2.78 ratio opinions

[PAYNEY05]

Hi Guys,
I have to change the diff as the 3.36 has called it quits. To get the car back on the road i have a 2.78 to put in.
Can anyone tell me the good and bad about using this ratio? I am running a 138 RED motor(stock) with HR 3 speed gearbox. Wheels are 15 inch.
Most of the driving i do is freeway or not too hilly,

Thanks,
Payney

[choppedfan]

Hi Guys,
I have to change the diff as the 3.36 has called it quits. To get the car back on the road i have a 2.78 to put in.
Can anyone tell me the good and bad about using this ratio? I am running a 138 RED motor(stock) with HR 3 speed gearbox. Wheels are 15 inch.
Most of the driving i do is freeway or not too hilly,

Thanks,
Payney

You'll end up pulling it back out, it will make car too sluggish.

Save yourself the hassle and wait for another 3.36

Mick

[choppedfan]

Use this gear/speed calculator Payney and you'll be able to see what the "performance "will be like, even the profile and width of your 15" tyres will affect the outcome

http://www.kabamus.com/garage/gears.html

Mick

[Mick]

yeah i think it will end up being a problem could be ok once up to speed on the freeway but you'll probly find you'll feel the slightest hill

[muza]

Use this gear/speed calculator Payney and you'll be able to see what the "performance "will be like, even the profile and width of your 15" tyres will affect the outcome

http://www.kabamus.com/garage/gears.html

Mick

Thats a ripper!!

[rosco]

A pretty hefty challenge for a red 138 - not so bad if you're running an auto.... but a manua - and especially without synchro on 1st.... hmmmm... you'll struggle - and, believe it or not - you'll probably use more fuel.... revs will be lower - but the load on your engine for most of the time will be with the power valve open....

You might have got away with it with a HG onwards 3 speed - with synchro on 1st and a lower 2nd gear.... but if you had that - you'd have to open up the transmission tunnel - why then wouldn't you fit a 4 speed or a Jap box with overdrive.......

Drop back to 3:36 and you'll enjoy good economy, reasonable power - and avoid a lot of grief.... and won't need any engineering....

Just for those who do not know - be very careful when playing with diffs..... if you are running the early red diffs - or the grey - you'll need the "coarse spline" axles..... some of the latter diffs are "fine splined"..... one won't go into the other.....

frats,
Rosco