6 speed 'box?????????

[miniblob]

Guys,

Really sorry if this has been covered (thought it had recently but couldn't see it when i searched!)

I'd love to get a 6 speed 'box in my touring when i change out the current 'box.

Are there any other models a 'box could be used from??
Anything else i should know??

You wouldn't believe the number of times i've tried to put it in 6th this week!!

[ed325i]

There are but you would have to leave the engine attached to it and drop the whole lot in.

ED

[ian332isport]

You need to change the diff ratio, not the gearbox.

6 speed BMW boxes are the same ratio in 6th as the regular E30 box in 5th. All you would gain is an extra ratio lower down. It would make no difference once you are in top.

All Tourings have a 3.91 diff ratio so something like a 3.73 or 3.64 would reduce the revs in top.

Ian.

[chu346]

So what about if you used a 6 speed with a 2.93 or simular diff, would that work?

[Markey]

I thought higher diffs gave you a higher top end with lower revs.

I was going to swap out to a 4.10 or which ever it is to give me same top end with less engine revs.

[Turbo-Brown]

Nay, it's the other way around.

If we said your engine was directly connected to the diff, a 4.1:1 ratio would mean that 1000rpm @ the wheels would give rise to an engine speed of 4100rpm.

If you changed the ratio to a 3:1, our 1000rpm at the wheels would give 3000rpm at the crank, but the acceleration wouldn't be as good.

[Markey]

Thats great im not worried about tha acceleration just cruising as i do lots of Mway driving.

Thanks

[miniblob]

6 speed BMW boxes are the same ratio in 6th as the regular E30 box in 5th. All you would gain is an extra ratio lower down. It would make no difference once you are in top.

All Tourings have a 3.91 diff ratio so something like a 3.73 or 3.64 would reduce the revs in top.

So i could, for example, steal a 6 speed 'box from an e34 or something and it would be quite easy for a mechanic to drop in??

I've got to change my diff anyway (need an lsd!) so how would the ratio's affect acceleration and top end?? I want a fast accelerating car, but do a lot of m'way stuff around 100 (upwards on weekends!!)

More than anything i'm just used to a 6 speed box, and if it doesn't slow me down and cost the earth, i will be tempted to give it a try!

[Widge]

It can be done, but I think you will find the 6 spd boxes come of engines that are mounted at a different angle to the M20, so once the box is on the gear lever is trying to come out the side of the transmission tunnel. Not that that can't be solved but it won't be a simple swap job.