kxdan01 Posted August 19, 2011 Report Share Posted August 19, 2011 Hey guys is there any advantage to removing my cats, i want the truck to be louder, now i have 2 Flowmaster 40"s welded in place of the stock Dual IN/OUT muffler exiting through the stock tailpipe and tip and it sounds great but i want it a little louder(though i may regret it later but f*** it) so i was thinking about removing the cats and putting straight pipe in their place, ill have a Wheatley 93 Tune to adress CEL and any LIGHT/MIL issues, and im not worried about emmisions or if its illegall or not, will i feel any power or notice any difference at all, good or bad, will it affect fuel economy or power in any way and will it really make it that much louder? Thanks guys and please help me out here, by the way im new here and look forward to sticking around a while, i ditched my Cobra and F150 and got a low mileage immaculate Silverado SS AWD in the Arrival Blue Color a few months ago and im so glad i did, what a cool truck!!! Quote Link to comment Share on other sites More sharing options...
Guest jasonhensley22 Posted August 19, 2011 Report Share Posted August 19, 2011 If you don't have to pass emissions, delete them. If you have to pass, install hi-flows. Best rule of thumb for this "Better flow = more hp" so cats will quiet it down a bit but rob a little bit of power, but not much, like probably 5-10 hp... Quote Link to comment Share on other sites More sharing options...
misterp Posted August 19, 2011 Report Share Posted August 19, 2011 Removing the cats will not gain very much, on a supercharged truck it will gain about 1+ tenths in the 1/4-m. It will make a definite difference in the exhaust, not very much louder but raspier. If you run forced induction, nitrous, or high octane fuel they must be removed or you risk melting them down; on N/A vehicles I would encourage you leave them on for legal reasons, especially if you ever resell the truck the new owner can force you to have to reinstall them (and any other emissions equipment) as a condition of sale. So if you really want to remove them, what I would do is to unbolt the factory Y-pipe and replace with a catless Y-pipe, that way for inspection or resale you can easily return the truck to original condition. Mr. P. Quote Link to comment Share on other sites More sharing options...
ThatTallCanadian Posted August 19, 2011 Report Share Posted August 19, 2011 It'll probably sound like shit tbh if you're running flowmaster 40's Quote Link to comment Share on other sites More sharing options...
The_aSSet Posted August 19, 2011 Report Share Posted August 19, 2011 It'll stink too lol Quote Link to comment Share on other sites More sharing options...
Sssz28 Posted March 13, 2017 Report Share Posted March 13, 2017 It doesnt throw a cel for removing them??? I'm about to do headers but one studs already broke and it's gonna take more time than I have currently. But I want some better sound/mpg. You anyone know who they sound cat-less with stock muffler? Quote Link to comment Share on other sites More sharing options...
SS-GTP Posted March 13, 2017 Report Share Posted March 13, 2017 Yes, you will get CEL for P0420 & P0430 - loss of catalyst efficiency in banks 1 & 2. I'm running no cats on a magnaflow muffler and above about 1/2 throttle it gets poppy/raspy. I'm considering installing high-flow cats to see if it will reduce that. Quote Link to comment Share on other sites More sharing options...
Sssz28 Posted March 20, 2017 Report Share Posted March 20, 2017 A simple tune out will correct those codes. But the mpg gain and power is the only reason Im gonna LT my new work truck. Quote Link to comment Share on other sites More sharing options...
cleansss20 Posted March 20, 2017 Report Share Posted March 20, 2017 I had lt headers, no cats and magnaflows on my truck and it sounded horrible. Drone and popping. I had to add in some resonators and x pipe and it sounds better. But unless you need to remove the cats I wouldn't. Quote Link to comment Share on other sites More sharing options...
SuperStock Posted November 10, 2017 Report Share Posted November 10, 2017 (edited) Removing the cats will not gain very much, on a supercharged truck it will gain about 1+ tenths in the 1/4-m. It will make a definite difference in the exhaust, not very much louder but raspier. If you run forced induction, nitrous, or high octane fuel they must be removed or you risk melting them down; on N/A vehicles I would encourage you leave them on for legal reasons, especially if you ever resell the truck the new owner can force you to have to reinstall them (and any other emissions equipment) as a condition of sale. So if you really want to remove them, what I would do is to unbolt the factory Y-pipe and replace with a catless Y-pipe, that way for inspection or resale you can easily return the truck to original condition. Mr. P. X2 Edited November 10, 2017 by Fast04Chevy (see edit history) Quote Link to comment Share on other sites More sharing options...
krackerkegley Posted February 7, 2018 Report Share Posted February 7, 2018 If you live in California don't throw them away, I had to buy OEM because that's the only one CA allowed on the SS and it cost me about $2k for both. Quote Link to comment Share on other sites More sharing options...
El new one Posted April 16, 2019 Report Share Posted April 16, 2019 Hello guys im about to install a cat back flowmeter 40 on my truck and i want the pipe to come out one on each of the side before the rear tires any suggestion on it Quote Link to comment Share on other sites More sharing options...
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