why are open headers bad for our cars

[er22bball0302]

why are open headers bad for our cars. i have heard that you will lose torque and or possibly ruin your valves? a friend of mine wants to install some exhaust cutouts

 

[Cobracide]

Backpressure on the exhaust provides vacuum on the other cylinders, making your engine more efficient.

 

[larrendeuce]

why are open headers bad for our cars. i have heard that you will lose torque and or possibly ruin your valves? a friend of mine wants to install some exhaust cutouts

If the primaries are too short the valves can cool too quickly, and warp. I don't know of anyone having problems with open longtubes, but open manifolds wouldn't be good.

 

[er22bball0302]

Backpressure on the exhaust provides vacuum on the other cylinders, making your engine more efficient.

wouldn;t back preasure in the exhaust be a postive preasure not a vacum? i could see how a vacume in the exhaust could benefit. the high preasure from combustion would move to the area of lower preasure(exhuast if there was a vacum), but i dont see how you would get a vacum?

 

[Cobracide]

wouldn;t back preasure in the exhaust be a postive preasure not a vacum? i could see how a vacume in the exhaust could benefit. the high preasure from combustion would move to the area of lower preasure(exhuast if there was a vacum), but i dont see how you would get a vacum?

When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.

 

[SVT98Snake]

backpressure creates a vacuum....and wha tI have heard about open headers allow heat to travel back into the ports which can ruin the valves...now whether or not that is true, I don't know....but it's better than chancing it.

 

[er22bball0302]

When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.

oh ok i see where your coming from now.