diff ratios

gemitup · newbie Joined: 22 Jan 2002 Posts: 4

g'day, Wicked site. was chatting to this dude at the werckers and he was saying the diesel diffs are a different ratio like 3.5:1 or some shit compared to the standard 3.9:1? My diffs rooted at the moment so was wondering if its possible just to change the stock diff centre to the diesel one ie. will it bolt strait in? or is there anything i need to change to bolt a complete diesel diff, torque tube etc to a petrol gem or is everything the same?

Bugle · tinkerer Joined: 08 Oct 2001 Posts: 221

Why would you wanna change to a lower ratio? The higher ratio will give better acceleration

Woz · tinkerer Joined: 05 Oct 2001 Posts: 126

but it would suit a more powerful engine better.

MatMan · tinkerer Joined: 04 Oct 2001 Posts: 280

Not if it's a more powerful engine with a narrow powerband. It would suit a bigger, torqier engine though.

gemitup · newbie Joined: 22 Jan 2002 Posts: 4

Yes thats what i have got. Im currently running a worked 4ze1 2.6ltr. So anybody want to have a go at my original question?

Cheers

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

I would say yes, they are a bolt-in, but I can't really tell you. I imagine the centre is all you need, but you might be better off trying to find an LSD centre from something else like a Commodore, lotsa talk about this of late.

Considering you're running a 2.6, then the 3.5:1 might make a little more sense, it would surely mean you aren't revving as high. Second gear will get you to about 80-90kmh instead of sooner. You might find 1st gear is better for taking off. I find 1st is too low sometimes and yr revving yr tits off for little until you grab second.

MatMan · tinkerer Joined: 04 Oct 2001 Posts: 280

I don't know about just the centre, but the whole assembly (diff, axles, torque tube, brakes) will go on, no fuss. That's prolly the better thing to do anyway cause you get the bigger drums with it.

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Ok,
This is the best i can do, the Diesel diff housing should fit under a petrol gem no problems (they have a different torque tube mount and handbrake cable), But diff centres, the Diesel centre is bigger than the petrol, and is not exchangable with other holden parts, thus cannot be swapped I believe this is the same centre in the non LSD Piazza diff's, they are also 3.5:1 ratio, But you can get a standard Gem diff and take it to any good diff reco'r and get the ratio changed as well as have a LSD centre fitted, this will cost about $1200 for complete reco, new everything, with a 2.6 you will need LSD, I hope this shed some light,
cheers