Open Headers

[Superium]

Whats the positives and negatives of running open headers opposed to being connected to a 2 1/2" catback exhaust system? ie. mileage, hp, high and low end torque, engine wear, etc.

[Tanya]

well, you could burn out the valves/seats I believe...
my stock exhaust one time fell off right after the downpipe, and the car WOULD not hardly move, was louder than hell. No low end torque whatsoever

[SilverMk2]

I think the law and your neighbors are going to be your biggest problems. My neighbors didn't like me driving around the neighborhood with just a small exhaust leak in my car not even at 1/4 throttle.

[Push]

Currently running open downpipe in my Cressida with Pacesetter headers. The car is loud as hell, I wouldn't recommand it if you live around an area were cops hate loud cars. Top End is improved, but bottom end sucks. I should just put my HKS catback system back on.

[Dave A.]

I wouldn't recommend running just an open header w/o some way of extending the collector and tweaking the backpressure. The backpressure most likely drops when you disconnect the exhaust system, and the valve timing on the 5M/6M/7M may not like the drop in pressure until you get up high in the rev range. Plus, it would be very LOUD.

The exhaust gas flow at the open collector w/o an extension pipe is probably pretty erratic at lower RPM and might possibly cause some reversion to occur until you get up in the rev range. The reversion of the exhaust gases is what can potentially overheat the exhaust valves as well as disrupt proper flow.

[Superium]

Well my neighbors hate me enough. I do have the collector pipe attached to it but since it was 5" short from the cat I figured Id set off a few car alarms around the block and give the good ole neighbors a preview of whats to come in the spring. I did notice the car did improve top end performance but no bottom end power at all since I cant spin the tires.
I will probably fab a 5" pipe with flanges on each side so I can take it off whenever I feel like it or just lose the whole cat and make a 17" extension or maybe do both and test the differences.

[dannymk2]

if you just want to piss off your neighbors run a pipe connected to the header out the side ir back of the car. it will give some backpressure and still be loud as hell.