I can't attach a .xlsm file. Here's a link to download it from my google drive. https://drive.google.com/open?id=0Bx...l84MnJYbEpEUVU
First off - I'm 90% sure these graphs are accurate, not counting drag, but want feedback. Is this **** all wrong? Idk, I was an English major.
My setup has been 4.1, 5 speed, N/A ~150whp for a while now. I recently grabbed 4.77 kia gears from local yard and swapped them in, along with poly bushing to replace my 150k mile OEM rubbers. The car is silly fun, and I can't wait to get it on track in a few weeks.
Before doing it though, I wanted a better visual of what the gear changes would do to shift points and acceleration and since the internet was failing me, I built my own road force/acceleration graph generator. Every Miata diff ratio combined with both transmissions, and simple macros to hide columns, turning different options on or off in the chart. Import your comp weight and torque numbers every 100rpm from 4000rpm to redline, and you can use it too. The main issue with this chart is it's setup for my redline, 7300. If yours is lower or higher, you need to adjust the tables a bit. (I can explain more if needed.)
Output acceleration is in g's. Converting everything to metric made life way easier. For me, the visuals are what matter. I can see my shift points and what combo is better at specific speeds. At Pocono this summer, I wasn't getting much over 125mph (gps), and the 4.77 allows me to be in torque peak pulling out of T5 at NJMP Thunderbolt and a few other key places, so 4.77 was a no brainer.
For those making a lot more power than me at different RPMs, hopefully this can help?
If anyone knows of a better way to change redline and have all the charts follow suit pretty easily, I'd really like to add that automatic functionality.
Part of the sheet with every combo turned on
Original intention, 4.1 VS 4.77, both with 5 speed
4.77 vs 4.77, 6sp, showing the clear advantage of the 6 speed past 75mph
3.636 5sp vs 4.77 6sp