Where can I learn about exhaust dynamics?

[Ben@SpeedTech]

Currently in my wagon I have about 325 hp and 400 ft lbs. at the flywheel exiting through 1 5/8 cheapo headers, 2.5" head pipes into a Flowmaster Y pipe, then 3" through a Dynomax race bullet, 3" over the axle, then into a 3"x 18" Dynomax round Stainless muffler exiting through dual 4" tips under the center of the rear bumper.

I'm going to put a new motor in the car this year with roughly 550 hp/ 500+ft lbs. I'll need to redesign the exhaust system and want to minimize power loss with a good design. I love the way my current system sounds and I'd like to keep the rear center exit, but there's only room for one muffler out back as I have it. I've been thinking about running 3" duals and then past the axle at the end have them merge into a single 3" at the rear muffler, OR maybe some stealthy flat black side pipes might a be cool option too.

I'm trying to avoid basic "opinions" or vendor swayed magazine articles sponsored by a specific company. I only have the budget to do the system once so I want to gain some insight/ understanding through some decent solid fact based (dyno numbers, flow charts, etc) exhaust flow info, and make good decisions on-

• Choosing the best header tube size based on the engine, i.e. 1 5/8, 1 3/4, stepped...
• effects of different size tubing (2.5", 3"...)
• 2 into single vs duals
• X vs H pipe
• muffler flow considering muffler design and placement
• how critical is back pressure and how does it affect power numbers
• power reduction/ increase, if any, with tail pipes
• effect of different size tail pipes than head pipes, i.e. 3" into 2.5" over the axle for more clearance
• power advantage/ disadvantage for using side pipes like old Vettes and Cobras

etc...

Anybody have or know of a good resource for some of this info? Thanks!!

[Twoblackmarks...]

There is not too much litterature on Exhaust tuning, to my knowledge atleast, I would recommend David Vizards exhaust opinions, he has dyno tested lots of exhaust types and changes.

From what I remember he says 2.2cfm pr. HP.
So 550HP needs an 1210CFM system for an zero-loss type system.

If you go bigger, you dont lose or gain power, but you get less noise reduction.

If you gain power with more backpressure/an restrictive system you have choosen the wrong camshaft, to a degree, since plugging the exhaust acts as shortening the Exh. Duration.

4-2-1 headers are often good for regular V8s because of the odd firing order seen by the headers.

X or H pipe always reduces noise, and usually gains power, never looses, but sometimes no gain and length is non critical.

Muffler design has something to say f.ex Flowmaster vs Dynomax, since they act different to changing the secondary length.
You should search for David Vizard on the net or buy his "how to build HP" book, there he writes about headers and exhaust, (and the rest of an engine), he has been in magazines some times too. He has nice graphs to look at.. HeHe..

Harold Bettes book "Engine Airflow" has some math about header sizes. The book has a lot of math for everything Airflow related..

There are a couple others to, one by a man named Graham Bell, and another one atleast, but they are pretty old, I have not read them. Just seen them in my dads Bookshelf.. I like Vizards fairly easy to read and understand books.