Why get aftermarket headers?

A combustion engine's main product is horsepower and torque, it's by-product is exhaust.
In order to be competitive in today's economic market this factory needs to produce torque efficiently. It has to use it's main ingredients of gas and air wisely and be able to rid itself of byproducts efficiently.
Exhaust is a by product of the explosions that are produced over a thousand time a minute in your engine. It is vented from the engine by way of the exhaust manifold through the catalytic converter, through the muffler and out of the exhaust.
Getting back to the engine for a minute, for it to be efficient it has to get rid of this exhaust quickly. Why? well inside your engine are things called pistons they suck in air and gas and spew out exhaust, while there trying to spew out the exhaust the exhaust ahead of it is trying to get out of the way, but it's having a bit of trouble. Instead of the pistons spending all their gas and air on producing torque there wasting a percentage of these resources because the back pressure of the exhaust gas is pushing back on the pistons. If you could reduce the back pressure you could increase the horsepower. This is where exhaust headers come into play.
Replacing the stock exhaust on your car with a sport or racing exhaust system will not only increase horsepower (6-18hp), but will also assist to give your car a more aggressive look and sound.
The average amount of Horsepower gain is around 8 to 14. It depends on the quality of the stock header your replacing.
Most high-end header companies tune the resonance of the header to create a pulse wave to suck the exhaust gases out, creating a more efficient exhaust scavenging which is really important in header design.
Headers are designed in different exhaust ratios from low end performance to high end performance. If you do a lot of city driving or if you want better take off when pulling a load you'd want a header tuned for low end performance. If you want better performance for the open road at high speed you'd want a header tuned for the high end.

Jegs.com

http://headers.com

summitracing.com

Heres one for those of you that take your trucks and suvs through deep water. The best way to make sure you dont damage the motor by getting water in it is to put a snorkel on. This way the level in which the water would have to be to kill the engine is above the hood or even roof.

Most everything you need you can get from your local hardware store. The parts you need are:
3" PVC right angles
3" PVC 45 angles
3" ABS pipe (Like PVC but weaker)
4" air hose for a air cleaner (Like dryer vent hose but stronger) Get this from local auto parts place
PVC pipe glue
A tube of caulk

Tools
A cut off wheel
Caulk gun
Drill
1/8 drill bit
metal file
Chop saw
1/8 metal screws

Installation:
Your first step is to cut a hole in the fender. use a cut off wheel to do this.

Now set up how you want the pipe to run from just inside the hole to where ever your external location will be.

Make sure the air cleaner is sealed with caulk so absoleutly now water can get in it.

To make the snorkel hose, it needs to be attached it to the air cleaner housing. Cut a piece of ABS and push and it over the housing. Drill a 1/8" hole through the ABS pipe and the housing. Screw it into place. After you have the ABS screwed into place you need to seal it. Seal all the way around the pipe and the housing. You also need to seal around actuator for the hot air intake as well.

After you get all the joints lined up and marked, install it on the truck to so you know the cuts are correct. Before it's glued together you need to wipe all pieces with a mild paint thinner. Be careful the paint thinner will eat the pipe so don't soak it. Next, you will need to sand it down with a piece of gray scotch-brite so the paint will adhere on the plastic. Before you paint use the caulk to seal the joints so there's no air leaks.

The distributer cap should be sealed with the caulk as well. Just run a small bead on the inside of the cap. You will have to replace it just about every time you change your oil. If you don't you will get carbon build up on the terminals.

The tranny and oil dipsticks need to be sealed.

use the 4" tube to conect aircleaner to external pipe.


http://www.powerblocktv.com

The Definition of Horse Power

How do you define horsepower? Ask a car enthusiast and most of the time you'll get a blank look, a shrug of the shoulders and maybe a guess along the lines of "What a horse can do!".

That answer begs the question: What horse? A thoroghbred race horse that can carry the small weight of a jockey with a lot of speed, or a working horse that can pull heavy loads albeit slowly? Obviously there is a more precise answer. Car manufacturers, despite their reputation for being creative regarding the horsepower ratings of their products for marketing reasons, require a more stable definition.

Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy.

Even more interesting is how the definition came to be. It was originated by James Watt, (1736-1819) the inventor of the steam engine and the man whose name has been immortalized by the definition of Watt as a unit of power. The next time you complain about the landlord using only 20 watt light bulbs in the hall, you are honoring the same man.

To help sell his steam engines, Watt needed a way of rating their capabilities. The engines were replacing horses, the usual source of industrial power of the day. The typical horse, attached to a mill that grinded corn or cut wood, walked a 24 foot diameter (about 75.4 feet circumference) circle. Watt calculated that the horse pulled with a force of 180 pounds, although how he came up with the figure is not known. Watt observed that a horse typically made 144 trips around the circle in an hour, or about 2.4 per minute. This meant that the horse traveled at a speed of 180.96 feet per minute. Watt rounded off the speed to 181 feet per minute and multiplied that by the 180 pounds of force the horse pulled (181 x 180) and came up with 32,580 ft.-lbs./minute. That was rounded off to 33,000 ft.-lbs./minute, the figure we use today.

Put into perspective, a healthy human can sustain about 0.1 horsepower. Most observers familiar with horses and their capabilities estimate that Watt was a bit optimistic; few horses could maintain that effort for long.

Although the standard for rating horsepower has been available for over 200 years, clever car manufacturers have found ways to change the ratings of their engines to suit their needs. During the famous horsepower wars of the 1960s, manufacturers could get higher figures by testing without auxiliary items such as alternators or even water pumps. High ratings backfired when insurance companies noticed them and started to charge more for what they saw as a higher risk. Manufacturers sometimes responded by listing lower horsepower figures, forcing enthusiasts to look at the magazine test reports to determine what was going on. In the early seventies the SAE (Society of Automotive Engineers) stepped in with standardized test procedures and the fiqures were more consistent.

Between 1922 and 1947, the Royal Automobile Club used a horsepower rating that was the basis for an automobile tax. The horsepower of an engine was determined by multiplying the square of the cylinder diameter in inches by the number of cylinders and then dividing that figure by 2.5. Using this dubious method, What we know of as a 385 horsepower motor found in the 2001 Z06 Corvette would be rated at only 48.67 hp!

There is a metric horsepower rating, although it is rarely used. The two methods are close, with one SAE horsepower equal to 1.0138697 metric horsepower.

One mechanical horsepower also equals 745.699 watts or .746 kW (kilowatts) of electrical horsepower. This means that if you really want to confuse people, you could complain about the 0.0268 horsepower light bulb your landlord has in the hallway as opposed to the mundane 20 watt measurement