: Header Theory?



keithsm2
01-27-08, 02:56 AM
What is the theory behind headers?? How do they work ...to create more HP??

lunarx
01-27-08, 04:14 AM
They don't.
The Maggie is what creates more power, not headers.

AAIIIC
01-27-08, 06:02 AM
They don't.
The Maggie is what creates more power, not headers.
:confused: Did you forget a smiley to indicate that you were joking?


What is the theory behind headers?? How do they work ...to create more HP??
Put simply, an engine is an air pump. If you can reduce pumping losses then the engine doesn't have to work as hard to pump air through itself. Freeing up the intake means it's not as hard for the engine to suck air in. Freeing up the exhaust means it's not has hard for the engine to pump air out. In addition, properly designed headers are tuned to optimize the scavenging effect, which improves the efficiency of the whole suck-squish-bang-blow process.

rand49er
01-27-08, 07:35 AM
... Freeing up the intake means it's not as hard for the engine to suck air in. ...:confused: You mean so atmospheric pressure can push air into the lower pressure of the combusion chamber created by the piston moving down. :D

Twitch
01-27-08, 08:47 AM
They don't.
The Maggie is what creates more power, not headers.

Yeh, funny guy!

Flyboy
01-27-08, 12:20 PM
:confused: You mean so atmospheric pressure can push air into the lower pressure of the combusion chamber created by the piston moving down. :D
:yeah:
Randy, you amaze me with your intelligence (REALLY). It's like an aircraft wing. We all know there is a "low pressure" on the upper surface of the wing as it moves through the air, but it's ACTUALLY the high (positive) pressure below the wing making it lift.

Good Job Man ! !

keithsm2
01-27-08, 12:24 PM
but why are headers less restriction than original manifold?? more area? also...I understand some back pressure is needed....otherwise NO manifold would be ideal.....so...hows all that figured out??

lunarx
01-27-08, 01:29 PM
Long Tube Headers give the escaping gasses from each cylinder an independent evacuation path.
That improves the scavenging effect which in turn leaves more room in the cylinder for fuel on the next intake stroke.

$2K for headers and exhaust and 25HP
or
$5.5K for a Maggie and 80+ HP.

Maggie is still the more prominent power adder. :lildevil:

Bueller
01-27-08, 01:57 PM
:confused: You mean so atmospheric pressure can push air into the lower pressure of the combusion chamber created by the piston moving down. :D

Yes, your motor is an air pump. Headers help each cylinder work together (scavenge) to pull the exhaust charge out and the next intake charge in at the same time. Shorty and long tube headers are tuned for different rpm ranges. Alot of products tune for peak hp so the dyno peak numbers look highest but suffer greatly in the midrange.:annoyed:

You spend 95% of your time in the midrange area...This is why Rick's Stealth V tune works so well. He tunes midrange and partial throttle instead of just WOT at peak rpm.

Check out this website that explains how a 4 stroke motor works. It is an old website that isn't updated anymore but still interesting. Can't wait for the comments:

http://www.mototuneusa.com/the_8_phase_motor.htm

I also break in any new motor (car, bike, or mower) according to this theory and have had the lowest maintinence and most powerful motors since::yup:

http://www.mototuneusa.com/break_in_secrets.htm

dkozloski
01-27-08, 02:58 PM
Headers are tuned like an organ pipe to present a rarefaction at the exhaust port of the engine in coincidence with the opening of the exhaust valve. There are documented cases of a properly designed exhaust system increasing the power output of a two-stroke engine by as much as 80%. The effects on a four-stroke are much less but still prompt the expenditure of literally millions of dollers in developement. A crack in an exhaust pipe at the header flange can send a car on the racetrack from the head of the field to the rear. The foremost exhaust system engineer in the world is Profesor Gordon Blair Q.U.B. Belfast, Northern Ireland. He is regarded by the Irish government as being a national treasure.

flyinlow
01-27-08, 09:29 PM
Long Tube Headers give the escaping gasses from each cylinder an independent evacuation path.
That improves the scavenging effect which in turn leaves more room in the cylinder for fuel on the next intake stroke.

$2K for headers and exhaust and 25HP
or
$5.5K for a Maggie and 80+ HP.

Maggie is still the more prominent power adder. :lildevil:

What the he** is a Maggie??