2016 Silverado-5.3-Muffler Delete done. Should I delete 3rd cat?

[SMID333]

Hey everyone! I love the little bit of added rumble the muffler delete gave me on my 5.3 - 2016 Chevy Silverado 1500. I left the resonator on, as I cannot deal with drone. I am wondering if deleting the third cat will do anything to add a little more sound? Again I think I definitely want to leave the resonator on as I am very fearful of having drone.  Any advice is greatly appreciated!

[CamGTP]

You're not going to notice much of a difference in my opinion. The 3rd cat is just a mini resonator and not worth the hassle of removing.

[KARNUT]

7 hours ago, CamGTP said:

You're not going to notice much of a difference in my opinion. The 3rd cat is just a mini resonator and not worth the hassle of removing.

In my experience when I put loud mufflers on a vehicle adding  small glass packs down stream would deepen the tone. And quiet it down a bit. I left it on.

[SMID333]

Cool thank you both, guess I’ll leave it on.  What about deleting the resonator at the rear? Obviously it’s going to be louder but do you think there’ll be terrible drone? I run a Range AFM disabler so it’s V8 all the time,  so don’t have to worry about the v4 drone but wondering if if get any v8 drone?  Thanks again!

Edited September 1, 2022 by SMID333

[CamGTP]

I have a dynomax system on my truck, so it's just the dynomax muffler with no resonator and I don't have any drone.

 

Never did it with just a muffler delete but it's likely to be the same.

[SMID333]

@CamGTP thank you bud, that makes sense and glad to hear it!

[pokismoki]

if you activate enrichent function in the ECU , I would delete the 3rd cat. 

[SMID333]

I don’t have a tuner but good to know thanks.

[CamGTP]

10 hours ago, pokismoki said:

if you activate enrichent function in the ECU , I would delete the 3rd cat. 

First time I've ever heard anyone say that. I've been tuning my trucks for years, even running E85 and never removed the 3rd cat. Never lost performance or melted down a cat with any modification to the power enrichment settings or commanded air fuel ratio.

[pokismoki]

I've had them melt down before on stock tune, i always figure that GM designed the cats to operate under their lean tune to last the 100K warrantee on this emmissions part.  i would remove it so, at a later date one can reinstall it and it will perform to spec, by not getting cooked with excessive fuel.. its just a thought I had, i doubt anyone will do it , unless they want a higher flowing exhaust

 

better yet take down the factory exhaust dont cut it up,  and buy the offroad system and add your own mufflers

Edited September 3, 2022 by pokismoki

[CamGTP]

What part of the tune in lean though?

 

You have tuning software just like I do, it's not hard to see that they run them rich like they always have since I don't know, forever? Sure stoich was changed to 14.1 for the E10 fuels but these DI trucks run 11's AFR right from the get go, that's not lean at all.

 

Lean would be 13's or higher at full throttle. And there is no lean burn mode on these trucks that are from North America. In fact in many calibration files the Cat Over Temp Protection is actually richer than the commanded AFR at full throttle, the idea is that the rich air fuel ratio will lower EGT's to try and save the cats. At a certain point too much fuel would be a bad thing and start doing the opposite.

 

If you ask me, changing the enrichment settings to a more respectable setting of around 12.5ish AFR would make the cats lasts the longest. It's not rich and it's not lean, so best of everything. Enough fuel to keep the cats working correctly and enough fuel to keep EGT's down. Plus ignition timing is a big factor as well, too low of timing would just be sending fire balls straight into the exhaust and melting them down.

Edited September 3, 2022 by CamGTP