What is the purpose of hedders? What do they do for your car?

Question

Do they just help the engine breathe better? I have no idea. Thanks.

Is there a chance if you install hedders that it might make you fail the gas/exhaust emissions test?

Answer 1

With most exhaust manifolds, the exhaust gas comes out of the engine and has to make several 90 deg turns, while trying to squeeze through a small opening into the pipe below. This costs H/P.

With headers, the gas comes out and makes gentle curving turns and then flows through a large opening into the pipe (collector) or directly into a muffler or converter. As the gasses reach the end of the tube, it pulls (scavenges) gases from the OTHER tubes with it, which helps the engine. The header tubes SHOULD all be equal in length so each cylinder does the same amount of work getting the gas out.

This may not seem like it would matter, but it does, if you are asking a engine to perform at it's potential

A good C.A.R.B. approved set of stainless headers will last almost forever, and the cast iron ones often crack and have to be replaced.

Answer 2

All you guys who think cast iron exhaust manifolds are the hot set up saw one apart sometime and see the unequal length runners, small diameters, tight bends and bulges for mounting studs and bolts. Small wonder engines run hot and suffocate at high designed rpm.
Many car companies offer dual catalytic converters, one per bank of cylinders. Why not feed the converters as efficiently as possible. The whole concept is tuning every port and pipe weather it may be the stepped design or the same diameter till the exhaust reaches the respective collector where the exhaust is scavenged out of a neighboring pipe inside the diversion cone to the collecter. A properly designed set of headers are worth 25 - 35 rear wheel hp. on any V8 engine.

Answer 3

Is a free flow exhaust system, They are use on racing engine. For street purpose is more of a waste. The increase is neglectable. Some might disagree with me but is pretty much true. Think on nickel and dime your efforts. You might get a 5% increase from heaters but you will not noticed that. Now add another 10% from an induction system, 10% more from a computer remap and bingo, you have 25% now you can say wow. But just headers alone... is just a waste. You have to match the intake and the exhaust to make it right.

If you are looking for more power, a computer remap can do wonder without removing a single piece of hardware. If you do not like it, you can come back for original settings. Beside, engines are tuned for the best fuel consumption, with the highest amount of power within their fuel economy with the best driveablility. You mess with any of that, you have to give some.

Answer 4

Exhaust Headers are a replacement for the factory exhaust manifold. Headers are simply a more efficient way of getting rid of the exhaust more quickly. They attach directly to the head and end somewhere before the catalytic converter. The faster you can get exhaust out and freash air and fuel in, the better the engine will run and the greater it's potential for making power will be.

Answer 5

Headers increase exhaust gas flow from your engine. You'll get more power if the engine breathes better, tho this may not be that simple on fuel injected motors. Yes, headers will affect emmissions readings, and it is illegal to modify exhaust systems in some places.

Answer 6

Yes, a free flowing exhaust path gives your car more horsepower, but modern auto computers are calibrated for certain back pressure in the exhaust system. The legally required catalytic converter will just impede the exhaust gas flow anyways, so I don't recommend headers except for racing cars.
Adding a dual exhaust system could help if your car has that option.

Answer 7

Ever tried to breathe through a small straw.

Now try a bigger one........

ADDED:
They should NOT affect the emissions gasses unless you have air injection that has modified. (late 1970s to mid 1980s)