Fastest gearchanges were pre-1990's

[autogyro]

he also forgets that today's boxes are much lighter than pre 90s boxes since they don't have a human crashing the gears

Geartrains are lighter today because the regulations force the minimum weight as low as possible to barely meet the replacement regulations.
We see a lot of gearbox problems at present because of this.
It is mainly a sop to aero.
The lighter rotating components do reduce shift times marginaly.
I agree that it would be difficult for a 'human' driver to change gear manualy with reliability and no damage using the current sledge hammer systems.
Most of the unsettling effects on the car from using them is masked by high downforce and current F1 gearboxes would appear highly crude if it was not for the illusion.
In Australia such a gear shift system came close to breaking Button's neck during the first upshift.
Of course if FF had his way there would no longer be a need for driver skill in motor sport.
We fought that attitude in the early 90s and many of todays F1 regulations were drafted directly against the arcade game concept.

[hardingfv32]

The problem comes when we try to compare a manualy triggered shift which is solely reliant on driver skill, with a 'modulated' semi or fully automaticaly triggered shift, where the modulation is applied before, during and after the actual shift 'overlap'.
In the later case, the modulation that occurs 'not' at overlap must reduce the torque being transfered from the engine to the road wheels and has to be added to the effective 'over all' shift time.
Of course few drivers today have the skills to effect a shift speed as fast as the modern systems but it was and is possible.

Well to say that a driver could be just as fast as a machine is literally true, but it is going to be a rare event requiring an element of luck.

"Fastest gearchanges were pre-1990's" this is clearly incorrect. As you have defined the problem, we need the lightest engine rotating weight possible. This would mean that the 1.5L '61-'65 cars had the fastest shifts.

Brian

[Richard]

Well to say that a driver could be just as fast as a machine is literally true, but it is going to be a rare event requiring an element of luck.

The numbers quoted in this thread show otherwise.

[hardingfv32]

The numbers quoted in this thread show otherwise.

Remember, autogyro said that a human can be equally as fast as a machine. It will be a rare event and might well not be documented, but in theory it is possible. The limit to the shift speed is the ''rotational moment of inertia' of the components, so that makes the 1.5L engine period ideal for the fastest shift record.

I know they probably used H patterns back then, so we are talking about a rearward shift movement with no sideways gate travel. Say 1-2 or 3-4.

This is also a fast shift competition with no concern over the well being of the gearbox or engine.

Brian

[flynfrog]

he also forgets that today's boxes are much lighter than pre 90s boxes since they don't have a human crashing the gears

Geartrains are lighter today because the regulations force the minimum weight as low as possible to barely meet the replacement regulations.
We see a lot of gearbox problems at present because of this.
It is mainly a sop to aero.
The lighter rotating components do reduce shift times marginaly.
I agree that it would be difficult for a 'human' driver to change gear manualy with reliability and no damage using the current sledge hammer systems.
Most of the unsettling effects on the car from using them is masked by high downforce and current F1 gearboxes would appear highly crude if it was not for the illusion.
In Australia such a gear shift system came close to breaking Button's neck during the first upshift.
Of course if FF had his way there would no longer be a need for driver skill in motor sport.
We fought that attitude in the early 90s and many of todays F1 regulations were drafted directly against the arcade game concept.

so now current cars are now faster but unsettle the car?

I will appreciate it if you would stop putting words in my mouth. Im sorry if you don't like that fact we don't drive 80s f1 cars anymore and the driver skill set is different than what you think is required but life goes on things change. Now if you will get back to proving your claim we are all waiting.......

[machin]

In the graph shown, the sequential gearbox is useing an extra gear in the acceleration curve shown. This on its own will level out the road speed curve and achieve a higher road speed no matter what the shift mechanism.

I'll say it again; are you looking at the same data?!

The sequential gearbox car isn't quicker because of the extra gear, but in this case actually inspite of it because the ratio selection on the sequential isn't optimum for this car....

I've marked up the chart to go with this explanation to make it easy to follow, :-

Both cars are equal up to 43mph. this tells us that the low first gear on the sequential car gives no extra performance (1st on the sequential is simply too low for a high-powered light weight car like this; there is not enough traction for the car to make use of the greater road-wheel torque that the low first gear offers, so the extra gear gives no extra acceleration and the additional gear change simply wastes time). At 43mph the sequential car completes a gearchange and falls very sligtly behind; about 1mph.

The two cars then accelerate equally up to 58mph (notice how the lines are parallel) when the H-pattern car changes gear, and loses a lot of time.

I've added a third line from 58mph onwards showing the acceleration of the H-pattern car if there were no gear change "lost time" (I've done this simply by copying and pasting the relevent sections of the H-pattern car's curve).

You can see that this amended curve actually increases its advantage over the sequential boxed car, and by the end of the chart (7.3seconds) would've been about 3mph faster were it not for the slow shifts. This indicates that the gear ratio selection on the H-pattern car is better than those on the sequential.

The pneumatically actuated sequential in this case is faster simply because it spends less time not accelerating (i.e. the gear shifts are shorter), it is not actually acclerating quicker when it is in gear, despite having an extra gear to use.

[Scuderia Nuvolari]

Please, when you compare these shifts for a lap, for a race, this can really affect a driver's ability to win a race. When he is on his last lap, leading by .5, shear driver fatigue from shifting can steal victory from him.
A near perfect example of this is Pierre Levegh driving a Talbot in 1952 Le Mans.

[flynfrog]

Please, when you compare these shifts for a lap, for a race, this can really affect a driver's ability to win a race. When he is on his last lap, leading by .5, shear driver fatigue from shifting can steal victory from him.
A near perfect example of this is Pierre Levegh driving a Talbot in 1952 Le Mans.

? the discussion is on the speed of shifts nothing to do with driver fatigue

[autogyro]

You can see that this amended curve actually increases its advantage over the sequential boxed car, and by the end of the chart (7.3seconds) would've been about 3mph faster were it not for the slow shifts.

Thanks for the graphs machin.

Why does it take your driver half a second to change gear manualy?
Is he still learning to drive?

[Scuderia Nuvolari]

Please, when you compare these shifts for a lap, for a race, this can really affect a driver's ability to win a race. When he is on his last lap, leading by .5, shear driver fatigue from shifting can steal victory from him.
A near perfect example of this is Pierre Levegh driving a Talbot in 1952 Le Mans.

? the discussion is on the speed of shifts nothing to do with driver fatigue

So you are saying that driver fatigue doesn't have any affect on the speed of that same driver's shifts?

[machin]

Why does it take your driver half a second to change gear manualy?

I would actually say it is about 0.35seconds:-



We are all still waiting for you to provide your own data.... to prove that the manual shifts are QUICKER as per your original post....

[mzivtins]

I often wonder how i can shift faster and smoother as a human on a upsidedown(race) motorbike gearbox...

I have no technical knowledge when it comes to gear boxes but please flame me if i'm wrong but isn't this hugely simple to answer?

Day-to-Day when i'm lazy my shifts involve: clutch-in, off-throttle, change, clutch-out, feed-throttle. Yes, riding like a grandad.

lets make that faster, clutchless shifts are lovely, high rpm, slight back off and the gearbox almost sucks the shift lever into the position.

So the next step for me would be to eliminate the need for me to control the engine rpm at shift... how can i do that as a human? I could be more accurate of course, a bit of practice maybe? But it just seems like common sense that introducing a computer controlled throttle cut would be the fastest and most accurate way to change the engine rpm surely? Maybe i'm just slow, but i cannot count crank speed

Anyway, I think the point i'm trying to get accross is: The OP needs to declare what he defines as a 'gearchange' is it, the time it takes the driver/rider to go from one ratio to the next?
Or the time it takes the mechanical elements to change from one ratio to the next specificaly within the gearbox?

I think the two yeild different answers.

[autogyro]

Why does it take your driver half a second to change gear manualy?

I would actually say it is about 0.35seconds:-



We are all still waiting for you to provide your own data.... to prove that the manual shifts are QUICKER as per your original post....

This one is certainly not.
It is slow for a road shift let alone a racing shift.

There is absolutely no reason mechanicaly for a manual gear shift to take longer to disengage and engage gears than any other form of gear shift.
The lever (or pneumatics) simply activate the syncro slidder hub.
Lever ratio from the long movement at the drivers hand to the much shorter movement at the actual hub ensure a sufficient increase in speed in the mechanism.
The movement between the disengage fork and the engage fork actuation in the middle of the shift, is never more than 0.04 sec capability in this weight of powertrain. I would expect 0.08 sec for full shift overlap time, maybe a bit longer if the flywheel is heavier than full race to cam match.
So the driver in this case is 'manualy' not makeing anywhere near the best use of the gear shifting system.
He is staying between selector fork actuation in neutral for way to long.
This cannot be from any limitation from the engine's inertia assuming it is the same spec of engine. The sequential manages the speed required to illiminate losses in acceleration all else equal.

[autogyro]

I often wonder how i can shift faster and smoother as a human on a upsidedown(race) motorbike gearbox...

So the next step for me would be to eliminate the need for me to control the engine rpm at shift... how can i do that as a human? I could be more accurate of course, a bit of practice maybe? But it just seems like common sense that introducing a computer controlled throttle cut would be the fastest and most accurate way to change the engine rpm surely? Maybe i'm just slow, but i cannot count crank speed

Anyway, I think the point i'm trying to get accross is: The OP needs to declare what he defines as a 'gearchange' is it, the time it takes the driver/rider to go from one ratio to the next?
Or the time it takes the mechanical elements to change from one ratio to the next specificaly within the gearbox?

I think the two yeild different answers.

Cutting the engine using the ignition or throttle only marginaly helps speed up the reduction in rotating input speed.
It is the rotating 'inertia' that has to be overcome.
Modulation of the shift in the modern systems is 'primarily' to 'smooth' the shift and to protect from rpm runaway and missed shifts.

If this modulation is before the actual shift overlap and or after it, which is nearly always the case in road semi and auto layshaft systems, then this modulation has to be added to the time taken for the over all shift because it is a reduction in torque transfer from the engine to the road wheels.

[hardingfv32]

It is the rotating 'inertia' that has to be overcome.

So the shifts should/could have been faster in the '60s with the internally lighter 1.5L GP engines?

Brian