Exhaust ypipe

[Stevo69]

Can anyone tell me why an off-road ypipe (from jegs) would install easily on a 99 silverado z71 ext cab w/5.3£, but wouldn't on a 2005 tahoe z71 w/5.3?

Why do I ask? 1st, because cats suck. 2) They've worked great on my other trucks in the past. 3) My stock ypipe is getting kinda roaches.

The pipe in question on jegs website is listed as fitting 99-02 silverado. However, I really don't see why it wouldn't also fit 99-06. For $189, it is so worth it.

Anyone....?

 

[z71hotness]

I'd like to know also

 

[drakon543]

i could be very wrong but ill toss it out there anyway because something relating to this year range was mentioned to me once. i believe the early version of the 5.3 tuning would allow the truck to run fine without the cats but you will get a cel. the later years wont run right without the cats in the system due to factory tuning. probably something stupid gm put in place to stop people removing cats.

 

[DRKN57]

That sounds right. I think I read that somewhere too.


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[Snowbound]

There is nothing in the exhaust system to tell the PCM if you have cats or not besides the post cat O2 sensors. If you put an off-road non catted y-pipe on and turn off the MIL for both B1S2 and B2S2 you won’t get any codes. But you also need to turn off the heated S2 codes on both also.
Option 2 without tuning is keep the post cat O2 sensors but get them out of the exhaust stream by using a O2 fooler. It’s a 90° elbow so the tips of the sensors aren’t directly in the pipe. I’ve heard mixed reviews about them. Some say they work and no engine light and pass emissions, others say they got low efficiency convertor codes.
Tuning it out is the best option.
As far as fitment I can’t offer any info. Not sure why it wouldn’t work. I believe some are separate pipes going to the muffler and some merge the 2 banks before the muffler.

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