Since I am quite new to the diesel scene please forgive the naive question but I am trying to figure out the efficiencies or inefficiencies of my 2001 F350 7.3 exhaust system.

I understand that the up pipes come directly off the exhaust manifolds from both banks of the engine feeding directly into the back of the turbo. In other words all of the exhaust gases from the engine must run through the turbo first.

Then the exhaust gases get routed through either the wheel of the turbo and/or through the downpipe which then allows the gases to exit the engine through the remainder of the usual muffler/exhaust system.

If I have this all right, then it seems to me that the exhaust flow from the cylinder heads is quite restricted at least until it passes through the downpipe. Does the changing of the up pipes help reduce this restrictive flow?

Does the use of a different turbo (perhaps with a bigger housing) assist in a better flowing exhaust process?

I know that having a bigger downpipe (4" versus the stock 3.5") will help and then of course either a 4" or 5" system all the way to the tailpipe.

The reason I ask is that I have had quite a few cars over the years and they all have been helped with aftermarket exhaust system especially when it comes to headers. On this forum there is very little discussion about headers for the 7.3 although they do exist.

Based upon my thinking above, it probably makes very little sense to change the exhaust manifolds to headers because the flow pattern is going to remain the same in order for the turbo to do its work.

I appreciate your comments. Again forgive my ignorance; I am trying to learn about this engine. Have already benefitted from this forum by changing to the proper oil, changing the fuel filter, going to biodiesel (B5), etc. Thanks

 

First off, welcome aboard. Second, your assumptions are essentially correct. Headers are availible but are usually not employed until you get into a situation where you are building a dedicated drag racing rig. For the most part, increasing performance works like this. Diesel are just like gasoline motors in the fact that all they really are is an air pump. The more air you can pump, the more hp you can make. The turbo helps in this process dramatically but it also makes upgrading a bit more compicated than for a gasser. The best way to make a stock rig better is like this. First upgrade I would suggest is better intake system. The Ford AIS intake is the best stock option availible. As far as cfm capability goes it can flow just as much as any aftermarket intake. Otherwise, there are several other aftermarket intakes that will work well as well. Next step would be the exhaust, at a minimum, you can swap the muffler with a better flowing design like the Walker BTM. A step up from that would be a cat back system and yet another step up would be a turbo back system that is either 4" or 5" all the way back.

Once you knock out those two, the third step in the upgrade process would be a turbo. Enlarging the various housings will flow more air, but will also change spool up times. Without going into tons of detail, you need to set your turbo for what you want to do. A quick spooling turbo will get you quick starts, but may not build as much power in the upper RPM ranges. A slower spooling, but higher volume turbo will start like a snail and be supper laggy, but when you finally get rolling it will pull like a son of a gun. These are good for dedicated tow rigs.

By this time, your system, is changed enough that if you haven't already done it, you need a tuner to help your computer manage the increased capacity. A next step might be larger flowing injectors and a larger flowing intercooler.

To correct my self, the TRUE first step should be a good set of guages. Pyro, Tranny temp, and boost pressure.

The thing with diesels is modding is a visious cycle and once you catch the bug, your hooked and you keep uprgrading and upgrading and upgrading and............................................... ...................................

 

I'll be in Vegas at the KOA behind the Circus Circus for 6 weeks starting Dec 1, stop by for a beer and some truck talk! I'll send you a PM with my site # and cell # after I arrive. In the meantime I've given a bunch of links below for your reading pleasure. These are some threads from the past several months, and now that I see the list, you'd better plan on at least 2 beers!

PSD Exhaust Systems...
https://www.ford-trucks.com/forums/672425-psd-exhaust-systems.html

Some interesting facts about HP...
https://www.ford-trucks.com/forums/669256-some-interesting-facts-about-hp.html#post5290668

On the one below, start at post #24 about how a turbo works as a "heat engine"!
I want to develop an idea i had for a diesel engine...
https://www.ford-trucks.com/forums/667504-i-want-to-develop-an-idea-i-had-for-a-diesel-engine-2.html

Estimating Your Maximum RWHP From 65-75 MPH WOT Acceleration Runs
https://www.ford-trucks.com/forums/667554-estimating-your-maximum-rwhp-from-65-75-mph-wot-acceleration-runs.html

A Quick Way To Estimate Your Dyno Results...
https://www.ford-trucks.com/forums/666835-a-quick-way-to-estimate-your-dyno-results.html#post5265024

What's The Net Volumetric Efficiency, VE (%), For A 7.3L PSD?
https://www.ford-trucks.com/forums/666686-whats-the-net-volumetric-efficiency-ve-for-a-7-3l-psd.html#post5267145

Turbo Surge, Turbonetics T61, GTP38R, & GT38 w/ 99.5 & Early 99 Wheels.
https://www.ford-trucks.com/forums/664991-turbo-surge-turbonetics-t61-gtp38r-and-gt38-w-99-5-and-early-99-wheels.html

Analysis Of Tenn's 6637 Restriction Data.
https://www.ford-trucks.com/forums/660609-analysis-of-tenns-6637-restriction-data.html

Equal MAF (lb/min) Does NOT Yield Equal HP!!!
https://www.ford-trucks.com/forums/659040-equal-maf-lb-min-does-not-yield-equal-hp.html#post5194401

When You Apply The Throttle, "The Tail Wags The Dog"!
https://www.ford-trucks.com/forums/658658-when-you-apply-the-throttle-the-tail-wags-the-dog.html

Engine performance vs increases in air filter inlet temp.
https://www.ford-trucks.com/forums/655390-engine-performance-vs-increases-in-air-filter-inlet-temp.html

MAF & RWHP With & Without An Intercooler!
https://www.ford-trucks.com/forums/654024-maf-and-rwhp-with-and-without-an-intercooler.html#post5152552

High Altitude Effects, Part 1 Cooling System (1 of 2)
https://www.ford-trucks.com/forums/653632-high-altitude-effects-part-1-cooling-system-1-of-2-a.html#post5157106

The Genedad 2 appears to be a success!
https://www.ford-trucks.com/forums/652772-the-genedad-2-appears-to-be-a-success.html

My rambling contribution to Tenn's CFM measurement project! (Part 1 of 2)
https://www.ford-trucks.com/forums/648181-my-rambling-contribution-to-tenns-cfm-measurement-project-part-1-of-2-a.html#post5084729

Drag Model Dissected... Need inputs to evaluate the pieces!
https://www.ford-trucks.com/forums/647127-drag-model-dissected-need-inputs-to-evaluate-the-pieces.html#post5073494

Getting ready to do some 6637 testing.
https://www.ford-trucks.com/forums/645117-getting-ready-to-do-some-6637-testing.html

A 340 RWHP F-350 vs an 800 HP Jet Powered Version... Who wins?
https://www.ford-trucks.com/forums/645343-a-340-rwhp-f-350-vs-an-800-hp-jet-powered-version-who-wins.html

Is this mod a first for a PSD pickup, and how do I analyze it?
https://www.ford-trucks.com/forums/644954-is-this-mod-a-first-for-a-psd-pickup-and-how-do-i-analyze-it.html

My Zoodad gave birth to a "Genedad"... comments welcomed!
https://www.ford-trucks.com/forums/642354-my-zoodad-gave-birth-to-a-genedad-comments-welcomed.html

Drag Race Analysis... An Interesting Story!
https://www.ford-trucks.com/forums/634460-drag-race-analysis-an-interesting-story.html#post4952627

I want 600 hp!
https://www.ford-trucks.com/forums/631407-i-want-600-hp.html

Torque Converters & Diesel Engine Breaking!
https://www.ford-trucks.com/forums/629052-torque-converters-and-diesel-engine-breaking-2.html#post4898894

HP & Torque... the REST of the story!
https://www.ford-trucks.com/forums/627653-hp-and-torque-the-rest-of-the-story.html#post4887611

 

Thank you Ernest.

I will take you up on your offer gladly. I am leaving for Australia on 11/30 to get married and won't be back until 12/27 but it sounds as though you will still be in Vegas.

WOW, I did not expect this amount of material but I will take a look at it all. I am not a mechanic by profession but I really am a gearhead who wants to know how things work to their best mechanically. I love performance but I really want to concentrate on making my F350 dually a very decent and more capable tow-rig for my 10k (loaded with 2 fine animals) living quarter horse trailer.

On my way to read. Thanks again. Ulrich

 

Yes, I'll still be in Vegas, I'll wait and send the PM when you return, or send me one if I forget.

BTW, if you've got nothing better to do during your honeymoon, check the local phone directories for a Joe Swartz, he's a High School buddy of mine, age 65, who moved to Australia years ago to get married, but unlike you, he never returned! I know he got divorced and was still there in 1990 and living at...

Joe Swartz
35 Rutledge St
Bungendore NSW 2621

I haven't got a clue where he is now, but If by chance there's only one name like that in the book, and it's a local call, tell him that Gene Kempe says hi, and find out how I can get in touch with him.

Have a safe trip, and I'll see you when you return. Bring your wife when you come to visit, she can go shopping with mine at a huge maul that's a short walk from the RV park, and we can drink beer and talk trucks!

 

Wow! You really need to start a thread on "How To Catagorize/Manage Your FTE Threads". That is sweet...