exhaust headers..

[vikid]

I feel this is the best and easiest / well affordable / effective mod.
Exhaust headers are often made of steel or lighter weight aluminum. Headers are designed to improve an engine's performance by allowing exhaust to flow more freely or by tuning the exhaust to enhance performance during a specific engine rpm range. Some headers also have a scavenging effect, which means they help pull exhaust gases out of the cylinder heads to improve performance. Many headers are available with a ceramic or other high temperature coating.

The idea behind an exhaust header is to eliminate the manifold's back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. These pipes come together in a larger pipe called the collector . The individual pipes are cut and bent so that each one is the same length as the others. By making them the same length, it guarantees that each cylinder's exhaust gases arrive in the collector spaced out equally so there is no back pressure generated by the cylinders sharing the collector

During the exhaust stroke, a good way for an engine to lose power is through back pressure. The exhaust valve opens at the beginning of the exhaust stroke, and then the piston pushes the exhaust gases out of the cylinder. If there is any amount of resistance that the piston has to push against to force the exhaust gases out, power is wasted.

In a normal engine, once the exhaust gases exit the cylinder they end up in the exhaust manifold. In a four cylinder or eight cylinder engine, there are four cylinders using the same manifold. From the manifold, the exhaust gases flow into one pipe toward the catalytic converter and the muffler. It turns out that the manifold can be an important source of back pressure because exhaust gases from one cylinder build up pressure in the manifold that affects the next cylinder that uses the manifold.

Now question - Why do factories roll out veh with manifolds and not the headers??? can someone from the gang throw some light.?? 8) 8)

[iguana]

Nice post Vikram.

Now an answer to your question is that Headers and bigger exhaust will make higher noise ... an manufacturer would like to keep the cars quite

The other thingis emission control as well. Thats why headers and cat back does not pass the traffic test

[vikid]

Nice post Vikram.

Now an answer to your question is that Headers and bigger exhaust will make higher noise ... an manufacturer would like to keep the cars quite

The other thingis emission control as well. Thats why headers and cat back does not pass the traffic test

Noise !!! no.. it purrs and is so soothing to the ears.. 8)

one could follow the firing order..

[Bulldozer]

U can tell that to Traffic dept when renewal coming

[Dee See]

Exhaust headers are often made of steel or lighter weight aluminum.

Some headers also have a scavenging effect, which means they help pull exhaust gases out of the cylinder heads to improve performance.

Many headers are available with a ceramic or other high temperature coating.

Now question - Why do factories roll out veh with manifolds and not the headers??? can someone from the gang throw some light.?? 8) 8)

Most definatly not made of aluminium! Mild Steel cheepies...T45 Stainless Steel is good a strong or inkanel as is used on the F1 cars.
I have a picture of my engine on a dyno rig in UK where the exhausts are glowing red hot under the load! Cool pic.

The scavenging types are known as extractor manifolds. I have these on my 130. Cost a small fortune...made of T45 Stainless Steel in the UK.
Extractor manifolds are designed to speed up the spent airflow of exhaust gases hence allowing more fuel/air mix in again more quickly.

Ceramic coatings are superb. Developed by NASA for the space program...you can touch them within a second of the engine being turned off! Ceramics don't conduct heat and yet can withstand temperatures that would melt normal steels.

Why don't cars come with headers from the factory?.... price mate. Most vehicles come with a cast iron primary stage manifold. Headers/extractors etc are hand made on a jig which takes time and money.

Regards.