BDHG940 Posted March 24, 2011 Report Share Posted March 24, 2011 Trying to figure out an ideal gear for my setup. My car was around 124mph at 6300rpm with a c4, 26" tall tire and 3.73 gear. I have been going over some calculators that I have found and seems like a 3.27 should get me around 145 at ~6120rpm. If anyone has anything to double check with that, let me know your number against what I came up with. As for the trans gearing, I really am not positive, its just the PA super comp c4 Quote Link to comment Share on other sites More sharing options...
Farkas Posted March 24, 2011 Report Share Posted March 24, 2011 Google a final drive calculator, noob. Quote Link to comment Share on other sites More sharing options...
Guest Spam Posted March 24, 2011 Report Share Posted March 24, 2011 I love this site. Try it out. http://www.catherineandken.co.uk/sti/tyres.html Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 24, 2011 Author Report Share Posted March 24, 2011 I have tried a few, Im just trying to get someone that can backup what I have found. Before I spend the money and time building this setup and I looked at some idiots site that give bullshit info. Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 24, 2011 Author Report Share Posted March 24, 2011 I love this site. Try it out. http://www.catherineandken.co.uk/sti/tyres.html thanks Quote Link to comment Share on other sites More sharing options...
Patterson Posted March 24, 2011 Report Share Posted March 24, 2011 For RPM at given MPH mph x gear ratio x 336 divided by tire height Quote Link to comment Share on other sites More sharing options...
Patterson Posted March 24, 2011 Report Share Posted March 24, 2011 For MPH at given RPM RPM x Tire Height divided by 336 divided by Gear Ratio Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 24, 2011 Author Report Share Posted March 24, 2011 wouldnt the trans gearing play any roll on that? The one link above needed trans gearing and I cannot find anything from the manufactures website for my c4 Quote Link to comment Share on other sites More sharing options...
Patterson Posted March 24, 2011 Report Share Posted March 24, 2011 You need the gear ratios Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 24, 2011 Author Report Share Posted March 24, 2011 Ill have to call them tomorrow and see if they have anything they can provide me. I bought the trans used so I have a feeling I wont be able to figure that out. Thats why I was hoping there would be some way to calculate from the info on the dyno and the other variables I know. Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 24, 2011 Author Report Share Posted March 24, 2011 For MPH at given RPM RPM x Tire Height divided by 336 divided by Gear Ratio using this we would have to assume the trans ratio would have to be 1:1 correct? Quote Link to comment Share on other sites More sharing options...
Patterson Posted March 24, 2011 Report Share Posted March 24, 2011 To figure out the final drive take the rear gear ratio and multily it by the ratio of the gear you are in. http://www.tciauto.com/Products/TechInfo/gear_ratios.asp C4 ratios are 2.46 1.46 1.00 PA may be able to tell you what amount of slip is on the converter also. Running at 1:1 at the 145 is 6127 rpm. Typical aftermarket converter is likely around 7%ish. so it would actually be 6127x1.07= 6556 rpm. I'm full of useless math like this. Quote Link to comment Share on other sites More sharing options...
BDHG940 Posted March 25, 2011 Author Report Share Posted March 25, 2011 Sweet man, appreciate it and I think Ill go with the 3.27 gear I just found then Quote Link to comment Share on other sites More sharing options...
Patterson Posted March 25, 2011 Report Share Posted March 25, 2011 Sweet man, appreciate it and I think Ill go with the 3.27 gear I just found then Sweet, lots of torque = not needing a super short gear. Quote Link to comment Share on other sites More sharing options...
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