S50b30 gearbox thought

[vanos]

I got the matching M3 5 speed gearbox for the S50b30
Been reading different things (I know this is dangerous and very stupid, as this make me think and that is stupid also),would a 6 speed 320d gearbox from a E46 be a good gearbox as it got some economy on a run due to the gearing of the top gear.
I'd have to workout what diff I'd need to make it work, or is this all a waste of time as the gearbox is suited to a oil burner which revs lower so wouldn't match the performance of a S50b30.

Just a thought

[ultralinear]

I believe DanThe has the E46 320d gearbox with his Alpina lump.

I imagine that the top gear is still 1:1 (guesswork!) so you could go ahead and use the M3 evo gearbox in that case, with a more sensible diff...

[vanos]

Cheers

[Mikey_Boy]

I think the ratios for the 6 speed are as follows??

1st Gear Ratio 4.23:1
2nd Gear Ratio 2.51:1
3rd Gear Ratio 1.67:1
4th Gear Ratio 1.23:1
5th Gear Ratio 1.00:1
6th Gear Ratio 0.83:1

But I could be wrong! I believe that there are (potential) synchro issues due to the clutch not engaging or disengaging properly - apparently sorted with a braided clutch slave hose?

Personally I think this would be quite a weapon - the only issue is the big gap between 1st and 2nd gear - depending on the use, I am sure a diff could be used thats good for both road or track?

DanThe is the expert here - I am just an interested observer!

[ultralinear]

See.. never trust guesswork!

[Mikey_Boy]

But then, you shouldn't trust educated guesswork either! Let's hope DanThe picks this up and puts 3 pence worth on the table...!



Cheers,
Mike

[vanos]

If the gear ratios are right, what ratio diff would be needed ?

[DanThe]

I think the ratios for the 6 speed are as follows??

1st Gear Ratio 4.23:1
2nd Gear Ratio 2.51:1
3rd Gear Ratio 1.67:1
4th Gear Ratio 1.23:1
5th Gear Ratio 1.00:1
6th Gear Ratio 0.83:1

But I could be wrong! I believe that there are (potential) synchro issues due to the clutch not engaging or disengaging properly - apparently sorted with a braided clutch slave hose?

Personally I think this would be quite a weapon - the only issue is the big gap between 1st and 2nd gear - depending on the use, I am sure a diff could be used thats good for both road or track?

DanThe is the expert here - I am just an interested observer!

Those are S50 Getrag 6 spd ratios, the 320d ZF ratios are only slightly different,
1st = 4.35
2nd = 2.5
3rd = 1.67
4th = 1.23
5th = 1
6th = 0.85

I am using a 3.15 ratio diff and find it very good

This is the least of your worries though, the box is tilted 10 degrees extra compared to an M50/S50 box, check out turks thread for some pics, the linkage is an arse...
The input shaft is shorter, the spline is the 'new type' so you only have solid clutch plates on the shelf, the slave mounts further back in the box.
I bought mine without realising any of this, I jumped in as it came up with only a few thousand miles and it was very cheap, if I was to do it again id go for an M54 6 speed.
I still need to make the clutch better, the release is not quite fast enough so the pedal is long = slow changes. I want to get this sorted for spring time when it comes out of hibernation

[vanos]

Cheers Dan, I take it it's you beautiful black chrome bumpered E30 in Total BMW this month

[DanThe]

It is

[vanos]

It is

Read it last night, SUPERB MOTOR, best car in the mag and the best read