There is no debate. Its simple laws of air movement. Bigger isn't always better, but if you go bigger, you have to do it right. Large volume of air leaving means more air has to be coming. Its not so much about "backpressure", its more about proper intake/exhaust volume matching. The exhaust velocity is key.

The whole "racer open header" concept is followed by a raft of other modifications to make it work properly. Take a motor with no modifications other than open headers and it won't run worth a hoot. I tried it. Take the same motor, open headers, open intake, machined heads with modified valves to move air in and out quicker and now you have something. At the same time you will need to modify the spark and timing to compensate for the air changes. Take the same motor, no modifications, but put a nice exhaust on it, it will run sweetly, sound sweetly, and prolly whoop the same vehicle with open headers and no complimentary mods.

 

I didnt realize there is laws of air movement

Think it falls moreso into aerodynamics what your talking about, which Im not so sure applies in this case.
And there is a huge debate about it, that the most experienced of car guys cant agree on. When you have a mechanical mechanism "forcing" air (exhaust) out of spaces, that is where the more air in vs out comes into less play. The mechanical mechanism only works so fast, so thats where it gets argued that an open exhaust type system is better, get the exhaust out as fast as ya can, then you can run more air/fuel producing more power.

Ive personally ran engines without exhaust manifolds on it, and they ran fine, no dofferent, just noisey. Lots of times it was on sleds, motorbikes and smal engines, but we ran a diesel tractor like that to cultivate a field with a short little pipe on the exhaust manifold (exhaust broke right off) and the tractor was loud but finished the field just dandy, with no noticeable difference in performance.

I see what your getting at for gaining performance, but I dont believe it does anything hindering current performance. Exhaust exits an engine through airflow, and air is like water, it will take the quickest most direct route to be efficient. With more air and fuel coming into an engine, a restrictive exhaust will hinder the performance.

There is a whole world of science behind it either side though.

Curious, which motor did you run with only headers on it that ran poorly like that, then fine with a full exhaust system behind that?
Only reason I am so curious, is when I was in my mid to late teens, I used to buy junkers and fix them up, drive them, and sell them, and we ran many with little to no exhaust systems, as well as crappy home made exhaust systems, and I cant remember a single time where the engine ran like total crap, and the exhaust straightened things out. I remember alot of them sure sounded terrible and loud though lol.

 

1983 F150/351W.

Being as you know it all and have done it all, I accept the fact that you must be far wiser than I could have imagined and I won't argue further...

Back to the topic...

Damned weather. I've got these flares here to install, but the trip from the car wash to the garage makes the truck too bloody dirty to put the flares on it. Guess I'll take the flares to the car wash and do it there

 

Guess being as you've done it once, and need to justify things you buy all the time, its probably wise you dont argue it further I didnt realize you or I had a degree in "simple laws of air movement". Ive just built a few engines, and worked on things lots in my life, more then one engine, and am sharing experiences!

Sometimes ya gotta experience things more then read what a manufacturer says on the box of that expensive exhaust ya just bought, besides its just a discussion anyways!

 

It`s hard to keep anything clean here, doing the flares in the car wash maybe the only way...

 

We had an afternoon of sun but it is a long way from dry around here too.

 

Its "dry" here this morning... but just due to freezing, so not sure if that counts!

 

our new street has a 1/2 inch layer of mud on it from dump trucks going to and fro the construction sites... A good freeze would be welcome.

 

Get much more snow down in Yorkton?

It kinda started for a little bit, but most of it melted yesterday so we are pretty much back at square 1.

 

Now the snow is rock hard form melting and freezing, I don`t think that it`s user friendly for skidooing.

 

We had about an inch on sunday night, its long gone with an afternoon sun on Monday. It frosts hard every night though, and leaves us with a muddy mess come afternoon. Stripped footing forms today...90lbs of clay on each foot isn't my idea of a good time. Crush rock heading in there tomorrow should make a cleaner working environment.

 

Almost sounds like you guys could use some rig pads!

 

what are rig pads?

 

Google Image Result for http://www.coastaltimbers.com/piclib/704.jpg

Hope that link works, basically a bunch of huge wooden pads. Thay are awesome, cause they dont sink in the mud like gravel does!

 

These rig pads look pretty heavy and only moved around by equipment.