Matching Lightweight Fly + Final Drive...

[PF Supercars Supra]

Whats up Guys,


Im setting my SI up all motor, was wondering how to match a good final drive with lightweight fly. I do use the car on the highway and around town but would also like to be able to drag and autocross the car. Engine Mods would be T1r Intake, 70mm Exhaust, T1R or Buddy Club Header, Spoon Larger Throttle Body.

Here are the options:

Final Drive:


FD2 Civic Type R- 5.06 Final Drive

King Motorsport- 5.84 Final Drive
6.33 Final Drive


Lightweight Fly:

ACT Streetlight - 8.4 pounds
11 pounds



Any help is appreciated!!

[ricetastic]

I wouldn't go beyond the 5.04 final drive just because the car is already revving pretty high at highway speeds and a 6.33 final drive would mean you would be around 4.5K rpm in 6th gear going around 65ish. 4.77 is about as high as I would go on the street and what do you know, the Si comes standard with that final drive. If your car spends a lot of time at the track the 5.84 and 6.33 final drives will help a lot but other than that I wouldn't go beyond a 5.04, heck I wouldn't go beyond stock. The gear ratios are obviously going to be the same but the maximum speed attained in each gear will be lowered in accordance with the top speed of the vehicle, so the top of 1st may only be 30mph vs. 36mph stock (at redline). I myself have never been a fan of using strictly one manufacturer so I would probably pair a BC header w/ a T1R exhaust etc etc but thats just me. Looks like your list of small yet tasteful mods is a great start to creating a N/A prepped street car. I don't know whether the rev-hang will eliminate any advantages of a lightweight flywheel, I would suggest getting a reflash either through Honda or from aftermarket vendors (i.e Hondata) to eliminate the rev-hang so you will fully benefit from a lightweight flywheel. Even the 08 si's have rev-hang it is just a little more suttle. Your car will rev up quicker and will be a heck of a lot easier to rev-match with a light-weight flywheel. I love the feather light feel of the OEM clutch but nothing beats a heavy duty race clutch that can withstand tons of abuse. With an after market clutch you can shift faster, the car feels like it engages better into gear and the overall durability of the clutch is increased. You don't really need a aftermarket clutch for an N/A car but I mean it'll def help at the track and during spirited driving.