Which exhausts connect right to the turbo?

[BDaugherty]

I have the stock 250K mile exhaust on my '03 Cummins. I'm considering either replacing the muffler or the entire exhaust. At this point, my question is: which aftermarket exhaust systems connect directly to the turbo and which ones connect the the cast iron elbow? I've been looking at PDF installation files and it can be hard to tell. With my truck being an '03, it has the smaller elbow. What is the benefit of direct turbo hookup vs cast iron elbow with respect to possibly installing a larger single turbo? Lots of questions in a short space, but maybe I can be enlightened.

 

[SierraRam]

I think you want to leave the elbow and connect to it. I have not seen any thet replace the elbow.

 

[AH64ID]

I believe they all connect to the elbow. But I would look for a 04. 5-07 elbow and get a 4" turbo back.

 

[JJPage]

I would look for a 04. 5-07 elbow and get a 4" turbo back.

I know this is the common belief, that will benefit, but not always the case, I will explain.

I was running a single 62/74/14 and having low end spool up issues(really???, not hard to figure now). After several phone calls with Industrial Injection, they determined I needed to change my 03 cast elbow to a 04. 5+ elbow to increase airflow. I obtained a new cast elbow and downpipe and replaced both. Spool up was slower and egt's were higher(at low to mid rpm's), seems the tighter elbow, by retaining heat and backpressure actually aided in spool up.

Only at WOT, high rpm, did the larger elbow benefit my application(and not measurable), and I believe this may be true on other's as well...

 

[Prairie Dog]

I think you'd find a normal pipe would burn out in that location plus, the elbow doesn't create any restriction.

 

[AH64ID]

Good info JJ, but I think on a HE341 the improvement will be across the board, but I am not sure as I have never ran a HE341.

 

[cerberusiam]

I was running a single 62/74/14 and having low end spool up issues(really???, not hard to figure now).

That is cuz that trubo is a P I G for spool, not really the elbows fault. A 62\71\12 works a lot better, even with the larger elbow.

The OP is running larger injectors and a TST on an HE341, good for spool but the larger exhaust should help a bit under heavier throttle. Spool should neot be a problem with that turbo even with a turbo back 4" exhaust. Some header pipe wrap and turbo boot will usually cure any issues that show up.

 

[JJPage]

What is the benefit of direct turbo hookup vs cast iron elbow with respect to possibly installing a larger single turbo?

Good info JJ, but I think on a HE341 the improvement will be across the board, but I am not sure as I have never ran a HE341.

Yes, on the factory turbo I can agree, but the OP was considering a larger single, so I was bringing some insight into possible non/issues.

That is cuz that trubo is a P I G for spool, not really the elbows fault. A 62\71\12 works a lot better, even with the larger elbow.

Yes, the 62/74/14 can be a pig, and not really the elbows fault, but can have consequences to the application. Prior to the 62/74/14, I ran a 62/71/14(12cm housing would have spooled faster) with the small elbow and downpipe without issues... until it came apart.



The OP is fortunate the HE341 is still intact, not many survive TST, unless they retained the factory boost elbow...

 

[BDaugherty]

Before I bought my current truck, I looked at an '03 6spd Cummins dually. It had what may have been a custom pipe coming right off the back of the exhaust housing going to a magnaflow muffler and then stock exhaust after that. I really didn't like the way it sounded. I'm currently torn between adding an aftermarket muffler in place of my factory one and just installing an off-the-shelf 4" system.

With regards to my factory turbo and the TST: My TST will back off at a preset boost or EGT level. Also, I nearly always run the TST on timing only or 40hp (1 or 2). It may be related to boost/egt derate or rail psi, but the truck isn't very smooth and really doesn't respond well to higher settings unless I keep the RPM's in the sweet spot. I don't know if it's just the nature of my HE341, but it just doesn't feel good and really seems to heat up in the mid 20's boost. My '01 with the HX35 seemed to come alive more.

 

[JJPage]

I really have not seen an OEM replacement exhaust system that eliminates the cast elbow, not sure there would be any gain one way or the other, it would have no affect on an aftermarket turbo. I have an MBRP system that I like, it does have a drone ever so slightly, it was more pronounced before the compound turbo's, it does not bother me. Whatever system, I would use the band/clamp type connectors versus the u-bolt clamps, then you can make adjustments later.



You have a newer TST with more sophistication than the earlier boxes, the original 03 twins program was snapping HE341 turbo shafts left and right, especially when adjustable boost elbows were introduced.



Let us know what you decide. Jess

 

[Shadrach]

Two things: First the elbow is where an exhaust brake goes, should you ever decide to install one and second the stock turbo ( should you ever decide to go back to one if you were to get rid of the truck ) comes with the elbow attached already. I have the same truck with a brake. I would leave it on there. I have about the same mileage on mine and the muffler is still original. I too am curious about replacement mufflers as sooner or later it will need to be replaced. I want to keep mine quiet. Shad

 

[goodguys75]

Two things: First the elbow is where an exhaust brake goes, should you ever decide to install one and second the stock turbo ( should you ever decide to go back to one if you were to get rid of the truck ) comes with the elbow attached already. I have the same truck with a brake. I would leave it on there. I have about the same mileage on mine and the muffler is still original. I too am curious about replacement mufflers as sooner or later it will need to be replaced. I want to keep mine quiet. Shad

live here in las vegas, it will last longer than the truck... ... mine is still shiny from like new.....

 

[Prairie Dog]

live here in las vegas, it will last longer than the truck... ... mine is still shiny from like new.....

Well sure but hows your dash and paint doing?

 

[MChrist]

Two things: First the elbow is where an exhaust brake goes, should you ever decide to install one and second the stock turbo ( should you ever decide to go back to one if you were to get rid of the truck ) comes with the elbow attached already. I have the same truck with a brake. I would leave it on there. I have about the same mileage on mine and the muffler is still original. I too am curious about replacement mufflers as sooner or later it will need to be replaced. I want to keep mine quiet. Shad

If you want to keep your truck quiet, and don't mind doing some fabrication, you could do what I did. . I went to our local truck repair shop and bought a 4" truck type muffler 30" long, 10" diameter. No drone and maybe just a few percent louder/deeper than stock. I think it was about $70.
No restriction, as it it 4" straight through, with expansion chambers to kill the noise. Those louvered ones seem to have a drone, from my experience.

 

[MChrist]

Two things: First the elbow is where an exhaust brake goes, should you ever decide to install one and second the stock turbo ( should you ever decide to go back to one if you were to get rid of the truck ) comes with the elbow attached already. I have the same truck with a brake. I would leave it on there. I have about the same mileage on mine and the muffler is still original. I too am curious about replacement mufflers as sooner or later it will need to be replaced. I want to keep mine quiet. Shad

If you want to keep your truck quiet, and don't mind doing some fabrication, you could do what I did. . I went to our local truck repair shop and bought a 4" truck type muffler 30" long, 10" diameter. No drone and maybe just a few percent louder/deeper than stock. I think it was about $70.

No restriction, as it it 4" straight through, with expansion chambers to kill the noise. Those louvered ones seem to have a drone, from my experience.

 

[Shadrach]

If you want to keep your truck quiet, and don't mind doing some fabrication, you could do what I did. . I went to our local truck repair shop and bought a 4" truck type muffler 30" long, 10" diameter. No drone and maybe just a few percent louder/deeper than stock. I think it was about $70.
No restriction, as it it 4" straight through, with expansion chambers to kill the noise. Those louvered ones seem to have a drone, from my experience.

Did the sound change? Years ago I put an HD type muffler on my 78 D200 and it sounded like a D600 delivery truck after that. Shad

 

[MChrist]

Sounds like a Cummins, just slightly deeper and slightly louder under power. At idle, more sound coming from engine than exhaust. Pulling out of driveway, I hear more engine than exhaust. Only when I get on it, do I hear a deep moan. I still have my cat converter, also, so that may alter the sound.
My truck came with one of those aftermarket louvered mufflers that was maybe 6" diameter and 15"-18" long. That muffler sounded deep and loud all the time with terrible drone while towing.

 

[AH64ID]

I run a 40" Donaldson truck muffler and really like it.

The part number is in the link in my sig.