worse MPG with open exhaust??????

[GREASEMONKEY72]

now ive got the stock ramhorn manifolds with glasspacks and theres about 2ft worth of pipe inbetween the manifolds and the packs and my question is if i cut the glasspacks off and leave it open will i get worse mpg? or will it be the same? its true duals with no crossover

cause i know the glasspacks do give some back pressure which helps with mileage but is it enough to where ill get worse mpg with open pipes?

how bout it andy?

[Huck]

My experience---new 350 crate motor--added edlebrock intake==lost 2mpg. added hooker headers==lost 2mpg. went back to stock intake with edelbrock 1406 carb---regained 2mpg. went back to stock dual exhaust using ramhorns--regained 2mpg. In both cases, might have gained higher rpm horsepower but lost low end torque. Trucks like low end torque much more then high rpm horsepower. Huck

[GREASEMONKEY72]

its the stock engine with stock intake/carb just with dual 26in glasspacks with about 2 1/2in pipe, about 2ft of pipe from the manifold to the glasspack with no crossover and it dumps out of the glasspack at the back of the cab

i know that the glasspacks do offer some back pressure but is it enough to lose mpg without them?

[GREASEMONKEY72]

[mplex2000]

If you are using louvered glasspacks, yes, they give tons of backpressure. Typically the ID of the inner piping (the part that holds the glass inside the outer shell, with the louvers sticking out) is quite small. Not to mention the louvers themselves, resticting the ID an disturbing airflow. They're some of the worst mufflers you can use performance wise, but for gas milage and tq might be ok.

If you ever saw one of the "old" 5.0 Mustangs, those people would get the off-road H pipe with no cats, they'd sit there wondering why they lost all their low end punch....well, their exhaust was TOO free flowing

[mplex2000]

If you are using louvered glasspacks, yes, they give tons of backpressure. Typically the ID of the inner piping (the part that holds the glass inside the outer shell, with the louvers sticking out) is quite small. Not to mention the louvers themselves, resticting the ID an disturbing airflow. They're some of the worst mufflers you can use performance wise, but for gas milage and tq might be ok.

If you ever saw one of the "old" 5.0 Mustangs, those people would get the off-road H pipe with no cats, they'd sit there wondering why they lost all their low end punch....well, their exhaust was TOO free flowing