ksbkrew Posted June 4, 2011 Share Posted June 4, 2011 Hello sorry for asking again questions about this swap but i can't find my happiness with the search button i 'm gonna swap my mk4 auto for a mk3 turbo R154 gearbox, My car is a UKspec i see all the parts i need to do the conversion but i've got some new questions now -can i keep my auto diff? -can i keep my auto ECU? what will be the consequence of staying with my auto diff if i can keep it? what shaft will i need? the front of Mk3 and rear of mk4? i'm french so don't hit me with my poor technical language:D many thanks Quote Link to comment Share on other sites More sharing options...
ripped_fear Posted June 4, 2011 Share Posted June 4, 2011 im not the guy to answer this as im am not very familiar with the r154, but why spoil a ukspec with a old box! why not go for the v160 if funds will allow of coarse. Quote Link to comment Share on other sites More sharing options...
ksbkrew Posted June 4, 2011 Author Share Posted June 4, 2011 because i'm aiming 420-430whp and the R154 will be good for me and cost twice less than the V160, that 's the only reason Quote Link to comment Share on other sites More sharing options...
David P Posted June 4, 2011 Share Posted June 4, 2011 You can keep the diff and the ECU. The gearing will just be slightly lower, better acceleration, slightly less top speed. Pat probleme Don't know re prop. Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 4, 2011 Share Posted June 4, 2011 You can keep the diff and the ECU. The gearing will just be slightly lower, better acceleration, slightly less top speed. Pat probleme Don't know re prop. Other way around. Slower acceleration, higher top speed (than the auto / 6 speed) Quote Link to comment Share on other sites More sharing options...
David P Posted June 4, 2011 Share Posted June 4, 2011 (edited) Other way around. Slower acceleration, higher top speed (than the auto / 6 speed) You really need to practice your sums. N/A 4AT 4.083 N/A 5MT 4.083 N/A 6MT 3.769 T.T. 4AT 3.769 T.T. 6MT 3.266 U.K. 6MT 3.133 http://www.mkivsupra.net/vbb/showthread.php?225050-Supra-specific-gear-diff-ratio-and-tyre-size-calculator Edited June 4, 2011 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
ksbkrew Posted June 4, 2011 Author Share Posted June 4, 2011 amesowe your link! Quote Link to comment Share on other sites More sharing options...
David P Posted June 4, 2011 Share Posted June 4, 2011 amesowe your link! Merci a' Homer Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted June 4, 2011 Share Posted June 4, 2011 Also doing an auto/154 swap. You need the front half of the Mk3 prop and the rear half of the Mk4 prop. And as above, n/a diff means crazy acceleration but less top speed But be advised the gear shifter will need extending Quote Link to comment Share on other sites More sharing options...
David P Posted June 4, 2011 Share Posted June 4, 2011 Voila, maintenant vous avec le information complete. Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 4, 2011 Share Posted June 4, 2011 You really need to practice your sums. N/A 4AT 4.083 N/A 5MT 4.083 N/A 6MT 3.769 T.T. 4AT 3.769 T.T. 6MT 3.266 U.K. 6MT 3.133 http://www.mkivsupra.net/vbb/showthread.php?225050-Supra-specific-gear-diff-ratio-and-tyre-size-calculator Bit cocky? Since I went R154, same speed @ 100 is at a lower rpm than with my old auto box. 2800rpm instead of 4k. Quote Link to comment Share on other sites More sharing options...
ksbkrew Posted June 4, 2011 Author Share Posted June 4, 2011 many thanks to all! Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted June 4, 2011 Share Posted June 4, 2011 Voila, maintenant vous avec le information complete. Bonnet de douche Quote Link to comment Share on other sites More sharing options...
spiderpigcity Posted June 5, 2011 Share Posted June 5, 2011 Also doing an auto/154 swap. You need the front half of the Mk3 prop and the rear half of the Mk4 prop. And as above, n/a diff means crazy acceleration but less top speed But be advised the gear shifter will need extending swampy, is it the manual or auto half of the rear mkiv prop you use? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted June 5, 2011 Share Posted June 5, 2011 Rear section of the auto prop, front section of the manual prop if its from a Mk3 Supra, if youre lucky enough to find a Soarer/chaser prop you might be able to use that instead Quote Link to comment Share on other sites More sharing options...
David P Posted June 5, 2011 Share Posted June 5, 2011 (edited) The gearing will just be slightly lower, better acceleration, slightly less top speed. Other way around. Slower acceleration, higher top speed (than the auto / 6 speed) You really need to practice your sums. N/A 4AT 4.083 N/A 5MT 4.083 N/A 6MT 3.769 T.T. 4AT 3.769 T.T. 6MT 3.266 U.K. 6MT 3.133 http://www.mkivsupra.net/vbb/showthread.php?225050-Supra-specific-gear-diff-ratio-and-tyre-size-calculator Bit cocky? Since I went R154, same speed @ 100 is at a lower rpm than with my old auto box. 2800rpm instead of 4k. I considered that a polite way to mention that you were wrong. Here's some more sums. V160 6th 0.793 V161 6th 0.818 W58 5th 0.783 A340E 4th 0.705 A343E 4th 0.705 R154 5th 0.838 A343E 0.705 x 3.769 = 190.48mph @ 6800rpm - 100mph = 3570rpm R154 0.838 x 3.769 = 178.34mph @ 6800rpm - 100mph = 3813rpm Edited June 5, 2011 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 5, 2011 Share Posted June 5, 2011 I considered that a polite way to mention that you were wrong. Here's some more sums. V160 6th 0.793 V161 6th 0.818 W58 5th 0.783 A340E 4th 0.705 A343E 4th 0.705 R154 5th 0.838 A343E 0.705 x 3.769 = 190.48mph @ 6800rpm - 100mph = 3570rpm R154 0.838 x 3.769 = 178.34mph @ 6800rpm - 100mph = 3813rpm God knows what gearing mine's running then. With the auto, a ton was at 4k, and now its a smidgen under 3, Quote Link to comment Share on other sites More sharing options...
David P Posted June 5, 2011 Share Posted June 5, 2011 (edited) Check the speedometer against a sat nav, it sounds like your speed sensor needs changing. Edited June 5, 2011 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 5, 2011 Share Posted June 5, 2011 What speedometer? Was using the shat nav. Its been two different gearboxes, and two different speed sensors. Quote Link to comment Share on other sites More sharing options...
David P Posted June 5, 2011 Share Posted June 5, 2011 The specs for all the trans and diffs are listed above and my results were courtesy of Homers' calculator. Either you are running a diff ratio that is not 3.769, or Homer needs to 'massage' his calculator? Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 5, 2011 Share Posted June 5, 2011 Probably my diff Quote Link to comment Share on other sites More sharing options...
David P Posted June 5, 2011 Share Posted June 5, 2011 (edited) To add to the confusion, an R154 with an N/A diff shows 100.01mph @ 4131rpm? What wheel/tyre sizes are you running? I have asked Homer for input. Edited June 5, 2011 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Homer Posted June 5, 2011 Share Posted June 5, 2011 I don't really understand the quetion here, but comparing an auto to r154 and assumung both are in top gear the r154 will always rev higher than the auto - the reason is simple, the 5th gear r154 ratio is shorter than the auto overdrive. If ugp has had the reverse either the diff was changed in between or the auto box was knackered. Something probably was wrong with your auto box (or rev counter/speedo?) as you won't get 100mph in 4th gear @4krpm in an auto for any stock supra. I'd go with incorrect rev and speedo reading - as standard they overread massively which doesn't help comparing to "real" speeds and rpm given in the calculator Quote Link to comment Share on other sites More sharing options...
Guest ugp Posted June 5, 2011 Share Posted June 5, 2011 To add to the confusion, an R154 with an N/A diff shows 100.01mph @ 4131rpm? What wheel/tyre sizes are you running? I have asked Homer for input. Wheels are 20's, not sure on tyre sizes off hand. The diff's a 2 way OS one, not sure on the ratio, but it's higher than the tt auto lsd I had in place previously. Quote Link to comment Share on other sites More sharing options...
David P Posted June 5, 2011 Share Posted June 5, 2011 Wheels are 20's, not sure on tyre sizes off hand. The diff's a 2 way OS one, not sure on the ratio, but it's higher than the tt auto lsd I had in place previously. Feed your rear tyre size into Homers calculator, then you will learn what diff ratio you have. Quote Link to comment Share on other sites More sharing options...
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