I read the back pressure article and i still have a question. What is the effective back pressure diamiter? Would it be equl to the exaust ports total diamiter? meaning... at the start of the exaust, just past the exaust valve, the total diamiter, lets say 1" multiplyed by four, should be equal to the end of the exaust diamiter(4"). WOuld this be the case or would a slight decrease in diamiter be nessisary?

 

It would be a decrease but Im not sure how to figure it out. It is a decrease because the cylenders all spend exhaust at different times so they do not really fill the entire pipe at the same time, kind of.



I think.

 

I didnt even think of it that way... its probably calculatable by using the volume of each cyclinder, diamiter of pipe, compression of the gas and mabye a few other variables..... the compdression of gas may have a direct effect on the velocity of exaust flow.

 

im not really sure how you would figure that out either. thats a great reason you DONT buy the cheapo ebay headers.

 

what i want to do is go 2" all the way out. i have a stock civic and it turns down to 1-1/2" after the cat, i am trying to figure out how it will effect my engine, not performance wise but livlyhood

 

i have also noticed on funny cars that they have strait pipes coming out of the engine

 

whats the difference between the dc header on e-bay & the one they sell in summit [about $1oo? ]i got a 97 with a cracked manifold & was gonna replace it with a header from e-bay ---good idea ?

 

the reference to ebay is talking about the "no names" that they carry; not a known name. I bought my intake from ebay and it's the same injen that you would get anywhere else just about 75 bucks less. It even still have the manufactor seal on it unbroken. Just remember the saying "you get what you pay for"

 

make sure its a DC Sports header, not a DC-S header. thats a cheap rip off brand.

 

lol they try what can i say