Transmission query

gazzol

gazzol

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Hi guys, I've got a Getrag 265/5 dogleg with a crunchy 2nd gear. I've toyed with the idea of putting in a higher ratio diff (3.9 or higher) and a 6 speed so I get better acceleration but still have a reasonable cruise. So apart from the obvious M5 options which would be very expensive are there any other 6 speed gearboxes that could be used? Any help as always greatly appreciated
 
Thinking aloud, one option is a non-dogleg 5 speed Getrag with a differential change, which has been my thought experiment on this board.
I have the 6-speed on the e39 M5 and the sixth gear gets me to speeds only needed if I am running from the law towards Tijuana. Five would be fine for me.
 
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Arde said:
Thinking aloud, one option is a non-dogleg 5 speed Getrag with a differential change, which has been my thought experiment on this board.
I have the 6-speed on the e39 M5 and the sixth gear gets me to speeds only needed if I a running from the law towards Tijuana. Five would be fine or me.
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6 speeds with a really high diff would be nicer. There are plenty of BMW 6 speeds it's just a question of whether the bolt patterns are the same and which flywheel would be needed
 
I drove a new BMWNA 1995 540i six-speed in Colorado at 115 in fourth gear thinking... "there are two more gears, what in this world do I need those for?"

Well I might have, can't commit to actually saying such a thing, must have been delirious, bamboozled, wack outa ma haed, er sumpin'. Don't quote me.
 
Honolulu said:
I drove a new BMWNA 1995 540i six-speed in Colorado at 115 in fourth gear thinking... "there are two more gears, what in this world do I need those for?"

Well I might have, can't commit to actually saying such a thing, must have been delirious, bamboozled, wack outa ma haed, er sumpin'. Don't quote me.
Click to expand...
I agree with what you're saying in that application, the gearing was too tall. What I wanted to do was put in a 6 speed and a very high ratio diff that way the car would have massive acceleration but still have a reasonable cruising speed
 
Based on a post on M5board, the e34 M5 5 (OD, not CR) vs 6 speed ratios are:

5-speed ratios:
1st 3.51
2nd 2.08
3rd 1.35
4th 1
5th 0.81

6-speed ratios:
1st 4.23
2nd 2.53
3rd 1.67
4th 1.23
5th 1
6th 0.83

Don't forget, you'll also have to figure out how to drive the speedo, since the 6 speed lacks the mechanical speedo drive of the 5 speed.

Looks like you'll mostly gain mechanical advantage in 1st, but 4th, 5th. and 6th are similar to the 5 speed 3rd, 4th, and 5th. You'd gain in the low gears, certainly, but is it worth that extra work? The late 3.8 E34 M5 bits should mate with a M30.
 
I have a 5spec M5 and first is pretty low geared as it is - I’d prefer a taller first gear and closer ratios and that’s with the heavier M5. Seeing that first gear in the 6speed is even lower I think the extra gear is effectively useless, unless doing hill starts with a caravan on a 1 in 3 hill …. assuming the figures above are correct
 
x_atlas0 said:
Based on a post on M5board, the e34 M5 5 (OD, not CR) vs 6 speed ratios are:

5-speed ratios:
1st 3.51
2nd 2.08
3rd 1.35
4th 1
5th 0.81

6-speed ratios:
1st 4.23
2nd 2.53
3rd 1.67
4th 1.23
5th 1
6th 0.83

Don't forget, you'll also have to figure out how to drive the speedo, since the 6 speed lacks the mechanical speedo drive of the 5 speed.

Looks like you'll mostly gain mechanical advantage in 1st, but 4th, 5th. and 6th are similar to the 5 speed 3rd, 4th, and 5th. You'd gain in the low gears, certainly, but is it worth that extra work? The late 3.8 E34 M5 bits should mate with a M30.
Click to expand...
Interesting information, thanks for that. If there's little to be gained I'll probably get my 265/5 (dogleg) repaired this winter.
 
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