Gear ratio question im really confused and not a math major, help!

noitseuq · #1 01-10-2007, 08:41 PM

im really confused on the whole ratio thing. someone please clear it up.

how does a wrx tranny with a center diff of 1.1:1 that is meant for a 3.90 rear compatible with a 3.54 rear in the svx

and if i decide to use this 02-03 wrx tranny with the gears below installed

Ratios for gears:
STi RA ratios: 3.083 (1st), 2.062 (2nd), 1.545 (3rd), 1.151 (4th), 0.825 (5th)
Center Diff is a 1.1:1

how will that work with my 3.54 svx rear? cause from the online calculator i found its giving me 5th gear @ 3000 rpm is 73.3mph and everyone else is saying that 5th at 3000rpm is more like 44mph???

someone help me out on this please

huck369 · #2 01-11-2007, 05:51 AM

Quote:

Originally Posted by noitseuq

im really confused on the whole ratio thing. someone please clear it up.

how does a wrx tranny with a center diff of 1.1:1 that is meant for a 3.90 rear compatible with a 3.54 rear in the svx

and if i decide to use this 02-03 wrx tranny with the gears below installed

Ratios for gears:
STi RA ratios: 3.083 (1st), 2.062 (2nd), 1.545 (3rd), 1.151 (4th), 0.825 (5th)
Center Diff is a 1.1:1

how will that work with my 3.54 svx rear? cause from the online calculator i found its giving me 5th gear @ 3000 rpm is 73.3mph and everyone else is saying that 5th at 3000rpm is more like 44mph???

someone help me out on this please

The WRX has a front diff of 3.90, but The 1:1.1 drives the rear diff, so the rear diff in a WRX is 3.54 (3.9/1.1=3.54) that is why the WRX tranny will work with a stock SVX rear diff.

SVXMAN2001 · #3 01-11-2007, 06:05 AM

not to hijack but is this an automatic wrx tranny? Cause if so is this the only auto transmission that doesn't require messing with the stock rear svx differential?

huck369 · #4 01-11-2007, 06:13 AM

Quote:

Originally Posted by SVXMAN2001

not to hijack but is this an automatic wrx tranny? Cause if so is this the only auto transmission that doesn't require messing with the stock rear svx differential?

Nope, this is about the WRX 5-speed...

SVXMAN2001 · #5 01-11-2007, 06:14 AM

ok so just for reference there is no one automatic transmission that will swap into an svx without having to mess with the rear differential?

huck369 · #6 01-11-2007, 06:36 AM

Quote:

Originally Posted by SVXMAN2001

ok so just for reference there is no one automatic transmission that will swap into an svx without having to mess with the rear differential?

That is correct to the best of my Knowledge...