04.5 Muffler restrictive?

[phicks]

How restrictive are the mufflers on the new 04. 5? I was talking to a shop in Salem Oregon and they recomended to install an aftermarket. Any members out there done this? Any benefits from doing it?

 

[JVolpe]

I don't know for sure, but seems that most posts from experienced Cummins owners have straight pipe or new high flow muffler very quick.



I am putting on Banks Monster Exhaust Saturday in hopes of lowering EGTs. I don't really think it provide any real performance improvement. But lower EGTs will allow the higher levels on little box.

 

[mattymac]

I took out the cat, replaced with 4in pipe into a 4in straight through magnaflow muffler. The rest is all stock piping. around $200 for me at a local muffler shop. The most expencive part was the muffler $120 or so. Egt's really didnt drop to far for me (maybe 100 degrees) but they climbed alot slower than stock. Plus the sound is awesome. Still quiet until I really roll on it then its as loud as my 01 24 valve.

 

[crobertson1]

mattymac,

I was thinking of having my cat fall off too. But if it doesn't have much of benefit, I'll just keep it from faling off. I'm keeping the muffler 'cause I like it quiet. I also had a LOUD '01. 5! So, if I keep the muffler without the cat, would it make much difference in EGTs?

Craig

 

[mattymac]

I say louder than my 01 but thats with the TST on kill. When I used to run it stock it just had a nice throty sound that wasnt offensive at all with very little in cab noise/drone. Its amazing how much sound the TST will give to one of these rigs. Ill try to go get a pic of the insides.

 

[mattymac]

Heres the pics:



1st is the inside of the Cat, Its hard to see but there is a very restrictive screen in there.



2nd is inside the muffler, looks just like your typical muffler, Very resrictive and you cant see through the other end.



3rd is the 2001 resinator and muffler VS. the 600 cat and muffler. Trust me when I say that its as heavy as it looks. Its probably pretty close to a half a 10th in the 1/4 just in weight savings!

 

[crobertson1]

Thanks for the pics. My question is: How would losing the cat and KEEPING the muffler affect the EGTs? The truck is going to remain stock and I like it quiet.

 

[mattymac]

I would think that together they are very restictive. Most of the EGT issue comes from the turbo, Camshaft, and programing. I would think that its kinda crude to remove one and leave the other, (like building a race motor and using the stock exh. manifolds VS headers) To best answer your question I would say that it wouldnt hurt your EGT's but not help them out as much as it could. Also if you say its going to remain stock then why would you be worried about EGT's? And also it you like it quiet?

 

[crobertson1]

I'm interested in lower EGTs because towing our TT at 9,000-11,000 ft and up some pretty steep grades here in Colo, it's pretty easy to see 1400* for extended periods. I have plenty of power but have to keep backing out of it to keep the EGTs reasonable. There's very little air here! That's also why I like it quiet. The '01 was so loud while towing, it was miserable.

 

[mattymac]

I can see your being concerned about the high EGT's in these motors stock but these new HPCR motors can be run alot hotter, longer, and harder then any of the previous engines. to my knowlage Cummins tested the 600 at 1450 deg for hours or days on end without a problem. To get these new diesels to pass EPA regs they have to run hot EGT's. Thats why earlier I stated about the programing, camshaft (lots of valve overlap in the 600's. ) and the tiny turbo. So cummins puts these motors through torcher tests that we can only dream of. If yoou want to stay quiet and loose some EGT's Id look into a piers bomber lite turbo. Its your stock turbo modified to spool quicker and loose EGT's. So the good things are quicker spool for better towing/driveability, Loss in high end EGT's, price isnt to bad, keep stock downpipe (great if you run an exhaust brake). But the bad thing is downtime. We all know how tiny these Exh. housings are and thats a major choke point so I would address the problem at the source.

 

[Motofreak]

Lost my cat and muffler

Removed both last week and installed resonator and new straight thru muffler. Dont know about EGTs as I dont have my pyro in yet but I will tell you it is very quiet. My 01 with Banks Monster exhaust was alot louder.

I am a bit bummed as I was expecting a bit more noise. Havent towed with it yet but driving down the road with windows up it is just as quiet as stock.

Rip at Source Automotive set me up nice

Installed new Afe with torque tube as well, just waiting on my box

 

[mattymac]

Motfreak, I have ridden in a truck with Rips exhaust and its quieter than mine. No drone in the cab at all.

 

[gsdog1]

What kind of issues can one run into with respect to removing the cat?



Thanks!



Matt

 

[jwilliams3]

The cat is only there for emissions.

Once removed you will notice improved performance.



--Justin

 

[Blakers]

The government does recommend having your cat neutered. I hear it all the time on TV. :-laf

 

[electraglide01]

Backpressure

Has anyone checked the pressure between the turbo and Cat stock / then straight piped? I was thinking of having the local muffler shop weld a fitting on the pipe so I could attach a pressure gauge or U-tube manometer. I was going to weld a swagelock fitting on then drill a hole so I could measure the static pressure.



Local shop wouldn't touch that big ugly thing in the pipe. Told him I'd be back for a 4" muffler extension for my tractor later.



I'm in the power business and we always try to measure the effects of any upgrades that we do to any engines. I'd like to know what I am going to get for going to a straight pipe..... Or a 4" straight glass pack. IF the Cat doesn't significantly increase the backpressure, might as well leave it on there (notice I said if - I think it is a crime to put a cat on a diesel).



Dropping the backpressure on the turbo should make it spool up faster and increase the effiency of it (all turbine devices function better with lower backpressure). However, the effect is directly related to the amount of gas (I say gas because the exhaust gas is air and burned fuel) flowing at any given time. The more gas, the higher the velocity, the higher backpressure. In other words, I don't know how much bang I'd get at 2000 RPM unloaded on flat graound vs 2400 RPM pulling a heavy trailer thru the hills... .



I punched the baffles out of my Harley's mufflers. Seat of the pants accel got better but it might have been due to liking the sound of those pipes ringing!

 

[Motofreak]

Mattymac

Yeah your right, I was worried that I would have it. Zero drone, pretty sure the resonator is what takes care of that. I`m thinking of trying it without the res see if that makes it a bit louder.

 

[Schicken bone]

I took the cat and muffler out at 2500 miles. put cold air on it and the truck came alive

 

[mattymac]

The government does recommend having your cat neutered. I hear it all the time on TV. :-laf

Bob Barker really tries to get this point across as well. :-laf

 

[Motofreak]

Placebo?

I took the cat and muffler out at 2500 miles. put cold air on it and the truck came alive

I did the same thing as well, However I dont really notice a difference. Granted I have only driven back and forth to work and havent towed yet (till this week-end. ) I didnt really expect any more power, I did it to lower my EGTs for when I get my box.

So you honestly noticed a difference?