Homer Posted April 30, 2009 Share Posted April 30, 2009 I've put together an Excel file which shows the effect of fitting various sized diff and gearboxes to the supra, it also contains a graphical chart showing the effect different tyre & wheel sizes and offsets effect both fitment to the hub and the effect on speed/acceleration. There are two main sheets on the file, Wheel size fitment and gear ratio calculator. Before it goes to the tech reference section, can some of you please review it and see if there are any errors or faults? Also, any suggestions for enhancement are welcome It took a silly amount of time to research the data and put this together, so hope it's going to be useful to someone Edit - updated with "final" version..Supra Gear & wheel size Calculations.xls Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted April 30, 2009 Share Posted April 30, 2009 Awesome. Thanks. Quote Link to comment Share on other sites More sharing options...
Pete Posted April 30, 2009 Share Posted April 30, 2009 That's quite a work of art! Quote Link to comment Share on other sites More sharing options...
RobD Posted April 30, 2009 Share Posted April 30, 2009 Thats awesome that mate! Well done easy to use also! Quote Link to comment Share on other sites More sharing options...
gordy07 Posted April 30, 2009 Share Posted April 30, 2009 Nice one homer you must have some amount of spare time on your hands Quote Link to comment Share on other sites More sharing options...
AshBhp Posted April 30, 2009 Share Posted April 30, 2009 Very good. Quote Link to comment Share on other sites More sharing options...
Wez Posted April 30, 2009 Share Posted April 30, 2009 Top stuff Quote Link to comment Share on other sites More sharing options...
Terminator Posted April 30, 2009 Share Posted April 30, 2009 (edited) That is great. Just noticed that top speed is always calculated at stock red line not desired speed, unless I am doing something wrong. Thanks for all your hard work, it is always much appreciated. The gear/diff calculator really shows the impact of sticking an auto diff on the V160 box Edited April 30, 2009 by Terminator (see edit history) Quote Link to comment Share on other sites More sharing options...
Homer Posted April 30, 2009 Author Share Posted April 30, 2009 Nice one homer you must have some amount of spare time on your hands lol, I have no spare time at all, that's why it took 6-8 weeks to finally get the thing together That is great. Just noticed that top speed is always calculated at stock red line not desired speed, unless I am doing something wrong. Thanks for the feedback Phil The top speed is indeed based on stock rev limit. If you need to find a the gear speeds at any specific rpm it can be entered in the "desired rpm" cell which will deliver the top speed in each gear at that maximum rpm. I will look into changing the top speed calc if a value is entered in that cell Quote Link to comment Share on other sites More sharing options...
Terminator Posted April 30, 2009 Share Posted April 30, 2009 Yep I understand now, just wanted to see the number in red numerals;) There are always a few awkward ones who have non stock rev limits:innocent: Quote Link to comment Share on other sites More sharing options...
TTRickeh Posted April 30, 2009 Share Posted April 30, 2009 Thanks for putting this together it's pretty nifty Does the facelift 6spd definitely have the same final drive as the tt auto? No point in me swapping diffs if so. Quote Link to comment Share on other sites More sharing options...
Homer Posted April 30, 2009 Author Share Posted April 30, 2009 Thanks for putting this together it's pretty nifty Does the facelift 6spd definitely have the same final drive as the tt auto? No point in me swapping diffs if so. According to all the info so far the facelift 6spd appears to have the same "smaller" diff as the auto. If you don't mind, would you be able to PM your VIN code details (chassis, model and diff code) so I can check on EPC to make sure it matches up with everything so far? Getting all the diff info summerised has been a nightmare! EDIT - Rick, did you see the last revision of the file or the first one? I updated the ratio's just after posting for the facelift 6spd based on some further info from Nic. Sorry for the confusion! Quote Link to comment Share on other sites More sharing options...
TTRickeh Posted April 30, 2009 Share Posted April 30, 2009 According to all the info so far the facelift 6spd appears to have the same "smaller" diff as the auto. If you don't mind, would you be able to PM your VIN code details (chassis, model and diff code) so I can check on EPC to make sure it matches up with everything so far? Getting all the diff info summerised has been a nightmare! Yeh sure i'll just nip out and check. Will PM you in a sec. Quote Link to comment Share on other sites More sharing options...
TTRickeh Posted April 30, 2009 Share Posted April 30, 2009 Ah so there is still better acceleration to be had Just checked the revised version. Sending over my details, potential spanner in the works (or should I say gearbox). Quote Link to comment Share on other sites More sharing options...
TLicense Posted May 1, 2009 Share Posted May 1, 2009 Good stuff Homer. Quote Link to comment Share on other sites More sharing options...
Alex Posted May 1, 2009 Share Posted May 1, 2009 Works for me, maybe you could add the Desired Top Speed in a second window to appease Termi? Or Termi edit the red numbers' field and replace the J11, J12 and J13 in the formula with N11, N12 and N13? See attached. Quote Link to comment Share on other sites More sharing options...
jevansio Posted May 1, 2009 Share Posted May 1, 2009 Poo, my car won't hit 200mph maxed out in 6th with an increased RPM Nice work though Darryl Quote Link to comment Share on other sites More sharing options...
jevansio Posted May 1, 2009 Share Posted May 1, 2009 Idea's for enhancements, use dropdowns for the various options where appropriate, I can do that for you & send you the sheet back if you wish Darryl Quote Link to comment Share on other sites More sharing options...
Alex Posted May 1, 2009 Share Posted May 1, 2009 Idea's for enhancements, use dropdowns for the various options where appropriate, I can do that for you & send you the sheet back if you wish Darryl Yep I agree that would help. I'd say go for it and post up a new copy Quote Link to comment Share on other sites More sharing options...
tDR Posted May 1, 2009 Share Posted May 1, 2009 Brilliant Darryl If you're J-spec auto you could reach 60MPH in 1st with an 8,500 RPM rev limit Or with a UK manual diff it'd only take 7k RPM and make it a ~230 MPH car, horespower permitting... If I keep my diff and put a v161 in for track work, it drops the top speed from ~192 MPH to ~165 MPH (~171 MPH with a v160) - sounds perfect for the job given there's not many tracks where you're gonna get a chance to get up there but you will benefit from the improved acceleration. (All with 265/35/18's) Quote Link to comment Share on other sites More sharing options...
jevansio Posted May 1, 2009 Share Posted May 1, 2009 (edited) I've updated the top speed as per Alex post & made the selections dropdown. I've sanity checked it but it may be worth a couple of others doing the same I ****ed it up, uploading new version now Edited May 1, 2009 by jevansio (see edit history) Quote Link to comment Share on other sites More sharing options...
jevansio Posted May 1, 2009 Share Posted May 1, 2009 Darryl FYI: I have created a new data sheet for the list info, I have given each list a name (you can see the name when you select the list contents where Excel would normally tell you which cell you are in). The lists are in alphabetical order (they need to be I think for LOOKUP to work correctly) I used the Tools... Data Validation menu on the Gear sheet to refer to these lists by name. I created 2 cells behind the graphs which lookup the names to their proper values (the values you had to type into the original sheet). I modified all cells to refer to these now rather than the dropdown boxes Quote Link to comment Share on other sites More sharing options...
Wez Posted May 1, 2009 Share Posted May 1, 2009 Would this explain why my trap speeds at pod were 10mph out and I was bouncing off my limiter in 4th? I have a pre facelift 1996 RZ-S with the larger diff casing, not sure what ratio that should be Quote Link to comment Share on other sites More sharing options...
jevansio Posted May 1, 2009 Share Posted May 1, 2009 Guys, can you download & check this sheet? I think I'm going mad with different versions lying about Supra Gear & wheel size Calculations Updated.xls Quote Link to comment Share on other sites More sharing options...
Alex Posted May 1, 2009 Share Posted May 1, 2009 To be a pita, I'd say split the top speed box in to and have a desired speed result and a stock limiter result, one above the other in the same bit. Quote Link to comment Share on other sites More sharing options...
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