roboldham Posted November 8, 2002 Share Posted November 8, 2002 Hello folks I have now had my motor for 4 weeks and am STILL trying to get my head around a "feature" of the Tiptronic system. I thought that when in "M" mode (ie. the steering wheel buttons control the gear shifting) that the gearbox would not seem to still have a mind of it's own. On my FTO (which I should really get around to selling!) when in Tiptronic mode the gearbox would stay in the gear it was told, unless I came to a standstill and it shifted to 1st - as it should. On the Supe say when I am in Top, and in "M" mode at about 3-5,000 revs and I floor it you wouldhave thought the engine would take the strain and keep in top to simply just accellerate normally. Instead it shifts down to 3rd and INTO THE RED ABOVE THE REV LIMITER! Surely this is totally arse about face, and it makes for embarrasing and possibly unsafe high speed overtaking on dual carriageways at that sort of speed (120?) Shouldn't flooring at these revs simply accellerate and not shift down when doing so thus above the rev limiter? Is this a prob, a feature or what? Anyone else experience the same? R Quote Link to comment Share on other sites More sharing options...
paulrenn Posted November 8, 2002 Share Posted November 8, 2002 Hi Rob, Wonder if this is some side-effect of KMH->MPH conversion? Like active spoilers deploying at the wrong speed etc. How did you have yours converted (I'm assuming its an import). Does sound a little dangerous, can you get it to one of the list experts for double checking? Quote Link to comment Share on other sites More sharing options...
roboldham Posted November 8, 2002 Author Share Posted November 8, 2002 Originally posted by paulrenn Hi Rob, Wonder if this is some side-effect of KMH->MPH conversion? Like active spoilers deploying at the wrong speed etc. How did you have yours converted (I'm assuming its an import). Does sound a little dangerous, can you get it to one of the list experts for double checking? Hmm interesting - although I thought the gear-select would have gone off gearbox rather than road speed? R Quote Link to comment Share on other sites More sharing options...
Darren Posted November 8, 2002 Share Posted November 8, 2002 Its a feature! If you are in top in 'M' mode it will still drive like normal auto. Which is nice and relaxing. If you come up behind a car and want to fly past you drop it a gear into say 3rd and hammer past. It will then not change up past 3rd till you make it but if you had to stop it will not make you pull away in third which would not be very impressive it will act as an auto again all the way back to 3rd but not above unless you do it via the steering wheel. It will also not let you change from 4th to 2nd at 130 leptons cos its got a brain! Hope this helps and makes some sense. Quote Link to comment Share on other sites More sharing options...
Terminator Posted November 8, 2002 Share Posted November 8, 2002 I have only driven a MKIV titronic box once and can't remember if it has a kick down switch, if it has this will override all functions as it assumes you really mean to go for it. Quote Link to comment Share on other sites More sharing options...
roboldham Posted November 8, 2002 Author Share Posted November 8, 2002 Originally posted by Terminator I have only driven a MKIV titronic box once and can't remember if it has a kick down switch, if it has this will override all functions as it assumes you really mean to go for it. Thanks guys - all made sense. But I still think its bad logic on the Supes behalf - changing down into the rev limiter is bad under any circumstance IMHO! Far better to have clever logic that says "oh I better hadnt do that and continue to accelerate in top" R Quote Link to comment Share on other sites More sharing options...
peter Posted November 18, 2002 Share Posted November 18, 2002 we have same prob also when flooring it I push the pedel past the kick down swich as I find that Icannot feel when the swich is engageing , is there a way to make the kick down swich more positive ? Quote Link to comment Share on other sites More sharing options...
eyefi Posted November 18, 2002 Share Posted November 18, 2002 this dont sound right to me. no autobox should shift into the redline or even near it, it doesnt make sense. if this is a "feature", which i doubt very much, its a shit one. i think it would have a feature of kicking down but not into the redline. it sounds like it could b something to do with a speedo, odo conversion to me. afaik the standard autobox ecu has inputs from the speed sensors and gearbox sensors, from which it makes decisions on what to do. if the speed sensor is fucked with a 5:8 ( is yr car delimited and converted to mph and odo reading in miles???? Quote Link to comment Share on other sites More sharing options...
peter Posted November 18, 2002 Share Posted November 18, 2002 I think the only way is to stop the thing from kicking down by disableing the kickdown switch black tt tiptronic no mods (yet ) Quote Link to comment Share on other sites More sharing options...
roboldham Posted November 18, 2002 Author Share Posted November 18, 2002 Originally posted by eyefi this dont sound right to me. no autobox should shift into the redline or even near it, it doesnt make sense. if this is a "feature", which i doubt very much, its a shit one. i think it would have a feature of kicking down but not into the redline. it sounds like it could b something to do with a speedo, odo conversion to me. afaik the standard autobox ecu has inputs from the speed sensors and gearbox sensors, from which it makes decisions on what to do. if the speed sensor is fucked with a 5:8 ( is yr car delimited and converted to mph and odo reading in miles???? I thought all this too - it could be a dodgy kmh to miles conversion. I am getting that ripped out and a TRL speedo conversion done very shortly, so I will let you know if that helps! R Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted November 19, 2002 Share Posted November 19, 2002 This could be a similar effect to the one mentioned regarding the normal auto-gearbox. When incorrectly converted from KPH->MPH a 5/8ths scaled speed signal ends up being sent to the ECU (which controls the gear changes). I think the gearbox takes more notice of road speed than revs and thus when it's at 100mph (160kph) it's actually thinking you're only doing 62.5mph (100kph) And in it's map (mind) 100kph and dropping down a gear won't hit the rev limiter. Another part of the code probably handles the rev limiter independantly. A lot of cars are driven on maps as it takes too long to work out the algorithms in real time, hence they rely on 2 dimensional maps. Give it a corrupted measurement and one of the axis of the map will be indexed wrongly and give odd effects. I'm not saying I know how the Supra ECU works but if I were building one I'd get rid of expensive working out of algorithms, which used many parameters and just map (fix) just the two most important. As I bet in the long run there would be no difference in the drive. (how were they to know you changed the signals) In the end the only 100% guaranteed way is to remove ANY and ALL conversion boxes and see what it is like running native Jap spec. Then if all is well, convert it and see if that changes things. regards Pete Quote Link to comment Share on other sites More sharing options...
Digsy Posted November 19, 2002 Share Posted November 19, 2002 Doesn't the VVTi have a mechanical odometer integral with the rev counter, which means intercepting only the speedo signal for the speedo conversion (rather than leaving the rebroadcast signal untouched as you can in a pre facelift car) a lot harder? Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted November 19, 2002 Share Posted November 19, 2002 The face life Supras do yes. But it only LOOKS mechanical. It is still driven by an electronic speed signal pulse from the same gearbox sender unit. It just has a stepper motor inside to turn some dials. You can still seperate the two funcitons, odometer and speedometer, with a little thought. It's also one fo the reasons why my DSC was designed to output a rebroadcast signal of its own so that if the odometer was modded to miles that the car could be supplied with the KPH signal. Regards Pete Quote Link to comment Share on other sites More sharing options...
Darren Posted November 22, 2002 Share Posted November 22, 2002 Mine kicks down but I have not noticed it red lining. But I normally change down on the steering wheel, maybe thats why I'm not experiencing the problem. Quote Link to comment Share on other sites More sharing options...
roboldham Posted November 23, 2002 Author Share Posted November 23, 2002 Originally posted by Darren Mine kicks down but I have not noticed it red lining. But I normally change down on the steering wheel, maybe thats why I'm not experiencing the problem. That's what's odd - I always change using the buttons too - but even when in M mode, and opening throttle fully in top the little f****r STILL changes down into the redline until I ease off. R Quote Link to comment Share on other sites More sharing options...
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