True Duals

scootertrash2004 · June 8, 2009

I have a 2009 GMC Sierra with a 5.3L. Does anyone know if I can remove the 3rd cat, and install " tru-duals" ?

66nova · June 8, 2009

First off, welcome to the forum.

Second...Why would you want to either remove that cat or install true duals? Are you just wanting the sound or are you expecting to gain power from "true duals".

If you remove a catalytic converter, you will probably get a check engine light, your truck will more than likely actually lose power because the computer will try to compensate for the miss readings and not to mention they are there for our environment.

Zembonez · June 8, 2009

First off, welcome to the forum.

Second...Why would you want to either remove that cat or install true duals? Are you just wanting the sound or are you expecting to gain power from "true duals".

If you remove a catalytic converter, you will probably get a check engine light, your truck will more than likely actually lose power because the computer will try to compensate for the miss readings and not to mention they are there for our environment.

I agree. Nothing but problems come from removing cats or trying to get around emissions on these new engines and nothing is gained from a true dual system on the stock engine but noise. I went with a Flowmaster 70 series big block on my truck with a single in and dual out setup. Sounds great!

Alljackedup408 · June 8, 2009

another option is high flow cats... but keeping the cats wouldnt hurt!

Darkanion · June 8, 2009

I think the "third cat" he's talking about is the resonator..

Darkanion · June 8, 2009

That said... Here's my take on it. If you want 'em, go get 'em. It's YOUR truck. Do what YOU want to with it. If I had asked opinions and listened to the folks on here, I probably wouldn't have done mine... and I'd probably still be thinking about it in the back of my mind.

Is it going to turn your pickup truck into a Camaro? No. Is it going to be the way you want it? Yes.

Here are a couple of threads from when I had true duals put on my Sierra Denali.

Original thread :

http://www.gm-trucks.com/forums/index.php?showtopic=70258

Someone else's thread, that got side-tracked/hijacked with a few pics of my installation :

http://www.gm-trucks.com/forums/index.php?...mp;#entry538748

If the truck is going to be driven on the streets, leave the cats. On the newer model trucks, they're "hi-flow" enough. So, I wouldn't see a good reason to replace them, unless you just want to.

What I think you are referring to as "the third cat" is a resonator. Different people have claimed different uses for it. When I had my new setup done, the guys at the muffler shop said I didn't need it. The muffler I bought had built-in crossovers, etc. and I've been more than happy with it... No drone at highway speeds. Although, I wouldn't mind it being a touch louder, from time to time. But, the CAI makes enough noise for me. So, it's all good!

Post-up pics and/or sound clips of whatever you do!

Oh, yeah! The "My Youtube" link in my sig has a couple of sound/video clips of the exhaust.

Later!

66nova · June 8, 2009

That said... Here's my take on it. If you want 'em, go get 'em. It's YOUR truck. Do what YOU want to with it. If I had asked opinions and listened to the folks on here, I probably wouldn't have done mine... and I'd probably still be thinking about it in the back of my mind.

Is it going to turn your pickup truck into a Camaro? No. Is it going to be the way you want it? Yes.

Here are a couple of threads from when I had true duals put on my Sierra Denali.

Original thread :

http://www.gm-trucks.com/forums/index.php?showtopic=70258

Someone else's thread, that got side-tracked/hijacked with a few pics of my installation :

http://www.gm-trucks.com/forums/index.php?...mp;#entry538748

If the truck is going to be driven on the streets, leave the cats. On the newer model trucks, they're "hi-flow" enough. So, I wouldn't see a good reason to replace them, unless you just want to.

What I think you are referring to as "the third cat" is a resonator. Different people have claimed different uses for it. When I had my new setup done, the guys at the muffler shop said I didn't need it. The muffler I bought had built-in crossovers, etc. and I've been more than happy with it... No drone at highway speeds. Although, I wouldn't mind it being a touch louder, from time to time. But, the CAI makes enough noise for me. So, it's all good!

Post-up pics and/or sound clips of whatever you do!

Oh, yeah! The "My Youtube" link in my sig has a couple of sound/video clips of the exhaust.

Later!

Michael,

I 100% agree with you on build what you want. Man if you want "true duals" go for it. I know for me, I tend to be a little short with my responses sometimes just because we are on a forum and I don't like boring the crud out of people. So, I tend to type the crust of the matter and leave out why I am saying what I am. I just want everyone to be well informed on the matter. Often guys come on here wanting the look of dual exhaust or think they are going to get a lot more performance from true duals because that's what they did 30 years ago. Both can be accomplished without the expense and extra weight of true duals.

First, you need to find out whether that is a cat or a resonator. I am not sure, but I have heard that the 09's have an extra Cat that the 07-08's don't have. I don't know for sure.

Assuming it is actually a resonator, then yes you can run true duals. BUT, this is why I typed my original post. What is the reasoning for wanting true duals. Is it for the dual exhaust look, are you looking for a certain sound, or trying to obtain a certain performance?

Because all of those can be accomplished without running true duals. And actually with most of the dual exhaust systems I have seen ran, you will actually get more power from a cat back system.

As far as high flow cat's go. No, they are not needed either. Not on your truck. Now if you change the cam, heads, and put a supercharger on it, that will be a different story. But if you go and change them now, you need to plan on getting a tune to compensate, and good luck with emissions test. This I know from experience. I had to replace the cat on my old truck, and I decided to go with a magnaflow cat because of the price. I passed emissions that year by literally 3 points and I had just done a tune up with new plugs, cap, wires coil, etc.

So, theres my long winded response. If you want true duals, go for. But, go into it knowing what you are going to get and not get. If you do go true duals, please, please make sure you have a crossover pipe (H or X or in the muffler) otherwise you should just stick with your stock exhaust, it will make more power.

Darkanion · June 8, 2009

I am not sure, but I have heard that the 09's have an extra Cat that the 07-08's don't have. I don't know for sure.

I guess I haven't been reading the exhaust threads enough. I hadn't heard that about a 3rd cat on the 09's...? The next time I'm by a dealer's lot, I may stop and look under one. That seems odd... and it makes me wonder why they need it and mine (and your's) doesn't??