Engine swap/rebuild

[pizzedaz.2]

What about the claims of KB air filters; specifically, their kit gives 10 more hp?

Also, what makes the 4.0l V6 so much more robust than the 3.3l V6? Is it just displacement or is there an improvement in the valve number/orientation?

[pizzedaz.2]

Doesn't the 4.0l get better mileage too?

[Muzikman]

I don't know if the 4.0L gets better mileage. If it does, it would most likely be that it does not have to work as hard to move the vehicles at the same speed. There is also in the design of the entire vehicle that has a lot to do with fuel efficiency too. Driveline (gears, transmission, axles, etc), aerodynamics of the body, tire size, etc. It;s like comparing apples to oranges.

There are many differences between the 3.3L and the 4.0L. It's a totally different engine. What makes it more powerful is everything from displacement to electronic control.

As for the K&N. IMO, not worth it. It might give a little HP gain (I REALLY doubt it's a true 10HP) and some fuel efficiency. However, it does this because it breaths better. And it breaths better because the filter is more open. Instead of using the filter media to filter the air, they rely on the oil on the filter to catch the dust and dirt. IMO, they let too much dirt in to be worth it.

Does anyone make a programmer for a first gen? Does anyone make headers? A free flow exhaust? A sealed, dry filter cold air intake (like a Volant). These would be your better "bolt on" performance options.

[pizzedaz.2]

Good, this is the knowledge I need.

[Xterra Mike]

Originally Posted by pizzedaz.2

So what triggered the rebuild in your case? Something catastrophic you can warn me about? What about a throttle body spacer? Did you order a rebuild kit from someone?

It was called "a need to see how deep in a puddle i could go without hydro locking it". Well i got pretty deep but never came out on my own power. I just sent it off to a machine shop. Expensive yea but worth it.

[pizzedaz.2]

So what did you do to it? Anything you would recommend or recommend to avoid? What does it do know as compared to before the rebuild?

[pizzedaz.2]

Oh, and what happened to the mileage afterward?

[Muzikman]

Well, in his case, I assume it ran after the rebuild.

If all you do when you rebuild an engine is replace it with the same parts, you'll get a fresh running engine that performs close to new.

Now if you start installing aftermarket performance parts during the rebuild, then you can increase horsepower and torque. Boring out an engine increases the cylinder size which will increases the horsepower, but also decreases fuel efficiency. Replacing the cam with a higher rise, or different shape will allow your valves to open more and/or open longer. This can increase your horsepower and even torque. This can allow more fuel into the cylinder and allow the exhaust to escape faster.

I have limited experience rebuilding modern engines and no experience in rebuilding new engine for high performance. All my knowledge comes from the old big block small block days.

[pizzedaz.2]

So your goal was a stock rebuild, per say? I wasn't looking for high performance really, just trying to get it over 200hp for safer highway onramp merging. I figured there might be small improvements, like the cam or headers that might give me a slight boost without having to consider the supercharger. Of course, this line of thought always gets me back to a diesel

[Xterra Mike]

well its actually not back in my Xterra yet so i don't know how much more power i will actually feel but i had the whole bottom end rebuilt. Basically i got a brand new motor. I basically went 20 over with the bore and bigger pistons but not by choice. As it was the motor was out of spec so i had no choice but to go with bigger pistons. This type of rebuild is expensive but i really didn't have a choice. If you looking for more power (200HP+) i would probably say aftermarket SC. I wasn't lookin for performance and it still is expensive.