Exhaust

[leon]

I'm planning to put a 5", turbo back, muffled pipe with a 6" tip on my stock 3500 qc 4x4. I've read the Donalson muffler is the way to go so I'll probably go that route. I'm not looking for loud  just like the deep diesel sound.  I haven't decided if I will buy a prefab bolt on, or take it to a local muffler shop. 

I definitely do not want droning or obnoxious loud. Do I need to do anything else or is this a good set up?

[Me78569]

I'd go with a 4" personally. 

[leon]

4" is too raspy to me. 

[sooxies]

36 minutes ago, leon said:

4" is too raspy to me. 

FTE Resonator isn't a bad option either.  To me straight pipes are more raspy, especially 4".  It will be less expensive to run a 4" setup than a 5".  Kits are easy to do yourself...hand tools and a reciprocating saw.   

[dripley]

I have been running a 4" with flow thru muffler since 2005, Banks. Raspy would not fit what I hear.

[Hawkez]

I have a 4" with a FTE Resonator.  I would look at getting band clamps rather than using the u-bolt style clamps.

[JAG1]

13 hours ago, dripley said:

I have been running a 4" with flow thru muffler since 2005, Banks. Raspy would not fit what I hear.

Dave, does yours have that real nice unmistakable sound of the Cummins? Not loud at all but just that nice mello roll of the Cummins engine?

 

 

13 hours ago, sooxies said:

FTE Resonator isn't a bad option either.  To me straight pipes are more raspy, especially 4".  It will be less expensive to run a 4" setup than a 5".  Kits are easy to do yourself...hand tools and a reciprocating saw.   

How long did it take you? I'm looking at doubling the time since getting old, I get all the tools under there, creeper myself in place and forget what I'm supposed to be doing

[jlbayes]

I much prefer the 5" to 4" exhaust. I ran no muffler with my 5" and it did not seem overly loud. Tho I was coming from stacks at cab level.

[sooxies]

55 minutes ago, JAG1 said:

Dave, does yours have that real nice unmistakable sound of the Cummins? Not loud at all but just that nice mello roll of the Cummins engine?

 

 

How long did it take you? I'm looking at doubling the time since getting old, I get all the tools under there, creeper myself in place and forget what I'm supposed to be doing

I would say it took me two/two and a half hours and i spread it over two days.  I was working in my garage when it was 15 degrees so I was going very slow.  Three/four cuts with the Sawzall and the stock exhaust came right out.

 

Tips I learned

• Lube up the rubber hangers beforehand
• Connect all pipe outside of the truck...ensure all ends will connect to each other (no ends are bent from shipping/handling)
• Hang everything loose then tighten front to back
• Have a second set of eyes for the tightening of the final pipe section (ensure it is positioned to how you like..it can change position when tightening the clamp)

There's more I'm forgetting...happy I did it myself though.  Now I can say I did it. 

3 hours ago, Hawkez said:

I have a 4" with a FTE Resonator.  I would look at getting band clamps rather than using the u-bolt style clamps.

Agree with 100% that.  I specifically looked for a kit with the Accu-Seal clamps.

[dripley]

3 hours ago, JAG1 said:

Dave, does yours have that real nice unmistakable sound of the Cummins? Not loud at all but just that nice mello roll of the Cummins engine?

To me it sounds like a Cummins and is not to loud. The only time I really hear is under a bridge and have my foot in it. Not to say I dont here it cruising but it is not that noticeable to me. I put it on in 05 and it still sounds the same. I did have one of the hangers come off and it opened up the pipe right at the tranny and it was unbearably loud. 

 

How long did it take you? I'm looking at doubling the time since getting old, I get all the tools under there, creeper myself in place and forget what I'm supposed to be doing

I feel so UN alone now. Happens to me all the time.

 

[Mopar1973Man]

I've been in several trucks with several different exhaust setup. All I can say is the larger the pipe typically the louder the exhaust becomes (outside measurement). As for cab sound levels, all depends on the pipe where it exits at and this will change the amount of noise or drone levels. I've seen 5" pipe trucks drone so bad that the owner and myself couldn't talk in the cab at all even on level ground at 65 MPH not towing. It got worse towing you would need ear plugs. Tips tend to amplify the exhaust note at the tip like an announcer yelling through old school megaphone. So if you're looking for quiet, smaller pipe diameter typically are quieter and muffler typically will kill the drone and noise off. 

[KATOOM]

The difference between my straight piped 2n gen stock 3" and the straight piped aftermarket 4" was the stock exhaust was not nearly as mellow sounding as the 4".  As for overall noise wise.....I'd probably say they're the same.

I'm not a big fan of the straight piped CR engines because they can get really rappy sounding.

[Mopar1973Man]

I'm running a straight flow through 3" muffler. It really can't be heard in the cab. Outside its very mellow sounding. I ran straight pipe 3" for a very long time but wen I started towing long distance the drone was a new problem. Now just adding the flow through 3" muffler the drone issue is gone. Still zero restriction like a straight pipe but without the noise.

 

https://mopar1973man.com/garage/modification/229-straight-pipe-exhaust-with-muffler/

Edited January 30, 2017 by Mopar1973Man

[CTcummins24V]

I ran stock, 4" straight, 4" w/muffler, 5" w/muffler and now 5" w/muffler and resonator.

 

5" is deaper sounding and I like the sound better, but drone was terrible at cruising speeds so a resonator is needed. My 2 cents

[leon]

So I met a guy with a 12v on Sunday. He said he owned diesel shop in Valdosta, and was making 500hp on his 12v. Looking at his truck I noticed he had stock diameter exhaust. When I asked why he wasnt running bigger he said it was important that the motor had plenty of back pressure. 

[Me78569]

He's smoking rocks... I wouldn't take ANYTHING he said with any value.

 

The basic design of a turbine operates on a difference in pressure on either side of the turbine well.    There is no reason at all to try and increase / hold backpressure past the turbo.  The more backpressure you have the smaller the pressure difference and the worse the turbo will perform. We don't have backpressure needs like a NA engine.  There is plenty of backpressure pre turbo just due to being pushed through a turbine.

 

Now there is absolutely no need to run a 4 or 5 " exhaust on a sub 400.  you might see some gain on a 500 hp truck, but honestly I doubt the butt dyno would notice.  

[KATOOM]

Anyone who has enough mechanical smarts putting together a 500 hp diesel should also understand how the exhaust works on a forced induction engine.  So he's either lying about the trucks true power.....or he bought it that way and has not a clue about anything related.

 

As for stock 3" exhaust, yes its plenty free flowing as long as the muffler is removed.....even though its not really 3" but more like 2.5" in the pinch bends.

But that said, I ran a straight piped 3" for years towing many trailers.  Although when we bought our 14k 5th wheel I found myself working at keeping EGT's in check while towing in the mountains during summer weather.  So I installed a straight piped 4" exhaust and the difference in EGT's was obvious and well worth the $300 purchase.

 

Lastly, adding a 4" exhaust generally wont add any hp worth mentioning, but coincidentally the first tow after installing the new exhaust resulted in slight clutch slippage.  So apparently the small amount of power I gained from added flow was just enough to push the limits of the stock clutch while towing my trailer.  I thought it worth pointing that out.

[015point9]

13 hours ago, KATOOM said:

But that said, I ran a straight piped 3" for years towing many trailers.  Although when we bought our 14k 5th wheel I found myself working at keeping EGT's in check while towing in the mountains during summer weather.  So I installed a straight piped 4" exhaust and the difference in EGT's was obvious and well worth the $300 purchase.

 

How much did it help EGT's. 

My stock muffler on 2001 is beginning to show its age.  Next couple years will be replacing. Muffler is rusting out on bottom.  

 

What set up would EGT's in check and not increase noise level?  Horse power wise I'm completely stock, usually towing 10K trailer.

Thanks

Edited January 31, 2017 by 015point9

[Mopar1973Man]

I'm still running stock 3 inch exhaust with a flow through muffler. No EGTs issues and good power. 4 inch would be good upgrade for 500 hp and higher.

 

Being i dont produce high boost with normal driving or towing there is no reason for 5 inch exhaust at all.

[dripley]

Speaking from 2005 when I changed mine to a 4" I was sold on the idea of the engine breathing better, ie allowing the exhaust to exit/flow out easier. Back pressure is the opposite and would just slow down the turbo. The exhaust has to move to spin the turbo, any restriction will just slow it down. The folks above know much more about this than I but are passing on to you as good of info as you are going to get. I have no regrets with my 4" just really did not know squat when I bought it.

4 hours ago, Mopar1973Man said:

I'm still running stock 3 inch exhaust with a flow through muffler. No EGTs issues and good power. 4 inch would be good upgrade for 500 hp and higher.

 

Being i dont produce high boost with normal driving or towing there is no reason for 5 inch exhaust at all.

There was something that always bugged me when I put my 4" on. It was the first time I ever cut a perfectly good part off of a vehicle and threw it away. Never crossed my mind it could last this long.