Steve-

I don't know what to tell ya. You are mistaken. My role as a moderator has no bearing on the advice I give. You wanted advice and that is what I gave. It just may not be what you want to hear.

You came here for advice. All I have to go by is what you have posted. You wanted better mileage. I also think you have mistaken the true definition of logic. Logic has no "good" or "bad" connotations. It has to do with how the decision making process works. Illogical only means a decision does not line up with the constraints of the problem. Change the constraints and that same decision becomes logical. Make sense?

For example, if your solitary goal was better mileage, then you would spend any amount for any gain. That means 1, 2 or 3 MPG would be sufficient cause for you to open your checkbook. But, we know that is not the case. So, somewhere there is a minimum amount of gain you are looking for. You set that at 25MPG. Ok, again logic based on that means you are looking for at least a 6MPG gain. Again, without the constraint of dollars, you could maybe achieve this. But...your whole goal is to save money, so, we all know there is only so much you (or any of us) would throw at the problem to achieve the goal. So, regardless of your desire to have a Trooper that gets 25MPG, I suspect it really is "25MPG at less than $X-dollars." Now we have something to work with, but it puts us back to numbers I gave you above.

But, you are looking to actually save money. Again, for example, you are not going to spend $5K to save $3K. That, is not logical. If you want to spend less on gasoline, it is logical only to spend money that you will see a repayment on in a reasonable amount of time. I don't know what that amount of money or reasonable amount of time is for you. But, if you have to drive 150K miles to see a break even (i.e. it would cost you the same to do nothing as it would be to dive into an engine swap), it might not be worth it to you. I am just trying to provide you the WHOLE story, as it is greater than simply what the mileage is.

On the aspect of rebuilding for the sole goal of increased mileage it is my opinion it is not worth it. If I had a 2.8 that was knocking down 19MPG, I would not touch it. At that mileage, it is in excellent condition. I would not even put a compression gauge on it. Tune it up and go. This is my personal advice from an "If I were you..." standpoint.

But...all of that goes out the window when you start talking about better performance. The 2.2TD is out as is the 2.8TD. The former for power, the later because of the EPA. I honestly do not believe you will see your goal from doing something like a 3.4 swap. Yes, theory might tell you there are efficiency gains, but you will be making more power, maybe more efficiently, but it is going to require more fuel. Remember, the 2.8 and 3.4 are the same family. They share the same mechanics. They are not OHV, they are not MPFI, the ECU is primitive, the 60* orientation of the cylinders is generally less efficient, (when compared to 90* and 180* blocks). I don't know what the stroke to bore ratio is, but I doubt it is ideal. These are all hard set parameters of the engine that you have to work around. They make more power, and you might end up with an engine that is more efficient, but it will most likely be getting lower mileage. It is a case of burning more fuel, efficiently. No matter what you do, it will be still pushing around a 5000 pound brick and it will take an immense amount of efficiency to overcome that.

You came to us looking for advice. From only reading your posts, I can't tell if you know one end of a wrench from the other. Again, you may, but that a factor here. You stated it is your daily driver and what you use for your HS work. I hesitate to suggest to anybody to highly modify a rig that they rely upon on a daily basis. There is a certain amount of reduced reliability whenever major changes are made. If you can address these issues and live with them, great. But, if you have to pay someone to do the work and the continued tweaking, it starts to really up the initial and continued cost of what you are proposing to do.

Do you see? There is more to the problem than "I want at least 25MPG." If you came to us and told us that your 2.8 was burning 2qts of oil every 500 miles, belching tremendous amounts of smoke and you were getting 8MPG, my advice to you would be different.

Again, I wish you luck. I also suggest that showing up on a 4x4 board and subtly insulting what we do, may not be the best approach. It may not be "logical" to you, but you are failing to factor in that this is a hobby and recreation for most of us here. Many of us also enjoy helping people like you who are looking for advice specifically tailored to Isuzus. We enjoy what our rigs do and cost and potential damage play a small role in that enjoyment. From turning wrenches ourselves to getting out and wheeling in some of the most beautiful places in this country, plus the comradarie we build, is all worth the cost involved and the very minimal amount of damage we incur while wheeling. In fact, in all my years involved in wheeling, I can think of very few people I know of (here) who have totaled their rig on the trail. Many more rigs have met their maker while on the asphalt.

Good Luck,
Michael