Is it bad for the engine to run open headers? I was told that the exhaust valves need backpressure to fully open properly and that open headers won't provide enough. And if this is true couldn't I just buy new rockerarms or weaker valve springs? Very possible that this is a dumb question.

 

on a stock motor you'll get what we call O2 reversion. It'll make your car think it's lean as **** and add fuel like a **** and make yer car run like total crap... Some bigger, high flwoing motors and FI setups are able to keep the O2s lit and oscillating nicely, but you can still get false readings from air dancing right around the primaries and screwing with A/F mixtures at the point of the O2 sample. If you're going to run open headers, at least get a minimum 6" extension. That should help a bit...

Backpressure is very important for holding motor vaccuum, something a lot of people don't realize... Some peeps are like, "dang man! My car's loud!" but anyone should know loud does not equal fast. Unloading backpressure means motor vaccuum is weaker and you're effectively working against the assisting of combustion.

As far as weaker springs... I'm not sure why ANYONE would want to diminish the strength of their valvetrain. Tell me if you know anyone who likes to drop valves?

 

When I was putting headers on, I stated it up with a open headers a couple of times. I just made sure the o2 sensors where in good. I had no problems at all - sounds mean as hell. Some people here have drivin around with open headers for a pretty good amount of miles with no problems either.

 

Ever see mufflers on a NASCAR machine? They run 500 miles wide open and their valves live quite well.

I ran a car with cut outs for years w/out valve problems.

Not a dumb question. But the answer is: It's OK mechanically. Now what it might do to an O2 sensor, I don't know. My race car was pretty low tech.

 

Do yall think it would be ok if I had a cut out after an off-road Y-pipe?

Thanks for the help.

 

haha, dude please... those cars dont have mufflers but they have a tuned exhaust system.. they are made to be as free flowing as possible w/o infiringing on the rules and yes they do have some back pressure. you can have a mufflerless system that has back pressure. for the valvetrain, they tune the valvetrain for every individual cyclinder... so they might have a motor where all the springs and rockers are different..

 

NASCAR's run boom tubes if I am correct.