Diff gears! 3.7's or 3.9's?

[HERONVY]

3.7 will still be a benefit. Holden's are pretty lazy off the line.

Yeah I agree, hear lots of good things about quick take off with the 3.7s , so looks as though ill still end up hunting a set down

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[james1988]

If your going through all the effort. I would go 4.11's everytime. Or atleast 3.9's.
There's going to be about 30% increase In revs.
And if you have done other engine work like cams etc you're not going to mind the little extra in fuel costs.
My friend went from 3.08 to 3.7 in his vt exec and it wasn't very noticeable.

 

[walesy]

My friend went from 3.08 to 3.7 in his vt exec and it wasn't very noticeable.

really?? i went from 3.08's to 3.46s and it was a big difference, then after my burnout comp days were over (after the respray) i went to the 3.9s for more drag friendly fun

 

[HERONVY]

If your going through all the effort. I would go 4.11's everytime. Or atleast 3.9's.
There's going to be about 30% increase In revs.
And if you have done other engine work like cams etc you're not going to mind the little extra in fuel costs.
My friend went from 3.08 to 3.7 in his vt exec and it wasn't very noticeable.

That being said ... If I went 3.9's or 4.11s would I lose alot of power mid-high revs?
Meaning quick take off, but gutless up high? Still liking the idea of 3.7s, seems like a good mediocre

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[wraith]

3.9 and 4.11 isn't that good on a manual you will find your self changing gears really quick.

 

[james1988]

Sorry. Since we were talking about 3.08 ratios I thought it was an auto.
Its a difficult decision. Cos it's such a expensive job to have to do again if you pick the wrong ratio.

 

[HERONVY]

3.9 and 4.11 isn't that good on a manual you will find your self changing gears really quick.

Yeah thats what im fearing, seeing it is a street car and i dont do burnouts, so 3.9's + 4.11's seem unnecessary

Sorry. Since we were talking about 3.08 ratios I thought it was an auto.
Its a difficult decision. Cos it's such a expensive job to have to do again if you pick the wrong ratio.

Yeah , i'll get under and have a look at what it has stamped on the diff and see where to go from there, pretty sure that walesy + haxzaw are right on this one about 3.45's though
Seems like 3.7's still seem like the go due to the "streetability" of them, they are a mediocre type choice, the car wont be revving its tits off and getting nowhere once it hits about 5-6k revs and will still be an improvement over the standard diff setup ..hopefully lol

Al

 

[Dr HaxZaw]

i reckon 3.7's are your best bet as well.... at 100kmh should only be a difference of about 200 revs by my calcs
not really going to effect fuel economy at all to me

 

[HERONVY]

i reckon 3.7's are your best bet as well.... at 100kmh should only be a difference of about 200 revs by my calcs
not really going to effect fuel economy at all to me

3.73's it is! chasing down a second hand set now

Al

 

[HERONVY]

Just got up underneath and it says ratio: 3.08:1 so yeah no wonder shes sluggish off the line lol

Managed to get onto a set of 3.73s for 300 brand new, so pretty stoked atm

edit: pic here:

Sorry for the bad quality, was difficult holding the camera all stretched out and was shaking when i took the pic lol
..its hard getting under lowered cars, should of jacked it up to get a better pic.. meh

Al

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