turbodreamz22

I plan on boosting a AP2 S2000. Now from what I read a lot of people say that the AP1 has better gearing for boost applications compared to the shorter gears on the AP2.

So my question is

What gears could I do to match the same gearing as the AP1? And is it worth it on a AP2 boosted?

B serious

You'd need an AP1 reduction gear. Or...just an AP1 trans.

Not a big difference in gearing.

A longer final drive is more effective and cheaper.

turbodreamz22

What's a good final drive? For the AP2 boosted ?

deepbluejh

N/A guys often like to use a lower final drive (4.54 or 4.77) to help compensate for a lack of torque. If you're going to boost, stock final drive (4.1) is recommended for most power outputs. People running over 500whp often find benefit in going with a lower ratio (3.9), but keep in mind this is going to put more stress on an already overstressed drivetrain.

baZurk

I think you are trying to generalize this when you shouldn't. Switching to an ap1 trans would be a downgrade. Stock ap2 gearing is fine for boosted applications (turbo or supercharger, since you didn't specify which one).

I have a turbo ap2. I switched to 3.9 gearing when I rebuilt my diff. It didn't make a huge difference, although having the longer gears will take advantage of the wide power band that I had with the quick spooling turbo I had.

The real question here is, what are your goals with the car? Turbo or SC? Street car, fun weekend car, track car etc? Do you already have a good condition stock diff in the car? How much power will you be making?

turbodreamz22

My apologies, I mostly likely will go with FULL Blown turbo setup with a 5858 turbo and PRob looking to make 450-500whp max. It will be my my street/fun weekend car. And yea the diff is a good maintained differential.

baZurk

I say stick with the stock diff and gearing. Jumping to a 3.9 doesn't make enough of a difference to do it without necessity IMO

Any gear lower than a 3.9 (3.7 etc...) will be much more costly to fit into the oem diff housing. Save the cash, and prepare to make the decision if the diff decides to fail on you (it won't be quick to fail at that power level unless it takes some serious abuse).

turbodreamz22

I used to own a 04 STI and I loved the car but having the shirt gears that it did, SUCKED for a highway style fun car. So I mean I know the AP2 has good gears but how short are they really?

B serious

You don't have an AP2 yet?

Leave the gearing alone and boost it first. Well...buy a car first....

Why do short gears SUCK for the highway?

B serious

Also...it seems people have gear ratios a bit mixed up.

Higher ratios are shorter gears.
Lower ratios are taller gears.

3.9 is a smaller number than 4.4, for example.