Jason Panciera wrote:
Steven Carter wrote:
Could you translate this for me?
FTA:
"Flipped 3rd and 5th gears and replaced 4th gear with an S gear to yield A-F-KA-S-Z ratios. Great autocross gearing!!"
Richard Casto, our resident Porsche transmission guru will have a much better explanation for you, but the idiot version goes something like this: swapping the positions of 3rd and 5th gear on the gear stack in the transmission yields a lower (higher) gear ratio...effectively making it seem like 3rd is more like 2nd and a half, and 5th becomes more like 4th and a half. Keeping the stock fourth makes a pretty high jump in gearing on the 3-4 shift, so the "S" gear kinda evens it out for 3-4-5.
In the transmission used in the early 911 and the 914 Porsche used a letter system to define gear ratios. "A" would be a 1st gear and "Z" a 5th gear. Given the racing heritage of the transmission and the wide range of factory gearing there are plenty of options for regearing. Some more expensive than others. A cheap and easy way to get a lower 3rd and 5th is to "flip" those gears. So you put 3rd in 5th and 5th in 3rd, but you also switch position on the input and output shafts. So a 5th 31:22 ZD becomes a 3rd 22:31 KA. It's not a true factory KA as the helical angle also gets flipped (backslash becomes a forward slash). But it is a common technique/trick that works for this transmission.
Jason basically has lower than stock gearing for 3rd, 4th and 5th.
Good luck on the sale. I am sorry to see it go.
Richard
_________________
Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.comMoney can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.
Login
Register
FAQ
Search
