2nd Gen Non-Engine/Transmission 2nd Gen Straight Pipe - Yea or Nay

[CChinman]

The last thread I found posing this question was from 2003. It was a mixed bag and essentially the respondents who were in favor of straight piping (muffler delete) enjoyed the sound while those not in favor were largely against the additional cab noise and external noise.

My question is more specifically targeted toward any added performance value gained with a straight pipe exhaust? Faster spool up?, Lower EGTs etc.

If you have info to share I would appreciate it as I look to possibly alter my 1997 3500.

Thank you,
Chris

 

[JR]

Absolutely no performance gains. Only hearing loss.

Most all mufflers are straight through anyway, so there is nothing to get plugged. And it is obnoxiously loud.

 

[bdenson]

x2 what jr said

 

[SnoKing]

x3 what jr said. In addition I got tried of the turbo noise from my BHAF and put the air box back with stock filter. At around 325/650-700 I notice no difference in performance or mileage. SNOKING

 

[VolsFan]

X4. 10 yrs ago when I was in college I would have disagreed. It was cute setting off car alarms w straight pipe. As maturity kicked in that stuff just isn't fun anymore and the drone was ridiculous. I have a resonator currently and like it.

 

[SAndreasen]

The last thread I found posing this question was from 2003. It was a mixed bag and essentially the respondents who were in favor of straight piping (muffler delete) enjoyed the sound while those not in favor were largely against the additional cab noise and external noise.

My question is more specifically targeted toward any added performance value gained with a straight pipe exhaust? Faster spool up?, Lower EGTs etc.

If you have info to share I would appreciate it as I look to possibly alter my 1997 3500.

Thank you,
Chris

Its cool till you hook onto a trailer for 12 or 14 hours and your head will still be ringing 3 days latter

 

[K.L.Schumacher]

When I bought my 96 3500 back in 1999 I went after about a year and put on 4 inch sewer pipe straight exhaust . Few years of that it started getting old and so 4 years ago as it was deteriorating and needed replacement I found a deal on a Magnaflow system. Took longer to cut the old crap out than to put the new in. Well 4 years later. No power loss or EGT spikes and so much nicer to live with. Much quieter in cab, No monotonous drone at highway speeds. Now I can hear the pleasant sound of the Cummins and not that drone at the back of truck. And the old exhaust was worse with the camper on.

 

[Ozymandias]

x6 Crazy loud, nothing you want to life with. Even a Flowmaster 50SUV makes it loud to the border.

 

[CChinman]

Thank you folks for providing some insight and personal experience wrt the straight pipe question. I will keep what I have at this point.

 

[Joseph Donnelly]

In 3" get the Walker 21468 muffler; in 4" the 21471. Straight through, perforated core (not louvered) so performance loss is 0.0 and a lot quieter than straight pipe.

 

[Mingoglia]

I think I could live with it around town, and it may even be "cool" for awhile.... but I'd absolutely hate it on the freeway. Drone sucks and is very fatiguing when driving. I still have the stock exhaust on my 2001, and plan on sticking with stock when my '15 comes in.

 

[damar]

When I started towing in 2002 I called Cummins Help Line and talked to an engineer about getting the most power out of the stock engine. He said the first thing to do was get rid of the reverse flow muffler Dodge put on at the factory. I put on a Magnaflow 12772 (4.0 in diameter ) with 4.0 tail pipe. Not really noisy. Wife didn't even notice the difference. Since it's stainless steel it's as good as new at 195,000 miles. At 82 I don't do much towing but still have the Ram.

 

[KATOOM]

I guess I have the only tolerably quiet straight piped Dodge Cummins. But I will agree that I've heard some loud Cummins trucks out there with guys that love to drive around town like their throttle pedal was replaced with an ON/OFF toggle switch.

Also, I agree as well that there are little power gains to be had with a straight pipe exhaust but let me share what I experienced.....

In order to lower my EGT's I removed the muffler and resonator. Yes, it worked but it also resulted in a terrible drone at around 2000 rpm. Then later on I learned about how to add some metal to the section of straight pipe in order to reduce the resonating sound waves which were causing the drone. Result was I significantly reduced the drone down to the point of complete toleration. Nice...

Then I bought a heavy 5th wheel and found that my EGT's were hard to keep in the safe zone so after already having an intake system, my only option was to upgrade to a 4" exhaust system. Upon ordering the new exhaust I chose to go straight pipe again too. Being fully aware of what causes droning, I made sure to use every OEM exhaust hanger/mount (which took some fabricating), and I had the exhaust tip extend out the side like it did from the factory. Along the lines of another subject regarding transmission temps, I also installed around 6 feet of exhaust blanket (not wrap) which runs almost from the turbo back to just past the transfer case. My exhaust pipe is securely mounted and blanketed and is surprisingly quiet.

In regards to any added power, we can call it coincidence if you so choose but immediately after installing my new exhaust, I was towing my trailer on the same hills and my clutch began to slip. So did I add just the very little power needed to cause the clutch to give? I'd say so because after pulling out my factory Luke clutch I found that it was in extremely good condition and not worn out or abused.

Point being is my truck is NOT loud or annoying. Its certainly NOT quiet either but that said, the engine clatter alone is far louder than the exhaust noise while idling. Only until I'm under a lot of power does my truck then get noisy. But so far no neighbors have ever been angry at me, and if anyone ever expresses how loud the truck is, its not because of whats coming out the tailpipe but rather whats coming from under the hood.

 

[Ken Roberts]

Straight pipe noise

These pictures were taken January 2013, if I remember correctly. The order is: Idle, in front of radiator....Idle, 3' from tailpipe, Idle, in cab, Idle, on gauge cover.
The next pictures are during the drive, as the engine came up to temprature. Truck was empty, not pulling a load and my foot was very lightly pressing on the LOUD pedal.
4" straight pipe, no muffler,no resonator.
This my friends, is loud, and the drone at highway speeds while pulling a trailer is quite loud. Someday, when it is warm, I have the time and I'm not feeling lazy, I will install a muffler.

EDIT-- It looks like the order is a little messed up, but you get the idea.

 

[KATOOM]

If there's anything I like to read in these threads.....its testing data. Nice work.

But that said, I have to question your process and your tools used in this test. No disrespect by any means either but Realistic products are adequate at best. Radio Shack isnt known for their top quality brand stuff, so accuracy in product capability will be at question.

But disregarding the quality of the reader and taking those numbers seriously, I cant but wonder if your testing procedure in the cab was correct. I'm understanding that you're not supposed to set a dB reader against anything as it causes excessive feedback noise which skews the readings. Case in point, the picture of you holding the reader is the lowest in the cab.

Also, reassuring as its well known amongst the diesel community, the ISB 2nd gen 24 valve engines are just plain LOUD. Clearly pointed out as your dB readings taken from in front of the radiator with the hood closed, the dB was 92. But.....when checking the levels at the tailpipe (with the tailpipe pointing directly AT the reader, no less) the levels were only 5dB higher. And this is on a straight pipe 4" exhaust truck. That right there is proof beyond all reasonable doubt that the engine rattle is the largest noise producing component on these trucks. I would wager a bet that if you opened the hood and pointed the reader at the engine, the dB readings would dwarf what comes from the tailpipe.

Hey.....in saying all this, I'm not trying to sway anyone to cut off their muffler. Thats not the point I'm trying to make. But for anyone to try and prove that they're somehow going to transform the 2nd gen trucks into these quiet little church mice by adding a muffler is far from reality. They're just obnoxiously loud by design and if I understand your signature.....you seem to like it that way.

 

[Ken Roberts]

Katoom,
I agree that the engine is the real noise maker on these trucks. I'm sure testing could be done in a different mannor, but I used what I had as I could safely use it. The rubberband kept the meter from rattling around, and I had to set it somewhere because it took one hand to steer and one hand to photograph. Putting the meter on the center console would have taken my eyes off the road for too long for my comfort.
Than being said, the pictures make a point. These trucks are loud. Mine is louder than most. The average driver has no idea how "loud" is loud. But they can look up OSHA's allowed dB levels of sonic safety and understand that if 85dB is safe for 8 hours and 95dB is safe for 30 minutes, they might not want to modify their stock exhaust as the drone from removing the muffler, creates excessive noise at a speed that I can't take a tail pipe measurement.
For me, I have spent decades in motorcycling racing, rock and roll bands, running loud equipment and things like that. I understand how "loud" loud is.
In closing, I do like almost all things that make noise and go fast. I just wanted to put some sound measurements into a discussion that didn't have anything more concrete than people saying how loud it seems to them.

PS. I own a KTM too!

 

[KATOOM]

Well at least you're a fellow KTM rider..... :-laf

I've always preferred things a little louder myself, which maybe stems from my racing days. Even still today, I "need" to hear the engine of whatever I'm driving/riding in order to best the terrain. I ride with guys who listen to music and I simply dont understand how they do it.

Good discussion too.

 

[SAndreasen]

What does one a them testers cost I'd like to do some testing .

 

[SnoKing]

http://www.amazon.com/Extech-407730..._sim_hi_1?ie=UTF8&refRID=1VFMT6Q83J2C2PX35P3G

http://www.radioshack.com/search?q=Sound meters

http://www.amazon.com/Mini-Digital-Sound-Level-Meter/dp/B001THX3M0

Snoking

 

[JR]

What did you say???? :-laf:-laf