Hi H2 team,

Read online 03 has 316 HP and the 05 has 325 HP. With both engines having the 6.0. Where does the HP gain come from? Thx!! Is the difference noticeable?

 

Well, they both have the identical lq4 engine. They might have changed something in relation to ignition timing and fuel mapping. There's a couple programmers on the market that will allow you to do that yourself. (The Diablo predator has a couple canned tunes and in moments you'll be putting out 25 more horsepower and more.) In a later models it also adjusts the variable valve timing, which also affects low end torque often negatively as the horsepower is bumped up. The OEM tune is really good for all around driving, but there are benefits you can get from putting in a tune designed for towing. I e: More low end torque, quicker shifts for the transmission to run cooler and live longer.

 

Thx 4 follow up. This is really interesting. Im getting blackbear performance in Jan. Look forward to having my exhaust, air intake, headers all on same page. What tune are you running?

 

I keep the H2 in stock trim.... It's got no rust, doesn't get driven a lot, and I've got a lot of comments from people in parking lots I can't believe it's going on 22 years old. It lives a rather sheltered life in my shop, protected from the elements and maintaining or hopefully increasing in value.

Now on my wife's 2014 Escalade with the 6.2, 6l80 transmission.... She commutes 50 miles per day round trip. I went ahead and bumped it up with the +25 HP canned tune, tightened up the shifting, turned off the AFM in the ECM, as well as did a full AFM delete mechanically and used an l92 GM camshaft... Her fuel mileage went from 17.1 to 20.3 MPG. Almost all of her commute is on a 60 MPH state highway, no traffic to speak of and on cruise control. LOL, she gets scared if she gives it more than about 1/4 throttle. But it also weighs about 2800 lb less than the H2.

That lq4 engine you have under the hood is probably one of the best all-around engine Chevrolet made. In stock trim there's no reason it shouldn't go in excess of 300,000 miles. The bottom end can handle almost double the horsepower without having an issue. But if you're going for more horsepower and torque, you will want to make some investments on the transmission side of things. The 4L65 is fine for normal driving, but is often the weak point if you start putting much more power to it. Remember, driving an H2 is like driving a Chevy Tahoe dragging a 2500 lb boat with you everywhere you go. That weight is why we don't get better fuel mileage. One of the few things that's not OEM on mine, as I have a larger transmission cooler up in front of the radiator. My transmission temps stay between 155 and 165 all the time. Temperature controls the most important thing on the transmission if you build horsepower on the engine.

 

Very cool, I did install the tru cool. Temps dropped 50/60 degrees. Never has gone past 150. I rebuilt trams with lots of sonnax parts including the 3/4 input drum. Reused the input shaft. Everything i read on ls1 boards it can handle 600 / 700 HP.

 

Yep, you're in great shape.
I actually prefer the 4l65 over the 6l80, simply because it's easy enough to rebuild yourself. The 6lady's a whole different animal with a lot more electronics, and has to be programmed before you ever start the vehicle. I prefer to keep it simple.