16 MPG ..... Please Help !!

[theholycow]

Grill blocking is exactly what it sounds like: Blocking off the grill. It is done mainly for aerodynamic purposes, although its effect on cooling may help too. Depending on your skill at fabrication you may be able to block it smoothly on the outside; if not and if you don't want to look silly then you can at least block it on the inside. You don't have to block off the whole thing. Most people do not.

On my 2002 GMC Sierra 1500 4x4 5.3L 3.73 I tried blocking it smoothly in front of the grill but my transmission cooler wasn't able to do its job (I programmed my ScanGauge II to display transmisison temperature). After that I found that I could very easily block it just in front of the radiator, behind the transmission cooler. I do 100% blocking.

Blocking it makes the air go around the wind-tunnel tested exterior of the vehicle rather than filtering through the parachute-like engine bay. It also helps preserve heat under the hood; too much cooling wastes energy, and many vehicles have too much cooling (especially when you consider driving style of someone saving gas, as well as regional weather).

I'm not sure mine has had a practical effect. It doesn't work for everyone. I took mine out for a while and recently put it back in, if not for fuel economy at least so it would warm up more quickly in this cold weather and give me heat sooner.

Common materials are coroplast (the corrugated plastic used for lawn political campaign signs and road spam) and clear or tinted Plexiglas.

[FrugalFloyd]

There's not much you can do to get better mpg from a 6 liter V-8 moving a loaded maxi-van, other than go slow. You want to see the country, so buy and use an Ultragauge, and keep your maximum speeds in the 55-60 mph range. I took my son on a 30 day trip around the country, in my '87 Chevy Astro van (w/4.3L). It averaged 15 mpg, with 17 mpg tops, driving 70-75 mph. Two decades later, I drove it on separate trips to TX and UT, and averaged 22 mpg, just by setting the cruise control at 60 mph.

I know you plan to live in it, and save months of lodging costs. I can't help but think that every $150-$200 tank fill would pay 2-3 nights lodging in a motel, or two weeks of campground fees. I think a person could volunteer in national parks 3-4 days/week, staying free in employee housing, and take a year to see the country with no expenses beyond food and gasoline. I've done it for a month at a time in Bryce Canyon NP, Chaco Culture NHP, and Black Canyon of the Gunnison NP. Add a month in Big Bend NP, a month in Yellowstone or Grand Teton NP, a month in Olympia NP, a month in Crater Lake NP, a month in Saguaro NP, and you get the idea. You could sell your RV, and do this trip in a family sedan.

Living in a NP, you'll really see it. You'll learn where the Peregrine and Prairie Falcons nest, what the local lizard species are, etc. You'll see the visitors' photos of their lucky Bobcat & Mountain Lion sightings. You'll have time to hike all the trails, & make lots of new friends. On your days off, you can see all the surrounding area for hundreds of miles. Most NPs have volunteer coordinators who'll let you know what housing is like, & whether they can use your skills. I do astronomy outreach, but I've led birdwalks, been a campground host, and answered questions at the Visitor Center information desk.

[PhileasFogg]

[QUOTE=SentraSE-R;158130]There's not much you can do to get better mpg from a 6 liter V-8 moving a loaded maxi-van

Really? Why is it that people are so willing to tell you you can't do something? A 25% increase in fuel economy is a 25% increase no matter what you drive. What you did would be like you asking a question and someone telling you to buy a bicycle and then telling you all the wonderful things about owning a bike. Why is it in this country everyone is wrong unless they do it the way we do it?

[PhileasFogg]

theholycow ...... Thanks! I'm gonna try that. I had the tires rotated and ballanced and I went to 75psi. I can see no difference in ride but hope to see a small percentage increase in MPG.

How do you feel about cold air intakes?

[FrugalFloyd]

Originally Posted by PhileasFogg

Really? Why is it that people are so willing to tell you you can't do something? A 25% increase in fuel economy is a 25% increase no matter what you drive. What you did would be like you asking a question and someone telling you to buy a bicycle and then telling you all the wonderful things about owning a bike. Why is it in this country everyone is wrong unless they do it the way we do it?

I never said you can't do it. I said your options are limited. It's simple physics, that it takes a lot of energy to get 5500+ lbs of van moving, and keep it moving. The powerplant to do it will guzzle half a gallon/hour just idling - a rate 3x more than a 4 cylinder engine.

Two things will get you 90% of potential fuel economy gains from your vehicle. They're slowing down, and conserving momentum. All the other stuff you read about (like CAIs, increased tire pressure, grill blocking, & aero mods) have a combined effect of less than 10% of potential FE gains.

[theholycow]

Originally Posted by SentraSE-R

Two things will get you 90% of potential fuel economy gains from your vehicle. They're slowing down, and conserving momentum. All the other stuff you read about (like CAIs, increased tire pressure, grill blocking, & aero mods) have a combined effect of less than 10% of potential FE gains.

This is very true. Adjustments to your driving are where you get the bulk of your improvements. Investing in modifications rarely pays off in fuel economy.

I do think more than 10% of gains comes from increased tire pressure, and someone willing to do extreme aero mods can get a HUGE amount of gain.

As far as CAIs are concerned: No, a CAI will not improve your fuel economy. If it has any effect it will reduce your fuel economy. Here's some reasons why (and there's a link in my sig with a more thorough discussion):

1. Temperature and density: Cold air is more dense. It takes more energy to push cold air through the system. Anyway, an aftermarket CAI is unlikely to make it any colder than the factory CAI that GM has been putting in its vehicles for two decades, which (usually) gets air from inside the fender.

2. Flow: Often cited as a reason for a CAI is increased flow capacity. If you are making all 367 horsepower all the time then you might benefit from a more free-flowing intake. In reality you will use 50-100hp all the time, a fraction of the flow that the system was designed for (manufacturers' engineers are no fools and have few compromises to worry about, they design the intake to match the rest of the vehicle).

This is especially true if you are trying to save fuel. With a mostly-closed throttle, that tiny little throttle opening is by far the biggest blockage, and the rest of the intake plumbing is not going to matter.

3. Temperature and density again: On some vehicles, what does help is a warm air intake or a hot air intake. Theories to explain it vary. I suspect that it allows them to open the throttle more for the same mass of air and fuel, reducing the throttle restriction, while also recycling some of the waste heat energy back into the engine.

[PhileasFogg]

Sentra .... You're not really helping here. I simply can't live in a car with a 4 cyl. I need a full size van. I found a full size van. I own a full size van. I know how big it is. I know how much it weighs. I know it drinks gas. Some of the places I go are just not tent friendly. Instead of buying an r/v that gets 8MPG I bought a van that gets 16MPG. So, by downsizing I have already doubled my fuel mileage. I am simply trying to to the best I can for the enviroment and still have a life.

[PhileasFogg]

holycow .... what about tuners like the Bully Dog? Do they work?

[PhileasFogg]

holycow ...... I lot of the stuff I have read suggest car makers are worried about emissions alot more than mpg. These sorces suggest there is alot to be gained from getting air in and out of the engine more efficantly. Do you think this is bunk?

[FrugalFloyd]

PhileasFogg,

You asked for help. I offered it. You've given no indication of what speeds you drive, or if you're willing to modify your driving to get better fuel economy. Instead, you keep focusing on finding a magic bolt-on accessory to your van. You already have it. It's your right foot.