I want to run true dual exhaust, and i'd Love to eliminate my catalytic converters if at all possible. I've always heard that if I cut the cats, i'll lose backpressure and make my computer get all kinds of error codes. Is this true? if so, is there any way around this? Someone at a local muffler shop told me that I should just put a smaller diameter pipe in place of the cat, to keep the backpressure there. Help me out and let me know what I should do.

Thanks in Advance

 

Actually you have a true dual system up to the muffler/tailpipe itself as there is no crossover prior to that.

To complete the true dual setup, take off the stock muffler of death, and replace it with two aftermarket units which exit out through each of their own tailpipes.

HOWEVER....one thing that's nice about the Tahoe's (old body style with the Vortec 5700) is that the cat-back system is easily unboltable at a flange just after the passenger side cat with three bolts. Then removing the passenger side rear shock (and lifting the back of the Tahoe off the axle) will allow you to remove the stock system in one piece. After which you can bolt up just about any cat-back you want albeit it may not be a true dual setup.

The only way you'll get SES codes if you remove the cats is if you don't use O2 simms in the post cat sensor wiring.

 

I just bought CMNTMXR's old 99 Tahoe catback, it's a Dynomax.

I did notice that an 02 sensor is in the exhaust AFTER the cats, so you would need at least one 02 sim if you removed the cats.

My truck is pretty rumbly with my stock style 2 into 1 Dynomax. I don't want it any louder... I have no cats on the Firebird and it has true duals, it's loud.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by CMNTMXR57:
<strong>Actually you have a true dual system up to the muffler/tailpipe itself as there is no crossover prior to that.

To complete the true dual setup, take off the stock muffler of death, and replace it with two aftermarket units which exit out through each of their own tailpipes.

HOWEVER....one thing that's nice about the Tahoe's (old body style with the Vortec 5700) is that the cat-back system is easily unboltable at a flange just after the passenger side cat with three bolts. Then removing the passenger side rear shock (and lifting the back of the Tahoe off the axle) will allow you to remove the stock system in one piece. After which you can bolt up just about any cat-back you want albeit it may not be a true dual setup.

The only way you'll get SES codes if you remove the cats is if you don't use O2 simms in the post cat sensor wiring.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Actually when i got it, it already had two muffler, and two pipes all the way back. It's a true dual setup all the way back. The main question I was wondering though is.... Am I going to experience any kind of problems at all by eliminating my cats? Other than the warning lights, which i'm going to fix by installing the 02 Sims.... Also, what size pipe should I run? I was thinking 2.25" or 2.5"... Thanks

<small>[ August 07, 2002, 10:28 PM: Message edited by: TahoeDawgZ71 ]</small>

 

Nice! Someone already split it. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

PCM wise, as long as you install O2 simms, you'll be fine. Performance wise, you may lose a little torque and the sound may become a tad bit more raspy. Perhaps a small tube welded in between both lines as a balance tube will help.

I believe the DynoMax I sold to John was a 3" system. If not, 2.5" would be the minimum I'd go and 3" max. There is no need for anything bigger than that especially when you are running two separate lines.

 

Why do you want to get rid of the cats? The stock cats on Vortec 350's are some of the best flowing around.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Neil 6.0:
<strong>Why do you want to get rid of the cats? The stock cats on Vortec 350's are some of the best flowing around.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Cats are the devil in disguise. I hate them. My buddy has a 99 Tahoe with true dual flowmasters (2 chamber), and it's no where near loud enough for my liking... so, it's OFF with the cats.

 

I just remembered..... If anyone is interested I have the Edelbrock Cat back still in the box for a '99 4 door Tahoe. Exhaust is all on the passenger side. If interested let me know and I can send you the part number and whatever else.

Thanks