Fastest gearchanges were pre-1990's

[autogyro]

Everybody seems to agree that numbers are what is needed here.

Unless anybody can prove anything, this thread will soon be closed...
A yes-no discussion is pretty pointless

Why are you again avoiding this issue Tomba.
I thought this thread was here for people to learn from.
Not so that illusive engineering can go on unchallenged if it suits the status quo.

I have quoted figures from my experience of developing competition gearboxes for decades and using them.
I cannot quote F1 figures or accurate figures from the companies manufacturing current systems.
It should be noted that neither F1 companies or any others seem prepared to back up their marketing promotions with figures either on this thread or anywhere else.
Does this make the subject of no interest to readers?
It is time the 'truth' was found.

[Pierce89]

Oh and Tomba, in my first post I did not refer directly to over all shift speeds.
I do say that manual gear shifts can be faster however.

they only thing that really matters is the overall gear change why even bother bringing up a debate on technical terms so you can argue that the tractor transmission will changes gears the same speed as an F1 car. We all know it's BS.


Lets see the data prove that the "gear shift" is faster.

Yes please. What he said.

[autogyro]

Oh and Tomba, in my first post I did not refer directly to over all shift speeds.
I do say that manual gear shifts can be faster however.

they only thing that really matters is the overall gear change why even bother bringing up a debate on technical terms so you can argue that the tractor transmission will changes gears the same speed as an F1 car. We all know it's BS.


Lets see the data prove that the "gear shift" is faster.

Yes please. What he said.

I agree, let us see the data that proves modern seamless gearboxes shift faster.
I have yet to see any.

[Tommy Cookers]

In the film 'Bullitt' the Mustang driver (Bud Ekins I believe, a former truck driver) always double-clutches on the up-changes. Can anyone tell me why ?

Hoping this lightens the mood !

[Richard]

We do have numbers, it was in the recent striped gearbox thread.

I looked back through my shift times last year. A sequential manual dog 'box and my changes varied from 80ms to 120ms (longer if I really made a mistake). If I were to fit a flat-shifter, then I could bring all of my shifts to 80ms, but I don't think that's really worth it! The changes are limited by how quickly the engine can move from max RPM to the RPM needed for the same speed at the next gear.

viewtopic.php?p=313956#p313956

[autogyro]

We do have numbers, it was in the recent striped gearbox thread.

I looked back through my shift times last year. A sequential manual dog 'box and my changes varied from 80ms to 120ms (longer if I really made a mistake). If I were to fit a flat-shifter, then I could bring all of my shifts to 80ms, but I don't think that's really worth it! The changes are limited by how quickly the engine can move from max RPM to the RPM needed for the same speed at the next gear.

viewtopic.php?p=313956#p313956

So with that particular geartrain and shift system, the 'shift overlap' (not the complete modulated shift with seamless system fitted)took 80ms and it would also take 80ms with flap paddles. The method of operation is actualy irelevent, it is only the actual shift overlap mechanism speed that counts, not how it is actuated.
Not very fast in this case then.
I can gaurantee a manual upshift down to 40ms or so on a medium sized geartrain.

Try to remember that as soon as you add engine or clutch modulation (seamless) the effective shift speed increases because of the inefficiency introduced to the torque flow.
If a seamless shift system fitted to this gearbox matched the 80 ms it would still be in effect much slower in transfering torque from input to output because of the pre and post overlap modulation.

[xxChrisxx]

"Sorry, I can't really see this going any further. We'll have agree to disagree"

[flynfrog]

I would think that a simple sound analysis should get us close. Take of the jump in RPM.

Autogyro as I remember you had a pretty good handle on sound recording do you have a method to measure this. If any one has a decent pre 90s sound clip I can take a stab at it.

now that I think of it I would like some one other than me to pull the sound clips please dont tell me what one is which I dont want to bias the results

[machin]

See below; Datalogger traces from one of my fellow competitor's car showing H-pattern manual vs a pneumatically actuated flat shift sequential in the same car. You can see there is no perceptable step in the acceleration on the flat shifter... as racers that's pretty much all we care about....



read more here:

http://www.xoomspeed.com/xoombox/xtrafl ... rmance.htm

[Richard]

As I recall, the main advantage of the semi-auto boxes is elimination of driver error in gear changes. It also allows the driver to keep their hands free to operate other equipment. All of which helps deliver more reliable and faster lap times.

[strad]

Milliseconds,,,today's shifts take milliseconds,,,even I can't shift that fast..Hell Ronnie Sox couldn't shift that fast.

[machin]

I am interested to hear Autogyro's reasoning for thinking that gear changes now are SLOWER than they were in the 1980's (the topic heading)...? and by slower I mean "take longer to accelerate from say 50mph to 55mph with an upshift at 52mph"... any other definition of "slower" just doesn't cut to a racer....

[autogyro]

See below; Datalogger traces from one of my fellow competitor's car showing H-pattern manual vs a pneumatically actuated flat shift sequential in the same car. You can see there is no perceptable step in the acceleration on the flat shifter... as racers that's pretty much all we care about....



read more here:

http://www.xoomspeed.com/xoombox/xtrafl ... rmance.htm

Thanks machin very helpful.
I can only see four gears in this shift cascade.
The 1st to 2nd upshift looks identical for both gearboxes.
The manual shifted box needs lower third and fourth gear ratios.
The rev drop is to much at these shifts.
This graph shows a comparison between a sequential shift mechanism and an H pattern lever.
There is a benefit in ease of operation using the sequential for the driver.
The speed of actual shift overlap is however the same .08 ms.
For the manual H pattern mechanism to meet this speed without spending to long in neutral or missing a shift, the driver has to be skilled enough to shift the lever not only from 1st to 2nd in a strait line as shown is achieved in the 1st to 2nd shift but also across the H pattern gate.

Note. this compares a sequential shift system with pneumatic operation.
The mechanism does not improve the shift overlap time at the actual engageing mechanism, which remains at a minimum of .08 ms, the lowest possible with this powertrains rotating components and their rotational moments of inertia.

Any extra loss of torque transfer from input to output of the gearbox, such as engine cuts etc must be added to the over all shift times if they are longer than the overlap times, to be totaly accurate.

The sequential gearbox shown is matched very well to the vehicle to advantage but it is not the ideal that could be achieved.
Ratio changes in the H pattern box would bring them level subject to a skilled enough driver.

[autogyro]

Milliseconds,,,today's shifts take milliseconds,,,even I can't shift that fast..Hell Ronnie Sox couldn't shift that fast.

Racing gearchanges have always only taken milliseconds.
The speed is dictated by the change in rpm of the rotating components, not the speed of shift mechanisms.

[autogyro]

I am interested to hear Autogyro's reasoning for thinking that gear changes now are SLOWER than they were in the 1980's (the topic heading)...? and by slower I mean "take longer to accelerate from say 50mph to 55mph with an upshift at 52mph"... any other definition of "slower" just doesn't cut to a racer....

You are again mixing resultant acceleration with my statements on 'shift speeds'.
Ignore the method for actuating the gearchange, this is irelevent to the discusion.
The shift speed is the time it takes for one gear to disengage and the next to engage.
Very simple requirement.
Manualy shifted this is only the time it takes for the engagement dog on one gear to disengage and the dog for the next gear to engage.
There is nothing else to time.
If you control the shift with methods to modulate the engagement rather than relying on driver skill, any engine cut or clutch disengagement designed to smooth the shift or balance the powertrain has got to be additional time taken for the shift if the modulation is a longer time period than the pure engagement sequence.