5.7 Hemi - Headers or programmer for best fuel mileage improvement

[blkram03]

Which mod seems to be the best for fuel mileage improvement headers or a programmer? I would like the performace increase associated with each but due the high miles I drive I am more concerned with fuel economy at this time. Also for you guys with headers do you seem to have alot bigger gains with long tubes compared to the shortys? Thanks!

This ad is not displayed to registered and logged-in members. Register your free account today and become a member on Dodge Forums!

[helopilot]

You will have bigger gains all around with the longtubes. As far as gas mileage I picked up gas mileage with both of them. I guess it also depends on how much you play.

[Stroker]

Realistically you would probably get better fuel mileage with the programmer because you would hear the louder headers and play more then with the programmer.

[HankL]

If you are really interested in getting a real MPG increase
you would have better success
with low rolling resistance tires
and improving the aerodynamics (by lowering, tonneau, underpan cleanup or vortex generators)

An aftermarket system like the MegaSquirt, FAST, Motec, or Electromotive
that uses a wide band O2 sensor could improve MPG at part-throttle
by allowing leaning the air to fuel ratio above 14.7 at cruise.
A 5% gain is possible around 17 to 1.

Shorty headers might give 2% gains at full throttle (like the factory 6.1 SRT headers)
http://ask.autoblog.com/2006/02/20/a...-7-and-6-1-v8/

Long tube headers would give closer to 4% at full throttle
like Dulcich found before his cam swaps:
http://www.popularhotrodding.com/eng.../0602phr_hemi/

but cat and muffler backpressure behind the long tubes could easily cut this in half.

Almost all street driving is done at part-throttle.
At part-throttle neither shorty or long tube headers will give any measureable MPG increase
but a low backpressure muffler and catalytic converter alone might give something below 1.

[truckin151]

A Superchips Flashpaq Programer set on the 87 fuel economy while running 89 in the tank gave me about a mile to mile and a half more when Im not gunning it and driving at the speed limit (aka slow). Headers will work fairly nicely for mpg as long as you do your entire system from the headers back (headers, high flow cats, and a good cat-back system). As far as what brands to use for headers you'll have to ask around because Im not 100% sure anymore. Just remember though that the better the engine can breathe in and out the better the overall gains will be.

[blkram03]

Thanks for your help! I was really wanting to keep this truck somewhat quiet so if I put headers on I was going to keep the stock exhaust. if I do that I probably won't get the gain I'm looking for. Sounds like I may need to look into the programmer. Changing the aero is not an option as the truck is a 4x4 with 34" tires.

[motorider228]

good idea. I <3 my superchip hahaha

[Stroker]

Actually if you get a well desighned dual exhauset with headers it won't be too loud. Of coarse you'll never completly hide that header sound but you can keep it pretty damn quiet.