marc_p Posted January 9, 2009 Share Posted January 9, 2009 The reason I ask this is because when I was at the Supra xmas meet me and Havard were talking about motorway driving in the Supra and I always felt like I wanted to change up a gear (yes I know I have the 5 speed so please no 'well get a 6 speed box' comments ), anyway it turns out my revs higher at the same speeds eg. 4000 @ 80, so is the factory LSD a shorter ratio? Quote Link to comment Share on other sites More sharing options...
garethr Posted January 9, 2009 Share Posted January 9, 2009 In the FAQs Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 Cheers, but it doesn't say if the LSD ratios are different or not. Quote Link to comment Share on other sites More sharing options...
Nic Posted January 9, 2009 Share Posted January 9, 2009 Are you comparing a 6spd TT and 5spd NA? The NA 5spd gearbox and final drive gearing are shorter on the NA compared to a TT 6spd. Quote Link to comment Share on other sites More sharing options...
Nic Posted January 9, 2009 Share Posted January 9, 2009 (edited) Cheers, but it doesn't say if the LSD ratios are different or not. The final drive gearing is different on the NA, 6spd and auto models. The EPC images below shows the different final drive gear ratios in the end column. J-Spec http://img139.imageshack.us/img139/9813/picture2di0.png I then have 2 European EPC options for the JZA80 a shown below. European http://img228.imageshack.us/img228/8536/picture3eg3.png http://img228.imageshack.us/img228/1044/picture4nm7.png Toyota sell final drive gear set kit if you wanted to change yours, they're not particularly cheap though. http://img99.imageshack.us/img99/7979/picture1vv2.png Edited January 9, 2009 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 Are you comparing a 6spd TT and 5spd NA? The NA 5spd gearbox and final drive gearing are shorter on the NA compared to a TT 6spd. Hi Nic, Nope, both mine and Havards are 5 speed N/A's but mine sits at higer revs at the same speed, I was just wondering if the fact it has an LSD has anything to do with it? Quote Link to comment Share on other sites More sharing options...
Nic Posted January 9, 2009 Share Posted January 9, 2009 Hi Nic, Nope, both mine and Havards are 5 speed N/A's but mine sits at higer revs at the same speed, I was just wondering if the fact it has an LSD has anything to do with it? If they are both NA 5spd's then the final drive gearing should be the same ie. 12 - 4.083, so the rpms should be the same in the same gear at the same speed. Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 If they are both NA 5spd's then the final drive gearing should be the same ie. 12 - 4.083, so the rpms should be the same in the same gear at the same speed. Oh.........back to the garage for a checkover I think before something else breaks:( Quote Link to comment Share on other sites More sharing options...
Nic Posted January 9, 2009 Share Posted January 9, 2009 (edited) Oh.........back to the garage for a checkover I think before something else breaks:( How are you comparing, just using the stock rev counter? There could be some difference between the accuracy of the rev counters. If you both have 5spd boxes and the stock 5spd rear diff, then both should be revving the same, at the same speed, in the same gear. What wheels/tyres do you both have, different rolling radius would cause a gearing difference between the 2 vehicles. A slipping clutch or wheel spin would cause the revs to raise. Edited January 9, 2009 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 How are you comparing, just using the stock rev counter? There could be some difference between the accuracy of the rev counters. If you both have 5spd boxes and the stock 5spd rear diff, then both should be revving the same, at the same speed, in the same gear. What wheels/tyres do you both have, different rolling radius would cause a gearing difference between the 2 vehicles. A slipping clutch or wheel spin would cause the revs to raise. Well I was just looking at the FAQ and the higher the speed gets the greater the difference get's between my revs and the stock revs. Mine is on 19's with(I assume) stock box and (again, I assume) stock LSD, It has had a new clutch and flywheel relatively recently so there should be know slipping. If I remember correctly the RPM vs Speed(in fifth) goes like so: 3000 @ 60 4000 @ 80 5000 @ 100 6000 @ 120 although give or take a couple of hundred rpm's on those figures. Quote Link to comment Share on other sites More sharing options...
Nic Posted January 9, 2009 Share Posted January 9, 2009 Mine is on 19's What size tyres ie. width and aspect ratio do have fitted? Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 What size tyres ie. width and aspect ratio do have fitted? 30 profile, 275 width Quote Link to comment Share on other sites More sharing options...
garethr Posted January 9, 2009 Share Posted January 9, 2009 Cheers, but it doesn't say if the LSD ratios are different or not.Sorry, I misunderstood. You were asking if the LSD ratio is different from the open diff ratio. Quote Link to comment Share on other sites More sharing options...
marc_p Posted January 9, 2009 Author Share Posted January 9, 2009 Sorry, I misunderstood. You were asking if the LSD ratio is different from the open diff ratio. Yup, I did a search, but I'm not really a 'search master' Quote Link to comment Share on other sites More sharing options...
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