how to up my gear ratio help please

[Skid Mark]

hi i was wondering if a diff from an auto s14 will up my gear ratio as i need slightly longer gears to stop me from over reving my s14 as the engine does not do a lot of mpg long distance @ 70 mph +

 

[yogi bear]

No, the auto diff is shorter than the manual diff.

You should be seeing 30mpg on a run at least. If not then your provle
Lies elsewhere

 

[Ysracing]

what ration is the auto diff ?

 

[Dex]

4.3

msglnjhgasyugasdjasasjdfhasjkhasdklbvgfsdk

 

[Ysracing]

i think this will help.
http://www.nissansilvia.com/forums/index.php?showtopic=337751

4.900 - C23 Serena SR20DE 4WD Auto

4.636 - C23 Serena SR20DE 4WD Manual, C23 CD20T 4WD

4.375 - R32 RB20DET 4WD, A31 Cerfiro RB20DET 4WD

4.363 - R34 RB25DE 4WD, R34 RB25DE Manual, R34 RB20E, R33 RB25DE 4WD, R33 RB25DET Auto, R33 RB25DE, R32 RB20DET, R32 RB20E,
C35 Laurel RB25DE 4WD Auto, C34 Laurel RB25DE 4WD Auto, C34 Laurel RB25DE Auto, C33 Laurel RB20DE Manual
A31 Cerfiro RB20DET, A31 Cerfiro RB20DE Manual, S13 CA18DET, S13 CA18DE, C23 Serena SR20DE 2WD, C23 Serena CD20T 2WD

4.111 - R34 RB25DET Auto, R33 RB25DET Manual, C35 Laurel RB25DET Auto, C35 Laurel RB20DE Auto, C34 Laurel RB25DET Auto, C34 Laurel RB20DE Auto,
S13 SR20DE (ABS),

4.083 - R34 RB25DE Auto, R33 RB20E, R32 RB20E (ABS), C33 Laurel RB20DE Auto, A31 Cerfiro RB20DE Auto,
S15 SR20DE, S14 SR20DET Manual, S14 SR20DE Manual, S13 SR20DET Manual, S13 SR20DE (ABS), S13 SR20DE

3.916 - S13 SR20DET Auto, S14 SR20DET Auto, S15 SR20DET Auto, A31 Cerfiro RB20E. 5 & 6 bolt

3.692 - S14 SR20DET ADM Manual, S15 SR20DET Manual. 5 & 6 bolt

3.583 - R33 RB25DE Auto, C33 Laurel RB20E Auto

* transmissions as stated, if not listed it means they are available in either Manual or Auto.

If anyone can add to this list, either if its ratio or cars that we can find the diffs in.

 

[SteveC200]

4.3

msglnjhgasyugasdjasasjdfhasjkhasdklbvgfsdk

3.9:1

 

[Skid Mark]

No, the auto diff is shorter than the manual diff.

You should be seeing 30mpg on a run at least. If not then your provle
Lies elsewhere

My car will never see 30 mpg as much as I would like to as it is running a5.7 v8 I'm not to sure Wat would bolt straight in to drop my rpm as I am only getting about 8 mpg at the min and1st and 2nd gear are a waist of time as it will pull away quiet happy in 3rd

 

[Mitch]

3.9:1

Also, check the ratio of your diff first and go from there. You may have a 4.1 or 4.3 in already

 

[Dex]

really? oops, my bad

 

[Skid Mark]

How would I check that would I have to take the diff out

 

[Jeffers_S13]

Jack car up, spin prop by hand, count wheel revolutions, use a paint pen to mark the start position in some way.