Hey guys some of you may know about my current exhaust setup. I have true duals with no cats, 18 inch glasspacks, and 18 inch tips. I am looking into getting a couple high flow cats because I get pulled over all the time for it being way too loud. It is VERY loud. What cats should I get? Any ideas? I mainly want it to be Magnaflow and it has to be high flow. Also I have been having idling problems ever since I got the exhaust. My mech. Teacher says it's because there is only 2 o2 sensors in the whole system and they are in one pipe. There are none in the other. So my other question is if I got cats and had 2 more o2 sensors drilled in, would it run better? What it does if you let it sit in park for oup to 10 minutes it will start to idle very low at like 200 rpm's and gives off a terrible odor and then gives off a really loud hissing sound from the throttle body. Help!!!!

 

If you want to quiet it down and have great performance exhaust flow, here is my plan for a single 3" exhaust system - using the stock Y-pipe, cut it off just ahead of the existing catalytic converter - then install Magnaflow Converter - 99047HM (dual 2" inlets, 3" outlet, front O2 sensor port) - add a section of 3" pipe from the converter to the muffler (also be sure to add a O2 bung in this pipe for the O2 sensor, just behind the cat - add 3" muffler (Dynomax UltraFlo Welded Muffler - 17233) and then add a 3" tailpipe to exit behind the rear tire.

 

I have true duals with 12" glasspacks so I know how loud it is . Gotta keep it under 2300 rpm's in town. Not sure where you're mechanic teacher came up with it running rough becaue of the O2's. Mine are both in the pass side exhaust and I have no problems at all. You couldn't exactly add another O2 sensor very easily either. Personally I wouldn't spend the $ on cats- they aren't cheap. Would be cheaper to get 2 different mufflers or add 2 more glasspacks to quiet it down some. Have you tried cleaning the TB, IAC? Any codes?

 

What diameter pipes are you using? 2.25 to 2.5, anything bigger with true duals won't flow well, unless your pushing 500 hp. Like trying to blow a candle out from 3ft away with your mouth wide open. 02 setup sounds okay. Your PCM wouldn't know what to do with data from two upstream sensors? After you figured out how to wire them into the circuit? Just a thought, but maybe your IAC can't get enough air coming in compared to what's going out.

 

Teach better familiarize himself with your vehicle... 1US and 1DS O2 is standard for '98.

Whilst stock they both see gases from both banks (both after the Y-pipe), my current setup only reads the RH bank on the US, and both on the DS because of the LT headers pushing the Y-pipe further back, but this has not caused any issues.

 

I am glad you know my pain! Haha. Yeah I knew that cats aren't cheap and also kind of figured that it would be quite difficult to add more o2 sensors. And that makes me happy that I am not the only one out there with just two o2 sensors In one pipe. I have ran seafoam through the intake and I have opened the flaps and looked in there in it is rather clean. The flaps are a little black though.. And IAC?

 

The diameters are 2" from the manifolds to 2.5 all the way to the glasspacks and after the glasspacks it's 2.25 to the tips.

 

Yeah that's what I thought also. LOL I think he just says that it's causing problems because he thinks it's too loud. Lol

 

IAC = Idle air control. Search this site and there are a lot of tutorials on how to clean it.

 

Okay. I will check it.