how do headers work?

Question

how do headers work?

which is better? 4-2-1 or 4-1?

which gives better performance?
which gives more power?

Answer 1

Headers work primarily by reducing back pressure. However, to understand the complex reasoning involved, think of a musical instrument like a trombone: the tones change by moving the slide, which is making the tubing longer or shorter. They also have harmonics at each position, allowing you to play several notes in each position.
An automobile header is similar to this in the respect that each header must be tuned to the engine on which it is mounted. In addition, the header has to be selected for the kind of performance you need. Just as in the case with instruments, a trombone would be hard pressed to hit notes as high as a trumpet because it is "tuned" for a different tonal region. Hence some engines are tuned to run best above 6000 RPM and some between 3000 and 5000 RPM.

In a 4 cylinder engine, as you suggest, (or in a V8 with two banks of 4 cylinders) you want to ask yourself how you are going to use the car. The 4-2-1 or tri Y header is usually suggested for mid-range performance, the 4-1 usually for high end. There are a few exceptions. The lengths and diameter of the pipes are important as they are designed according to the flow of the exhaust port and the engine RPM. Hence it would do you little good to take a full race header and put it on your street car with no other modifications. In fact, you can conceivably lose power by doing this.
The complexity of the exhaust system in general is that each cylinder has its unique exhaust cycle, but the exhaust port of a cylinder may be open when another cylinder is exhausting. This means that each cylinder affects the other in some way. A cylinder's exhaust pulses, like an explosion of air comes from your mouth when you say the letter "P." Tuning a single cylinder is hard enough but when you get into multiple cylinders, it requires lots of experimentation. Those little exhaust explosions tend to affect adjacent cylinders in unforseen ways oftentimes.

Since each engine has its unique characteristics, it is beneficial for you to ask a reputable company which works with your engine what you should use. There are lots of people whose engines produce tremendous power above 6000 RPM who would lose a drag race to a car with an excellent torque curve in the low and mid range.

Answer 2

Headers are designed to allow each cylinders' exhaust to flow with even resistance through each tube in an effort to even out the engines power flow. A cylinder with higher resistance will tend to run weaker than the others on a typical engine, which will affect the vacuum in the intake, which will affect the air/fuel ratio to all cylinders, which will generally reduce total power at different power bands. To get the most from an engine, the exhaust should be tuned to the intake.
Just bolting on headers will help most engines run better, but paying attention to your intake manifolds capabilities and the size of your intake valves will guide you to choose the best headers for your application. The best way is to match the headers' rpm range to what your engine is set up for. A stock engine will work best with smaller headers, while an engine with a big lift cam and larger intake valves will work better with larger tubed headers. Remember than it is all a give-and-take scenario, meaning what you get in high end power will usually take away from idle quality.
Get a book on building performance engines and read it for more info if this is still interesting you as it will give much better data. Have fun!

Answer 3

Headers provide a path for the exhaust that has much less resistence to flow than traditional exhaust manifolds, and they dissipate heat better. As far as which style, it kinda depends on what you're trying to do. Most of them for the street are 4 into 1. If you can, get larger diameter pipes, like 1 3/4 as opposed to 1 5/8, and ceramic coated ones are great for heat dissipation

Answer 4

first off 4-1 work better,, and how they work is really simple they let the engine breath and get rid of its exhaust a lot faster than stock manifolds do,,this increases horse power,,and sometimes helps with fuel economy also,,any time you Can get rid of the exhaust faster it will help one,,as far as power there is not much difference in the 4-2,,and the 4-1 ,,i hope this helps,,i own a repair shop,,and do a lot of this .

Answer 5

4-1 i guess