Exhaust system info

[Tittle Diesel Performance]

This will be some testing info I've tested personally over multiple trucks for those looking for that perfect sound. Really has zero effect on power but if you want that great cummins grumble we all know and love then think about this one>>>>

 

so your in the market for an exhaust? There is tons of options and brands....so brand is pretty much irrelevant... only changes really are the outlet angle. MBRP comes back on a 45* outlet, Diamond eye 90* outlet and some others do 60*. Really it doesn't make that big of a difference other then the amount of sound you hear in the cab. Windows down 45* is quietest, 90* is loudest. You'll hear it crack and echo off everything. Windows up 90* is quiet at speed USUALLY, 45* can start to drone at speed due to the low pressure area behind the exhaust pipe/tip. It's not much but it exists. Larger the tip the more drone at high speed.

 

So brand isn't a big deal. Now 4" VS 5", so there isn't a difference in power, we run 4" down pipes on second gens and the flow rate of 4" OD pipe is (3.8" roughly ID) is such a high CFM that it doesn't really matter on a 5.9 liter. Your Peterbuilt 13l CAT engine would like 5". So that said 5" is deeper, tighter fitting and tends to drone more in the cab. Yes it sounds better and I use 5" whenever possible. I love the deep grunt and burp sound, it just screams cummins! Cheap 4" systems will gain you the same power but it's a little more raspy.

 

Now the MOST IMPORTANT part! The material!!!! This makes a huge difference in sound, no performance gains but the sound change is amazing. So alluminized tubing that 80% of us run is honestly crap...in salt conditions it corrodes in a way that turns it a black color over the years. The wall diameter is usually a hair thinner depending on manufacture. The pipe itself TYPICALLY isn't truely round, when it cools the seem in the tubing warps a little So assembly sometimes can be a bear. My personal pet-peeve...drone. Alluminized vibrates, bad...you hear it under the truck, you hear a sound reverberation in the exhaust note and worst of all it vibrates and resonates into the cab from the pipe vibration under the truck. I absolutely hate drone, it's annoying. That said, stainless steel is the best! Even with a thin wall tuning the vibration/reverberation and sound dampening of the stainless is second to none. Yes the tubing is vibrating still since it's connected to the engine and of course everything vibrates but, it flexes less and holds up better to conditions. No corrosion. Some surface rust may show since it's probably from china but it'll last much longer. From personal experience a stainless system also has a much more crisp and clean sound. A to B the drone is near gone in the cab even with 5" straight pipe and a large s300 or 400 turbo that's loud beyond loud. One reason stacked trucks sound the way they do is because the stack is stainless which cleans up the exhaust note. A 4" stainlesss exhaust vs 5" alluminized, the 4" sounds better and cleaner. Much more of the deep burp noise. My personal fav is the 5" stainless though, if you want to make people think you have a small pecker in your wanna be Peterbuilt this is what you use. Deep, crisp sound with little to no drone. Each truck is different, the amount of hangars and style hangar make a big difference as well. Stacks attached to the bed, vibrate the bed and cause droning well same with under carriage exhaust. Make sure your insolators are soft and properly sized. It'll help tremendously.

 

ive personally had 7" stack systems that you couldn't hear in the cab with the windows up, a floating stack system looks a little weird when driving, it moves independent of the body floating on the insolators attached to the frame. But it's very quiet when you want it to be. This also reduces the stress on the pipe, turbo and manifold as the engine twists under load.

 

from personal experience: I've got 2 2nd gens, one with 4" stainless straight pipe and one with 5" alluminized with a diamond eye stainless muffler (came with the truck brand new but I'm going to switch!) if you listen to both trucks in person the 4" stainless sounds much cleaner, crisper and more angry when your on the throttle. The 5" sounds like the echo in a tunnel. Like multiple vehicles are racing due to vibration and reverberation. 

 

Now for some word to the wise info...please for the love of god don't use the stupid crush clamps... they are crap. They bend the alloy pipe so bad it hardly ever comes apart without a torch. If you want to swap turbos or mufflers or whatever don't use crush clamps. I've had so many that are so bad I just cut pipe, butt it together and either band clamp it or weld it. It really sucks to do guys... if your gonna run stainless, good stainless  pipe doesn't like to bend, so the crush clamps will actually bow and not compress the pipe but rather itself. it tends not to hold and a few miles later you got yourself an axle dump you didn't want it even an open down pipe and the muffler is in the grill of a Prius....don't use them. SO that said, the best, easiest and most adjustable/usable way is the overlap-band clamp. Slide your pipe seconds together, overlap the band clamp and get it really nice and tight. Some will have a pin hole leak right around the bolt location, if that's a problem you can use some paste on the pipes swelled overlap to help seal it for inspections and such. Now you can switch down pipes, mufflers, axle dumps etc without getting the hammer out. Just unbolt and slide apart! Stainless once again is the easiest for this and less opertunitly to leak. DO NOT use alloy band clamps. They are so weak you'll just break them! Regardless of what pipe you have to use get the stainless clamps. They hold up much better and longer. They keep there shape a little better also and seal/grab way better. If you don't have a swell overlap there is Butt-band clamps for 2 identical pipe sections to mate. Again stainless clamps are best. Little flexing means a tougher exhaust and better connection. 

 

Now that your up to date....spend the dang money and get a good exhaust, the $260 special online will work yes but sound isn't great, it doesn't last as long and though stainless is much heavier it's only about 20lbs. Unless your doing a full race build it's not gonna matter... you'll be happy you went for stainless in the end. Exhausts usually go on and stay, make sure your gonna be able to live with it for 5-20 years of ownership when the dodge body is gone and your riding the frame and engine cause it's all that left lol

[Guest 04Mach1]

I agree stainless is the only way to go for tone and durability. I've got a Silverline 4”stainless pipe with stainless muffler system on the 01. This exhaust will likely out last the truck.

 

Also just about 100% of class 8 trucks leave the assembly plant with a full stainless exhaust system now days.

[Tittle Diesel Performance]

That and production gas vehicles all use stainless for longevity. If you get stock replacement for 'walker exhaust system' it's not and it's garbage tube that rusts in a year just like a flow master muffler. Worthless garbage!

[Ironforger]

On 8/25/2018 at 8:06 PM, 04Mach1 said:

I agree stainless is the only way to go for tone and durability. I've got a Silverline 4”stainless pipe with stainless muffler system on the 01. This exhaust will likely out last the truck.

 

Also just about 100% of class 8 trucks leave the assembly plant with a full stainless exhaust system now days.

How does your truck sound with this setup? I know most folks love the deep loud sound our trucks produce but I'm looking for something quiet without affecting performance. 

 

Thanks!

[Mopar1973Man]

57 minutes ago, Ironforger said:

I know most folks love the deep loud sound our trucks produce but I'm looking for something quiet without affecting performance. 

 

I'm running a 4-inch Diamond Eye Exhaust with the muffler. When you get on the throttle she still talks. But cruising she is near quiet as a church mouse. I hear my turbo spooling more than the exhaust. 

[Rogan]

18 minutes ago, Mopar1973Man said:

 

I'm running a 4-inch Diamond Eye Exhaust with the muffler. When you get on the throttle she still talks. But cruising she is near quiet as a church mouse. I hear my turbo spooling more than the exhaust. 

I agree.  I've had mufflered 4" DE and MBRP, as well as 5" mufflered DE on previous trucks.  As M73M stated, they'll growl when you're on the skinny pedal, but nice and quiet when cruising.  Turbo-whine is also increased a little with the bigger pipe, and stainless seems to even produce a little greater whine and throatiness over aluminized steel.

[Ironforger]

1 hour ago, Mopar1973Man said:

 

I'm running a 4-inch Diamond Eye Exhaust with the muffler. When you get on the throttle she still talks. But cruising she is near quiet as a church mouse. I hear my turbo spooling more than the exhaust. 

Good info, thanks. I found this at summit racing:  https://www.summitracing.com/parts/dep-k4212s/overview/year/2002/make/dodge/model/ram-3500

 

 Are you running an exhaust brake?   I'd like to get an exhaust brake in the future, wondering if the above pipe setup will work without modifications if I decide to do an exhaust brake.

 

Thanks!

[Dieselfuture]

2 hours ago, Ironforger said:

Good info, thanks. I found this at summit racing:  https://www.summitracing.com/parts/dep-k4212s/overview/year/2002/make/dodge/model/ram-3500

 

 Are you running an exhaust brake?   I'd like to get an exhaust brake in the future, wondering if the above pipe setup will work without modifications if I decide to do an exhaust brake.

 

Thanks!

This is what it says in description. "

The kit fits right up to the factory cast iron elbow that comes of the turbo. "

So it's meant to be used with a 3in outlet that hx/hy35 have. If you're not planning on upsizing the turbo this would work good. 

[Guest 04Mach1]

8 hours ago, Ironforger said:

How does your truck sound with this setup? I know most folks love the deep loud sound our trucks produce but I'm looking for something quiet without affecting performance. 

 

Thanks!

 

Compared to stock factory restrictive exhaust the Silverline has a louder audible tone. The tone is deep and rumbly at idle and driving, turbo whistle is definitely more noticable. The YouTube videos I listened to before buying didn't do justice to what the system actually sounds like. I actually like it a lot because it's not raspy like most aftermarket straight through diesel mufflers are, it doesn't sound like a farm tractor, and it doesn't drone at freeway speeds. 

[Mopar1973Man]

I can tell this between 13 years of 3-inch exhaust and now nearly 2 years of 4-inch diamond eye exhaust... The 4-inch is louder even with muffler installed. Then there was zero EGT difference and zero MPG difference. Made no performance impact. Being I hit my highest MPG on 3-inch exhaust.

[Rogan]

9 hours ago, Mopar1973Man said:

I can tell this between 13 years of 3-inch exhaust and now nearly 2 years of 4-inch diamond eye exhaust... The 4-inch is louder even with muffler installed. Then there was zero EGT difference and zero MPG difference. Made no performance impact. Being I hit my highest MPG on 3-inch exhaust.

I agree with Mike 100%.  However, a fuel-miser like himself would not see benefit of a larger diameter exhaust, other than for audible tone gains. 

However, in a high-boost situation (here's where thermodynamics come into play), this is where you'd see the difference in stock 3" vs larger exhaust sizes.  As your boost levels increase, so does your IATs, cylinder pressures, and EGTs.  With the much hotter air leaving your engine, the molecules are greatly expanded.  The stock 3" piping doesn't allow for the added expansion of the gasses and slows down the flow through the system.  As they travel down the pipe, they cool and contract, requiring less 'volume'.So even a 4" downpipe into a 3" exhaust would still help a bit.   Bear in mind, though.  The choke point on the HY/HX is the 3" turbine outlet in a high-boost situation.  The faster you can get the exhaust gasses out and away from the engine, the less heat-soak you encounter.

 

But if you are a mileage chaser, you'll get no gains in anything, other than loudness and tone. 

[Mopar1973Man]

My average cruising boost is 2 to 3 psi. Then cruising EGT's 550 to 600 degrees. If you where to measure post turbo I'm going to bet it's about 100 to 150 degrees cooler. 65,000 miles a year and 90% of the time cruise is set a 65 MPH.

[Rogan]

18 minutes ago, Mopar1973Man said:

My average cruising boost is 2 to 3 psi. Then cruising EGT's 550 to 600 degrees. If you where to measure post turbo I'm going to bet it's about 100 to 150 degrees cooler. 65,000 miles a year and 90% of the time cruise is set a 65 MPH.

Exactly my point on you gaining any benefits from a larger diameter exhaust.  65K mi a year?  and that truck only has 350k on it?

[Mopar1973Man]

This why most performance add-ons do nothing for the performance like custom intake horn, and exhaust because the normal daily driver isn't going to flowing enough my make a huge difference. 

Edited August 30, 2018 by Mopar1973Man

[Tittle Diesel Performance]

13 hours ago, Rogan said:

I agree with Mike 100%.  However, a fuel-miser like himself would not see benefit of a larger diameter exhaust, other than for audible tone gains. 

However, in a high-boost situation (here's where thermodynamics come into play), this is where you'd see the difference in stock 3" vs larger exhaust sizes.  As your boost levels increase, so does your IATs, cylinder pressures, and EGTs.  With the much hotter air leaving your engine, the molecules are greatly expanded.  The stock 3" piping doesn't allow for the added expansion of the gasses and slows down the flow through the system.  As they travel down the pipe, they cool and contract, requiring less 'volume'.So even a 4" downpipe into a 3" exhaust would still help a bit.   Bear in mind, though.  The choke point on the HY/HX is the 3" turbine outlet in a high-boost situation.  The faster you can get the exhaust gasses out and away from the engine, the less heat-soak you encounter.

 

But if you are a mileage chaser, you'll get no gains in anything, other than loudness and tone. 

 

I don't have the mathmatical conversion in front of me but actually for a tuned only 24v VP44 truck 3" straight pipe/flow threw muffler actually moves just enough CFM at sea level conditions under full available fuel and rpm the injection system and head can support. I had a chart showing the capabilities of CFM of 3"-4-5" ID tubing and unless your running a cam, larger turbine, compounds etc above stock levels then it actually works fine. One part you left out though is turbine scavenging, 3" in theory under wide open conditions can chase a small vacuum behind the turbine wheel pulling the exhaust threw the wheel more efficiently when the WG isn't open. As for thermal dynamics the heat post turbo changes very little from 3 to 4". Most poeple go 4" for sound, room to grow later, and everyone who makes Diesel setups start at 4" to maximize potential performance being they don't know if your truck is stock or 1000hp so they essentially over-do it. 3" sounds nice some times, 4 does also, 5 does too. Depends on which sound your going for and how much potential power your gonna make in the future. 4" was tested on the dyno years back on a common rail to determine when 4" can't flow enough volume and power would start to fall off due to back pressure. They made 1150hp on the dyno before they got a 1.5hp loss lol the CFM rating to HP is potentialled to support 500-600hp before restriction comes into play. Of course there is a lot of factors involved in that, what engine, turbo, manifold, tuning, fuel etc but along the basic principle line 3" is technically enough. If I find my notes on it I'll copy it over for you. 5" is all sound, and what a sound it is!

12 hours ago, Mopar1973Man said:

This why most performance add-ons do nothing for the performance like custom intake horn, and exhaust because the normal daily driver isn't going to flowing enough my make a huge difference. 

 

Yeah intake horns, grid heater delete, 3.5" intercooler tubes, and billet compresseor wheels are all a joke. Extremely little gains unless your running extremely high rpm, large cylinder heads, cams etc for intense air flow. Stock trucks=0 gains. But the "dual ram" style intake horns have known to show a few HP gains even on stock tuned trucks . The stock cast plenum doesn't flow to the 5-6 cylinders well at all, the second horn above those cylinders do give a little more air and lower individual cylinder IAT's since the air in the plenum has less time to transfer thermal energy. Granted there isn't much time to do so but there have been some dyno A-B tests independently on a 12v P pump truck with no fuel plate and they gained 6hp/27lbsft with no other changes just from more volumetric efficacy. There was like a 40-50* peak EGT drop. Cruise conditions weren't tested but that is one modification that does show some form of gain.

 

if you go to 4th gen stuff the intake horn makes a difference, specially 6.7 engines in general. There pretty restricted due to emissions restrictions.

[Mopar1973Man]

35 minutes ago, Tittle Diesel Performance said:

Yeah intake horns, grid heater delete, 3.5" intercooler tubes, and billet compresseor wheels are all a joke. Extremely little gains unless your running extremely high rpm, large cylinder heads, cams etc for intense air flow. Stock trucks=0 gains. But the "dual ram" style intake horns have known to show a few HP gains even on stock tuned trucks . The stock cast plenum doesn't flow to the 5-6 cylinders well at all, the second horn above those cylinders do give a little more air and lower individual cylinder IAT's since the air in the plenum has less time to transfer thermal energy. Granted there isn't much time to do so but there have been some dyno A-B tests independently on a 12v P pump truck with no fuel plate and they gained 6hp/27lbsft with no other changes just from more volumetric efficacy. There was like a 40-50* peak EGT drop. Cruise conditions weren't tested but that is one modification that does show some form of gain.

 

In all that said... 90% of the people here set their cruise control for 65, 75, or 85 MPH and not think about it. The daily driver there is next to zero gain to be had with exhaust or intakes for a daily driver. Yeah, if you jumped on a dyno or raced quarter mile now these little tidbits will add up to little off your quarter mile time or just a few extra HP/TQ in the curve. Still, in all majority of the people on this website drive their truck to and from work and haul trailers up and down the highway. I've learned long ago not to bite the hype of performance this or performance that because those number only applied to someone that was WOT all the time. Now the daily driver whole different story and different factual numbers come from them.

[Guest 04Mach1]

My butt dyno and fuel gauge measured zero benefit to replacing the OEM 3 inch exhaust with aftermarket 4 inch exhaust but the cool factor was improved by looks and sounds good and replaced the rotted OEM exhaust. The more I work on raped Dodge, Ford, and Chevy diesel trucks the more I realize the bolt ons are mostly "COOL" and do little for funtional engine improvement for the average Joe with the daily driver or tow rig pulling the fifth wheel RV.

 

My favorites are still the kids that spend a ton of money for all the bolt ons then put a tuner on with canned tunes that throw a ton of timing and fuel into the engine causing increased cylinder pressures leading to quick catastrophic engine failure like broken rings, pistons, or even rods with windowed engine blocks. I'm finding this particularly occuring on newer trucks with ATD and EGR deleted using aftermarket tuning. Just had a deleted 2016 Duratrash with 86k miles that broke a rod and windowed the block from bad aftermarket H&S Performance tuning. The owner couldn't afford the repairs and now is stating GM will cover it. He doesn't believe that he voided the engine warranty by deleting the ATD and EGR. I wished him best of luck. I suspect he'll be pissed when the dealer advises him different.

 

[Ironforger]

On 8/29/2018 at 4:20 PM, Dieselfuture said:

This is what it says in description. "

The kit fits right up to the factory cast iron elbow that comes of the turbo. "

So it's meant to be used with a 3in outlet that hx/hy35 have. If you're not planning on upsizing the turbo this would work good. 

 

Thanks. I've researched a bit on the exhaust brakes, most of them replace the factory cast elbow. So that's simple. No modifications needed to the exhaust.  Lots of great info in this thread. Much appreciated. So I think I'll get the 4" stainless diamond eye setup with muffler. It's actually about the same price or cheaper as the oem system replacement anyway and will never need to worry about it rusting out. Previous owner of my truck had it setup as a welding rig, straight pipe no muffler. It's just too loud and my neighbors hate me so I'm sure the diamond eye with muffler will be an improvement. Just a work truck. Not looking for bad-*** sound or performance. Tempted to get an edge comp or juice, but I need to learn more about the edge products.

[Mopar1973Man]

2 minutes ago, Ironforger said:

Tempted to get an edge comp or juice, but I need to learn more about the edge products.

 

I would only suggest an Edge product if you plan on remaining STOCK injectors. I would suggest Quadzilla for people planning on running larger injectors. Problem, I had with Edge Comp even with RV275 was it was impossible to tune out the smoke. Then the timing is a canned tune so you never really get the tune you need. This was a reason back in the day of being forced down to 55 MPH because as soon as the engine load rises the timing dropped like a rock.

 

5 minutes ago, Ironforger said:

I've researched a bit on the exhaust brakes, most of them replace the factory cast elbow. So that's simple.

 

I would look at PacBrake if you are going to do an exhaust brake setup. Much better than my old school Jacobs brake.

 

6 minutes ago, Ironforger said:

I'll get the 4" stainless diamond eye setup with muffler. It's actually about the same price or cheaper as the oem system replacement anyway and will never need to worry about it rusting out.

 

Just consider the thought of the aluminized diamond eye. The factory exhaust was made with the same aluminized pipe as well and went all these years. Stainless pipe from what I found out typically cost more but will not last much longer than the aluminized pipe. I've got the 4" Diamond Eye with muffler now. Very quiet system. The aluminized pipe is holding up great against the salt on the highways. Just the clamps will rot off before the pipe does. 

[Ironforger]

4 minutes ago, Mopar1973Man said:

 

I would only suggest an Edge product if you plan on remaining STOCK injectors. I would suggest Quadzilla for people planning on running larger injectors. Problem, I had with Edge Comp even with RV275 was it was impossible to tune out the smoke. Then the timing is a canned tune so you never really get the tune you need. This was a reason back in the day of being forced down to 55 MPH because as soon as the engine load rises the timing dropped like a rock.

Great info, good to hear feedback from someone experienced with the Edge products. I'll research further before dropping money on a tuner or injectors.

4 minutes ago, Mopar1973Man said:

 

 

I would look at PacBrake if you are going to do an exhaust brake setup. Much better than my old school Jacobs brake.

Thanks! I'll look into the PacBrake setup.

4 minutes ago, Mopar1973Man said:

 

Just consider the thought of the aluminized diamond eye. The factory exhaust was made with the same aluminized pipe as well and went all these years. Stainless pipe from what I found out typically cost more but will not last much longer than the aluminized pipe. I've got the 4" Diamond Eye with muffler now. Very quiet system. The aluminized pipe is holding up great against the salt on the highways. Just the clamps will rot off before the pipe does. 

Good info. Thanks!

4 minutes ago, Mopar1973Man said: