exhaust setup...Back pressure

[87WhiteStang1]

I want to redo my exhaust. I want to go with the BBK 1 5/8 Ceramic coated long tubes, BBK offroad X pipe and Mac Pro dumps(pre-axle)... my question is will i have sufficient back pressure with this setup? my car is pretty much stock 302. Also if you have any better reccomendations let me know. Thanks

 

[stykthyn]

I hate the word back pressure, what you want is flow. when you go with a system that is too large it causes turbulence which will in turn slow down the gasses leaving your pipes. to answer your question though, you should be fine with that set up.

 

[mwood]

Assuming you don't have to worry about emission standards, let the exhaust flow. Why else would cars with open headers run faster? Good night, you ever see top fuel with 1 inch pipes?

 

[NIKwoaC]

I hate the word back pressure, what you want is flow. when you go with a system that is too large it causes turbulence which will in turn slow down the gasses leaving your pipes. to answer your question though, you should be fine with that set up.

+1000000000

"Back pressure" is this abused hillbilly misconception that won't seem to die. When it comes to exhaust systems, you want the best flow and velocity possible in order to scavenge the highest amount of exhaust gasses from the cylinder as possible.

That setup will be good for your car, but I would suggest you avoid dumps if you want to enjoy driving the car. Dumps should be saved for track-only cars, they are noisy and you'll have fumes creeping in through the windows when you're sitting in traffic.

 

[stykthyn]

Assuming you don't have to worry about emission standards, let the exhaust flow. Why else would cars with open headers run faster? Good night, you ever see top fuel with 1 inch pipes?

does he have a top fuel dragster?!!? no he has a stock 5.0 that is lucky to push 200 to the ground. if you want your car to sound like a garbage truck go ahead and run open headers.

 

[mwood]

does he have a top fuel dragster?!!? no he has a stock 5.0 that is lucky to push 200 to the ground. if you want your car to sound like a garbage truck go ahead and run open headers.

Was trying to make a point, not suggest he run open headers or has a topfuel. Nowhere in racing to find this theory of back pressure. No reason to run smaller exhaust or try to create back pressure.

 

[stykthyn]

your not creating backpressure, you are encouraging flow or "exhaust scavenging" if you want to sound fancy about it. if he was laying down over 1k horse and spent all of it with the tach pegged out then sure I would recommend open headers.

 

[mwood]

This is simple. Your piston creates the presure to intake air/fuel mix and output exhaust. The bigger more open flowing your heads and headers, the more hp you will make. Why do you think you find 408w's on ebay with little procomp heads advertizing 475hp while people like Jay Allen or Jim Woods build 408's with larger ported canfields or trickflows and 1.75+ headers pushing 600hp or more. Simple answer: flow. Still not sure, try drinking a malt through a coffee straw. Let your engine breath and it might take your breath away.

 

[stykthyn]

so now we are comparing a built 408 to a stock 5.0