You need to evaluate your needs for the tractor. What do you intend to use it for? What do you envision it's capabilities to be?
Personally, my opinion is to go no less than 40 hp, and 4000 lbs. Adding weight is fine, but adding hp is problematic once bought. You don't want to end up like a banty rooster, just scratching around on top of the ground without getting anything done. But, not all situations require the same tractor. What do you want to do with it?
Ya mean adding Nitrous isn't a viable option?
Diesel, bro.......probably be adding propane and more turbos!
I agree, and adding a new injection pump and injectors. But, it's not only for gas motors. Here's what Gale Banks Engineering has to say:
Now that we have an overview of nitrous oxide injection on gasoline engines, let's consider nitrous oxide and the diesel, or more correctly, the turbo-diesel. To begin, a turbo-diesel has no air throttle. It is free to intake as much air as it can draw, or the turbochager can supply, on every intake stroke. Therefore, hot rodding the diesel is a matter of supplying the engine with as much fuel as can burned by the air available at maximum power. In fact, you can overfuel a diesel in the quest for power, but that results in excessive exhaust gas temperatures that will kill the turbocharger and the engine. It also results in black smoke from the exhaust (see "Why EGT is Important" elsewhere on this site).
Let's assume you've modified your turbo-diesel to the point that it is overfueled and belching black smoke under a full load. What can you do? One solution is to add nitrous oxide injection, but in this case, you would not add extra fuel because you're already too rich. Three things happen when you do this. First, the extra oxygen from the nitrous oxide leans out the mixture and the black smoke will be reduced or eliminated. Second, the excess fuel will now be burned for extra power. And third, exhaust temperatures will decline since less afterburning of fuel will occur in the exhaust manifold and the intercooling effect on the intake air will drop the exhaust temperature by a roughly equal amount.
When you think about it, adding nitrous oxide injection to a diesel is easier than adding it to a gas engine because you don't have to mess with adding extra fuel. In fact, there's no point in doing it unless you're already in an overfueled condition.
We've probably started something here that will quickly find its way into the pickup pulling power contests. If you've been to such a truck pull, you've seen the black smoke from overfueling. At Banks, we design our systems to increase engine airflow, and then we add fuel. Of course, if you go even further and intentionally overfuel a Banks power system, injecting some laughing gas just might bail you out before the pistons begin to melt and change holes.
