What diff ratio will I need?

The Diff.

To get the fuel economy i expect with the V6 conversion the diff ratio will have to change.  I haven't checked what my current ratio is but I'm guessing it is above 4.1:1.  Trekka has 31 x 10's on all four corners which is a bit bigger than what the VT commodore came out with 205/65 r15's, so the Trekka has 31 inch tyres and the commodore 25.5 inch tyres. (According to these calculators differentials.com  and tyre size conversion.com)   

So that is a difference of 5 1/2 inches or 21.5% (don't just trust any online calculator I tried a few and when I worked the numbers back, eg 25.5 + 21.5% = 30.98, they were off. I ended up using this one, csgnetwork percent change calc )

So as a VT has a 3.08 ratio diff and given there is a 21.5% increase in tyre diameter does that mean I just add 21,5% to 3.08?  Giving me 3.7422.  Well I bloody hope so, as that means I can use a 3.727:1, 3.909, or a 4.1 Hilux LSD differential, .  Diff sizes sourced from Drive train gearing bible

After using csgnetwork  Rev calculator I think a 4.1 diff will be the to go.

Commodore V6: 205/65R15 tyres, 25.5 inch diameter, 3.08 diff, Auto 4th .0696
= 1836 rpm@104kph (65mph)

Trekka V6: 31 inch tyres, 3.727 diff
= 1828 rpm @104kph (65mph)

Trekka V6: 31 inch tyres, 3.909 diff
= 1912 rpm @104kph (65mph)

Trekka V6: 31 inch tyres, 4.1 diff
= 2010 rpm @104kph (65mph)
= 1856 rpm @96kph (60 mph)

Now i just gotta find out exactly what diff I have in the Trekka, it sorta looks like a Hilux differential, but not quite.

What do you do with a 3y engine..

With the 3y not cutting it an engine swap is in order.  302, c4 auto, and a nine inch, that would be cool.  What about a turbo diesel, nah, after hitting google I feel the best option is the Buick 'echotec' engine.  I plan to use the Commodore V6's auto as well,  the diff will be changed or modified so i can get a airlocker or Lsd install and ratios to suite the V6 auto combination.  With the correct diff ratio I believe I should be able to get better economy than the Merc which only gets around 8km per litre and if it ends up the same as the Merc thats ok, I am driving a garden shed down the highway.

Will it fit? Thats the first job. There are a few shops offering V6 conversions for hiace vans so I dont delieve there will be any problems with it fitting in the engine bay as the design of the delta is basically the same as the hiace. I hope to install the new engine from underneath as it should be the easiest way. The way I see it is that l've basiclly got two parallel pieces of C section, if the v6 fits between them alls good, just add mounts and may be a crossrail or two and the jobs done.  Then its just the power steering, air con, disc brakes up front, new diff and tail shaft, easy peasy, wait a sec there's the radiator, air con condenser...

Natsnud said:
03-10-2005 05:52 PM
Went to a wrecker today and got the following approximate dimensions for a VR Commodore V6 engine:
Length: 560mm - flywheel outer to crank pulley nut outer.
Width: 530mm - Outer to outer of cam covers. Add about 70mm for exhaust header to header.
Height: 670mm - bottom of front sump to top of plenum box.
I dont think there would be any difference to the Ecotech engine.
Hope this helps others. Still havent got the weight yet.
I cant believe no one could tell me these dimensions!

(from justcommodores.com.au forum) 

Thanks Natsnud, gotta love google, so given that there is 630mm between the chassis rails and the v6 is 600mm with the headers still on, the engine will fit in 'Trekka'.

The search continues

De li ca (space) L wB, and search. I started thinking I could build a pod that would side out the back of the of a delica, hey I could now consider a SWB. I also thought i could create a small 'pop top' by getting the one with the big sunroof in the back, providing a small area with head room.  Mate, I had bits coming out and poping up, actually I thought it could work well.  I would of used a full roof rack on top of a 'Dellie' with the pop top built into it, big zippered openings in the canvas so I could get to the extra spare on the front of the roof rack and extra jerry's on the back, but it was still going to be smaller than the Merc.  Sharon and I have done a good amount of travelling in van's.  Across america, around western eroupe with a little side trip to Prahg, almost 2 month's in NZ, of course around Australia in the Merc, and I certainly can not leave out a year in a Bus complete with two kids, a dog (BD - Bus Dog), and a XD Falcon in tow.  Its fair to say we have an idea when it comes to what we want out of a van and the size of the delica wasn't cutting it.

Roger, my brother in law, has a truck wrecking buisness called 'Lorry Land', if you are thinking England sorry it's NZ,  its there that I saw a Daihatsu Delta Van.  We were visiting while on our NZ adventure in 'Kozi', a ex Britz hiace hightope, Sharon said I would be pushing the next time we got stuck, and I did. Maybe it was because of the off road adventures that my eye was drawn to the Delta as it was being delievered to Rogers yard.  The ground clearance was good and was as big, maybe bigger than Kozi, so with that in mind instead of typing the usual search into gumtree, in went 'daihatsu delta'. I didn't think I was serious about Daihatsu Delta until this one turned up on gumtree...