Will a side exit header on my b18c5 create enough backpressure? Right now I'm in the build-up process so my motor is mostly stock but I don't plan on running a side exit header until it is built. What do I need to do to run one? Is it necessary? Will running one ruin my engine a lot faster? Any help would be appreciated, Thanks

 

almost every car in the all motor/pro-stock class use side exit headers

 

[shamless plug]The October issue of OverRev has an article all about the myths of backpressure. [/shamless plug]

Now, that said, you dont want backpresssure. Backpressure = the devil (or at least one of his lieutenants) . What you want is flow velocity.

The headers in AM/PS are tuned-length, usually custom built for an individual motor. That said, it all depends on what you are doing with the car and how the motor is built.

 

i once heard bisi say that thier is a horse power gain from running under pan.

the air under the car (idealy) flows faster than the air on the top of, or the side of the car and therefore creates a lowpressure area under the car that flows from front to back.

your exhaust is "encouraged" to migrate from the high pressure of the combustion chamber through the header, to the low pressure area under the car more so than it is to an area of slightly higher pressure, such as on the side.

i dont recal how much power he figured that it is worth, probably only like two or three, but i wouldnt second guess anything that he says about NA power

 

thats my limited understanding f it, someone feel free to correct me if i am explaining it wrong

 

Wow, that's an interesting concept...Additional scavenging through Bernoulli's principle. Hmm...

 

Well my concern was burning up valaves and pistons. Of course this information was given to me by a v-8 guy but he knows a thing or two and since I'm new to these engines I was curious if I'd be rebuilding my engine all the time because I don't get enough backpressure. Thanks for the posts

 

yah thats about right it bernollies equation and some fluid dyanmics,
(basic physics)

 

i have heard of the burning up valve scenario, but i dont know if there was ever any truth to it. from what i've heard others say it is hype.

 

If the car doesn't run lean as a result of switching the exhaust, then I don't see how you could burn an exhaust valve. A carb'ed car might be sensitive to open headers vs a more restrictive exhaust, but that shouldn't be an issue with an EFI car that's not totally screwed up.

 

Is anybody running a side exit header that can tell me from experience the pros and cons?

 

the biggest pro is it can be made to fit alot easier then having to run it under the pan. another big thing is its ALOT quieter inside the car. other then those 2 reasons its really a personal preference.

 

Please don't say the "B" word haha.. Most do not understand it . High undercarriage pressure is a plus Wonder what that concept relates to... Simply running it underneath the oil pan does not necessarily mean that it will produce results.

I guess there really are more then two reasons