High MPG work truck

[oil pan 4]

The twin turbos breath great going up an 8,600ft hill.
The suburban was loaded down with all my tools aside from the welder and plasma cutter and still managed 20.7 mpg on that tank.
It has plenty of power seemed to be going up the hill better than the two 4cyl 2006+ nissan and misu I was stuck behind, it wont have any problem pulling a car a 2,600 to 3,600lb car on a car dolly.

[oil pan 4]

The suburban can out run the Kia Rio while loaded down with house hold goods for a move while pulling the trailer which was also full (level with the 2 foot high wood sides).
But the suburban cant keep up with the kia on hills, at least when loaded down, because it starts to slow down and run hot.
My engine almost bought it today, it was between 107 and 110'F in southern NM and while going up a mountian the temp gauge almost went into the red.
I will be back out that way in the middle of july, so I best have it sorted by then.
I orded a new aluminum radiator to put in before this trip but it didn't make it to my house before I had to leave.
Also the water injection will be hooked back up.

Also I am in dire need of aero mods. Last tank I did a slow drive from roswell to clovis going about 45 mph most of the way with no wind and hit nearly 30mpg on a short distance tank.
Even if I really didn't get an honest 30mpg due to tank to tank filling its got to be at least 26 to 28 mpg.
I guess if I could get rid of the winds that would help a lot too.
The only costant I seem to have is constantly blowing winds.

[oil pan 4]

Got my 3 and 3.5 inch piping to replace the lame 2.5'' piping going between the T76 and HE351VE.

[elhigh]

I'm loving this thread. Not a Chevy fan, don't own a diesel, but I'm getting a huge charge out of it just the same.

Your Sub is an aerodynamic nightmare. If you're cracking into the middle 20s with nearly no aero improvements, I think you're in for a shock.

Judging by your temperature reports, I'd skip any front end coverage, unless the headlights are recessed. You could add an airdam that would reduce engine bay pressure and improve airflow through the rad. That's a good thing.

Wheel skirts at the rear. The wheelwells on the Sub are gigantic, big whirling air buckets, there's a lot of improvement to be had there. And almost any kind of bellypan will be good for you.

I know you're already up on all this, I'm just dying to see how it turns out.

Thanks for sharing.

[oil pan 4]

Originally Posted by elhigh

Judging by your temperature reports, I'd skip any front end coverage, unless the headlights are recessed. You could add an airdam that would reduce engine bay pressure and improve airflow through the rad. That's a good thing.

I have been putting off installing an air dam for a long time. Its one of the solutions to fixing the running hot while going up hill in 100'F+ temperatures.

Originally Posted by elhigh

Wheel skirts at the rear. The wheelwells on the Sub are gigantic, big whirling air buckets, there's a lot of improvement to be had there. And almost any kind of bellypan will be good for you.

I have some rust over the wheel wells. When I repair it I was going to stretch the body lower over the wheels a little bit.
I don't really care for belly pans. It seems an air dam and side skirts give about 75% of the benifet of a belly pan will see for about 10% of the work and materials.

[oil pan 4]

Here is the new intake piping.

[Diesel_Dave]

Do the twins spool up faster or slower than a single?

[oil pan 4]

They are always on the boost unless I drop below about 50mph in overdrive.
I like the setup, there is almost no lag other wise.

[oil pan 4]

I finely got around to measuring how much power it takes to turn a P/S pump.
It looks like if you can keep the P/S turning at 850rpms it takes hardly any power to turn, around 150 to 200 watts.
But when you bring it up to a more normal cruse speed say about 2,000 rpms power draw goes up quite a bit. It took a little over 500 watts to keep it turning at that speed.
For my suburban 500w gets about a half MPG.
I'm going with a clutched setup.

Now to shutter?


Or not to shutter?


That is the question

[Joggernot]

Originally Posted by oil pan 4

My engine almost bought it today, it was between 107 and 110'F in southern NM and while going up a mountian the temp gauge almost went into the red.
I will be back out that way in the middle of july, so I best have it sorted by then.

I lived in southern NM for 15 years. I know what you went through. Every vehicle ran hot and the air-cooled motorcycle ran very hot. I never saw a semi with the radiator covers closed during the summer. Had to have all the cooling available. Air Dams were popular in Carlsbad for the Honda and small car people.

Joggernot