Give me some cheap, easy mpg increasing ideas

[DenaliAK]

Thanks for all the responses. I've been thinking about it, and for now I'm just going to leave it be. I know with the AWD I'm never going to see a huge improvement, but I'm a long-term, practical guy and like snowjay pointed out, even marginal improvement can be worth it in the long run. However, I have a couple of other priority projects first, and not enough money to do them all at once, so I'm going to hold off on the intake and exhaust for now. I have to replace the rear suspension first, which with airride is not a cheap endeavor.

We're actually getting around 14mpg in town, which isn't bad, and only marginal improvement over that on the highway with the highest average so far of 14.8mpg. That is largely a product of the terrain our few highways are in. They aren't giant freeways like many places, but two-four lane meandering roads, up and down mountains, around corners, often having to slow down and speed up constantly to match traffic in front of you.

 

[withac]

Lets do the math. I'm going to use round numbers just because it's easier, but feel free to use your own.

Truck has a 26 gal tank.

A 1 mpg increase means I can travel an extra 26 miles per tank.

26 miles at 13 mpg is 2 gallons of gas.

2 x $2.50 = $5 per tank.

Lets say you fill up once a week.

$5 x 52 = $260

So if you can get a CAI for $300 and it gives you a 1 mpg increase then it will take a little over a year (1yr 2 mos) to get pay back on it or ~20,000 miles (13mpg * 26gal * 60weeks) using the numbers above.

That means a $500 exhaust to get 1 mpg would take about 2 years or ~35k.

I saw a 2 mpg increase from my CAI so the return on my investment would be half as long.

 

[DenaliAK]

But that increase was on a Tahoe, right?

Denali's don't have a 2 wheel drive option, they are full time AWD, which makes them less efficient by design. If that was on an AWD, though, that would probably be worth the investment. Gas is $3.20/gallon here, so I could make up for a CAI in under a year in gas savings.

 

[withac]

But that increase was on a Tahoe, right?

Denali's don't have a 2 wheel drive option, they are full time AWD, which makes them less efficient by design. If that was on an AWD, though, that would probably be worth the investment. Gas is $3.20/gallon here, so I could make up for a CAI in under a year in gas savings.

My '** is a replacement for a 2,000 Durango R/T 5.9 that was totaled. It had full time four wheel drive, I could not take it out. It would engage when needed then kick itself out. I could lock it in but I could not disengage it. I dont' know if that's the same as AWD or not. I put an AirRaid CAI in it. I saw a 2 mpg

 

[snowjay]

I saw a 2 mpg increase from my CAI so the return on my investment would be half as long.

Yup. 7mos using my example numbers. But if gas is more expensive and/or you were getting better than 13mpg to start with the time it takes to break even increases.

 

[Max]

Intake, e-fans, longtubes, exhaust, tune. I average 18mpg highway and 15-16 city depending on my mood. I'm quite heavy on the throttle.

 

[snowjay]

Ok, lets run some more realistic numbers...

26 gallon tank
17mpg average
1 tank a week
$2.75/gal for gas
2mpg increase (since that seems to be common)

2 mpg = extra 52 miles per tank.

52 miles at 17 mpg is ~3 gallons of gas.

3 x $2.75 = $8.25 per tank.

$8.25 x 52weeks = $429/yr saved with 2mpg increase

$300 CAI w/ 2mpg increase pays back in 8.5mos or 16k miles.

 

[SoderholmJ]

I just bought an '03 Denali. It's an awesome truck, very nice, but sucks gas. I don't expect to ever get great mileage, but I'm sure there are some easy and fairly cheap ways to improve on the stock setup.

From my other car experience, I'm guessing high-flow exhaust will help, but I don't want anything crazy loud. I don't mind a little rumble on acceleration, but at cruising speeds I'd like to keep cabin noise to a minimum. Any ideas, suggestions (better intake?), etc. would be appreciated.

Sorry if this is a repeat question.

check out the flowmaster 50 series mufflers. I hear they are quiet when cruising but once you pound the gas it'll let people know you're around. I ordered the flowmaster force 2 exhaust system that comes with it, putting it on in about a week.

 

[Z15]

$300 CAI w/ 2mpg increase pays back in 8.5mos or 16k miles.

Your dreaming right?

Anyone ever hear of Westers Tunes?

Here is what he says about increasing air as with a CAI system

7. Decrease AIR !! This flies in the face of what is sold out there today, but if you can decrease the amount of air entering the engine (due to the fact that this is a closed loop system as of 1996 OBD2) you will use less fuel, too. Ideally, you want to maintain the same horsepower required to combat air friction, rolling mass losses, etc...but do it with LESS AIR !!

Let me illustrate. A closed loop system maintains the air fuel ratio at 14.7 lbs air to 1 lb of fuel. This is maintained for idle, cruise and in some cases, even at wide open throttle.

If you have 60 grams/sec air entering the engine at cruise, you're using 4.08 grams of fuel per second. If the cylinder pressures are increased without creating harmful exhaust byproducts, or if these byproducts are controlled by the catalytic converter, we can gain mileage by decreasing airflow through the engine while enhancing the spark curve to maintain the same rear wheel HP.

On the chassis dyno, we can get vehicles down to 45-50 grams air/sec maintaining the same air fuel ratio, and same wheel HP as stock--and the overall result is less fuel consumed ! 45 g/secs works out to 3.06 g/fuel used in the same time period--or an almost 25% saving. We can't gain this in all vehicles of course--this example was resultant data from a 2007 6.0L HD 3500 GM truck.

This flies in the face of every aftermarket product out there claiming that it saves fuel--you will never gain mileage by increasing airflow through a gasoline engine in a mass airflow type system.

Because we carefully remap the spark curve with a remapped ECU, we in effect are increasing cylinder pressure without adding fuel. Increased cylinder pressure translates into more useable torque and power to maintain the power required for 'rolling resistance' of the vehicle down the road. The increase in horsepower often results in better fuel economy--although we do not guarantee mileage gains--as we cannot determine how YOU drive, and what your driving habits are.

 

[rigo_jones]

http://cgi.ebay.com/ebaymotors/Mazd...ies?hash=item2302a1d0f7&_trksid=p4506.c0.m245

its been dyno proven by a magazine to give at least 1-.5hp and save gas lol. ive used this and it does work i had a 97 prelude that needed a tune up and the motor would vibrate hard at idle more than normal i put this while the car was running and it smoothed the idle i was surprised. i bought mine at harbor freight tools. just put one on my tahoe.