Tech Theory - Sequential Gearbox for road use

Freewheel · 02-27-08, 10:07 PM

There was a claim in a thread here a little while ago that the world's first synchro sequential gearbox was in use. I am prompted to ask several questions;

1. My very basic understanding of sequential gearboxes is that they are inherently more likely to shift cleanly than an H-pattern box, so is synchro really necessary?

2. What kind of difference does sequential shifting make to the packaging of a gearbox compared with H-pattern?

3. Does the shifting method change the capacity of the gearbox in any way, including reliability?

4. In this era of electronically controlled shifting, are we likely to see manual sequential boxes widely used on road or are we more likely to get an electronic manual?

5. Aside from Gearfox, has anybody actually made one, and is it available?

My interest is primarily technical, and clearly I've never used a sequential dog box, but it might help somebody out there with a concept.

John · 03-02-08, 02:58 AM

Quote:

Originally Posted by Freewheel

There was a claim in a thread here a little while ago that the world's first synchro sequential gearbox was in use. I am prompted to ask several questions;

1. My very basic understanding of sequential gearboxes is that they are inherently more likely to shift cleanly than an H-pattern box, so is synchro really necessary?

2. What kind of difference does sequential shifting make to the packaging of a gearbox compared with H-pattern?

3. Does the shifting method change the capacity of the gearbox in any way, including reliability?

4. In this era of electronically controlled shifting, are we likely to see manual sequential boxes widely used on road or are we more likely to get an electronic manual?

5. Aside from Gearfox, has anybody actually made one, and is it available?

My interest is primarily technical, and clearly I've never used a sequential dog box, but it might help somebody out there with a concept.

I dont know a whole lot about this topic, but i think i can handel your 4th question: i recall reading over some posts where people were talking about how annoying it is to shift though all the gears all the time when driving on the street. It was apparently especially annoying when an un-expected stop occurred. I would think that we wont be seeing any sequential tranmissions in street cars outside of whats on lambo's and ferrari's; those you can put into automatic mode!

Mendeola makes some transaxles that are manual sequential, you can take a look at theirs.

Tim Kay · 03-02-08, 02:12 PM

Given a choice, without a doubt, I would opt for a sequential. I've been driving a Fortin sequential for 3 years in an off-road car and love it. My past two BMW's, 645 and M6, are true manual sequentials and have been awesome to drive and dependable.

What I truly like about the Fortin sequential is the ability shift without the clutch due to dog rings, no syncros. The BMW is an electronic\hydraulic controlled clutch that is absolutely seamless and easy enough that my 16 year old son drives it without a worry.

RichardH · 03-02-08, 05:07 PM

the new Audi R8 has a sequential box, so they are about.

Wayne M. · 03-03-08, 09:21 PM

This would be more like shifting a motorcycle.

wanni · 03-03-08, 09:56 PM

Hi friends,
The sequential synchronised manual shifting, has nothing to do with robotised/paddle shifting.
Sequential means that via a cam law on a drum, you can shift one gear after the other just by pulling the lever for up and pushing for down like motorcycles. No way to jump a gear.
Not dog for reliability and NVH purposes.
Only Gearfox has made it, because I am so crazy to insist in that way, which is the correct base for a real quick paddle shifting.
Shifting via a sequential makes more fun and it seams closer to a racing device.
The GearFox units are available, but...............the dollar/euro exchange rate does not help you friends of the other side of the ocean.
The Apollo Gumpert and the Tramontana are using it as a unique solution.
Believe that the synchronisation of a drum driven shifting mechanism is not easy at all. But I reached the target with some patented solutions.
For more, just come to my E-mail.
Regards
Wanni

Tim Kay · 03-03-08, 10:27 PM

Quote:

The sequential synchronised manual shifting, has nothing to do with robotised/paddle shifting

Yes but robotized/paddle shifting has everything to do with sequential shifting

wanni · 03-03-08, 10:45 PM

My friend,
as soon as you can shift directly to neutral from an high gear, it is not a sequential.
Ferrari is H pattern based, Lambo and Audi as well. They are all using Graziano transmissions, or paddle or H manual.
Only the SMART is a real sequential.
The sequential shifting is mechanic and it would need only one actuator for up and down. The robotised you are mentioning are using at least 2 actuators. One for front rear and another for left right.
Or like in the BMW one valve for each gear.
Regards
Wanni

Tim Kay · 03-03-08, 11:18 PM

Wanni, yes, I stand corrected

BMW refers to thier box as "a 7 speed manual sequential with electro\hydraulic actuation" and you can not go from high gear to low gear without hitting all gears in between. Albeit, you can go into neutral via the shift lever at any time.

On the other hand, Fortin and Mendeola transmissions are true sequentials due to the fact shifting takes place via a drum mechanism. And as you mentioned, neutral can not be had from any gear higher than 1st.

wanni · 03-03-08, 11:23 PM

Quote:

Originally Posted by aladinsane

Wanni, yes, I stand corrected

BMW refers to thier box as "a 7 speed manual sequential with electro\hydraulic actuation" and you can not go from high gear to low gear without hitting all gears in between. Albeit, you can go into neutral via the shift lever at any time.

On the other hand, Fortin and Mendeola transmissions are true sequentials due to the fact shifting takes place via a drum mechanism. And as you mentioned, neutral can not be had from any gear higher than 1st.

Not to be a pain in the a.s, only for the correct form.
Thanks for your superior understanding.
Ciao
Wanni

Freewheel · 03-03-08, 11:37 PM

Now I understand.

Have you found that a sequential manual has any advantages or disadvantages over an H pattern manual? (Assuming all else is the same)

I can think of these, but don't know whether the answer is better or worse;

Shift reliability (much improved - I hope!)
Weight
Torque Capacity
Package size

anything else?

Chris P. · 03-04-08, 11:17 AM

A big difference, which is one reason why you see it in race cars is the speed of the shift. Now, before everyone jumps on the fact that electro-mechanicals is what makes the shifts REALLY fast, just compare a purely mechanical and purely manual H-pattern shifter to a sequential one. The sequential is inherently faster and you don't miss a gear.