Better MPG for Tahoe 99

[DPX Magnum]

I have a Tahoe 99 5.7L that is equiped with and bug deflector and rear air deflector. I have changed the airfilter, the spark plugs, the wire sets and the distribution cap (and rotor). My MPG is around 16, I live in Sweden and the 1 US gallon costs near 9 dollars so its pretty expensive. :sad72: I mostly drive on highways at around 60 MPH.

So naturally I would like to improve my MPG.
Is performance chipping worth it? I have the standard exhaust system and I think I would have to change that together with the air-filter which would cost a lot. Or can I just do the chipping without changing anything else?
How about changing the size of the tires? (I currently drive with 245 standard wheels).

Should I do all of the above or is sufficent just to change one or two of them to get an increase in MPG. Which would give me the higest increase in MPG per dollar spent in gear. (US gear costs a lot due to imports and customs so they can cost up to 3 times as much than prices in the US):biggun:

 

[Andrew99Tahoe]

Better MPG

I have recently add a 1in Power Aid(Air Raid) throttle body spacer. Increased my MPG on my Tahoe. I also have a 6in lift and 35in tires.

 

[Woodstock]

MPG

16 MPG isnt all that bad; how many miles (km's) are on it? Easiest way for better mileage is to get the engine to breathe better. There are 2 resonators on the air intake. One is a big black box right on top of the throttle body. It unbolts easily, leaving the port that needs to be sealed. I found a rubber plumbing cap, I think it was around a 2 1/2 inch, at Lowes. You'll want it to be a bit snug going on, warm it up with heat gun until its soft and it will go on easily, then clamp it down with hose clamp. The other one is in between the air filter box and the inner fender wall. A sawzall, hacksaw, whatever you have will take this off fast. Be creative sealing this one, I cut a patch from an old radiator hose and clamped it with some silicone inside. If you have a decent air filter installed, you can remove the top of the air box, leaving the filter exposed, freeing up more airflow. This will also improve your throttle response and low end torque. (A LOT) Your truck will sound more like a truck, also. A better performing exhaust will get all that extra air out. I've heard the throttle body spacers are good but havent tried one yet. Upgrading your ignition with a performance coil, wires and plugs might give you a little mpg boost. If you're already getting 16, I think any more improvements may be counter-productive as far as cost is concerned, unless you drive enough to justify it.
Last time I checked mine, it was 14.5. I'd be thrilled to get 16

 

[DPX Magnum]

Thanks for the responses

I often use the enigine heater before I start the car in the mornings. I also have relatively high air pressure in my tires and no unecessary cargo/weight.
The car has a rear air deflector, does anyone know if it does any good? My rear windows still get dirt and im thinking of taking it of.

I need to change tires soon and Im wondering if I should go for a bigger size from my standard 245's, anyone have any experience with changes in MPG when changing the tire sizes?

My exhaust system is new so I would not prefer to change that, when I drive on the highway I have well below 2000rpm since I dont drive that fast. I belive that it might not help much to change to a bigger exhaust system as I am driving so slowly anyways and that the gain in MPG would be minimal. Anyone disagree?

I also have a question regarding removing the top of the air box, leaving the filter exposed. Can I use the original filter for this or do I need to buy another verision?

 

[Woodstock]

better mpg

I wouldnt change the tire size; going smaller is not a good idea and larger will kill your mileage. The air deflector, as i understand, is supposed to keep the dirt and mud from sticking to the rear window. If you still have dirt collecting there, removing it couldnt hurt. I dont have one, so I cant speak from experience. As far as the exposed air filter...If you look at a cold air intake system, its basically an exposed air filter with a streamlined intake tube from the filter to the throttle body. An aftermarket system will run a few hundred dollars minimum. Like I said, if you have a decent filter and the area you travel isnt dusty or sandy, opening up that box isnt going to hurt anything. When I tested mine with the lid open, I only drove a short distance, since I have a cheap filter in it right now. With a quality filter; I see K&N around here a lot, I dont see why it shouldnt work well when exposed. I've been playing with an idea of cutting a section out of the lid on the fender side and cover it with a fine wire mesh screen to stop any large debris that might get in the engine compartment. I dont mind spending the money on parts that work, I'm doing this to get an idea if it will be worth the investment.