Hamish Posted September 9, 2021 Share Posted September 9, 2021 Moved from Greta's "Miss-fire over 4000 rpm" thread https://sideways-technologies.co.uk/forums/index.php?/topic/8993-misfire-4000-rpm/&tab=comments#comment-130401 my 2nd gear OD has been used a lot but i suspect a different box and switch arrangement alloy switches are on the top. its an early tr6 box later tr6 boxed have switches on the side of the top case remote. H Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 9, 2021 Share Posted September 9, 2021 (edited) Hi Hamish. I've got the 3 rail gearbox in the wee car which has a different switch arrangement to the TR/Saloon boxes. The remote has an extension with a cam and a switch on a bracket out front. This is a pic of a GT6 box with the selector switch on the gearlever but basically the same. The reverse light switch is under the extension Edited September 9, 2021 by Escadrille Ecosse Link to comment Share on other sites More sharing options...
PeteStupps Posted September 9, 2021 Share Posted September 9, 2021 10 hours ago, Escadrille Ecosse said: I am interested in the second gear OD option for the Spit. I would prefer to go the second inhibitor switch route if anyone had info on that? Hopefully this is legible and doesn't upset anyone for copyright reasons... Courtesy of Dirk Devogeleer and Club Triumph: Close-up of the circuit diagrams - original at top, modified version beneath. Link to comment Share on other sites More sharing options...
PeteStupps Posted September 9, 2021 Share Posted September 9, 2021 Ah @Escadrille Ecosse, I think your question was aimed at Greta's mention of an "additional inhibitor switch" from Mike Papworth, I misunderstood. If my OD survives the RBRR I'm going to look into designing a circuit using a clutch pedal switch to disengage the OD. That seems like it would be a nifty solution. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 10, 2021 Share Posted September 10, 2021 (edited) Thanks @PeteStuppsI was thinking of the second switch when I wrote my post but I might have a look at that. Just slightly concerned at having to remember not to use it in first @mpbarrettI'm curious about your comment about dropping out between 3rd and 4th. How does that work with the selector switch on the column/gear lever? @Gretamy apologies for hijacking your thread Edited September 10, 2021 by Escadrille Ecosse Link to comment Share on other sites More sharing options...
andymcp Posted September 10, 2021 Share Posted September 10, 2021 I'm planning on trying this circuit to drop the O/D out between shifts. Feel free to comment... Link to comment Share on other sites More sharing options...
DeTRacted Posted September 10, 2021 Share Posted September 10, 2021 That looks sort of OK except the indicator lamp in series with relay 2 coil. As drawn they would both have to be 6v items. Both relay2 coil and the lamp need to be in parallel to be 12v ones. (If it is a J type I would have taken the earth returns for relay 1 and the solenoid both through the interlock switch. That way the OD is still inhibited in 'wrong' gears even if the relay sticks closed. ) Link to comment Share on other sites More sharing options...
andymcp Posted September 10, 2021 Share Posted September 10, 2021 Thanks! Good job I posted. It's for a D-Type O/D... Link to comment Share on other sites More sharing options...
DeTRacted Posted September 10, 2021 Share Posted September 10, 2021 42 minutes ago, andymcp said: It's for a D-Type O/D... Ah you can't do the both-through-the-interlock suggestion then. The solenoid takes too much current. Link to comment Share on other sites More sharing options...
andymcp Posted September 10, 2021 Share Posted September 10, 2021 Link to comment Share on other sites More sharing options...
DeTRacted Posted September 10, 2021 Share Posted September 10, 2021 That'll do it. Link to comment Share on other sites More sharing options...
Hamish Posted September 10, 2021 Author Share Posted September 10, 2021 For those like me without electrickery understanding revington tr do them at a cost https://www.revingtontr.com/engine-transmission/gearbox/logic-overdrive-device it’s what I use. They use the switches on the box. going up the box is fine but on the way down it’s trickier eg 3rd od to 2nd is a big step. As you need to move the gear lever or flick the switch out by hand. a momentary switch on the dash to engage up and a clutch switch to disengage would be good. Just dip the clutch and no gear stick waggling would work. but you can’t have the clutch switch operating the od or every gear change would be trying to operate the od. you see it’s beyond me already. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 10, 2021 Share Posted September 10, 2021 Thanks Hamish, I rather like that. I was wondering how the triggering could work using the existing column switch. I do rather like the idea of getting the OD to drop out when changing gear now I understand the point. And I see you have even managed to get yourself linked through RTR. Link to comment Share on other sites More sharing options...
PeteStupps Posted September 10, 2021 Share Posted September 10, 2021 2 hours ago, andymcp said: This is a neat solution, I like it. Mind if I copy it?! 57 minutes ago, Hamish said: a momentary switch on the dash to engage up and a clutch switch to disengage would be good. Just dip the clutch and no gear stick waggling would work. Hamish this is what andymcp's circuit does (in case it's not apparent!), the clutch only disengages. To get OD on 2nd as well you'd need to lose the 3rd/4th inhibitor - think it's slightly different on the TR box though. For my 3-rail Spitfire I would stick with OD enabled on all forward gears, with a changeover relay driven off the reverse-light switch to inhibit on reverse as it does now. The clutch would disengage OD if I ever accidentally left it on and dropped down into first. Here's my current messy circuit diagram, which relies on a warning lamp and good luck to avoid accidental OD in low gears. Ignition-switched power is sourced from green wire on left, which flows through changeover relay to the OD column switch unless the reverse switch operates. 12V from column switch then operates the OD relay to energise the solenoid. Lamp comes on as soon as the OD relay operates. It works as expected, lamp is a bit too bright for night driving but at least it's noticeable. (Sincere apologies @Greta for the massive thread drift!) Link to comment Share on other sites More sharing options...
Hamish Posted September 10, 2021 Author Share Posted September 10, 2021 2 hours ago, Escadrille Ecosse said: And I see you have even managed to get yourself linked through RTR. ha ha yeah he did ask too Link to comment Share on other sites More sharing options...
mpbarrett Posted September 11, 2021 Share Posted September 11, 2021 23 hours ago, Escadrille Ecosse said: @mpbarrettI'm curious about your comment about dropping out between 3rd and 4th. How does that work with the selector switch on the column/gear lever there are 2 switches on the gearbox one for third and fourth gear and the standard reverse and and momentary push switch to select OD. All the logic is done in software in a 8 pin Microchip embedded processor. It drive a relay to power the OD and another relay to turn the reverse lights on and turns on an LED when OD is engaged (the LED flashes when in reverse, why because I can). Basically the logic is if in reverse OD is disabled, and can only be selected if in 3rd or fourth. Press switch to turn on and again to turn off. I had planned to measure the car speed (sensor on prop UJ bolts) and then turn OD on automatically above a certain speed.... Can give you more details if you want. mike Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 11, 2021 Share Posted September 11, 2021 Cheers Mike. That's really interesting and helpful and I understand what you've done there. I am rather like Hamish in respect of the processor based logic control though. It's way beyond my comfort zone. However a logic based control for the OD makes so much more sense than the very basic mechanical switch and interlock from the 1960s. I am very tempted. Link to comment Share on other sites More sharing options...
mpbarrett Posted September 12, 2021 Share Posted September 12, 2021 could be done in a small (nano) Arduino. Cheap to play with, plenty of 12v power 5v activated relay boards on Amazon etc so easy to put something together. Just need to be careful with the power supply design for the processor as I have found that the Ardunio do seem susceptible to noise on the power supply lines when used in car applications. Worth implementing the built in watchdog timer in the code just in case it crashes..... Mike Link to comment Share on other sites More sharing options...
Nick Jones Posted September 12, 2021 Share Posted September 12, 2021 1 hour ago, mpbarrett said: Ardunio do seem susceptible to noise on the power supply lines when used in car applications Speeduino too….. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 12, 2021 Share Posted September 12, 2021 1 hour ago, mpbarrett said: could be done in a small (nano) Arduino. Cheap to play with, plenty of 12v power 5v activated relay boards on Amazon etc so easy to put something together. Just need to be careful with the power supply design for the processor as I have found that the Ardunio do seem susceptible to noise on the power supply lines when used in car applications. Worth implementing the built in watchdog timer in the code just in case it crashes..... Mike Mike you are great and very polite is assuming I properly understand even 50% of that. I now need to go and look up Arduino, activated relay boards, automotive power line noise, watchdog timer and coding and I should be a bit more up to speed Sorry, not being cheeky it's just that I realise how far things have moved on since I was playing with electronics 40 odd years ago! Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 12, 2021 Share Posted September 12, 2021 Just now, Nick Jones said: Speeduino too….. Oh and I'll go and look that up too, thanks Nick Link to comment Share on other sites More sharing options...
Nick Jones Posted September 12, 2021 Share Posted September 12, 2021 53 minutes ago, Escadrille Ecosse said: Sorry, not being cheeky it's just that I realise how far things have moved on since I was playing with electronics 40 odd years ago! At the user level things have got infinitely more powerful and probably easier to use. At the design level....... forget it! Speeduino is a family (extensive family these days) of engine management ECUs based on the Arduino platform. Offer a high features, low price alternative to Megasquirt. Chris has one controlling the Spitfire injection etc. It was a fairly troublesome experience (mostly but not entirely resolved) and sensitively to noise has been one of the big bugbears with it. Link to comment Share on other sites More sharing options...
DeTRacted Posted September 12, 2021 Share Posted September 12, 2021 22 hours ago, Escadrille Ecosse said: I am rather like Hamish in respect of the processor based logic control though. It's way beyond my comfort zone. ... and dare I say it , rather OTT in my opinion (but each to his own). Perhaps it's because my electronics training came long before PICs were even dreamed of but I was always taught to keep things as simple as possible, commensurate with the function required. Two relays is all you really need for the 'logic' as per Andy's circuit above. Even if you want to get complicated and have only one momentary switch to operate it on and off, the most you need is a couple of transistors in addition. Since this is a fixed-function device there is absolutely no need for programmability, and voltage glitches don't affect relays. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted September 12, 2021 Share Posted September 12, 2021 1 hour ago, DeTRacted said: ... and dare I say it , rather OTT in my opinion (but each to his own). Perhaps it's because my electronics training came long before PICs were even dreamed of but I was always taught to keep things as simple as possible, commensurate with the function required. Two relays is all you really need for the 'logic' as per Andy's circuit above. Even if you want to get complicated and have only one momentary switch to operate it on and off, the most you need is a couple of transistors in addition. Since this is a fixed-function device there is absolutely no need for programmability, and voltage glitches don't affect relays. So then, going back to this circuit from Andy On 9/10/2021 at 11:37 AM, andymcp said: Would it be possible to achieve the clutch dropout function by filing a slot at the neutral position of the 3rd/4th interlock cam? Link to comment Share on other sites More sharing options...
rogerguzzi Posted September 12, 2021 Share Posted September 12, 2021 2 hours ago, Escadrille Ecosse said: Would it be possible to achieve the clutch dropout function by filing a slot at the neutral position of the 3rd/4th interlock cam? Hello All I haver done that on a single rail gearbox I made a new cam and it works on 2nd as well and fitted an extra switch I have also done it on a 3 rail gearbox but just for 3rd and 4th (can not find photo will look later) Link to comment Share on other sites More sharing options...
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