QTEC electric cutout

2k2TahoeSS · January 16, 2003

Thinking about a QTEC electric cutout. It lets you control how much you want the cutout open. Sounds mighty happening to me. What you think, though, about putting it BEFORE the cat? Too loud? Too much loss in lowend power? Thx.

Ben

gandolphxx · January 16, 2003

I added mine after the cats - less hasle with the O2 sensors, same effect - it sounds like the number 5 freight as it is

MiSdIrEcTeD_1 · January 16, 2003

Theres no sense in putting them before the Cats.... Its not gonna get you another 1/2 horsepower, and its not worth going to all the trouble of buying O2 sims to make it work... The idea of having electric cutout(s) is cool though... Makes things a lot less hectic compared to climbing under there and unbolting your exhaust or pulling off cutout caps... Good luck with it and let us know how it all turns out...

2k2TahoeSS · January 17, 2003

What exactly is involved in these O2 sensors? how mch do these doo-higgies cost? Thanks

Ben

MiSdIrEcTeD_1 · January 19, 2003

Unless you are trying to squeeze out that extra 10th of a sec in the 1/4 mile, and are running a MAF tuner or LS1 edit of some sort, spendidng the money on O2 Simulators is not for you.. I dont remeber them being outrageously expensive, but just trust me when I say its more of a hassle than anything especially being that its not gonna help you any... I say if you are set on having the cutouts, buy them and put it right behind the cats like anyone else would... Dont create more problems than you should have to solve...

CMNTMXR81 · January 20, 2003

About $50. You can find them used for $20-30. Kinda pointless unless you are #### bent for loose on removing the cats. Like misdirected, said, the minimal gain you'll get from completely removing the cats and putting simms in to trick the PCM into thinking everything is their and working correctly isn't worth the cost you incurr.

Now if sheer sound is your quest it may be. But personally I don't like the sound of catalytic converterless LS1 engines. Too much raspiness.

You're better off getting a set of hi-flo cats like Random Tech's and leaving your O2's alone.

BigTex · January 30, 2003

MiSdIrEcTeD_1 - sounds like you have been MiSiNfOrMed. If you have cutouts on these LS1 based vehicles and are running cats, you do want them before the cats. Cutouts before the cats have proven themselves many times to provide HP and TQ across the rpm band. You dont need O2 simms or programming either. The rear O2 sensors are in place to verify the cats are working properly and make no difference in the tuning. If you open the cutouts for a WOT blast, then close them up afterwards, the rear O2s will still be functioning as designed.

If you just want a cutout to make everything loud, stick a single cutout after the factory Y ppipe, before the muffler. If you truly want to be a Tahoe "SS", you need them in front of the cats.

MiSdIrEcTeD_1 · January 31, 2003

So lets just say we have a Tahoe, already with dual exhaust, and we buy 2 cutouts, and place them before the cats, (which is right after the first set of O2s) And when these cutouts are opened there isnt gonna be any kind of SES light involved??? Not saying you are wrong, just going by what I have always been told... ???

BigTex · February 1, 2003

As long as you have the cutouts closed during startup and normal warm up time, you won't get the P0141 or P0161 codes. If you open them up for a quick blast, then close them up, you shouldn't get an SES light. Now if you are cruising the local hangout with the cutouts open to attract attention, its more likely that you will see an SES light. If you do happen to set a code, either reset the PCM, or let it clear itself. These codes usually clear themselves if they run their internal tests successively and pass.

One other note - If you squeeze a cutout in before the cats on the factory Y pipe, use some sort of extension pipe off the cutout. Say its a 2.5" cutout, put another flanged pipe off of it for at least several inches. At low rpms, its possilbe for external air to effect the front O2 sensors and cause the vehicle to run improperly. This usually isnt an issue in the upper rpms.

99Silver6.0 · February 6, 2003

Buddy of mine has a QTec on his 02 T/A and it broke after 3 days. Maybe opened it and closed it twice and it stopped working. I had to lose the cats on my truck. Sounded retarded when I took off the muffler and added a Hooker muffler. I actually gained a few HP when I took the cats off.