Ok, point in an aftermarket exhaust header is to allow more exhaust to flow? This then increases torq and horsepower? Quite honestly just dont know what an aftermarket header does that a stock does not. Increase in gas milage? The thread search really doesnt seem to be of much help.

 

an aftermarket header flows better than the stock manifold. The decrease in back pressure increases your torque in your higher rpm band. So basically your engine doesnt have to work as hard getting the exhaust out which causes you to have more power.

 

smoother airflow from engine to exhaust = more power spent going faster than power spent pushing air into exhaust

 

Solid

1. What makes a header Illegal for Street use?

2. Isnt back pressure necessary for the motor to run properly?

 

1. i dont think anything about the header is illegal. you need to have a cat on your DP tho.

2. you will still have back presure. that all depends on how big of pipes you have. i wouldnt go any bigger than 2.5 for dp and catback

 

Reason I ask about the header being legal for street use is because of a description of the weapon R header saying that it was for offroad use only.

 

company's do that so that they can bypass some stupid bylaw for modifying vehicles. we get a ton of corvette's with s/c on them and they all say for off road use only on the blower.

 

Thats how they dont get into trouble for selling it, its a disclaimer so they cant get sued because your car didnt pass emissions tests or exceeded noise etc. The higher flow will also help yea keep engine temps done a little too. Its kinda pointless to do IMO unless your doing your hole exhaust because its only gonna run a smooth as its tightest point.

 

the weapon r is a header/dp and the dp has no cat. thats why it says illegal use.

 

and so are stage 3 comp cams but what cops will ever know???

 

If you are going to do the header also get a downpipe with a high flow cat. This will help with a non raspy noise (unless ur into that) and be street legal. But you will still have a stock exhaust not as big as the header and downpipe restricting some of the flow. So to do it right get the header, dp, and catback system which then u will have no exhaust restriction from engine to tailpipe giving you the most power.

 

I was just questioning the header. I understand all of the other stuff. Just didnt know if it still applied to the header.

One thing I didnt think about is, When replacing these parts, a tune would be necessary right?

psudo Open header w/ 4 highflow cats and 4 mufflers......lol JK.