What diff ratio

[Treecrusher]

Can anyone confirm what diff ratio should be in a v5 wrx new zealand new with trans code TY754VN1AA.

It seems every wrx around this era has 4.44:1 but mine has 3.9:1. Does this sound right?

Thanks in advance.

[cpt kernow]

3:9 sounds better than 4.44.

Check scoobymods they've got a list of all specs there.

I read somewhere (in a spec sheet) that all Imprezas have 3.9 where as legacy's and Foresters have got the taller highway gears

[funkytown]

 cpt kernow said:

3:9 sounds better than 4.44.

Check scoobymods they've got a list of all specs there.

I read somewhere (in a spec sheet) that all Imprezas have 3.9 where as legacy's and Foresters have got the taller highway gears

the STI's have 4.444 and RA's ver1/2 have 4.111. Its random as what has what. I think the old v1 RS had a 3.9

* not a complete list

[Koom]

 funkytown']

[quote name='cpt kernow said:

3:9 sounds better than 4.44.

Check scoobymods they've got a list of all specs there.

I read somewhere (in a spec sheet) that all Imprezas have 3.9 where as legacy's and Foresters have got the taller highway gears

/quote]

the STI's have 4.444 and RA's ver1/2 have 4.111. Its random as what has what. I think the old v1 RS had a 3.9

* not a complete list

The early legacy auto's had 3.9. The RS was 4.111, GT 4.444.

3.9 is the "longest" ratio and 4.444 is "shortest"

[Guest]

3.9 is a highway / top end speed ratio

when compared to the 4.444 and 4.111

[cpt kernow]

Then how come the NA's have 4.1's and turbos 4.4's

For example

my mates legacy tz sits at 3100rpm at 100kmh

Another friend has a v5 sti wagon 2900 at 100kmh

My s/tb sits at 2700rpm at 100kmh And mines definately got the 4.44:1?

Odd. Looks like time for google!

[Koom]

With both of those gearboxes shown, they have different top gears (as well as final drive ratios) and those 5th gear ratios are pretty tall. So it doesn't all come down to purely the final drive ratio, its a combination of fifth gear and final drive.

You'll find that STI gearboxes are often around 0.825:1 for fifth and RA gearboxes are 0.972:1

The V5 STI's had a "taller" fifth gear than most STI's (i.e. 0.738:1) but also had a 4.444 final drive.

To get your head around final drive ratio's etc, think that for a 4.444:1 ratio diff, the driveshaft has to rotate 4.444 times for the wheels to rotate once. For a 3.9:1, the driveshaft only has to rotate 3.9 times for the wheels to rotate once. So if everything else remains the same, the engine driving the 3.9:1 diff will be rotating less at the same speed.

But Subaru don't always keep everything else the same and keep changing the gear ratio's on us.....

[Guest]

 cpt kernow said:

Then how come the NA's have 4.1's and turbos 4.4's

For example

my mates legacy tz sits at 3100rpm at 100kmh

Another friend has a v5 sti wagon 2900 at 100kmh

My s/tb sits at 2700rpm at 100kmh And mines definately got the 4.44:1?

Odd. Looks like time for google!

OK a TZ and a V5 wont be listed on the same gear chart !

Differnet model years and model run differnet ratios

Also remeber that your tacho is just an indicator as to rpm, often they are out by a few hundred rpm

to get overall drive ratio multiply rear diff ratio by the selected gear ratio

This will show the relation of engine rpm verses wheel rpm

[cpt kernow]

Sweet-gearboxes made easy!

It's all fun ay?

[Guest]

TY754VN1AA is a gearbox that I have no data on Sorry

[Treecrusher]

Cheers all,

There is some good information in this pdf:

http://www.filefactory.com/file/ag1c044/n/Subaru_Transmissions_Specs_pdf

But unfortunately it doesn't give the diff ratio of my particular trasnmission.

[tydon]

can anyone confirm the gbox ratio of TY754VN1AA