Do headers and muffler really improve mileage?

[JimM68]

Any engine mods are there to increase power.
If you use the power, you WILL spend more on fuel.

If you don't, u might see a mileage increase.

Course if u leave it the way it is, and drive it at 60 or less, u will probably see the same mileage increase.

[RLKBOB]

Agreed. I replaced the tired old 302 in my Bronco with a stoutly built 351W. My mileage went from 10-11 mpg to 15-16 mpg. A lot of people don't believe me or understand how. My only explanation is that the engine doesn't have to work nearly as hard to move the vehicle so it doesn't need as much gas. I can see the same concept with a MH; performance improvements increasing mpg(assuming you drive it the same after the improvements). Since MHs weigh so much and the mileage is so low to start with I imagine it would take a huge increase in power to see much of a difference. If you start with 5 mpg it would be a 20% improvement just to get to 6 mpg and it would take a serious performance increase to raise your mileage 20%.
I haven't been on a trip in our new-to-us class C yet but I'm not expecting great mileage(I'm realistic). After a few trips I'll try a few SBF tuneup tricks(K&N air filter, cap, wires, plugs, open gap up a little, advance timing a little, hotter coil and some other little stuff) just to see it it makes much of a difference on this big block, big butt MH.
If I see any improvements I will post them up.

[WeatherTodd]

headers will allow the engine to exhaust and shed heat alot quicker.
Cold air intake will allow air to enter the engine easier.
The simple fact of straightening an intake tract or exhaust tract increases the engine operating efficiency.
That being said... Banks charges ALOT of $$ for inferior quality pieces. A quality header is made of stainless with thick mounting flanges.

[DAN L]

Quote:

Originally Posted by RLKBOB I haven't been on a trip in our new-to-us class C yet but I'm not expecting great mileage(I'm realistic). After a few trips I'll try a few SBF tuneup tricks(K&N air filter, cap, wires, plugs, open gap up a little, advance timing a little, hotter coil and some other little stuff) just to see it it makes much of a difference on this big block, big butt MH. If I see any improvements I will post them up.

i would advise using an S&B oiled gauze air filter element. it is thicker than the K&N for better filtration and is also a low restriction filter.
there is a lot of info on K&N filters in the archives of this forum.

[JimM68]

Again, modifying an engine to produce more power and then not using it seems silly...

When I had. My ole pace arrow, i'd leave the light with my foot on the floor, and keep it there to criusing speed, and got 8 mpg.

I put an ultrapower tumer on it. Now I left the light at half throttle, accelerated to cruising speed, and got 8 mpg.

I bought the knight. I leave the light and flooorboard the throttle and hold it there until I reach cruising speed... and I get 8 mpg.

It really doesn't matter.
It takes a given amount of power to accelerate a mass to a given speed. With aerodynamics of a shoebox, ditto for keeping it there.

Some r happy accelerating and driving very slowly, a.nd they will be rewarded with 10 mpg.

Me, I'll get 8. It really doesn't matter what I drive.

[donandmax]

No increase in mileage....... Banks system.......I mean NO increase.....Power ?....Maybe

[TXiceman]

A header can be tuned for more torque or for more HP...designers choice. For an RV you do want more torque.

donandmax, we put the Banks system on a 1999 Minnie Winnie class C and while it did not have a kick in the pants power increase, it did improve the mid range power. It was easier to pull hills and there was a slight gain i fuel economy...mostly due ot driving it a bit easier on the road.

Ken

[bbeane]

Not much is going to help your fuel mileage. Simple matter of X amount of weight + large frontal area takes horsepower which takes fuel. So if you where getting 8 mpg and you managed to improve it 10% that ain't much.
Now if you need major exhaust work (manifolds, studs) headers couldn't hurt.

[frankdamp]

On the 460, IF the headers warp, switching to Thorley or Banks doesn't cost a lot more than having the OEM manifolds re-machined and re-installed. At least the "Banana-bunch" types won't warp and crack.

We had a very difficult time with manifold problems on our '85 E-350 based Class C. Very expensive to fix.

[tekrsq]

We put Headman headers and a set of Flowmasters (I think the 44 series) on our 87 when the stock manifolds cracked. When all was said and done, it was actually cheaper than buying new OEM manifolds.

Having said that, We didn't see any incresae in mileage. In fact, it went down a little, but with noticeably more torque. And the sound is an added bonus in my opinion. Sound like a NASCAR going down the road.