Okay well recently i had to take one of the headers off the car to replace a gasket since I had the y pipe off after i installed the header back on the engine --- i decided to start my car up to see for the hell of it what it would sound like with open headers before i had put the y pipe back on. It was awesome... shook the whole garage... so i for the hell of it i wanted to run it around the block... car was idling fine too it around the block got on it alittle ran okay... kept driving it staying close to the house got on it again and it started missing on mid rpm... seem like the idle was acting up as well after i got on it and slowed down... drove it back to the house... started it back up again and the idle was fine again... rev it up didnt seem like it was missing.... this was with longtube open headers.... Im thinking could it be the o2 sensors causing this since there close to the end of the header... anyone have this problem...??? The car is a 95 z28 built 383 supercharged longtubes.... i already have a borla exhaust with a cutout installed by the inlet but its no where as loud as todays start up... Reason i ask is because i wanted to run dual cutouts near the the front off the headers... i really hate to spend the money if this is always gonna perform like that when driving with the cutouts open.. i just want the cutouts for like car shows,,, and maybee getting on it here and there on the road...i read it might be because 02 sensors, backpressure needed,,, needs to be tuned for open headers,etc,etc please let me know

 

Yes, the problem is that the O2s are too close to the opening of the exhaust.

The sound of the inevitable exhaust leaks from having cutouts will get old faster than the novelty of open headers.

 

Don't need back pressure.

 

Backpressure is needed in order for the blower hot air to mix properly with the hot exhaust gasses. Otherwise it will never spool and hit VTEC.

 

So there is no way I can run open headers without having my car act up... not gonna run them all the time.. like I said just here and there for car shows or cruises... but like I mention it was acting up like it wanted to stal out on me last time after driving for a couple mins

 

Burnt plug wire for the miss and get cutouts.

 

When I was younger and had no money I ran long tubes with 6 inches of pipe welded to them and honestly never had any issues.

 

As mentioned, it's likely your O2s are too close to the outlet of the header flange so it's going to mess with the fueling. If you want the sound you are looking for, just do a single cutout before the muffler and be done with it. There is a good spot on the I pipe before it goes over the axle.

 

I ran open headers on methanol for 2 years, like others have said the O2's won't work if they are too close.

 

Open headers are super ******* annoying anywhere but the strip. There, you better have a decent setup to be making all that ******* noise.

 

yup

get a cutout. Your neighbors, passengers, cops, general traffic, and the rest of the world will thank you. Don't get me wrong I love the sound of open exhaust, but I love being able to choose when it's open much more.

 

You need 15-18 " of pipe from the 02 s and opening be it open headers or open cutout to allow the 02s to read rite.

On my car I needed to lower the shift point on the 2-3 shift. down to 500 rpm ( to 6300) below the limiter ( 6800) 1-2 shift set at 6500 as it wrapped up a little faster when open exh.
my 02 Johnny

 

I mention it was acting up like it wanted to stal out on me last time after driving for a couple mins

 

I ran cutouts after the long tubes for about a year with e-cutouts. It was awesome to dial up the noise any time I wanted. The downside is that they hung super low to the ground and the e-cutouts can break if you tap one of them on the ground. If you don't plan on running e-cutouts, removing the plates by hand is even less fun. Clearance is tight and I couldn't get the top most wing-nut on the driver side, so you'll probably have to carry a wrench or socket to get them off.

In the end, I went with homemade true duals. I didn't lose anything in the 1/4th - comparing open LT runs vs true dual runs. IMO, you get a better sound quality out of true duals and have 90% of the volume.