TBDevelopments Posted February 18, 2013 Share Posted February 18, 2013 Had my 1997 6psd TT for a few months now and as i'm getting used to the car the ratios of speed vs RPM in various gears just seems wrong to me going from online information. I asked Jurgen who imported the car and he said the cars got a V160 gearbox, but i've not had it on my ramp yet to confirm myself so looking at all options. Tonight i was testing a few speeds out and at 80mph (speedo and gps) my tech is reading 3100rpm (i'll confirm this digitally once i get the avcr installed) so 80mph = 3100rpm on my car going from internet information it should be 80mph = 2666rpm on a V160 80mph = 2751rpm on a V161 (not taking that mines a v160 for granted) the 80mph i'm 100% sure is correct, i checked the other speeds as well at quick glance and there running higher RPM that listed as well. Can anyone confirm these numbers on there 6psd TT, or is there a shorter final drive kit available for the supra that i don't know was fitted? I don't mind just curious, Started when i saw people claiming the stock gearbox ratios will do 205mph and 197mph at stock 6800rpm redline just seemed stupidly high when calculating revs and speed as i'm driving. Going on the maths i've seen then at 6800rpm mine would do 175mph so quite a bit shorter if there are modifications done Tim:blink: Quote Link to comment Share on other sites More sharing options...
listy Posted February 18, 2013 Share Posted February 18, 2013 Are the wheel + tyre height similar to stock? Could have knocked the speedo out a bit if not. Or if its an import, the speedo may also be reading slightly wrong if not converted correctly. Or are you using a GPS or similar to gauge speed? Quote Link to comment Share on other sites More sharing options...
Justin Bieber Posted February 18, 2013 Share Posted February 18, 2013 And what kind of diff are you running fella? Stock torsen i'd guess? Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 yes sorry forgot to say they are running on standard facelift 17's wheels and tire sizes. speed is just confirmed on the satnav and both read the same, not the most accurate i know but better than a guess. I'd say speed is about right as if its reading under it would be setting off the 30mph speed cameras lol, as for spec of the car its all very standard, but that doens't mean it has always been standard in japan and some bits left in i don't know about. At this point i'm totally in the dark on its appearance underneath as well, i have planned to get it on my ramp and give it all a good check over but i've got the project from hell in my garage at the moment hogging my ramp, anyone who knows me will have been informed all about this haha. So at this point anything is just a guess until i can get underneath. Just seems funny that its so far off. Quote Link to comment Share on other sites More sharing options...
listy Posted February 18, 2013 Share Posted February 18, 2013 The previous quoted figures will be for a new car also I would presume. Bearing in mind the age of these cars now, the engine probably needs to work a bit harder to do the same job. Plus, manufacturer figures can never really be trusted Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 gear ratios don't work that way buddy. this is just cruising down a motorway, hardly any throttle what so ever so at those power levels car is operating at very low power outputs and sits a perfect 80mph at 3100rpm Tim Quote Link to comment Share on other sites More sharing options...
James Posted February 18, 2013 Share Posted February 18, 2013 (edited) 3100rpm on a V160 should give 89.1mph in 6th (70.6mph in 5th). 2783rpm on a V160 will give 80mph in 6th. 3100 on a V161 should give 86.3mph in 6th with the same 70.6mph in 5th. 2873rpm will give 80mph in 6th on a V161. *EDIT* These values are for a 255/40/17 rear tyre with a 3.266:1 diff. Edited February 18, 2013 by James (see edit history) Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 ok there slightly different to the information i was getting but still mines way off that. Tim Quote Link to comment Share on other sites More sharing options...
Justin Bieber Posted February 18, 2013 Share Posted February 18, 2013 A tt auto diff with a v160, and stock tyre sizes at 3100rpm = 77.2 mph, there's a gearing calculator here: http://mkivsupra.net/vbb/showthread.php?184490-Supra-specific-gear-diff-ratio-and-tyre-size-calculator&highlight=gear+calculator If you have 255/45/17's on the rear, with the auto diff and the v160 it comes out at 80.3mph if that helps at all Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 mmm i wander if or why there might be an auto diff in there, seems strange. away to tell them apart or did they use the same casing as its all internal? Tim Quote Link to comment Share on other sites More sharing options...
Justin Bieber Posted February 18, 2013 Share Posted February 18, 2013 I've heard of a few people putting auto diff's on for the acceleration benefit. Unfortunately I don't know how to tell them apart, sorry mate! Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 ok buddy, at this point its all sceptical anyway Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 Vin plate is showing V160 A03B if thats any use also Tim Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted February 18, 2013 Share Posted February 18, 2013 My money is on you having an auto diff, I had the same readings on an old supra of mine running this set up, I changed the diff and normality returned Quote Link to comment Share on other sites More sharing options...
spikedjack Posted February 18, 2013 Share Posted February 18, 2013 Possibly swapped out for an auto diff, should accelerate a touch quicker in which case Quote Link to comment Share on other sites More sharing options...
Guigsy Posted February 18, 2013 Share Posted February 18, 2013 Don't forget. The rpm guage is far from pinpoint accurate Quote Link to comment Share on other sites More sharing options...
Jamesy Posted February 18, 2013 Share Posted February 18, 2013 as before prob got an auto diff. i have an auto diff in the do-luck and it makes for a much better fast-road driving experience/track day set up. Quote Link to comment Share on other sites More sharing options...
Geo Posted February 18, 2013 Share Posted February 18, 2013 the diff as far as i know has not been changed, unless it was changed in Japan?? but you'd need to take it out to know for sure, i know, myself and jurgen did not change the diff. Quote Link to comment Share on other sites More sharing options...
SPG Posted February 18, 2013 Share Posted February 18, 2013 Small case manual diff is what the vin reads. Quote Link to comment Share on other sites More sharing options...
kwalker705 Posted February 18, 2013 Share Posted February 18, 2013 it'll be an auto diff on there.... or small case, whatever you prefer to call it. My aristo has a V16* box and a small auto diff and its at 3000rpm at 80mph in 6th. horrendous on long drives but absolutely brutal acceleration ! Quote Link to comment Share on other sites More sharing options...
SteveC Posted February 18, 2013 Share Posted February 18, 2013 The tachometers on these are known to read high and are classed as within tolerance even when displaying something like 10% (can't remember the exact figures) over actual rpm. I'm sure the figures are in the workshop manual somewhere. Once the engine is spinning at 3-4000rpm, the permitted tolerance is only to read high, not below actual rpm. Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 right ok thanks guys for the feedback. i'll get a better understanding once i get the avcr in and can take a digital display from the ecu RPM feed. Is there any strength differences between the Auto and Manual diffs? i understand there is 2 different diffs you can get a large and small or something depending on years Tim Quote Link to comment Share on other sites More sharing options...
SteveC Posted February 18, 2013 Share Posted February 18, 2013 Found the tachometer testing info. It's at 5000rpm where it shouldn't read below the actual rpm, but you can be see from the attached info, these tachometers usually read on the high side by around 10%. Quote Link to comment Share on other sites More sharing options...
SPG Posted February 18, 2013 Share Posted February 18, 2013 right ok thanks guys for the feedback. i'll get a better understanding once i get the avcr in and can take a digital display from the ecu RPM feed. Is there any strength differences between the Auto and Manual diffs? i understand there is 2 different diffs you can get a large and small or something depending on years Tim Correct, A03B = Small Case LSD B03B = Large Case LSD Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted February 18, 2013 Author Share Posted February 18, 2013 whats the real differences between the 2? Quote Link to comment Share on other sites More sharing options...
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