Tonight I was able to replace my cat with an Aero 4040xl the resonated version. Before I just had the cat and the muffler delete pipe and the truck pulled really good on top end. I was hopping that the 4040xl was going to make the truck a little louder, change the toneand pull even better on the top end. I think that it did the opposite. Its quieter and seems like a real dog now, and im wondering if it might have raised my EGT's. I live about 10 minutes from mywork witch usually doesn't even give the truck enough time to warm up and its 12 degrees outside, when I got home I left it running so I could get out and listen to the exhaust tone while idlingthe tail pipe seemed really hot for the short drive burn skin hot. I don't have an EGT gauge yet so I can't actually verify that its hotter. Yes I did install it correctly so that can't be it. Does anyone have any ideas, does it need break-in time. You guys have praised this muffler so much I thought that I was doing a good thing but maybe I should have left the cat in its place and saved my money for something else.

 

The tail pipe was hot due to the fact the CAT was not absorbing the heat. As far as performance goes I would say its due to back pressure. The lack of. The turbo is real sensitive to back pressure as you could see from removing the muffler.

 

I did not think of it that way, I see your point. What is more free flowing the Aero 4040XL or the cat. I would figure that if the muffler was more free flowing that I would have noticed a increase in noise, andit didn't it got quieter. Driving at 70 and putting the pedal to the metal it felt that the truck pulled better with the cat than it does now.

 

Yes the muffler is more "free flowing" less back PSI for the turbo. Thous a loss in torque.Louder NO Why because it is a muffler. Got quieter YES because it is a muffler. If you would like for me to get in to detail on exhaust to air ratios to explain I will. But you have to have back PSI to a point on a CTD truck. Why? Because the turbocharger is an air compressor. By spinning at high rpm, the compressor side takes in huge volumes of air, forcing far more into the intake manifold than an unaided normally aspirated engine could take in. The compressor is on the same shaft as the turbine, which drives the compressor by drawing HEAT energy from the exhaust and converting it to the mechanical energy that spins the shaft. The more HEAT that can be retained in the gas when it reaches the turbine wheel, the more power the turbocharger will have to move more air. In a nut shell you need some back PSI for heat. All your heat is going out your tell pipe.

 

yes it's going to need time to "break in", it'll go thru it's hot & cold cycles for about a week (200~300 miles for me) and then start to shine. I was not impressed too much when I 1st put it in but after about a week it started to perform better. I had this happen on the last 3 muffler installs I've done so I dont think its an aero only thing.

 

Yeah, I'm with Steve on that one. I've had mine for several months now, and its gotten a little louder. In fact, it's starting to be a little too much without the cat, I'm thinking about having it reinstalled. I couldn't sneak up on a deaf man with this thing right now. It does sound wicked though. if I gently get on it and it doesn't down shift,,, my goodness,, the windows on ppls houses rattle, it sounds like a big rig coming down the road.

 

Was it ok to install it in place of the cat, or should I have put it where the muffler used to be? Would it be louder closer to the end of the tailpipe? I started the truck up before I reconected themuffler deletepipe and tailpipeand it sounded better than it does now.

 

I've never heard any other truck with an Aero installed so I can't say which is better than the next, but Imounted mine back where the stock muffler was and not only does it sound great, but I have zero in cab drone noise.

 

I have dual in line AERO 4040s and the only time it is LOUD is in first gear and when it first shifts into overdrive, any other time it sounds ok but it doesnt necessarily get louder with the more throttle I apply.
But the AERO I installed where the cat was is only 2 days old and has only got 50-60 miles on it. So it will need to be broke in. So maybe it will get louder

But to answer your question. Yes. All mufflers need a hot and cool down cycle even on gassers. They also fill up with soot.

so yes give it about a weekor 200-300 miles