smg, auto or 7 (yes, 7!) speed manual - The Unofficial BMW M5 Messageboard (m5board.com)

Gus · 10th March 2003, 18:44

I have heard that the 7 speed may be an option on the E60 - the more we push, the more likely it will happen!

kees · 10th March 2003, 19:20

Why would you want to push a 7-speed manual? Doesn't it make more sense just to get an engine with enough torque to be able to deliver in combination with a 6-speed manual?

As it stands you can't feasibly max out 3rd, 4th, 5th or 6th gear in most countries without already being highly illegal.

Gus · 10th March 2003, 19:23

If they are prepared to allow any manual shift I'll be a supporter - don't know why a 7 speed has been proposed though!

zzzzMD · 10th March 2003, 19:32

I agree with keesdh. If given a choice between auto and manual, I would naturally choose manual, but 7-speed seems eminently unnecessary with a 500+ hp engine with good torque. Rowing the gears is great, but the ratios would be so close with a 7-speed, that you would constantly be red-lining the engine, or be much higher in the rev band without wanting it. If the car were auto only, shorter gearing might be better, i.e., 6-speed auto.

Hutzal · 10th March 2003, 21:02

i read somewhere that the 7th gear would serve as an overdrive gear for highway driving...Mabey ME could elaborate on this more.

PhilSeastrand · 11th March 2003, 01:28

I bet we could find articles written when 6-speed transmissions become popular about why you don't need 6 speeds. Likewise for 5-speeds, 4-speeds, etc.

At some point it does become too much, I just don't know when that point is. For "automatic" systems, the more gears you have the better the computer can choose the most optimum gear. That's why the CVT is starting to become popular. I suspect in a few years, CVT will be the only "automatic" transmission found.

Racerboy · 11th March 2003, 01:49

Quote:

Originally posted by Hutzal
i read somewhere that the 7th gear would serve as an overdrive gear for highway driving...Mabey ME could elaborate on this more.

The M5's sixth gear is already an overdrive, I think it is like a .80 or thereabouts. Why you would want two over drives is beyond me and why you need 6 gears at or above 1:1 in a street sedan makes no sense at all. In the Veyron or the Enzo, cars capable of speeds in excess of 200mph I could see a 7spd (sequentials), but not in the M5. Just my 2 cents.

DoctorV8 · 11th March 2003, 02:27

6th is a 0.83:1 ratio, and the rear end is 3.15:1.

The M5 revs at about 2500 rpm at 80 mph. It gets only 21 mpg on the highway.

A similarly powered Corvette has a 0.75:1 fifth and 0.50 sixth with a 3.42 rear end. At 80 mph it revs at 1700 rpm and manages 28-30 mpg! Sure, you have to downshift to pass, but it's nice to cruise at 100 mph with the tach reading 2100 rpm.

I'm all for a second overdrive.

Finality · 11th March 2003, 03:42

Why not simply make the single OD gear very tall? Something like 0.60? Power drop too severe?

Enigma · 11th March 2003, 21:06

For an SMG 7 gears = good
For a manual 7 gears = more work

Currently the M3 and M5 lose some time around the track because gears 2,3,4 are spaced too far apart. You want to keep the engine running as close to its HP peak as you can at all times on a track.

Again the M is a performance car not some big torque buick. If you are too lazy to shift to get the engine into its powerband then get a regular car with an auto.

zzzzMD · 11th March 2003, 22:22

I think that the engine would be in the fattest part of the torque curve more often with more closely-spaced gearing, as in 7-spd manual, but mileage would probably suffer being higher in the rev range more of the time. With sixth being another drive gear, and not an overdrive, I'm not sure how the balance would play out. It WOULD probably be more annoying on the Garden State Parkway on a Friday afternoon.

Enigma · 11th March 2003, 22:24

Quote:

Originally posted by zzzzMD
It WOULD probably be more annoying on the Garden State Parkway on a Friday afternoon.