View Full Version : Diff Ratios


I&J
09-07-06, 17:38
Whilst we've been going over the car it was suggested that it would be a worth while modification to change to a higher diff ratio. It was mentioned that 3.55s would be a good start.

I understand that you get into you rev range a little quicker and that you'd be reving higher at say a 100, not that it matters as I don't do highway driving...actually I was considering taking it to Bathurst this year but my best mate told me not to even consider it...yeah probably not a good idea up on reid getting trash or something while I'm trashed.

Also what sort've gains could be expected over the quarter mile. Much? Half a second...I'd take an easy gain like that anyday :)

VL GRA
09-07-06, 19:56
I wouldn't expect half a second by going to 3.5s which i think the gears you would be going to would be 3.45s. 3.7s would be noticbly better on take off but would rev higher at 100 kays.Is your motor stock or have you got some modifications?

I&J
14-07-06, 23:47
The only mod is a Cam and tune.

I'm not too phased by the motor revving slightly higher.

Ok so if I decide I'd like to give this a go could you suggest someone in Melbourne who'd be able to help me.

Would I just ring up, advise of them of the car etc. and what I'm after. Would I need to keep my centre or let them have it as an exchage? And what would I expect to pay for something like this.

Thanks.

ILLUSIV
15-07-06, 02:08
Go 3.9's if your not worried about revs and you don't do much highway driving.

It would probably be worth getting the LSD cones replaced, and the diff rebuilt with new bearings... if you get gears also, I'd guess about $1000 to $1500 depending on where u go, and gears etc..

Walkie
15-07-06, 15:55
If you have a bigger cam go for the 3.91's. I put a set in mine and it was the best thing I ever did. The revs on the freeway are not as high as people think, at 100km/h mine sits on 2,300, hardly revving its head off. To be honest my fuel consumption went down as I could get into 5th a lot earlier.

VL GRA
15-07-06, 16:26
Revving at 2,300 at 100km/h is pretty good. I would also get the rest of the diff done while you have it out. Make sure to ask for the orignal gears back too!

I&J
16-07-06, 10:52
Thanks for the advice.

I'll make some enquiries next week.