Exhaust systems for better mileage

Looking for some advise about changing my exhaust to a Gibson exhaust to get better mileage. They claim to get 2 to 3 MPG. with no other mods.



Also what does everyone think about K&N airfilters.



Thanks

Don’t waste your money.

Unless you make engine mods that take advantage of a free flowing intake/exhaust system, it’s a waste of money. Also, these free flowing systems only come into play when you’re running at wide-open-throttle. How often are you going to be at wide-open-throttle?

Tester

…and if you are interested in frequently driving at wide-open throttle, how interested are you in better fuel mileage?

Re: The K & N filters, I would add that there have been many cases of people who ruined their Mass Air Flow sensor (MAF) as a result of the excess oil coming off of that filter.

Think about it:
Since all vehicle manufacturers are interested in getting the best possible gas mileage from their vehicles, don’t you think that the vehicle manufacturer would have used similar devices if they really worked as advertised?

I don’t know about a stock F150 (Is yours stock exhaust?) But for most cars and personal trucks today, there is little or nothing to gain (mileage wise or power wise) unless there has been some serious modifications.

Back in the 60’s most cars would gain by improved breathing, but the auto makers have all figured it out that they can do the same things for little or nothing.

K&N filters come in two flavors. Most if not all the K&N filters sold to replace the existing filter are “oiled” filters. They are known to cause problems often when the owner fails to get the oiling part right. It can damage the MAF. The dry cone K&N filters don’t have that problem, but unless you have done serious modifications, it is nothing more than a fix looking for a problem.

Unless you want to reprogram your car’s computer to take advantage of the less restrictive (or tuned) exhaust, as Tester and VDCdriver have noted - save your money.

Think of preserving your money. Some day you will be nearing retirement or buying a house or you will be 55 years old and you will absolutely have to have a K&N filter and a free-flowing exhaust system. If you are already there, disregard my answer.

You’re unlikely to increase your gas mileage.

Your F150 is the beneficiary of the engineering expertise of the Ford Motor Company. The Ford engineers are some of the best in the business, and their mission it to make sure every vehicle that comes out of a Ford factory has the best combination of reliability and fuel mileage they can possibly come up with.

If you change something, your mileage will suffer.

The Ford engineers know how to design exhaust systems, and they equipped your F150n with the best exhaust system on the market.

Why do you think someone else has a better idea?

If you modify your truck’s exhaust system you’re wasting you’re money.

Run tire pressure at the maximum, advance timing (if possible) until it detonates, then back it off until detonation ends, then test that the starter doesn’t get kicked back in a hot re-start, i.e., run timing as high as possible. Install a vacuum gauge and keep the needle high…

Nothing but nothing improves tha gas mileage of a vehicle like replacing the loose nut behind the steering wheel.
Do you speed? Quit doing that!
Do you accelerate towards red lights? Quit doing that!

“Run tire pressure at the maximum”

Especially considering that this is a pickup truck, and the OP may take that recommendation as using the maximum tyre pressure listed on the tyre, that would be a bad idea.

Pickup trucks can have some handling problems to start with due to the weight distribution. For safe handling the owner should be careful about keeping the tyre pressure close to the manufacturer’s recommended values as indicated in the owner’s manual.

The “maximum pressure” indicated on the tyres is NOT a recommendation. It simply means the tyre is not designed to every run safely above that pressure. The tyre manufacture does not even know what car or truck they may be used on.

http://www.tiresafety.com/

This is sponsored by a tyre manufacturer Bridgstone - Firestone and instructs the reader to check the owner’s manual for the correct tyre pressure.

Here is another from the Goodyear site.

Check Your Air Pressure
Keep your tires properly inflated and you could improve gas mileage by more than $1.50 every time you fill your tank. The recommended tire pressure for your vehicle is located on a sticker inside your driver-side door or noted in your owner’s manual.

You might also try the US Department of transportation.

http://www.nhtsa.gov/cars/problems/E...intenances.htm

They say:

You can find the correct tire pressure for your tow vehicle in the owner?s manual or on the tire information placard.

…do you carry a few hundred lbs of unnecessary junk around in the truck? Quit doing that!

Do you warm up the engine for more than 15 seconds or so in the winter? Quit doing that!

Do you use drive-up windows at banks and fast food joints? Quit doing that!
(Both your wallet and your butt will thank you)

It should be noted that the majority of those MAF sensor failures have been the result of over oiling the filter after cleaning it. You can’t fault K&N for the ineptness of the customer. They warn against over oiling in the instructions that come with the filter and with the cleaning kits. I’ve had a K&N on my Bronco for the past 230k miles and the MAF sensor is hasn’t had any problems, and I’ve had one on my Mustang for about 60k miles and again, no problems.

But as far getting better mileage. The OP would be wasting his/her money. Almost all vehicles today are tuned from the factory with mileage in mind, as there are CAFE standards to meet.

One mod that would help, especially in winter is a warm air intake (WAI)

Do some research online to see if this is something you are capable of doing.

Dont waste your money on K&N.

A “warm” air intake? How would introducing warm air into the engine help with anything?

Allow me to perform some fuzzy math. Let’s assume a new exhaust system improves fuel economy from 13 MPGs to 15 MPGs, and that you drive 10,000 miles per year. At a price of $2.75/gallon, the new exhaust system will save you about $282/year. As long as your new exhaust system costs less than $1,400 (including credit card interest, if necessary), and you can substantiate the fuel savings, it would be a wise financial decision.

If you really believe a new exhaust system will save you 2 to 3 MPGs, you better get a guarantee in writing. It might not give you any fuel savings, and if it doesn’t, you will have a long fight ahead of you to get your money, and your old exhaust system, back.

K&N air filters are expensive, and require maintenance. If you buy one, you will have to clean and oil it, which, in my opinion, isn’t worth the effort, and go horribly wrong if you make a mistake. You are better off buying paper filters from the auto parts store or a discount retailer and changing them when necessary.

you do lose some power—but you gain in overall engine efficiency. Saves fuel.

you do lose some power—but you gain in overall engine efficiency.

I don’t understand that comment (on how there’s an efficiency gain).

Warm air is already partially expanded, which means you’ll end up with a less-dense mixture in the cylinder as you begin your power stroke. That leads to a decrease in efficiency.

Help me understand what you’re thinking.

A warm air intake or WAI is a system to decrease the amount of the air going into a car for the purpose of increasing the fuel economy of the internal-combustion engine.
All warm air intakes operate on the principle of decreasing the amount of oxygen available for combustion with fuel. Warm air from inside the engine bay is used opposed to air taken from the generally more restrictive stock intake. Warmer air is less dense, and thus contains less oxygen to burn fuel in. The car’s ECU compensates by opening the throttle wider to admit more air. This, in turn, decreases the resistance the engine must overcome to suck air in. The net effect is for the engine to intake the same amount of oxygen (and thus burn the same amount of fuel, producing the same power) but with less friction losses, allowing for a gain in fuel economy, at the expense of top-end power.

I wouldn’t go that far. Certainly there are cost constraints involved. We all know that Detroit has some the finest bean counters anywhere.

I understand what you’re saying about why warm air intake will improve mileage. With carburetors of yesteryear, it was easy to understand cause and effect.

However, with today’s ECUs, doesn’t the above description depend on how the ECU is programmed?