You can justify it however you want to justify it, but the truth of the matter will remain still be the same; spending money on performance parts for fuel economy reasons is a losing proposition.

As FortyFords stated, opening up the intake & exhaust with performance parts is just allowing the engine to breath better, but, once it starts cycling more air through, it is also going to start adding more fuel in order to maintain the appropriate air/fuel mixture.

As for all of these manufacturers' and their inflated claims to providing better fuel economy, I just have one word to say, "ADVERTISING". And it obviously works, because aftermarket performance parts is a multi-billion dollar business.

 

Well, I did it on my Sub, but I don't think I will do much with the "Beast". The original owner has already eliminated the muffler, I just have the cat and pipes. I reprogrammed the sub(had to run premium), had a trueflow intake, and an Aero-Turbine exhaust. It ran great but still couldn't pull my TT without overheating. It had plenty of power, but only 3.73 gears, and a weak cooling system. It was louder than my straight pipes! I'm a little uncomfortable with no muffler at all. I am thinking about an Aero-turbine with a resonator to takes some of the volume away. It was never too loud to order food as the diesel guys sometimes say. The V-10 stay [retty quiet under 2000 RPM, but if I punch it, she snarls pretty good!

 

thanks again guys

 

Change the oxygen sensors. They can account for 15% or more better economy.
Change all the filters, disconnect the battery for one hour, then start up the truck and let it idle for 3 minutes. This will re-establish thecomputer for good performance.
Ensure that the engine compartment is clean like new, and all belts and electrical
wiring is perfect. Be easy on acceleration( under 2000rpm).
Use cruise control on the highway, under 70 mph, and you should get 15 mpg
Make sure all excess weight is removed from the back seat and the box.

 

An open exhaust on a gasser is definately a waste as earlier said. It will draw more fuel than needed and a lot of it goes unburned and out the tailpipe. A gasser needs a little back pressure to operate effeciently. One thing that will help is if you have a camshaft setting guide and set the camshafts properly. Mot set at the factory is for making it run with the least trouble. I have seem them off as much as 10 degrees. Get someone that knows what they are doing and have them check it. It can be worth at least 3 to 4 miles per gallon when set right. Comp Cams will give you the specs for free. All you have to do is call them.

 

Does my cat give enough back pressure? I only have a cat and pipes.

 

If I was running a gasser, I would have a dual setup with a set of the factory cats (federal regulation), a crossover and and a set of mufflers that I could see through, with dual pipes exiting right behind the rear wheels (factory look). With the pipes out the back, it makes it easier for the local gestapo to stop you as all the noise is concentrated at the rear and they would know that it has been modded.

With only one cat, you may have more back pressure than you need. It does not take much. You want the engine to push the exhaust, but not to have to use power to do it.

Also, once you get past the cat, increase the pipe size 1/4 inch (make it square, not balloned), then when you pass the muffler, increase it another 1/4 inch. Starting out with 2 1/2 pipe at the headpipes will give you a 3 inch exhaust at the tips. The lips will keep the exhaust from backing up and will also add more cooling to the gas. The cooler gas will contract and draw the heat faster down the system, thus more efficient.

A good sound, slightly moderate backpressure. An example of a good muffler will have a solid pipe with cutouts straight through it. The Bully Dog muffler I have on my SD can be installed with the cutouts facing the engine (little restriction but, quieter) or facing the tailpipe (no restriction, no noise reduction). Mine faces the tailpipe.

 

Made a 120 mile run yesterday with the truck and my 20 foot trailer with about a 3,000 # car on it. Limited the times it turned over 2,000 rpm's, and got almost 15 mpg's. Thanks alot guys...

 

120 miles is not enough to give you an accurate reading. It ususally takes about three tanks. Then average the miles per gallon, you will notice quite a change.

 

My 1999 f350 SC AT 5.4l 3.73 gears 132,000 miles was gitting only 6.5-7.5 MPG Then I pulled the factory plugs and am gitting 9-12MPG depending on the weight of my boot.


Fat-Fab.com

 

"If I was running a gasser, I would have a dual setup with a set of the factory cats (federal regulation)" AND "With only one cat, you may have more back pressure than you need."

This does not make sense. how can two cats give less pressure than one?

 

With one cat on each side, it can handle the exhaust flow with less restriction than having both pipes dump into one cat as designed from the factory.

This will give you an expample. I had a '79 T-Bird with a big block 400 that ran it's exhaust system into a single line with one cat and a muffler/tailpipe. The car produced a little over 170 horses. I removed the muffler (straight piped) and gained 6. I changed the exhaust over to a dual with a crossover (dual cats) and straight piped) and it went over 190. The results was better fuel mileage (15 to 19), more horsepower and the emissions actually went down about 30%.

The dual cats actually had less work to do over the same area of cleaning space, resulting is less back pressure. As the engine did not have to push the exhaust into a single outlet, it worked more effiecently (sic) and the crossover balanced the exhaust pulses making for a smoother running engine.

I know that this was done on an older vehicle, but I would say the the principal would work on today's modern engines also.

 

I know greater fuel mileage would be great. But in all reality, we drive a truck that has the aerodynamics of a house, large engines, and heavy wieght. If you really think about it, you have to spend money to save money. Why really bother. Lets take all the money we spend on upgrades and performance and buy a oil company for us ford guys. FREE GAS FOR EVERYONE ON HERE

 

I like that idea. Ford only gas stations, and for FREE!

 

CharleyG,

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