# 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:** 46
**Author:** ![SSmokinn\_SS](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@SSmokinn\_SS](https://forums.speedlife.net/u/SSmokinn_SS)\ **Post date:** [March 27, 2009, 6:41am UTC](https://forums.speedlife.net/t/racing-in-montreal-canada-3-25-09/243092/46 "2009-03-27T06:41:31Z")
> [@\*\*\*\*\*Official: Mighty Meet Thread\*\*\*\*\*](https://forums.speedlife.net/t/official-mighty-meet-thread/10918/644): > > i want to see flow tests of how restrictive this exhaust is, or you claim it is. i can see if you went from dumps, to a full exhaust. id be more concerned with that awesome y-pipe system. whats the diameter of the stock exhaust?? an NA car doesnt have nearly the effect on the exhaust as a turbo car does(you have headers, and ypipe, plafs car seems to do just fine all around with a header/ypipe/stock catback combo)… na cars need back pressure while turbos create it. it has been proven time and time again on LS1tech that long tubes alone create the back pressure NA LSx cars need. Anything after the long tubes, only creates more back pressure… also, The LM1 is one the freest flowing exhaust… kind of funny. I found this thread on LS1tech and he has my same mods down to the cam…and they are saying the least amount of back pressure would be best…but hey, they wouldnt know would they?? > **[how much back pessure is needed? - LS1TECH - Camaro and Firebird Forum...](https://ls1tech.com/forums/generation-iii-external-engine/1077881-how-much-back-pessure-needed.html)** > > Generation III External Engine - how much back pessure is needed? - I was getting currious if I actually have enough back pressure. I will be running a LS1, with stock 241s, and a MS3. I have all the bolt ons also. The exhaust is currently... ooo, found another… > **[Backpressure argument with brother - LS1TECH - Camaro and Firebird Forum...](https://ls1tech.com/forums/generation-iii-external-engine/1065883-backpressure-argument-brother.html)** > > Generation III External Engine - Backpressure argument with brother - Ok so me and my brother have been haveing a little dispute regarding backpressure. He insists that a certain amount of backpressure is needed to create a vacuum to suck out... its funny your talking about back pressure and needing it…last time I checked Adam is running open headers and doesnt have a issue… O shit. I found this stickied on ls1tech about back pressure… > **[Mod Guide: Induction and Exhaust (PLEASE READ BEFORE POSTING) - LS1TECH -...](https://ls1tech.com/forums/generation-iii-external-engine/520845-mod-guide-induction-exhaust-please-read-before-posting.html)** > > Generation III External Engine - Mod Guide: Induction and Exhaust (PLEASE READ BEFORE POSTING) - Preface: The LS1 like any other engine works as a system, treat is as one, you want to get as much air in and out as you can. The plethora of mods out... "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." but he wouldnt know right? --- _[View the full topic](https://forums.speedlife.net/t/racing-in-montreal-canada-3-25-09/243092)._