11-14-2005, 11:04 AM
Can someone explain the purpose of the crossover tubes on a stock 4into1 exhaust system. The tubes connect between the no1 and no2 exhaust headers, and between the no3 and no4 headers. They are located about 10" from the exhaust ports. They are held in place with springs. My guess is they alter the resonance and improve response at some rpm range.
It would be easier to prep and chrome the exhaust if they were removed and welded shut, as well as cleaning up the appearance. What effects can be expected from this mod?
I will probably just have to try it.
11-15-2005, 11:34 PM
It helps to even out exhaust pressure between cylinders thus increasing torque. By cutting them and chroming you are losing power and adding weight....good idea!!
11-16-2005, 01:18 AM
Air mass, velocity, and volume up to the point of the crossover is what controls combustion chamber evacuation when both valves are open. It's all inertia and fluid dynamics. Pretty complicated stuff. If your crossover is futher, it will pull the air harder, but rob power on the exhaust stroke. Too short, and you'll leave exhaust gas in the combustion chamber during the topout between the exhaust and intake strokes. Velocity stacks work on the same pricipal. The piston rounds off at the bottom of the intake stroke and starts back up, but the intake valve is still open. This is because the inertia of the air in the velocity stack is pushing more air into your cylinder. I hate being a physics geek.
11-16-2005, 07:08 AM
Yosh used to charge extra money to make their headers "Duplex" as they called it, and you want to chop them off to help your chrome them?