Differences between 2001 and 2006 Tahoes (fuel economy)

[masospaghetti]

I just purchased a 2001 Tahoe C1500 with the 5.3 liter engine and 125,000 miles. I noticed that the fuel economy ratings for the 2001 model are a couple points lower than the 2006 model with the same engine (13/16 compared to 14/19).

Seems like a large difference for the same chassis and powertrain.

What were the differences here to improve the later models' fuel economy?

 

[treehan77]

electric fan is one thing.

 

[MidnightOutlaw]

Possibly Drive by cable (2001) vs drive by wire.

 

[Fless]

4WD vs 2WD? Different diff ratio?

 

[Mudsport96]

One is the electric fan. But the biggest thing is the computers processing power and tuning. The 2001 has the" red/blue" P01 512kb computer and the 2006 has the "green/blue" P59 1Mb computer. The newer has basically double the computing power than the old.
Look at it this way. The basic engine( block, pistons, cam, heads, manifolds)... are all the same. The throttle body is controlled on the 06 by the computer. The 4l60e is the same both years. Gearing may be different too. But engine wise it is the same thing.

 

[B-train]

ALL KINDS of stuff go into the equation. I had just the opposite: 2000 4x4 5.3L extSb got the same, if not better than my 2006 exact same truck. 2000 had 3.73, 2006 had 3.42.

Depending on your driving, there are variables up the Ying yang. Just learn your truck, then adjust as needed. Maybe less throttle, a lower gear longer, etc

 

[Mudsport96]

ALL KINDS of stuff go into the equation. I had just the opposite: 2000 4x4 5.3L extSb got the same, if not better than my 2006 exact same truck. 2000 had 3.73, 2006 had 3.42.

Depending on your driving, there are variables up the Ying yang. Just learn your truck, then adjust as needed. Maybe less throttle, a lower gear longer, etc

I will second this. Even on the older vehicles, gear ratio and having the engine in the sweet spot is key. Guys in the obs ford world have found out Ford goofed when they put the 3.31s, 3.08s in the f150s with the straight 6 and 302. Swap up to the factory 3.55 or even aftermarket 3.73 and guys see an increase of anywhere from 2 to 5 mpg. The 2.73 geared guys just stay out of Overdrive and seem to get the same effect on the highway.
I did an experiment in my old truck. And at 55-60 in 4th gear I got between .5 and 1 mpg better than in Overdrive. But rpms were 20% higher so more wear and tear. And at 300,000 plus miles I try to give her a break most of the time lol.