HOW TO: Improve your MPG

[Okura_hubby]

Actually, the #2 is only partially correct and #6 is incorrect.

More airflow simply mean your computer adds more fuel (more power, but not better gas mileage). This idea goes back to the old carburated days when there was no computer that meticulously monitored your fuel/air mixture and adjusted for conditions each millisecond. Back in the carburated days adding more air could lean up the mixture a tad and achieve slightly better economy. Combustion efficiency was no where near the 99% level it is today. An aftermarket air filter or high-flow intake really won't do anything from gas mileage despite with people say. You can always get more efficient airflow by opening up the throttle.

If your engine has more power (avalable power), then that means to go 55mph your engine is not working as hard, thus burning less fuel. Because it is more effecient. It is producing more power per stroke/cycle so it requires less cycles to do the same job.

I saw your thread on altitude. The higher you go, the less air is available, so your engine becomes less efffecient I would think an engine would be more effecient at lower altitudes where air is thicker and the engine can gain more power per stroke. Also you pointed out less air means less air resistance. This is true, I know the Liby is a brick with high suspension so not exactly aerodynamic so not sure how fast you would need to go to notice a difference. And you would probably be burning more gas to get that fast since the altitude has less air for the engine..

RPM is not constant with HP. Depending on many factors that change dictate how fast RPM's must be to equal same HP. Forgetting wind, terrain and driving habbits.. To go at a said speed requries X amount of HP. Depending on Temperature and Altitude will dictate how much air per cycle the engine can process which will determine how much HP each cycle produces. So the cooler and lower you go the thicker the air the more effecient the engine.

But the problem is everything is in a constant state of change. Temperature, your location (altitude), your driving habits, duration of your drive. It all affects things.

 

[tjkj2002]

. The higher you go, the less air is available, so your engine becomes less efffecient I would think an engine would be more effecient at lower altitudes where air is thicker and the engine can gain more power per stroke. .

Modern FI virtually eliminates the efficiency difference between sea level and high altitude,the power difference is there but the efficiency is virtually the same.

 

[Okura_hubby]

I was watching a Top Gear show where they drove these trucks up some mountain somewhere, where the air was so thin they were having head ack's.. And they noted their engines were sucking for HP.

Your engine is nothing more than a pump. So if there is less air for it to pump, then less HP.. So to get the same results Speed or torque or whatever you will need to apply more gas (decreasing effeciency)..

 

[tjkj2002]

I was watching a Top Gear show where they drove these trucks up some mountain somewhere, where the air was so thin they were having head ack's.. And they noted their engines were sucking for HP.

Your engine is nothing more than a pump. So if there is less air for it to pump, then less HP.. So to get the same results Speed or torque or whatever you will need to apply more gas (decreasing effeciency)..

Not with modern FI,yes HP will be reduced but the effeciency will not.Reduced power is the by product of "leaning" out the fuel/air mixture to keep the same effeciency.

 

[Okura_hubby]

After I posted this I read some other threads on other forums. And people were reporting they actually got highter MPG when they went higher elevations..

And it made sense. The computer was reading the air density (thinner) so it leaned out the fuel mix. Saving fuel. Computers.. Got to love them.. Ha .. But I suspect since less air and less fuel the engine is not producing the same HP per RPM.. Less bang.. If not then why not lean out the engine and bring in less air so its more effecient all the time.. Hmm

 

[tjkj2002]

After I posted this I read some other threads on other forums. And people were reporting they actually got highter MPG when they went higher elevations..

And it made sense. The computer was reading the air density (thinner) so it leaned out the fuel mix. Saving fuel. Computers.. Got to love them.. Ha .. But I suspect since less air and less fuel the engine is not producing the same HP per RPM.. Less bang.. If not then why not lean out the engine and bring in less air so its more effecient all the time.. Hmm

To much heat,bye-bye pistons and heads.

 

[Okura_hubby]

Your comment about more heat is based on more RPM's? Or is it something else?

 

[tjkj2002]

Your comment about more heat is based on more RPM's? Or is it something else?

The leaner the fuel/air mixture the more heat in the combustion chamber.

A rich fuel/air mixture will naturally runs cooler and a lean fuel/air mixture naturally runs hot.

 

[ndz]

I bought a drop in K&N filter. that gave me an extra 3-4mpg. Then i broke off the tab that used to be where im pointing. that gave an additional 4-5mpg.

You must be registered for see images attach

edit: i should mention my old paper filter was ready to be changed out

 

[tommudd]

So you are saying by installing the K&N and breaking off the air intake you got 7-9 MPG more :happy175::happy175:
Come on now

 

[danh7029]

You forgot pumping up the tires to the safest maximum pressure,
Clean air filter, and good engine tune

 

[tjkj2002]

You forgot pumping up the tires to the safest maximum pressure,
Clean air filter, and good engine tune

Never air up your tires to max PSI unless it's the rear tires on a 3/4+ pickup used for towing with E range tires.Less contact area which means less traction and effects handling.

 

[baer jeeper]

I bought a drop in K&N filter. that gave me an extra 3-4mpg. Then i broke off the tab that used to be where im pointing. that gave an additional 4-5mpg.

You must be registered for see images attach

edit: i should mention my old paper filter was ready to be changed out

hmm did exact same thing also changed the spark plugs(cause they were worn out) also went to synthetic oils engine and diffs. according to packaging i should have seen a 12-15 mpg gain.. :smokin: back to stock mpg 20-21mpg no where near the possible 30ish lmfao

 

[samlesher]

For those with a manual transmission, I have read quite a few arguments between those who say you should coast in neutral to save gas (when going downhill, etc) vs. those who say it's actually more efficient to stay in gear at all times.

Does anyone have two cents to offer on that, specifically in regards to the NV-3550?

 

[tjkj2002]

For those with a manual transmission, I have read quite a few arguments between those who say you should coast in neutral to save gas (when going downhill, etc) vs. those who say it's actually more efficient to stay in gear at all times.

Does anyone have two cents to offer on that, specifically in regards to the NV-3550?

If going downhill stay in gear,not only for safety but it will actually shutoff the fuel going into the engine if your not stepping on the gas pedal.If in "N" your still using gas since the engine is idling.

 

[sevenhelmet]

Hey, I didn't know that! Cool.

 

[pure_mahem]

Could always switch to Diesel or propane, lol!

 

[Liberty65]

I don't know if it's the same with the automatic transmission, but I would change line #1 to specifically state that the reason not to go fast is because the engine will rev higher. I'm not sure the exact level, but I heard that the 3.7L engine was most fuel-efficient at around 2200RPM, which for me is 6th gear at 65mph. I've tried going various speeds on the highway and resetting the overhead MPG gauge and found that 65mph is optimal (for 6th gear).

So to say it a different way, I actually get better gas mileage going 65mph than going 60mph or 70mph.

2005 with a six speed ******....Wow I had know idea they made them with that. What kind of mileage are you getting on the highway @65mph? Do you have an intake or exhaust upgrade? Thanks.

 

[baer jeeper]

I liked my reply to a post so much I decided to turn it into a How To.

This post is brought to you by Scotch Ale, made by your friends and mine at Depot Street Brewing. So dark, not even light can escape (not their official motto, but that's how I've been pitching it).

DISCLAIMER: I have a tendency to be brutally honest (especially when I've been drinking). Some people may take it the wrong way, but remember, it's nothing personal, I'm just an ass (especially when I've been drinking).

Most manufacturers have already done everything they can to improve your MPG. These days, it's a great selling point. Translation: you will sell more vehicles if they have better fuel economy. They only limiting factor are those bastards at the EPA and their emission standards.

There are 6 things you can do to improve you fuel economy:

#1 Change your driving habits. Slowly accelerate from stops, don't accelerate uphill, coast downhill as much as possible, draft, and don’t go above 60 mph.

#2 Increase your airflow by adding an aftermarket intake and exhaust (with mandrel bends). (There isn't much cost benefit here, MPG increase is minimal and parts aren't cheap). This will give you a slightly leaner air/fuel ratio (ideal is 17:1). This ensures there is enough oxygen present to achieve as close to 100% combustion as possible. There will be an increase in H20, CO2 emissions along with NOx (NO, NO2 and N2O), and a decrease in non-combusted hydrocarbon emissions. Any change will be minimal and SHOULDN"T (but might) affect emission tests. An increase in air also increases the number of particles you let into the engine, decreasing engine life. Again the effects are minimal.

#3 Add an underdrive pulley. Basically, this robs power from other components on the drive belt and delivers it to the engine. Those components include: your A/C (so it won't cool as well), power steering, and your alternator (so your battery won't recharge as quickly). Not very cost effective and you gains will be minimal. The pros might not outweigh the cons if you like your A/C or you pull a lot of current.

#4 Improve your aerodynamics. Lower the front end and spray your entire vehicle with Teflon. You chose the wrong vehicle for aerodynamics, and it's not a very cost effective solution.

#5 Lose some weight. Don't carry around unnecessary weight. You lose 1% economy for every 100 pounds. Go on a diet, take a dump, whatever it takes to drop a few pounds (pun intended). For more extreme results Lose the A/C compressor, radio, roof rack, spare tire and jack, all the seats (except the driver's seat), and all of your interior molding and upholstery. You could probably eliminate 250 pounds and gain .5 mpg efficiency. But think of all the money you'd make selling parts of eBay!

6 Move to sea level, or below (stay above the water please). You lose 3%-4% economy for every 1000 feet you are above sea level (unless you have a supercharger or turbocharger to cram more air in).

I'd like to thank my friends Copy & Paste, Microsoft Word, SpellChecker and alcohol, the cause of...and solution to, all of life's problems.

#1 should be maintenance

 

[Lightningdan]

If you live in an area that sells ethanol fuel, stop using it and use straight unleaded, you should see a gain of 2mpg more without the corn in your fuel. I know here in South Dakota, if I run the ethanol fuel my mileage suffers for it.