gear by the end of the block or second? I tend to do a lot of inner neighborhood (zig zaging through the city) driving and my concern is that if I'm in third I'm going to need to drop it into second to bend the next block. That's shifting two more times than i need to. Also how much of a first gear do you have? Is it still usable?

My car has a Dinan chip, 19" type III injectors and a custom stainless exhaust (w/o resonator). With the 3.73 is really never bogs down - the low end torque will pull it right up on cam (well maybe with 5 people in the car going uphill with the AC on). Cincinnati is all hills and twisty streets going from one to two lanes - so I've been thinking about the 3.91 LS I have in my garage (love that torque) - bet really, I think the 3.73 is the best overall combo if you do more city than highway driving (and the stock 3.46 really wasn't bad). I don't ever noitice the need to drop from 3rd to 2nd to keep in the power band, only for tight corners do I shift down to 2nd.