Turbocharger Posted March 10, 2009 Share Posted March 10, 2009 Just reading the diff ratio thread, which turned into a Compushift thread, has raised a question in my brain which is further off-topic and so warrants a new thread. I have a hydraulic / cable controlled 4HP22 gearbox which locks up the torque converter when I reach 35mph (light throttle) or 50mph (heavy throttle) in 4th gear only. I'd like to be able to lock it up in 3rd. I guess there's some clever hydraulics which stop it locking in lower gears or if there's a big speed differential across it (or else there'd be a helluva bang). Does anyone know enough about the innards of these boxes to know if there would be a sensible hydraulic route to locking it up 'manually' on demand, probably by another valve block? Obviously the risk of throwing lumps of gearbox out of the side is then on the driver... Quote Link to comment Share on other sites More sharing options...
simonr Posted March 10, 2009 Share Posted March 10, 2009 Don't know about these, but there are other auto boxes - including the 4sp box fitted to later Suzuki Vitara's which is electronically controlled. The ECU is pretty simple and to lock the torque converter - you just short one pair of wires together. There is a thread on Pirate about this - with the chap using it for engine breaking down hill. Si Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted March 10, 2009 Share Posted March 10, 2009 So you've managed to kill the engine In this thread and are now looking for new and exciting ways to kill the rest? Try sand in the diffs - that should take you the rest of the way Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 10, 2009 Share Posted March 10, 2009 The EH electronic version of the same box fitted in my Fairy locks the TC in 3rd, probably no help at all but thought I would mention it Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 10, 2009 Author Share Posted March 10, 2009 Cheers both - my Tdi won't bolt to a Vitara box (and it'd probably blow it apart anyway). Just an idle thought really, I'd quite like it to do more than 22mpg, that's all... Quote Link to comment Share on other sites More sharing options...
white90 Posted March 10, 2009 Share Posted March 10, 2009 Drive another car 22mpg seems about right for what you have Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 10, 2009 Author Share Posted March 10, 2009 Damn Quote Link to comment Share on other sites More sharing options...
ciderman Posted March 10, 2009 Share Posted March 10, 2009 Drive another car 22mpg seems about right for what you have What about a Prius Damn Quote Link to comment Share on other sites More sharing options...
ashtrans Posted March 10, 2009 Share Posted March 10, 2009 Hi, I am told it's possible to get the hydraulic ZF to lock the converter manually with a switch by fitting a solenoid to the converter apply circuit in the valve body but I have never done it, one of the reasons being once locked you really need to unlock it before you shift to 4th and then relock it. shifting from 3rd locked to 4th locked will not be good for the autobox. you can set the compushift to lock in 234, 34, 4th only or never, I tried 3rd and 4th but it was quite jerky and not nice at all do we just stick to 4th only, the new generation of compushifts due out soon will have the ability to manually lock the converter using a button, this will help : long hill climbs in 3rd, reduced heat build up crawling all day in 1st or 2nd for the crop sprayers, reduced heat and improved fuel efficiency downhill engine braking when off road. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted March 10, 2009 Author Share Posted March 10, 2009 Thanks Dave - the idea of shifting the box while the t/c's locked isn't appealing - I guess it's time to put that idea to bed. A Compushift box would be lovely but the rest of my truck doesn't justify the ££ spent in just the gearbox! Jase - I'll keep my little gay car for when 40mpg is required... Quote Link to comment Share on other sites More sharing options...
Daan Posted March 10, 2009 Share Posted March 10, 2009 how about a manual box? Quote Link to comment Share on other sites More sharing options...
Lara Posted March 11, 2009 Share Posted March 11, 2009 I have this setup on my HP24e Illuminated button on the dash to lock TC at any speed in any gear, automatically un-locks when you shift to another gear or if the engine goes bellow pre-set parameters. ie 3kph in low box 20kph in high box, certain rpm/speed thresholds etc. Very useful for cruising conditions and off road. Lara Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted March 11, 2009 Share Posted March 11, 2009 Just reading the diff ratio thread, which turned into a Compushift thread, has raised a question in my brain which is further off-topic and so warrants a new thread. I have a hydraulic / cable controlled 4HP22 gearbox which locks up the torque converter when I reach 35mph (light throttle) or 50mph (heavy throttle) in 4th gear only. I'd like to be able to lock it up in 3rd. I guess there's some clever hydraulics which stop it locking in lower gears or if there's a big speed differential across it (or else there'd be a helluva bang). Does anyone know enough about the innards of these boxes to know if there would be a sensible hydraulic route to locking it up 'manually' on demand, probably by another valve block? Obviously the risk of throwing lumps of gearbox out of the side is then on the driver... I don't know much about this, but I can see it being expensive. Maybe a cheaper option would be to retro fit Land Rover's HDC system, I know its not the same, but if you could fiddle with it and lower the speed down a tad it may answer the question. Quote Link to comment Share on other sites More sharing options...
JST Posted March 11, 2009 Share Posted March 11, 2009 HDC on a none ETC vehicle - cheaper to get a new auto eletronic box. TC - my tgv does 23mpg at best with an HP24. but its on slightly bigger tyres than std. Quote Link to comment Share on other sites More sharing options...
missingsid Posted March 11, 2009 Share Posted March 11, 2009 What about a Prius Havent you seen Top Gear? An BMW M3 has better mpg than a Prius when the Prius is flat out. Marc. Quote Link to comment Share on other sites More sharing options...
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