So, I am in parts acquisition and planning stages on this and trying to figure out my gear ratio information.
Car is a 75 Triumph Spitfire, hacking on an NA miata front and rear suspension (yeah, gonna stick tires out 4 inches past the fenders) and powering with an R1 (year not yet determined)
So far I have the spit (a roller with only minor rust that I have $60 in), Miata rear suspension, Miata front corners. Serious cut and weld stage comes after my Bugeye Sprite Resto moves under its own power (should be months).
This will be for autocross and trackdays.
So, starting at tires, I am planning for American Racer 13's (13x8) with a diameter of 20.3 inches.
Miata rear ends will be either 4.1 or 4.3 (have a 4.1open, have a line on a 4.3 torsen, numbers suggest 4.3, but this is where I need my sanity check.
I found transmission gear ratios for an exemplar 2008 R1 in the following two links.
http://aperaceparts.com/tech/2008yamahayzf-r1.htmlhttp://www.motorcyclespecs.co.za/model/ ... 1%2008.htmThese suggest (looking at 12.5k RPM) that 1st gear will go to 70mph and sixth runs out at 139 (purely theoretical, drag may have a bit to say about it, then again, decent power...)
does this make sense?
I did some thrust calculations using Jason Rhodes sheet and a rough looking dyno chart to source the torque
http://www.rhoadescamaro.com/build/?page_id=591I am showing that 1st gear motospit vs 2nd gear Lotus Elise has the motospit out-pulling everywhere.
So thats what i have done so far.
Is this all making sense? Most autocross builds would be looking for topping 2nd gear at 70mph, but then again, thats using sane RPM limits. If I ran gears to make that happen (a theoretical set, not one I have found to buy) top speed would be absurdly unusably low.
Is first really that tall?
Does it work out? (car runs ok, not too boggy)
Do most BEC guys put in alternative transmission gears to overcome this or something?
I just need a general, "yeah, you arent missing anything, you are on the right course" from people who have been there.
-Mucho appriciated! (sorry for the ADD thought-streams)