Z71 Mileage improvements

[TexasCowboy]

My 97 Z71 has 129,000 miles on the 5.7L engine, running stock size M+S tires on the original aluminum rims.

 

Looks like i'm averaging about 11 MPG in the City and 16 on the highway at 65MPH.

 

Other than doing a brain swap and installing a new vortec 5.3L v8 with the sierra electric assist motor, any suggestions for improving fuel economy - highway driving is the most important.

 

Here's what i've been thinking:

 

(1) Change gear ratio in rear end

(2) Remove tailgate and replace with webbing strap

(3) Possible cold air intake system

(4) Remove fanbelt driven fan, install electrical fans

(5) Replace wheel bearings with precision machined bearings

(6) Balance and precision match tires

(7) GO to ultra high mileage (hard compound) highway tires

 

Anybody have experience? The 11mpg in the city sucks.

 

--roger

[Wingnut]

The only thing you can do to your truck to get better mileage across the board, and get pretty much no argument from people here, is get a tune.

 

My tune is for performance, and it still added 1 MPG. You can get a mileage tune if that's your poison though.

 

Most the things on your list either don't work for everybody (like the tailgate thing, I've documented better highway mileage with my stock tailgate up), or cost so much that you'd have to drive 400,000 miles for the mileage savings to pay for the modification.

 

I've never had a CAI give me anything but a loss of bottom end power and a lighter wallet.

 

What's your current gear ratio?

 

Oh, and I will say this...If you're getting 11 mpg in the city, there's something wrong with your truck. I'd start by fixing that problem before worrying about a mod

 

 

Welcome to the forum, by the way

[Buggle_96]

Option #2, you will lose mpg leave the tail gate on.

[cerbomark]

run max tire pressure(40+ lbs), synthetic oil.

 

with those many miles, maybe a good tune up and going over everything to see it s working properly.

[rossn2]

Option #3: Change the drivetrain over to full synthetics. Use good quality synthetics like Redline, Amsoil, Royal Purple, etc.

Change engine oil, tranny oil, xfer case, frt and read ends....you can gain 1-2 mpg doing this and it would be a cheaper first thing to try...

 

 

Option #2, you will lose mpg leave the tail gate on.

 

<{POST_SNAPBACK}>

 

 

[2007VictoryRed]

Thats nothing i got 6 mph in city 8 on high way in my 454. good luck

[Giant]

What is all done in a tune up?

 

This is what I'm thinking

 

-Fuel Filter

-Air Filter

-Plugs

-Wires

-oil change

-Grease everything you can get grease into

-Throttle body cleaning

-Injector cleaning

-Check exhaust/cat for wear/blockage

-Check and top off all fluids

-Rotate/balance tires

-front end alignment

-check tire preasure

 

IS there anything that I'm missing?

[asilverblazer]

(1) Change gear ratio in rear end

Requires front too.

 

(2) Remove tailgate and replace with webbing strap

Waste.

 

(3) Possible cold air intake system

Factory is more than sufficient.

 

(4) Remove fanbelt driven fan, install electrical fans

Not good for towing, it is a truck right?

 

(5) Replace wheel bearings with precision machined bearings

I wouldn't expect much of a gain.

 

(6) Balance and precision match tires

Same as 5.

 

(7) GO to ultra high mileage (hard compound) highway tires

Same as 5.

 

Your city mileage seems a little low, but the 16 highway is the norm, anybody drving an extended cab 4x4 have not and will not get 20 mpg, unless its all down hill at 60 mph with a strong tail wind. A 2wd with a real high rear end gear maybe.

[up4x4]

The milage you are seeing is typical, I have a 95 ext cab 5.7 Z71 4x4 and get the same milage. nothing you do will affect milage it'll only cost you more money, put that money in your gas tank you'll be further ahead. I know from experience- Headers, true dual exhaust, throttle body spacer, KnN cold air, new distributor, high performance wires, plugs, always used synthetic oil, even tried the acetone theory and still get the same milage. I wish I had that $3,000.00 to put in my tank now.

[Buggle_96]

Thats nothing i got 6 mph in city 8 on high way in my 454. good luck

 

<{POST_SNAPBACK}>

 

 

 

Push on the throttle!

[M J]

yeah mythbusters proved taillgate down as opposed as up WORSENS gas milage, where as the web helps (but we're talking about adding 1/10 MPG)

 

idk iv ewanted to upgrade from my 4.3 V6 std cab to a v8 z71 extended, but this might discourage me

[gyusher]

Along with everything that has been said. In my mind the most important thing to look at is the driver.

 

What you can do;

1)- Drive slower.

2)- Drive smoother

3)- No jack-rabbit starts

4)- Use the brakes less

5)- Put an egg under your right foot (so to speak)/ light touch

6)- Avoid long idle sessions and long warm-ups

7)- Avoid 'pumping' the gas while driving

8)- Use cruise on flat roads

9)- Do not use cruise on hilly roads

10)- Think about it while driving. . .

 

Other;

1)- Proper to increased air pressure.

2)- Bed cover / do not remove tail gate.

3)- Keep it clean / clean car uses less fuel

4)- Synthetic oil (2mpg in my case)

5)- Avoid using AC

6)- Proper engine tune

7)- Change brands of fuel

8)- Everything that has been said already.

[SierraSLT]

* Replace O2 sensor, Thermostat (if going bad)

[97Sierra4x4]

I got a cheapo short ram air intake that just intakes right where the stock airbox was. But draws from the engine bay not the right fender well. I got .5 MPG increase with that and better throttle response. But as SierraSLT recommended, its mainly how you drive your truck. Lotta fun=more gas

[yeehaw87]

Ive gotten as good as 22 mpg going home 60 with the wind behind me, and thats about as good as it gets, as far as installing an electric fan, yours is driven by a clutch, so when the fan isnt needed, the clutch lets loose and doesn't take away power. Basically suck it up.