Sequential manual transmission.

[chernaudi]

Can some one give me some info on the history of seqential manual transmissions used in racing(namely open wheel, rallying and sportscar racing)?

I'd like to know what was the first SM Gearbox, the first that was completely sucessful, and it's evolution to the present day. And I'd like to see how the major systems evolved, from the beginnings, to stick shifted SMGs, to the current paddle shift systems(electro hydrolic for F1 cars, and electro pnumatic for most sportscars, like the Audi R8 and R10, and the Bentley Speed 8 for example).

[Al Weyman]

I would have thought the Hurst shifter for 4 speed manual gearboxes must have been amoungst the first, I am not sure if it was a purely upshift type for drag racing or whether it down shifted as well, never really been able to find that out.

[AU N EGL]

Hewland sequental, and Xtrac are the two big producers of sequential transmissions.

A new company Holinger out of Australia makes a 'relativly' affordable transmission now.

[zac510]

New isn't quite the word for Holinger

[chernaudi]

But where did this begin with SMG's? I know that Chapparal tried to use an early version in the 2F and 2J. And Porsche used their PDK(Porsche Double Clutch) on the 962C, and Audi used a similar system on the Sport Quattro rally cars(this was the predcessor to their DSG/S-Tronic SMG system used on their road cars).

Was there anything that came before this, and what was the first system that actually worked(the Chapparal system was never particulary reliable).

[Leighton Irwin]

Motorcycles used sequential shifts for many years. The Vixen and Walker F4 cars used them in the 60's. F4 is still popular in Ont. and all use motorcycle engines and trannys. 750cc and 4 strokes on methanol. 2 stroke run pump gas.

[AU N EGL]

Originally Posted by chernaudi

Was there anything that came before this, and what was the first system that actually worked(the Chapparal system was never particulary reliable).

Jim Hall's Chapparal tranmissions were 2 or 3 speed automatic transmissions with torque converters. Correct they were not reliable, but very very inovative.

[chernaudi]

From what I've read about them, they used straigh cut gears(like modern racing transmissions), and didn't use a conventional clutch. And all that was required to shift them was back off to 3/4 throttle and move the lever.

[AU N EGL]

The Holinger and the Jeraco use dog eared straight cut. No backing off the throttle. Full speed ahead.

The Xtrac also use straight cut, no backing off on the throttle here either.

But just listen to the C5R shifting the Xtrac as it laps on Lemans

http://www.youtube.com/watch?v=s2vqzJ6EcTM

and listen as the downshifts Laguna Seca 2006

http://www.youtube.com/watch?v=FHeIr6zLeF0

[chernaudi]

But nearly 40 years of R&D can make a lot of differnce. Moden racing SMG's use electronic Shift without Lift systems.

[Rubinho]

Originally Posted by chernaudi

But nearly 40 years of R&D can make a lot of differnce. Moden racing SMG's use electronic Shift without Lift systems.

A micro-switch on the gearlever will signal to the ECU that a gear shift is imminent and it should cut spark is all that is required to implement a full-throttle-upshift system.

Less crude is to strain-gauge the gearlever to provide the signal. This gives a more solid gearlever (as the movable switch housing is not required) and the exact gearstick force which should initiate the cut can be tuned. The length of cut (and loss of accelerative torque) can be minimised to suit application and driver.

[Chucky]

The first F1 system was used by Ferrari in 1991 (?). It was the last V12 designed by John Barnard and he only included a sequential shift because a conventional H pattern lnkage was too hard to package!

It wasn't until later when they figured out what a performance advantage it was.

[greenamex2]

Originally Posted by Chucky

The first F1 system was used by Ferrari in 1991 (?). It was the last V12 designed by John Barnard and he only included a sequential shift because a conventional H pattern lnkage was too hard to package!

It wasn't until later when they figured out what a performance advantage it was.

Is anybody able to quantify the benefit in terms of lap time?

[Notso Swift]

Originally Posted by zac510

New isn't quite the word for Holinger

Like MoTeC, another overnight sucess from Melbourne