7 speed manual

[Rich764089]

Just interested to know why there aren't many 7 speed manuals on the market, e.g. even 200mph+ supercars like the M600 only have 6 gears, right?

Who makes 7 speed manuals other than Porsche?

 

[Goldeneye]

When you say 7 speed manual, do you mean in the traditional sense? I.e. with a clutch and gear shifter? In which case, I've never heard of a manual gearbox with 7 gears. Can you imagine the mis-placing conundrum?!

 

[Rich764089]

When you say 7 speed manual, do you mean in the traditional sense? I.e. with a clutch and gear shifter? In which case, I've never heard of a manual gearbox with 7 gears. Can you imagine the mis-placing conundrum?!

Well yes, I realise there's potential for catastrophic mis-placement! But I guess there is for any manual box.

Thought the 991.2 Carrera S had one but could be wrong...

Yes, i meant traditional manual.

 

[C240Sport97]

Aston Martin Vantage can also be had with a 7 speed manual gearbox, like the current 911 Carrera S/4S

 

[Spin_bowler]

There it is...

 

[Rich764089]

Which begs the question: why haven't others done this? Particularly M cars before they went auto only. Or cars like the M600.

 

[190]

ZF make a 7 speed manual for cars although I'm not sure I'd want one. Including reverse there are 5 positions in the lateral plane of the H shift pattern. MB make a 16 speed transmission for trucks in an 8 position double H pattern plus a high and low ratio to make 16 in all.

With the torque provided by forced induction engines I can't see much need for that 7th gear.

 

[Bellow]

When you say 7 speed manual, do you mean in the traditional sense? I.e. with a clutch and gear shifter? In which case, I've never heard of a manual gearbox with 7 gears. Can you imagine the mis-placing conundrum?!

I suspect that is a big reason. I think the Porsche box has an interlock that prohibits the potential to 'wrong slot'.

Well yes, I realise there's potential for catastrophic mis-placement! But I guess there is for any manual box.

Six speed has only three longitudinal gates with the centre (3rd/4th) plane spring biased.

 

[Rich764089]

ZF make a 7 speed manual for cars although I'm not sure I'd want one. Including reverse there are 5 positions in the lateral plane of the H shift pattern. MB make a 16 speed transmission for trucks in an 8 position double H pattern plus a high and low ratio to make 16 in all.

With the torque provided by forced induction engines I can't see much need for that 7th gear.



View attachment 115354 View attachment 115355

Thanks. Interesting!

But the argument for not having 7th gear due to torque would carry to auto boxes too, yet they have 8 or 9 gears nowadays...

 

[Rich764089]

I suspect that is a big reason. I think the Porsche box has an interlock that prohibits the potential to 'wrong slot'.

Six speed has only three longitudinal gates with the centre (3rd/4th) plane spring biased.

Good point on the spring bias.

I guess the extra design/engineering costs and extra potential for catastrophe just can't be justified! Always intrigued me though.

 

[DSM10000]

Thanks. Interesting!

But the argument for not having 7th gear due to torque would carry to auto boxes too, yet they have 8 or 9 gears nowadays...

It's mainly about emissions

Usually the top gear is an overdrivre ratio.

Also, with diesels having a lower rpm range the multiple gears help performance and economy.

 

[Martin 1]

If the Veyron can reach 250 mph on 6, whats the point ? Under normal conditions, how the hell do you remember which gear you're in ?

 

[Rich764089]

So when you change gear you stay in the power band....?

 

[Bellow]

So when you change gear you stay in the power band....?

How narrow a power band do you have in mind?!
Thin line re acceleration advantage. No drive is transmitted during the shift and a gated lever is as slow as it gets.

 

[Rich764089]

How narrow a power band do you have in mind?!
Thin line re acceleration advantage. No drive is transmitted during the shift and a gated lever is as slow as it gets.

My point was if you have 6 gears to 250mph as in the example above, you're likely to be off boost when you change. Surely?

 

[Bellow]

My point was if you have 6 gears to 250mph as in the example above, you're likely to be off boost when you change. Surely?

Next time I'm out in my Veyron I'll check....
I can only guess, but there must be broad enough torque (ie boost) range and abundance of torque to permit only six gears. Naturally aspirated motors are the peaky ones. Those race bikes of the 1960s that revved to upwards of 18,000rpm and had tiny cylinders had 18 speed gearboxes.

 

[Rich764089]

Next time I'm out in my Veyron I'll check....
I can only guess, but there must be broad enough torque (ie boost) range and abundance of torque to permit only six gears. Naturally aspirated motors are the peaky ones. Those race bikes of the 1960s that revved to upwards of 18,000rpm and had tiny cylinders had 18 speed gearboxes.

I'm just off to Aldi in mine so I'll let you know
I'm sure it can cope with only 6 gears, but is it optimal. Maybe that was a bad example, but didn't old big turbo cars like 911s and cossies suffer bad lag because when you changed gear you were off boost?
Also an auto car with the same engine will probably be quicker at accelerating with 9 rather than 6 speeds as you can optimise to stay on peak power better...?

 

[A.J.]

Next time I'm out in my Veyron I'll check....
I can only guess, but there must be broad enough torque (ie boost) range and abundance of torque to permit only six gears. Naturally aspirated motors are the peaky ones. Those race bikes of the 1960s that revved to upwards of 18,000rpm and had tiny cylinders had 18 speed gearboxes.

My Chiron has 7 gears

 

[Bellow]

I'm just off to Aldi in mine so I'll let you know

Take mine - I insist!

I'm sure it can cope with only 6 gears, but is it optimal. Maybe that was a bad example, but didn't old big turbo cars like 911s and cossies suffer bad lag because when you changed gear you were off boost?

Probably, but I suspect turbo technology and engine management advancements have closed the gaps - so to speak.

Also an auto car with the same engine will probably be quicker at accelerating with 9 rather than 6 speeds as you can optimise to stay on peak power better...?

Yes, and, especially against a manual gated shifter - auto boxes are much faster changing.

 

[Bellow]

My Chiron has 7 gears

It's a double clutch transmission Bugatti use - yes? In which case 7 speeds make sense.
I know that Ricardo developed the transmission but not much more. They will be heavy gear-sets to handle the torque. Probably unpleasant to shift manually.