Chevy Silverado Hybrid, help with mpg mods!

[Tralavoi]

Ahoy folks!

Just got this truck recently. Love it so far. Joined up on this site to see what I could do to improve the mileage as best I can. The truck already does pretty darn well. EPA says 20 city/23 hwy. It doesn't do that unless you have a tail wind. Otherwise it is fairly close.

Unfortunately Chevy decided to put their biggest engine in the darn thing, so when the 6 liter V8 kicks in the mileage takes a dump. I have no idea why they didn't go with a v6 or something, but it is what it is. The truck is completely stock so far, looking for ideas on what to do to improve the mileage of that v8. I am not an engine/car guy at all. I am in software engineering so computers don't scare me, but working on engines goes over my head.

It seems that the cylinder deactivation thing from GM favors the V8 most of the time, I was wondering if there were any computer mods out there (Scangauge or something?) that would modify the machine to favor the v4 most of the time. This is probably pushing it, but I wonder if anyone was able to modify the computer to have a manual switch for v4/v8 mode instead of an auto switch.

It doesn't have a bed cover yet, that is first on the list.

Any ideas would be much appreciated! Picture should be attached.

[Daox]

Well, as I recall, GM did a fair job of aeromodding the thing already. However, you can still do some good I'm sure. I'd start blocking off some of the grill. A scangauge or ultragauge will let you know if the fan is kicking into much (or a light wired into the fan side of the fan relay). I'd get your tires pumped up to a higher than factory spec. That should be a good start worth an mpg or two maybe. Most of all learn how to manipulate the hybrid system of the truck to your best advantage. That is where the scangauge will really help you out.

[MetroMPG]

Welcome! You're the first GM hybrid pickup owner I've met. One former neighbour had the Escalade hybrid -- same drivetrain technology if I'm not mistaken.

Anything you can do to reduce rolling and aerodynamic resistance will help the engine to go into cylinder shutdown mode sooner & longer. Do you have an easy way to monitor when it's in that mode -- a light on the dashboard?

Increasing tire pressure will help reduce rolling load, as Tim mentioned.

Anything you can do to reduce aerodynamic load will make a bigger difference. Did the truck come with those bars on the front end? Removing them would help. As would removing the running boards. (Also counts as weight reduction, which also helps... killing 2 birds.)

A tonneau will also help. An aero cap/aero shell will help even more!

Start a fuel log - start tracking your progress! And welcome to the forum.

[Tralavoi]

Thanks all!

The mileage is pretty darn good for a full size pickup. Definitely need to look into the tonneau or a topper.

Anyone know of any mechanical things I can do?
Air filters?
Exhaust systems?
Air intake?

It seems that computer modification is out of the question due to the hybrid control module.

[sarguy01]

Originally Posted by Tralavoi

Thanks all!

The mileage is pretty darn good for a full size pickup. Definitely need to look into the tonneau or a topper.

Anyone know of any mechanical things I can do?
Air filters?
Exhaust systems?
Air intake?

It seems that computer modification is out of the question due to the hybrid control module.

Exhaust and intake are too much money for too little return, if you even get a return. Some of those products might lower your mileage.

Without a lot of testing, no one can really say if any of these products are going to help your mileage. The makers of these products always seem to claim mpg improvements, but with no evidence.

But, warm air intakes can be made for cheap. They sometimes help mileage. Testing is involved.

Air filter? Stick with good old OEM.

[Cobb]

Id start with removing your bumper and blocking half of your grill. Do you haul or tow with your truck or is it just your dd? You can try sidewall psi on your tires and adjusting the nut behind the steering wheel.

[Goldenstate]

Full size truck mileage is always a challenge. We see the small economy cars hitting 40-50 MPG and our big trucks seem like to increase mileage, is close to beating our heads against the wall.

Synthetic oils in engine, transmission and differential will be a big step in the right direction. I drive mostly around town and some short road trips on good roads so dumped the spare tire and jack. With a 25 gallon tank, I often run on the bottom half of the tank which reduces fuel weight by about 72 pounds.

Keep us informed as to how your modifications work.

[CFECO]

Welcome to the full size truck world! What year is it? I agree with most, remove the brush bar, air tires to sidewall max, over inflating is just STUPID same with removing all the mirrors, save 1/2 MPG and kill someone???? They make Aero kits for the front of GM trucks to get the street rodder look, one of those or at least a good air dam is a start. Main thing is start a fuel log so we can see progress.

[oil pan 4]

Make sure the your truck still has LLR tires.
This was one of GMs cheap tricks to improve the highway mpg of the hybrid trucks over the non hybrids.
Because with out the aero tricks and LRR tires hybrids and non hybrids got almost the same highway milage.

These aero features and LLR tires could have been put on any truck or SUV but GM only saw fit to put it on hybrids.

[CFECO]

Hybrids, "on the highway" are generally just ICE powered vehicles.