Does anyone know what the cross sectional area of any X (cross connected) exhaust is at the point where the intersection occurs?
Is it significantly reduced from twice the nominal individual bore enough to create back pressure? I can't see to measure the area on my Switzer because it's inside the muffler can.
Thanks, Bob

 

Hi Bob, which part are you talking about (see pic of my Cargraphic below)? Are you referring to the pipe that connects the 2 mufflers? That's called the "balance pipe" (?? anyone corrects me as needed) and is there, I believe, to reduce resonance. Not sure about this at all; I was told at one time.

I do not believe the size of the balance pipe will affect back pressure much. As for the rest of the pipes, in as much as pressure drop is proportional to length and radius, and that the lengths here are short, and that the catalyst and muffler cause proportionally much more resistance, I do not think (not sure) the diameters of the connecting pipes affect back pressure as much.
That said, you could see in the Cargraphic the pipe between the catalyst and the muffler IS huge, bigger than any other I've seen and almost as big as the catalyst itself! The exit from the muffler, to the tail pipe, is down to the size of a soda can.

I do know that the sizing of the pipes affects the frequency response of the exhaust. And bigger pipes are important for the low frequency gutteral growl component of sound.

 

What are some of your concerns Bob?

 

Cannga
It appears your system has a balance pipe that would not reduce the cross sectional area. Some systems have the pipes 'siamesed' to achieve the balance.
Neil.
This is more of a general question for mods down the road with your bigger output turbo's. Is the point of the X a restriction? Perhaps it makes no difference.
My thought was the exhaust pulses or waves would fill in better with the siamesed X design and cancel better than with a balance pipe design but there might be marginally more restriction. Certainly with your system there is a very smooth tone at high output compared to independent pipes which might suggest that.
Bob

 

Yes it is a very open and un-restricted crossover in the middle. This system has uniquely designed pipe transitions and diameters that help keep the noise down and the flow up.

When we did that dyno pull on the sledgehammer, it ran through the same system that is on your car right now with the exception of cat delete pipes, and it produced 1100hp at the flywheel. No worries Bob