Anyone ever ran an open header at the track?
 

You see alot of the muscle cars and big displacement engine owners doing it. Anyone here ever done it on their Hyundai? Better or worst track times with it?

Worst. You need backpressure.

Negative. You need a well-engineered exhaust and backpressure is your enemy. This is not even open for debate.



Result #2 on a well-phrased google search:

http://my.prostreetonline.com/forums...php?t-1639.htm

I'm not even going to get into it, but tanc is right.



Your not trying to "gain" back pressure, but you need 1psi +/- for optimum flow. and to help pull the gases out of the runners.



Stop believing everything you see on your Google searches

Look, you guys are free to be wrong if you want, but backpressure in an exhaust pipe is not what you want. Google results are handy for informing the uninitiated, not for my own education ;)

Seems like you misunderstood my statement.



Stock exhaust manifold, you need back-pressure. Ebay exhaust manifold, you need back-pressure. Unless your spending $1500 to have a custom engineered manifold that is flow-tested, dyno'ed etc to run open dump, do not run open dump.



Go to the track, get any manifold available for our vehicles. Do a run with free-flow exhaust, than one with no exhaust. Let me know what happens. Heck, even go to the dyno. We don't drive big displacement engines, we've the displacement of a pop bottle.

Nothin pisses me off more at the track than when some doucher runs a open exhaust......and runs a 15 sec quarter

It's not that you need back pressure, you need velocity and ideally some scavenging. It is often true that an exhaust system with more back pressure will make more power, but it is not because of the back pressure.

Hasn't that myth been killed yet? Power loss from less back pressure is either a tuning issue or from loss of scavenging. read p 3-4 Backpressure: Friend or Foe?

187sks nails it