Calling all 99-07 Silverado Ecomodders!

[77Racing]

I just picked up an 03 Silverado and am averaging about 17.2mpg with about 90% highway driving (which is my normal)

I am looking for ideas that could put me over 20, maybe closer to 22mpg.

Electric Fans, Underdrive Pulleys, Tuners, Intakes etc... Would love to hear some experiences and suggestions!

Thank You!

[aardvarcus]

Some suggestions-

You will get better advice if you include more details on exactly what kind of truck you have, for example Engine(5.3L?), Transmission(4l60e?), Gearing(3.73?), Model(1500?), Drive(4x4?), Cab(Extended?). Pictures help too.

On my 2001 2500HD 4x4 8.1L/Allison X-cab, I had good luck with a custom in-person tune from Black Bear Performance. It gives better mileage, unless you like to push the go pedal in which case it goes faster and gives worse mileage.

Aerodynamically, a tonneau cover got me a MPG or so for city driving, not much for around town. For big gains from aerodynamics, look through some of the aero-cap threads others have made under the aerodynamics section of this forum.

I have not done this yet, but E-fans are a big gain from a clutch fan, but I have heard of reliability/quality issues with aftermarket fans. Many choose to repurpose a fan from a junkyard to get OEM quality at a reasonable price. Be sure you get a fan or fans that are comparable in CFM to your stock fan, especially if you haul or tow.

Don’t overlook tires, heavier and wider typically hurt your MPG. Taller can be good or bad depending on the situation, but typically taller goes along with heavier and wider and ends up hurting your MPG. Wheel and tire weight affect the amount of energy it takes from the engine to get you moving. Tread pattern, tire quality, and air pressure are also important factors to your rolling resistance.

[77Racing]

Yeah that would probably help now wouldn't it... FAIL!!!

5.3 (not sure on gearing) Automatic 4x4 1500 extended cab...

I will be towing a 16' car trailer with a 3000lb race car on the weekends but I know MPG will be terrible with that.

do you know what the stock CFM of oem fans are? I guess I need to measure my radiator and find out of the LS1 fans will fit lol!

[spacemanspif]

Everything said above is good info. I think most truck guys use factory F-body fans with good success. I'm not sure any e-fans pull as much as the mech fan but as we all know, cooling systems are overbuilt.

Intakes won't help you gain power or MPG. Factory intake on that truck is one of the best flowing GM had, it beats the LS1 intake and only the LS6 intake beats it above 4500rpm but doesn't have the torque (main reason I haven't put a car intake on my Monte). A port job might help but is probably not worth the effort/price.

Is it just a road truck? Consider lowering it. Use more street friendly tires (if you have knobby ones right now)

A real tune on a dyno will cost you about $400-500 but will get you better gains than an "out of the box" unit

Buy a scangauge/ultragauge

Upper grill block should help a little too especially with how much front end those truck have

edit: 5.3s only came with 4L60E trans. which is good and bad. Good because you have the better OD, bad because you are already using the better trans and getting 17mpg lol.

If it makes you feel any better, my Monte only gets 19mpg and that car is way lighter and (I hope) had better aero...so you aren't doing so bad lol.

[77Racing]

I meant an intake tube, I probably should have clarified that too.

I really do not want to do anything suspension wise because as it sits with my trailer etc, everything sits perfect when hooked up with the car and tire rack set up on it.

I honestly did not even think of a tonneau cover. I would probably end up with a vinyl one only due to the stuff I take to the track on Saturdays but I would assume they are all fairly close.

Thanks

[darcane]

17.2mpg isn't bad to start with. 20mpg may be a challenge. See my sig for some ideas (I had an '03 Silverado, 4.8L 2WD ext cab, long bed).

Originally Posted by spacemanspif

Everything said above is good info. I think most truck guys use factory F-body fans with good success. I'm not sure any e-fans pull as much as the mech fan but as we all know, cooling systems are overbuilt.

Most truck guys use the '05-'06 full-size truck E-Fans. Silverados, Tahoes, and Burbs all switched to E-Fans in '05 and they bolt right in.

Step-by-step example here:
I installed 2006 E-fans on my 2001 - Chevy Truck Forum | GMC Truck Forum - GmFullsize.com

However, you need a harness and you need the ECU altered to trigger the fans. Blackbear is typically the easiest way to get this done.

[samwichse]

I don't know about tonneaus
Pickup Truck Tailgates | Fuel Economy - Consumer Reports News

I'd say a lawn edge aeromod in the front (maybe down the sides too)
https://www.google.com/search?q=lawn...w=1113&bih=866

Partial grille block... something easy to remove when you tow.

A Scangauge or Ultragauge... that'll probably be your single biggest mileage gainer.

[Frank Lee]

Yeah, 17 is awesome.

Last time I did a survey of all the full-size gas pickups in the EM garage, nobody- or was it one?- was averaging even 20.

[2000mc]

*type erase edit derp* ....yea what darcane said

[Koots]

All the standard tricks will help. I think lowering, tonneau cover, grille block and air dam mods would do good things.

I wish they still made diesel options, my K5 Jimmy w/6.2-700R4 would get under 20MPG when you were driving it hard. When I lifted it and stuck 35" tires on it, I was still seeing 15-18MPG on average.