Tracker is your best bet for fuel mileage - upper 20's, samurai will be lower 20's. The cost of any engine swap will be way more than you'll see in fuel savings. It'll take many years to get the $$$ back from the swap. Diesel swaps are great - IF you're a rock crawler... and that's what you're doing the swap for. The days of cheap VW diesel swaps are long long gone.

And, for what it's worth - diesel doesn't have much HP, but HP doesn't mean squat in off-road. It's all about torque, and diesel has loads of it all across the RPM range.

Also consider the box style Isuzu Trooper if you want a cheap SUV with good gas mileage. I see a lot of Grand Cherokees for cheap now, but if memory serves, the MPG is bad.

Tracker is your best bet for fuel mileage - upper 20's, samurai will be lower 20's. The cost of any engine swap will be way more than you'll see in fuel savings. It'll take many years to get the $$$ back from the swap. Diesel swaps are great - IF you're a rock crawler... and that's what you're doing the swap for. The days of cheap VW diesel swaps are long long gone.

And, for what it's worth - diesel doesn't have much HP, but HP doesn't mean squat in off-road. It's all about torque, and diesel has loads of it all across the RPM range.

Also consider the box style Isuzu Trooper if you want a cheap SUV with good gas mileage. I see a lot of Grand Cherokees for cheap now, but if memory serves, the MPG is bad.

I thought about buying an isuzu trooper once, but I found that the 4 cylinder (2.6 liter) has a head gasket and cracked head problem, and they only get somewhere around 17 mpg.

Seems the adapter kit is a little more for the diesel compared to the sidekick kit, the 1.6na diesel seems to go for a reasonable cost, about the same as a 16v sidekick engine. And I figure the diesel should get at least 50% better mileage. Not to mention diesels are simpler and last longer than gas engines. I figure i drive about 10000km per year, 23mpg is about 1 liter every 10km, so thats 1000 liters a year, at a dollar a liter I'd be saving at least 3-400 a year. And then I could run it on vegetable oil and save a little more on long trips. So I figure I should be able to make the extra money back in two or three years, after that its all gravy.
Judgeing by the sounds of things, it isn't much more difficult to swap in the diesel compared to swapping in a sidekick engine, I've even read its easier to swap the diesel into the samurai, than it is to swap the sidekick engine into it.

Chris B, your profile doesn't say where you're from, but since you're using the metric system I'll assume you're not in the US. If that's true, then diesel MIGHT be a better deal for you. I love diesel, but it's VERY expensive in the US, because diesel motors are rare here.

Ah yes, I live in Canada. I have always wondered why that is, why you guys don't like the diesel cars, it seems like a better engine in every way, a little louder but other than that.. The smart car is a perfect example, its been for sale here for a few years with a diesel, getting 65mpg, and its just now available in the US but with a gas engine that only get 45mpg or something like that. I just dont get it.

Probably for the same reason we won't adapt the metric system 

Diesel is BY FAR a better choice for off-road. More low end torque, better MPG, more reliable...

We don't either.I like desiel but can't afford the swap

Alright maybe you guys can asnwer me this. Would you expect to see an increase in mileage swaping the 1.3 for a 16v FI from a sidekick? Or is this just done for power? Just quickly looking on the internet it seems the sidekick is rated for around 22mpg, while the samurai is rated for 28 or so.

Diesels weren't very common here because Americans want the quicker throttle response of gas and then there is the emissions crap. If you are going to bother doing the diesel swap, try looking for the 1.6 turbo or 1.9 turbo. They shouldn't be much more than the non turbo versions and tons more power and mileage.

Alright maybe you guys can asnwer me this. Would you expect to see an increase in mileage swaping the 1.3 for a 16v FI from a sidekick? Or is this just done for power? Just quickly looking on the internet it seems the sidekick is rated for around 22mpg, while the samurai is rated for 28 or so.

Tough call.  I would think you would see a slight improvement in mileage due to the engine not having to work as hard and the fuel injection.  But you usually put larger tires on an such at the same time, and that reduces it.