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Indeed. What I am concerned about are the people that really don't know any better...and they purchase this (or any) catback thinking they're going to get 18/30 out of it due to misleading(?) advertising.
Perhaps, but if thats what they really expect they deserve the results.
 

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You don't balance it with backpressure. Ask ANY reputable header or exhaust designer/manufacturer out there.

A good header (and to some degree exhaust) relieves backpressure and creates a vacuum. Smaller diameter tubes create the velocity necessary to scavenge at lower RPM's. Larger tubes facilitate scavenging at higher RPM's. Longer the tube lengths pull torque lower in the rpm band.

If backpressure helped (instead of velocity), you'd simply use crush-bent pipes instead of mandrel smaller diameter pipes.

http://www.ssheaders.com/header.htm

http://www.magnaflow.com/05news/magazine/05sportc.asp

http://www.burnsstainless.com/TechArticles/Theory/theory.html

http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm
Read the magnaflow article and it talks about backpressure, and the need to have some.

Like I said, run your LS2 with no manifolds and exhaust and see what happens.
 

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Read the magnaflow article and it talks about backpressure, and the need to have some.

Like I said, run your LS2 with no manifolds and exhaust and see what happens.
Where in the article are you reading that? The article doesn't mention that at all. It says to MINIMIZE backpressure and MAXIMIZE velocity.

And you're STILL not understanding scavinging, which is what a good header system and exhaust promotes. The power gains from exhaust scavinging have nothing to do with backpressure.
 

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Where in the article are you reading that? The article doesn't mention that at all. It says to MINIMIZE backpressure and MAXIMIZE velocity.

And you're STILL not understanding scavinging, which is what a good header system and exhaust promotes. The power gains from exhaust scavinging have nothing to do with backpressure.
I fully understand exhaust gas scavinging and why you would want it. And yes, this article says to minimize backpressure and maximize velocity, but remember, it is a balancing act between the two. That's why different types of exhaust systems make differenct levels of power.

I think we are saying the same thing, however, describing it in a different manner/vocabulary.
 

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I fully understand exhaust gas scavinging and why you would want it. And yes, this article says to minimize backpressure and maximize velocity, but remember, it is a balancing act between the two. That's why different types of exhaust systems make differenct levels of power.

I think we are saying the same thing, however, describing it in a different manner/vocabulary.

No - it says to minimize and maximize it does not say to balance. Velocity and scavenging make the best TQ and HP numbers....:yes:
 

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No - it says to minimize and maximize it does not say to balance. Velocity and scavenging make the best TQ and HP numbers....:yes:
To me, minimize one variable and maximize another is a "balancing act".
 

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Scavenging is based on your backpressure. Varying backpressure effects the location of the stationary shockwaves that form inside each exhaust tube. On log style manifolds, these waves are just left to collide. On headers, the waves stretch to varying distances, depending on the exhaust pulses. As one speed of air (pulse) hits the other speed of air (backpressure) it creates a Mach wave. A second wave can speed it back up. It's similiar to a Venturi.

The shockwaves, created by backpressure, in turn create the vacuum that causes scavenging. Low backpressure allows air to move through the cylinder faster, giving you great high RPM horsepower. With the right tuning, a naturally aspirated engine can actually pull more than atmospheric pressure due to enough vacuum. Torque, however, is created by slower moving air, and a relatively higher backpressure.

Open headers and straight pipes can't be beat at the track (and are fairly handy in boosted conditions). For trucks like ours, I would maintain enough to keep my torque band in the 3500-4500 range. But, that's just my IMO. And I am NOT an expert at exhausts or engines.
 
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