robby
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| posted on 3/1/07 at 07:45 PM |
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compressed air gearchange
dunno if anyone's done it this way before, if so, sorry! used a wee 12v compressor to fill a cylinder ( old fire extinguisher), and a ram to
shift the gear linkage. two micro switches behind the wheel, wired thru the horn wiring, and that's about it. oh aye, there's a valve
thing that lets the ram rest in mid travel, and work both ways, up and down. passed sva today, didn't want to cost anyone time or money till i
knew it was ok! think it cost about £130 for the valve and ram. anyone interested and i'll try and get photos from camera to here... could take
me a while though!
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DIY Si
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| posted on 3/1/07 at 07:46 PM |
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Sounds good that. Only 1 question, how fast does it react/change gear?
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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Jon Ison
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| posted on 3/1/07 at 08:04 PM |
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Seen it done with soda stream bottles on a drag bike, that was quick, the gear change as well as the bike.
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robby
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| posted on 3/1/07 at 08:08 PM |
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dunno, mate uses it on his sprint car, and he's about the fastest up here i think. (supercharged gsxr) so it canna be too bad. i've also
wired a relay off the up change switch, killing the feed to the coils, so it's foot to the floor, click the switch, no clutch. and an override
to get up from first to neutral without conking out!
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DIY Si
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| posted on 3/1/07 at 08:16 PM |
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Mmmm, sounds even better. I was just curious/worried about the cylinder emptying or running low on pressure and leaving you stuck in gear. Have you
tried it for long road runs yet? I quite like the idea, but would need reassuring as I break down enough as it is!
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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RallyHarry
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| posted on 3/1/07 at 08:25 PM |
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not really a new one ...
Was looking at pressured cylinders a few years back and even found some chaps that used them for 5-speed gearboxes (robotized gearbox as it's
called)
It all boiled down to reliability and weight, a lot have tried them and tossed them ( and the idea), it's not worth the hassle of calibrating,
leaks and the fact that it's quite hard to get the "correct" force to engage without crunching gears if it stops midway.
So, yes it's possible.
But when the compressor has broken down 7 times, the air pressure drops on track etc, they all tend to go electrical ...
But I really hope I'm wrong and that you have found the answer we all have been looking for, anyway please show us a picture 
I guess i'm not the only curious one around here
Cheers
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robby
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| posted on 3/1/07 at 08:37 PM |
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It all boiled down to reliability and weight, a lot have tried them and tossed them ( and the idea), it's not worth the hassle of calibrating,
leaks and the fact that it's quite hard to get the "correct" force to engage without crunching gears if it stops midway.
never calibrated, no leaks, a wee bit trial and error on position for smooth change. bit vague on reliability - let you know at the end of the
summer!
ps used the low pressure warning switch off a lorry's air brakes to keep switching the compressor on when the pressure drops, mate just fills
his bottle once for the race, so pressure loss not a prob.
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carlgeldard
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| posted on 3/1/07 at 09:28 PM |
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Don't MNR do somthing like that.
Carl
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carlgeldard
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| posted on 3/1/07 at 09:33 PM |
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MNR's System
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robby
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| posted on 3/1/07 at 10:11 PM |
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hmm... seemed to have made an arse of the quote in that last reply... those photos could take longer than i anticipated...
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Simon
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| posted on 3/1/07 at 10:30 PM |
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If you are going to use on the road, and will need the pressure reservoir topped up, you could use a small Halfords type tyre pump. Just remove all
outer casing and use small pressure switch.
Loads of drag/sprint bikes use this system, either with or without a cut out.
ATB
Simon
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robby
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| posted on 4/1/07 at 04:03 PM |
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yeah, that's what i used simon, bypassed the digital readout etc.
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trogdor
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| posted on 15/1/07 at 03:24 PM |
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does anyone have any pics or schematics of this sort of gearchange? will it work with any type of gearbox? Am just musing about future projects......
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robby
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| posted on 15/1/07 at 08:14 PM |
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still haven't got round to getting photos, might try tomorrow. will work on any bike gearbox.
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mooner
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| posted on 16/1/07 at 01:14 AM |
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New to the site. here's another option Pingel electric shifters.
http://www.pingelonline.com/eshifter.htm
Shifter demo videos
http://www.pingelonline.com/shifter_demos.htm
And these guys make a paddle shifter for cars. http://www.westracecars.com/
[Edited on 16/1/07 by mooner]
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trogdor
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| posted on 16/1/07 at 09:47 AM |
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some pics would be great, not sure this is going to be any good to me, i am prob gonna have to change the gearbox in my saab at some point, as its
goona be bolted to a zetec soon and they were only orginally designed for a 3 cylinder 2 stroke engine! so will prob blow it up at some point and was
thinking what i could use as a gear shift as a opposed to making a new linkage i could use this compressed air idea, am not sure what gearbox tho,
some sort of transaxle, maybe audi or renault.
thanks for the links, they are really interesting though the shifter is abit out of reach for me!
[Edited on 16/1/07 by trogdor]
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tks
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| posted on 17/1/07 at 08:43 AM |
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yupsz
should be do able to make it DIY
Air bottle
Compressor
Fittings and PU hose
Pressure switch
2 Electric valves
a 2 way cilinder with enough stroke to pull and push..
problem i saw was the compressor at 12volts.. they all get only 2.2Bar (tyre pressure) and it gets a while to get them sow far also durability and
duty cycle takes me of trying it.
Used RC servo´s they are positionable and give also fast torque also they can be programmed to move exactly whats needed and not just a hard pull /
push!
Tks
The above comments are always meant to be from the above persons perspective.
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