Heard a lot about straight pipes in the 96 and was looking for a little bit more info about it

 

Well...what information are you looking for. A straight pipe will be loud as hell and offer no performance benefit.

 

If you're talking about replacing the catalytic converter with a straight or "test" pipe. It's illegal as all get out. It will mess with your computer and won't increase power. Keep in mind messing with the emissions system is a Federal offense and if you have emissions testing, it will fail the visual test even before they hook it up.

 

Never straight piped my 3.9, but I did have a flow master 2.5" single in with duel 2.25" outlets that sounded V8ish at idle, anything above idle it was v6ish sounding, and loud. Got pulled over 3 times twice by the same cop in a 3 month span. Straight pipe will only make people despise you for straight piping a v6, lol. I think they are worse than the ricers with they're straight piped Civics, like that annoying bee that circles your head while your trying to work. There's loud, and then there's obnoxiously loud that makes you Target for cops. It's your truck, so do as you wish. Race cars have straight exhaust because they run wide open throttle where the straight pipe ads power that's it, at a much higher rpm than that 3.9 will ever run. 3.9 is built for economy. If anything take it to muffler shop and do what I did shouldn't cost much more than $200 and it'll still sound decent for a v6. It'll get louder as the muffler breaks in from all the heat and cold cycles.

 

Removing the cat doesn't affect your computer or tuning. The o2 sensor for you air fuel ratio is before the cat, removing it does free up some exhaust flow, but I would still recommend some kind of muffler, the v6 sounds terrible when its completely straight piped.

 

96 is the first year of OBDII, where there is a sensor behind the cat as well. It doesn't have as much of an affect on mixture/fuel economy, but, it does have some, and if the cat isn't there, the PCM tends to whine about it. I don't *think* that prevents it from going into closed loop though.

 

The sensor behind the cat has nothing to do with the air to fuel ratio, all it does is monitor the cat and set off a CEL if something is off.

 

Rumor has it that it will also SLIGHTLY alter mixture to get the cat to warm up faster...... Likely nothing you would notice in your fuel mileage calculations though....... I can't find any hard info on it.

Still and all, no cat would tend to set codes, though, it seems the 96-97 OBDII versions aren't quite as finicky about it as the 98 and up guys are. My 96 had a hollow cat, and never set a code.

 

Same for me, my '96 blew the cat out the tailpipe, until it completely hollowed itself, and it has never set a code.

 

my 96's cat became all rattley and I cut it out and put a cheater pipe in its place, at least 25k miles ago/ no CEL yet. and it runs as well as ever.....