# racing in Montreal, Canada 3-25-09 **URL:** \ **Category:** Shift518 Automotive\ **Created:** [March 26, 2009, 10:04am UTC](https://forums.speedlife.net/t/racing-in-montreal-canada-3-25-09/243092 "2009-03-26T10:04:32Z")\ **Posts on this page:** 1\ **Showing post:** 52
**Author:** ![AMD\_IS\_THE\_BEST](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/amd_is_the_best/32/6342_2.png) [@AMD\_IS\_THE\_BEST](https://forums.speedlife.net/u/AMD_IS_THE_BEST)\ **Post date:** [March 27, 2009, 2:46pm UTC](https://forums.speedlife.net/t/racing-in-montreal-canada-3-25-09/243092/52 "2009-03-27T14:46:05Z")
> [@FS: DVD's and other misc. items](https://forums.speedlife.net/t/fs-dvds-and-other-misc-items/16269/16): > > read my quotes above. > > this was pulled from a sticky on LS1tech created by a Mod. > > ""Header Basics by Loren Barnes, President, S&S Headers, Inc. > > You have probably heard words like: back pressure, scavenging, tuned length, merged collector, rotational firing order, compatible combination and many others that meant something, but how they relate to a header may be a little vague. This article should give you a basic understanding of how a header works, what the terminology means, and how it plays a part in the header’s performance gains. > > The first misconception that needs to be cleared up is that a header relieves backpressure, but a certain amount of backpressure is needed for optimum performance. Just the opposite is true. A good header not only relieves the backpressure, but goes one step further and creates a vacuum in the system. When the next cylinder’s exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term “Scavenging” means.“” > > yes, back pressure does matter but simply just putting on long tube headers per say on my car, takes care of the back pressure. I could run open headers for all I wanted and wouldnt loose any back pressure, but with a muffler like i have now, I Gain back pressure…so Im already adding onto the back pressure that my car already has. Thats all fine and dandy but there is still resistance also know as back pressure. --- _[View the full topic](https://forums.speedlife.net/t/racing-in-montreal-canada-3-25-09/243092)._