The semi-Comprehensive M60b40 into E30 swap Q&A

[Mr Two]

It doesn't seem like the 6 speed is THAT much worse.

Assuming they are geared for the same top speed in top gear, a 6 speed car will be WAY faster than a 5 speed around a track. Gearing is awesome, and its one reason why my friends S2k keeps up as well as it does.

[george graves]

If you match the ends for the tranny/diff , then any good driveshaft shop should be able to do this given you take the needed dimensions.

Keyword is "good". I tried 4 local shops. Most of the mom-and-pop kind DS shops won't touch BMW shafts. The ends are joined to the tubes using friction welding at the factory. People say that places that repair semi drive shafts do the best job for less.

[Jean]

It doesn't seem like the 6 speed is THAT much worse.

Assuming they are geared for the same top speed in top gear, a 6 speed car will be WAY faster than a 5 speed around a track. Gearing is awesome, and its one reason why my friends S2k keeps up as well as it does.

Not that it matters, since he isn't looking to build a track/autocross/hpde car, but most people pick 5speed over 6speed actually to shift less :) S2k vs e30/v8 is like apples and oranges though. S2k keeps up because it keeps making hp higher and does not run out of air by 6k, and of course it's gearing was chosen for it's lack of torque.

[mkcman17]

it's not to say that i haven't/won't track my car, it just won't be a purpose track rat. drive-ability for me is tops, but i don't mind rowing gears either.

i just like the idea of bolt-up oem stuff as opposed to custom fabbing, where applicable.

[Jean]

Well, both 5speed and 6speed are bolt-up :) Drive shaft should be the LEAST of your worries with this swap to tell you the truth.

[mkcman17]

i was referring more to trans mounts and driveshaft, but you get my drift.

[BruceBe]

i just like the idea of bolt-up oem stuff as opposed to custom fabbing, where applicable.

The 5-speed is a "bolt-up oem stuff" affair, with the exception of the shift linkage modifications, which are reasonable.

For racing, at a given track, we try to maintain the engine between torque peak and HP peak, and then attempt to minimize the number of shifts. This is what drives the transmission and differential gear selection. If the torque curve is relatively flat and broad, with quite a bit of separation between TQ/HP peaks, the car will tolerate and thrive on wide gearing.

Given the trade-offs associated with installation complexity, cost, and intended use, the 5-speed could be a good choice.

Best,
-Bruce

[Mr Two]

Not that it matters, since he isn't looking to build a track/autocross/hpde car, but most people pick 5speed over 6speed actually to shift less :) S2k vs e30/v8 is like apples and oranges though. S2k keeps up because it keeps making hp higher and does not run out of air by 6k, and of course it's gearing was chosen for it's lack of torque.

This was vs my S52 car, that makes all it's power up top as well. I also had a buddy build a trans for his B16 powered Civic hatch for track use that only had a top speed of 115 or so. It was geared perfectly for NSS here and the car was fast as hell.

Is the only added complexity for the 6 speed the trans brace fab and DS fab? I saw something about severe trans tunnel modification but it seemed to be for the auto only.

[bmwmech1]

Is the only added complexity for the 6 speed the trans brace fab and DS fab? I saw something about severe trans tunnel modification but it seemed to be for the auto only.

This is correct^^^... The 6 speed is a significantly larger unit, both in size and weight, as I've had both on my shop floor and compared them. In all of the builds I've researched, there have been no mods necessary to the tunnel. Because of the length difference, both the trans brackets and the DS have to be custom made, but that is it, in my understanding. The nice thing about the 5 speed is it is a completely bolt-in affair, using off the shelf parts. With a lower numerical rear gear, the freeway RPM's will not be overly annoying and the increased torque from the V8 will still make the car very quick from a standstill. Final drive ratio in the 5 speed is 1:1 and the 6 speed is .83:1, IIRC. It really is a matter of preference and how much extra work one is willing to do for the 6 speed install...

Garey

[BruceBe]

The nice thing about the 5 speed is it is a completely bolt-in affair, using off the shelf parts.
Garey

Garey - did you find a collection of OEM bits that make the shifter a bolt-in? Just curious - I'm pretty happy with what we've come up with, but I'll almost always defer to the factory, when the parts will fit.

-Bruce

[bmwmech1]

Garey - did you find a collection of OEM bits that make the shifter a bolt-in? Just curious - I'm pretty happy with what we've come up with, but I'll almost always defer to the factory, when the parts will fit.

-Bruce

Haha, I've not gotten to that point yet. I had heard that the E28 stuff may work, but I can't confirm. I was just planning on shortening the E34 stuff to the right dimensions. I guess I should have said that in my post you quoted, so as not to confuse anyone... it's an "almost" bolt-in affair, Lol! I was more referring to the trans mount and DS being OEM stuff... forgot about the shifter.

Garey

[dothadance]

room for turbo?? :D

[FunfGan]

Diff size/ gearing with 5spd? The threads I've read say even a 2.95 is a little high, but I can get a great deal on a 3.25...

[bmwmech1]

Diff size/ gearing with 5spd? The threads I've read say even a 2.95 is a little high, but I can get a great deal on a 3.25...

I'm running a 2.93LSD in theory only right now, since the car only sits in the shop and stare back at me, so I'll report back once it actually runs, lol!

Garey

[FunfGan]

I'm running a 2.93LSD in theory only right now, since the car only sits in the shop and stare back at me, so I'll report back once it actually runs, lol!

Garey

Thanks! Haha. Feel free to chime in anybody else, trying to get this stuff saturday :p