Flow Master Type Muffler

[bikerpaul]

I have changed to a K&N air filter to help the mileage. which helped a little bit. I have been told that until I put a muffler that flows better, I won't see any real mileage increase. Is this true, or just somebody trying to make a sale? I have the 4.6 liter engine w/ a 4.10 rear-end. I have been getting 17-17.25 mpg in the last 2 weeks. I was getting 16 mpg and it suddenly jumped. I am told that the refiners have gone to a summer blend on fuel and it gets better gas mileage.

 

[Moot]

The 4:10 axle ratio is the killer.

 

[bikerpaul]

That's true, but with the low powered 4.6 liter engine, the extra grunt of the 4.10 gear is needed. I had a run last week with a 1800 lb. load, on flat land it ran okay, but when I got into the hilly terrain of eastern Ohio, it had a hard time. If I went to a 3.73 gear, it would only make it worse. So I'm thinking again about the Flow Master type muffler to bring the mileage up, along with a power increase I'm told about.

 

[Dynamite 1]

the freeflow exhaust will help. but you cant just throw a muffler on and be done with it. most of the time along with restrictive cats and mufflers [ DONT FORGET ABOUT THE CATS ] the pipes themselves are part of the problem. to many bends, 90's and to small a size. i have a 97 model 4.6 and it was a little sluggish. but after a complete exhaust mod it woke rite up. you can also have the shift points in the trans modified to be more efficient plus they can tweak the fuel to air mixture and increase both performance and mileage. it all depends on how far you want to go and how long you plan on running the vehicle to recoup the cost. i also agree w/moot the rear gear is a killer.

 

[LDB]

+1 on the gearing hurting mileage however the need for it is also understandable. I like analogies even though some of them are groaners. This one reminds me of the engine being an industrial size sink and the K&N filter being an extra large faucet sort of like changing from a garden hose to a fire hose. The sink can only accept so much without draining so the Flowmaster is the bigger trap in the drain pipe. It will help but as mentioned the various curves as well as the diameter of the other pipes will affect how well the increased input can be evacuated.

 

[Dynamite 1]

great analogy !!!!!!!!!!!!!!

 

[Jack_Berry]

your filter breathes better from larger holes allowing larger particles of dirt into the engine. remember that. might be better to repl the air filter more often than let in larger dirt particles. p

just got cats replaced and see an increase in mpg. 2800 mile trip avg 17.3 at 60 mph. high of 19.6 and low of 14.73 thru neb. coulda been the fuel as every other leg was over 16.

 

[Dynamite 1]

oem cat replacements or aftermarket freeflow cats by a reputable exhaust mftr? did you have any other exhaust work done?

 

[greg334]

Jack,
How many miles on the van when you replaced the cats?

 

[guido4475]

It seems like there is this Fed-Ex van driver that I run into quite often, real nice guy, that has a ord van with a 5.4 gasser and he said by using K&N airfilters and Flowmaster muffler his fuel mileage now hits 18-19 mpg on the highway, using cruise.Don't know how true this is, but what reason would he have to lie to me in the first place?

 

[LDB]

Their filters combined with a freer flowing exhaust will definitely improve fuel mileage although as mentioned it does allow larger particulates to pass. There is also debate on oiled versus non-oiled elements.

 

[bikerpaul]

Their filters combined with a freer flowing exhaust will definitely improve fuel mileage although as mentioned it does allow larger particulates to pass. There is also debate on oiled versus non-oiled elements.

I use K&N air filters in all of my vehicles, and I always use their oil.

 

[greg334]

K&N is not a good filter for diesels, it doesn't matter what they or others seem to say because they and other "free flowing" filters seem to let too much silicon (sand and fine dirt) into the intake and hence into the oil.

There is a debate about oil/no oil but that's not the real issue, the bigger 'holes' in the filter is the real issue. I have had a couple pre-filters on GM products that had to be clean and sprayed with oil.

 

[bikerpaul]

I have the 4.6 liter (281 Ci) gasoline engine. Does this make a difference?

 

[greg334]

Not that I see, dirt and sand is dirt and sand.

 

[fastman_1]

I've used K&N filters in everything I have ,van ,car,motorcycles, and never had a problem, they claim to filter better than a paper filter and I believe it. and Gibson makes a great Free Flowing muffler .