Hi guys I am new to this forum, I own a 93 Express van, that I use to transport my motocross bike.

I am looking into changing the diff centre to get more speed and less torque, I am in 3rd gear by the time i get to 70kph, and it chews alot of fuel, revving highly to sit on 110-120 out on the country highways going to races.

I just want to know if anyone has done this before ? and does anyone know what the standard diff ratio in one of these is ? and what other Mitsi diffs I could change it with ?

Hi ya!
Unfortunatley you have found the quaundry that most Van drivers have discovered...It takes a lot of force to punt a van thru the air at 110 kph. Due to the lack of torque thats inherint in a four cyl eng they have to rev to maintain a reasonable highway speed.
Should you lower your diff ratio you will find that your actually using more throttle to maintain your speed as well as having to use more throttle getting of the mark!

As a van driver it would be an ideal world for it all to be down hill and have a tailwind!

A simple experiment with a few sheets of masonite will easily prove how hard these vans work to proprel themselves along.....
Nail a few sheets of masonite to a frame to roughly cover an area of about 7 ft (2mtrs) by 7ft (2mtrs)

Dont make it too heavy as you will have to pick it up and run with it!

These sheets of masonite represent the frontal area of your van.

Pick up this frame and run into an oncoming breeze!........Not easy, and if your fit you may have achieved FIVE kilometers per hour....Imagine the forces involved when your vans doing 110 kph!

There is no easy way to get these vans to do a decent mileage on a trip other than slowing down to say 85/90 kph. (or tuck in behind a truck and enjoy the tow!)
You cant beat the laws of physics....
Sorry for the disappointing news!

According to the manual in the glovebox of my 98 express, the petrol diff ratio is 4.7:1 or something, the MWB is slightly diff(4.6 or something) and the diesel is 4.222:1(can get exact numbers but they are very close to this). would shave a few hundred rpm just gotta find a diesel diff:)

I also believe that the ratios are a little short, remembering that these vans are designed to carry almost a tonne in SWB form and more in MWB etc, it still has plenty of guts at 100 in 5th when empty! My work van has around 400+KG of gear and it has trouble over 105km/hr but these are both 2l carb, the 2.4 could pull a lot more i think.