Technical exhaust basics

OK, I got a pair of Brockman Mello Tones (20")-and they very well built so far. So for my edumication, I am going to run dual exh. on my basically stock 312 Y block. do I want a closs over pipe and if so is it an H or X pipe? What exactly does the cross over pipe do?

Thanks,

Mike

 

A crossover pipe kind of evens out the pulses and helps quiet the "raspiness" of certain exhaust tones. But if that's what you're after (think I-6 with headers) go for it.
In a non hi-performance application, "H" or "X" doesn't matter.... let your checkbook be your guide.

 

Not much room depending on the year of the car and transmission.

 

I wouldn't bother with a crossover. Just use a good old fashioned straight dual exhaust.

 

For "basically stock with Mellow Tones", a crossover is a rabbit hole for your exhaust to 'make a left turn' that doesn't actually do all that much.

 

I agree with Jim. I do not use a cross over.

Ben

 

Tried to reduce the noise on a BBC powered 57 truck. Put in a crossover pipe. Made absolutly no difference whatsoever.

 

Thanks, just trying to educate myself before I go in and talk with the shop to build it. So the cross over pipe will not be installed.

 

I've got an H pipe on my 455 Buick with dual exhaust. It definitely balances the tone and pressure and smooths the sound of the exhaust. I like the result in the sound. For the record, the crossover pipe on mine is probably only about 4" long. The longer the distance between your pipes, the less result in sound I would expect. As far as performance, you won't notice a difference between the X-pipe, H-pipe, or nothing at all for anything other than an all-out performance car.

The thing that I will say about mine, is when you disconnect the exhaust pipes from the manifolds it's a bear to get them connected again without leaks. If you have headers it's probably easier. Because both sides of the exhaust are connected to each other and come up at an angle, I've learned that loosening the manifolds from the cylinder head, tightening the manifold to pipe connection, then tightening them onto the head is the way to go.