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Pneumatic Sequential Shifter

 
Old 07-16-2018, 09:25 AM
  #81  
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Please use a tripod

Looking great.
Is it weird that neutral had the prop spinning?

Just had a realisation that whilst wonderful all this comes from the engine bay which is quite tight for space. The boot is pretty empty.
Would recommend a dip switch to enabled reversion of the cables.

Measurements of the gearing would be interesting to all I'd think.
Distances and angles from center point sort of thing.
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Old 07-16-2018, 10:17 AM
  #82  
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The output does spin in neutral, but will stop if I hold it. There must be some friction from the input shaft onto the main output shaft that spins it unless there is some load.

I think the distances I measure on this box are different to a standard 5 speed and also a 6 speed. The gates are all similar but how far the input shafts move in and out depend on the sizing of the dog teeth which allow for different movement to the synchros. Also the straight cut gears are much wider and everything is shuffled around in terms if gear placement.

Part of the tweaking has been adjusting the amount of movement as R and 1st to some extent requires a longer move than 2 to 5th.

I've decided to build up a spare engine to test this box. I'm worried about damaging my race engine which is fairly unique. I'm also going to use this 2nd engine build to experiment with a couple of ideas. So I'm going to run my lightened crank, spin it up high and see if I swiss cheese the block. I'm also going to run my ported head with SR20 valves and Astina cams. It's going to be an interesting build in itself.
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Old 07-16-2018, 10:27 AM
  #83  
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Hydraulic coupling is why it spins in neutral
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Old 12-10-2018, 09:01 AM
  #84  
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Great work!
I'm looking at doing something similar for my 6R4 project car as the Ford Sierra Cosworth gearbox in in the back, the gearchange is set too far back in the cabin. I have a mechanical converter to revert the change direction to standard but it is a bit clunky and a sequential conversion would be ideal.
One question, how do you stop the cylinders holding pressure on the change forks after a gear is selected?
I see the MME motorsport kits have a linear pot on the cylinders presumably so the system can see the amount of throw achieved.
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Old 12-11-2018, 12:31 AM
  #85  
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My system uses magnetic sensors on the cylinders to test if they achieved a successful shift. They are also used to display to the LED gear indicator. Once successfully in gear, the pneumatic valves shut so that there is no load on the shift forks, but I've adjusted them so there is some wriggle room on each gear.

Basically the logic goes like this:

Detect shift button UP
Send signal to ECU to cut ignition, wait 5 ms
Fire pneumatics to move out of gear into neutral wait 10ms then fire horizontal move if required to the next gear plus another 10ms wait
OPTIONAL: Wait for revs to drop to within rev threshold via CANbus rpm signal
Fire pneumatics to move into gear
Check magnetic sensors to see if gear was achieved
Disable ignition cut
Turn off pneumatics

Detect shift button DOWN
Fire clutch pneumatic
Fire pneumatics to move out of gear into neutral,
Turn off Clutch
Fire Throttle opener
Wait for revs to raise to within rev threshold via CANbus rpm signal
Disable Throttle opener
Fire pneumatics to move into gear
Check magnetic sensors to see if gear was achieved
Turn off pneumatics

I need to get this box installed in my car, the only thing holding me up is that I don't want to run it on my race engine in case I hit the wrong gear... so I'm building up a spare engine. The spare engine is a bit ambitious as I'm running a chopped crank, DIY ported head with cams out of whatever I could find. Plus I've had a few side projects on the go that has kept me busy for the last 3 months. I'll get there soon.


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Old 12-11-2018, 03:36 AM
  #86  
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Give yourself a pat on the back, pal. Pretty impressive.
I've some experience myself with Arduino when I built a dual sonic height sensor for the air suspension on my van. Great to work with.
Mines a syncromesh box so would be a little easier than your dog but I think I'm going to struggle with space in the gearbox tunnel to fit the linkage. I'd have to make a plate to bolt onto the top of the gear lever mounting holes inside the car to mount the linkage and cylinders, that should work.
Do you have a parts list so far? I'm going to start sourcing parts ;-)
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Old 12-11-2018, 08:01 AM
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Originally Posted by knights19 View Post
Give yourself a pat on the back, pal. Pretty impressive.
I've some experience myself with Arduino when I built a dual sonic height sensor for the air suspension on my van. Great to work with.
Mines a syncromesh box so would be a little easier than your dog but I think I'm going to struggle with space in the gearbox tunnel to fit the linkage. I'd have to make a plate to bolt onto the top of the gear lever mounting holes inside the car to mount the linkage and cylinders, that should work.
Do you have a parts list so far? I'm going to start sourcing parts ;-)
I don't think pneumatics are gonna play nice with a synchromesh engagement, they work well for MadJaks dogbox cause dogs have to be shifted hard and fast. Synchromesh would likely just jam and not go into or out of gears cleanly, too many teeth in the way, not to mention synchros themselves.

I'd suggest looking into how the BMW SMG gearboxes worked if you wanna pursue the idea. Similar to what you're talking about, they were a regular synchromesh 6 speed with actuators fitted to shift gears, but because of the synchros I believe they had to do it all with the clutch fully disengaged--which to me kinda defeats the purpose, it just becomes a clumsy automatic.
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Old 12-11-2018, 08:15 AM
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Plenty of cars use ASMs (auto-shift manual) which are just that to drive, a clumsy auto but that is still better than a clumsy manual becuase my lever is in the wrong place.
No good me looking at the BMW system, not going to help my Ford gearbox. My application is more about gear selection than clutch disengagement and I wouldn't need necessary engine rpm match needed for dog changes.
My current gear selection is a problem and the syncros should slow the gears to allow the change even with air change. I don't need a dog box as my syncro box is already strengthened for 300bhp. Anymore power and I would have to go for the dog but certainly not for the gear change quality unless it was dog and sequential :-)
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Old 12-11-2018, 08:24 AM
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Originally Posted by knights19 View Post
Plenty of cars use ASMs (auto-shift manual) which are just that to drive, a clumsy auto but that is still better than a clumsy manual becuase my lever is in the wrong place.
No good me looking at the BMW system, not going to help my Ford gearbox. My application is more about gear selection than clutch disengagement and I wouldn't need necessary engine rpm match needed for dog changes.
My current gear selection is a problem and the syncros should slow the gears to allow the change even with air change. I don't need a dog box as my syncro box is already strengthened for 300bhp. Anymore power and I would have to go for the dog but certainly not for the gear change quality unless it was dog and sequential :-)
I don't understand--what vehicle is this in that you can't reach the shift lever?

As for the BMW trans, I just meant to look at it for setup guides, not to actually use parts from it. From what I've read the BMW trans is unique in that it really is just a manual gearbox with servos added, and can be converted back and forth to a proper H pattern box. The ASMs you're talking about are just selectable automatics, and don't share any internals with a manual transmission.
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Old 12-11-2018, 09:24 AM
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Ah. You've answered a post without reading the thread :-)
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Old 12-11-2018, 10:18 AM
  #91  
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You _might_ be able to get pneumatics to work on a synchro box by running lower air pressure or some sort of spring mechanism in the linkages that applies a softer constant force.

My setup uses 2 x 3 position air cylinders each controlled by the 3 x 2way valves. This is a fairly complex way to do it and I found it really hard to get any info on how to control it. It is far simpler though to use 4 cheap ebay air cylinders and piggyback them in pairs. Not only is the valving more simple but the logic is easier to code.

I spent some time tonight putting together the bottom end for my spare engine. It is a crazy build with parts recycled from all over the place plus being a test rig for a few ideas. Here are the specs:

NA8 block, oil squirters removed
Oil pump with oil pressure relief valve blocked up
2000 pistons and rods (higher compression)
lightweight bladed crank
Billet water pump bypass plate
BP05 head, ported, cnc chambers, decked 1.5mm
Nisssan SR20DE valves (+2.15mm I and +1.65mm E)
Protege intake cam (2Y)
VVT exhaust cam
SuBs, Eibach springs

Most bits are either left overs from my race engine, machined by myself or picked up cheap / free. I think all up it will cost me less than $300 including gaskets, rings etc. It will probably also cost me 200 hours too.
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Old 12-11-2018, 10:27 AM
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Originally Posted by knights19 View Post
Ah. You've answered a post without reading the thread :-)
Oh now I see, you started referencing arduino controls on a van of some sort so I got confused.

I really think the pneumatic setup for a synchro box is not going to work and is vastly overcomplicating the system. like MadJak mentioned, you'd need some sort of constant, gentle pressure to allow the synchros to do their job before the next gear will engage. Why not just run a FWD shifter setup wtih cables? Surely that will be more effective from both function and cost perspectives, even with adding some bell-cranks like MadJak built.
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Old 12-11-2018, 10:35 AM
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Originally Posted by themonkeyman View Post
I really think the pneumatic setup for a synchro box is not going to work and is vastly overcomplicating the system. like MadJak mentioned, you'd need some sort of constant, gentle pressure to allow the synchros to do their job before the next gear will engage. Why not just run a FWD shifter setup wtih cables? Surely that will be more effective from both function and cost perspectives, even with adding some bell-cranks like MadJak built.
The pressure and speed of the actuators is easily controlled with inline adjustable valving.
I could make a manual cable system which would maybe give a better feel than the rod linkage system I have but ideally a H pattern to sequential converter is what I'm after. If I had a spare 15k I could just buy a Quaffe sequential box, but alas no. A mechanical drum system converter would likely be better too, but I've not found one yet.
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Old 12-11-2018, 10:44 AM
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Originally Posted by knights19 View Post
6R4 project car as the Ford Sierra Cosworth gearbox in in the back
This sounds like it needs a build thread.
Ive always wanted to build my own "Group B" 6R4
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Old 12-11-2018, 11:02 AM
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Originally Posted by Full_Tilt_Boogie View Post
This sounds like it needs a build thread.
Ive always wanted to build my own "Group B" 6R4

Took me 4 years, raced at 6 events last year.

Gear change much improved when I put the reverse gear lock-out slug back in the box but could be better hence my interest in the thread.
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Old 12-12-2018, 12:11 PM
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Maybe a 12v electric linear motor may be better for me, mounted directly to the shaft through the end of the box.
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Old 12-16-2018, 10:25 AM
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Originally Posted by knights19 View Post
Maybe a 12v electric linear motor may be better for me, mounted directly to the shaft through the end of the box.
Thats probably going to give you some really slow shifts unless you get a bunch of torque in them and use really short linkages.
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Old 12-16-2018, 05:02 PM
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Originally Posted by Leafy View Post
Thats probably going to give you some really slow shifts unless you get a bunch of torque in them and use really short linkages.
A company in the UK called proshift sells some beefy solenoids for motorcycle shift kits. We're trying that on our FSAE car this season.
They are huge but fast.
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Old 12-17-2018, 06:34 AM
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These shut down solenoids are plentiful and have two circuits, pull and hold. Not sure if it is useful in this application but I thought I would mention it.

https://www.ebay.com/itm/New-Fuel-Sh...9/281632465737
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Old 12-18-2018, 11:29 AM
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Originally Posted by MartinezA92 View Post
A company in the UK called proshift sells some beefy solenoids for motorcycle shift kits. We're trying that on our FSAE car this season.
They are huge but fast.
I Guess if you're going to act directly on the shift rod you really only need a pretty short 3 position linear setup to push in and out on the rod, and a 3 position rotary setup that you could probably do with a permanent magnet motor, timing belt/pulleys and 3 limit switches.
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