RE: 911 RSR debuts at Silverstone
Discussion
Dr Clive said:
"Automatic clutch"? - No, with paddle shift the clutch remains engaged, on the upshift the ECU cuts the ignition momentarily whilst the current gear disengages and the next one engages, so no need to come off the throttle either ("flat-shift"). On the downshift the ECU uses inputs from revs and road speed to blip the throttle to match the revs when the driver requests the change with the left paddle. Not disengaging the clutch sounds brutal, but the dogs are made to take the strain.
I'm sure you're right, I was avoiding the fine details as I'm not aware of them.However (not disputing what you say but looking for more detail) - how can the throttle be 'blipped' with the clutch still engaged?
To achieve a blip surely the clutch must be at least partially engaged - or the gearbox be between gears? If it is the latter surely it's not between gears long enough for the blip to be effective?
Joe911 said:
However (not disputing what you say but looking for more detail) - how can the throttle be 'blipped' with the clutch still engaged?
To achieve a blip surely the clutch must be at least partially engaged - or the gearbox be between gears? If it is the latter surely it's not between gears long enough for the blip to be effective?
Knock your car in to neutral from a gear without using the clutch and you'll have no problem blipping the throttle. If you get it right, you can also force the next gear in without the clutch. Not a good idea in a normal road car box, but a dog box actually works better without use of the clutch. All the auto blipper does is rev the engine whilst in between dogs and bangs the next gear in when the speeds match. No clutch required.To achieve a blip surely the clutch must be at least partially engaged - or the gearbox be between gears? If it is the latter surely it's not between gears long enough for the blip to be effective?
RacerMike said:
Knock your car in to neutral from a gear without using the clutch and you'll have no problem blipping the throttle. If you get it right, you can also force the next gear in without the clutch. Not a good idea in a normal road car box, but a dog box actually works better without use of the clutch. All the auto blipper does is rev the engine whilst in between dogs and bangs the next gear in when the speeds match. No clutch required.
Yes indeed - but the between gear time needs to be tiny - how is that enough time for a blip (even an electronically activated one)? I assume they are looking to complete a downshift in, what, 0.1s?Joe911 said:
RacerMike said:
Knock your car in to neutral from a gear without using the clutch and you'll have no problem blipping the throttle. If you get it right, you can also force the next gear in without the clutch. Not a good idea in a normal road car box, but a dog box actually works better without use of the clutch. All the auto blipper does is rev the engine whilst in between dogs and bangs the next gear in when the speeds match. No clutch required.
Yes indeed - but the between gear time needs to be tiny - how is that enough time for a blip (even an electronically activated one)? I assume they are looking to complete a downshift in, what, 0.1s?In F1 they've used so-called "seamless-shift" 'boxes for some time now, which perform the changes in the order of ms, and they still manage to perform a blip on the downchange.
DC
Joe911 said:
Yes indeed - but the between gear time needs to be tiny - how is that enough time for a blip (even an electronically activated one)? I assume they are looking to complete a downshift in, what, 0.1s?
It's unlikely to be that short. Downshifts can be done at a fairly leisurely pace as there's no benefit to be had from downshifting as fast as you can upshift. Whilst the upshifts on a race sequential are now in the region of 50ms (or 0.05s), a downshift could well take 200 to 300ms (0.2 to 0.3s). Added to that, the fact that the ECU can blip the throttle considerably quicker and more accurately than the driver, and the fact that a low inertia race engine revs at a rate that's like to be >10,000rpm/s, then even 0.2-0.3s is plenty of time.Remember of course that for a number of years in F1 now, the control systems are able to calculate the position of the gear teeth on meshing gears and fire them in at the right moment. Add to that in the last 5 or so years systems that engage two gears at once to help speed up or slow down the input shaft to match the wheel speed and you can see that simply applying a blip whist in neutral between gears on a decent sequential is a fairly straight forward task.
Have a read of this: http://www.geartronics.co.uk/paddleshift.htm on the Geartronics website about their paddleshift system for race sequentials. It's got some very good, un-marketing like explanation about how it all works
RacerMike said:
Knock your car in to neutral from a gear without using the clutch and you'll have no problem blipping the throttle. If you get it right, you can also force the next gear in without the clutch. Not a good idea in a normal road car box, but a dog box actually works better without use of the clutch. All the auto blipper does is rev the engine whilst in between dogs and bangs the next gear in when the speeds match. No clutch required.
Many moons ago I drove my R5 GT Turbo from Reading to Henley On Thames when the clutch cable snapped using this method. Traffic was fun.Obiwonkeyblokey said:
Many moons ago I drove my R5 GT Turbo from Reading to Henley On Thames when the clutch cable snapped using this method. Traffic was fun.
This brings back memories of the late 80's - I had a broken clutch cable a couple of times in my R5 GT Turbo too and became practiced at changing gear without a clutch. Such a great little car - when it worked. SD and P said:
This brings back memories of the late 80's - I had a broken clutch cable a couple of times in my R5 GT Turbo too and became practiced at changing gear without a clutch. Such a great little car - when it worked.
lol, brilliant, so did I!!! At least 3 times, once I went from central London to Surrey with no clutch. didnt do the starter motor any good though when pulling away from lights.Oh the good old days
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