I'm specing out a semi transmission build for my em2 civic and I need some help from people with experience...

The car is going to be an all around performer. mostly spirited mountain driving, maybe some 1/4 mile runs with a little autocrossing thrown in, but mostly a fun street car. I will be using a smallish turbo, hopefully making around 220 whp.

Right now i have the stock ex trans, i've purchased a lsd, but before I put it in, I would like to know if its worth it to switch out to longer fd ratio. Or just keep what I have.

Here is a plot of the stock ratios




here is the hx 3.842 fd and 5th gear.




Would the fd benefit me performance wise, or would it do the exact opposite.

I figure I could stay in boost longer, less wheel spin, only have to shift twice in the quarter, and would drop my rpm at 80mph fro 4000 to 3200 in 5th (which should give me better mpg).

Plus if i ever do decide to build the motor for bigger power, I think the shorter gears would be a hindrance, especially on street tires.


Anyone have any input???