For the fact checkers - I meant to type in the last post that the 6.6 IH gas engine makes more power and torque then the 6.9 diesel. NOT more then the 7.3. 6.6 gas engine and 7.3 diesel are near equal. A 7.3 IH gas engine however will walk all over a 7.3 diesel as is the case with just about any gas versus diesel when bore, stroke, and aspiration are the same.

 

That is like saying the 6.4 twin turbo engine evolved from the 6.9/7.3

Just because the 6.9/7.3 came 1stdoesnt mean the the 6.4 evolved from it. Same goes for the 446 to the 6.9/7.3

 

He probably says "go fetch me some tin foil" when he needs to cover up some leftovers.

 

This post is for everyone, not just to you, jdemaris.

In spite of the arguing This this thread has been very interesting and informative although I haven't read every post yet.

As to your first point: The formulas used by the Mfrs. to calculate exhaust flow are probably the same generic formulas used to calculate air flow through any tubing, piping or duct work with various bends, elbows etc. such as used in HVAC duct design in large office buildings for example. (I was going to buy software to do that at one time- part of HVAC estimating software). These basic formulas were surely established in scientific testing laboratories with typical configurations of pipes, tube's, ducts, with bends, joints, elbows, etc. In my view I don't think it would be necessary for an automotive manufacturer to re-invent the wheel and establish new formulas for exhaust flow in an exhaust system, especially in a standard production vehicle.

An exception might be for some special high performance project application like a race car for the Daytona 500. Even then I don't think they would re-invent the formulas and would just rely on exhaust flow measurements. The resultant exhaust system is certainly going to be far superior to the standard production exhaust system and that fact alone should resolve this whole question!

ALSO, the way I see it, published data on the capacity of air flow out of an exhaust system is a nominal number at best and cannot account for resistances in the system due to varying conditions of fuel/air mixtures, exhaust gas temperatures, etc. which are scientific calculations and measurements far beyond what is needed for producing a mass production vehicle. See below:


The difference with specific reference to this ID diesel discussion would be variation in exhaust pressures, volumes and temperatures through the same exhaust system under different driving conditions. That flow can be estimated mathematically with consideration for those conditions or it can actually be measured under those various conditions, HOWEVER, they are not building a space probe to land on an orbiting asteroid, nor are they building a high performance vehicle for racing. They just want to build vehicles and send them out the door to be sold so, IT'S NOT ROCKET SCIENCE and GOOD ENOUGH is good enough - That is how I see it.

As for the second point: '"Old people" facts? Yeah, correct ones.'

In my view, you should understand that, at least in terms of exhaust, these published 'facts' are only in the context of what I described above and for practical use, not for precision rocket science for landing a robot on an asteroid or even for a high performance racing vehicle.

You are right, in a practical sense most so-called fundamental facts, accepted theories and proofs don't change for long periods of time unless and until someone discovers that the applied scientific concepts and proofs were in error which sometimes happens. We need these fundamentals to work with whether or not they are totally true and accurate.

I am an "Old people" and I will speak for myself. I am 65 and I have experienced a long term debilitating medical condition which caused some cognitive impairments (concentration impairment, etc.) due to that chronic illness plus the side effects of pain medicines. I've often compared this to what I imagined the beginning stages of Alzheimer's disease would be like. I have finally been CURED of this illness at great cost after much medical research!! It's a long recovery ahead but here is my point:

For my whole adult life I've been entirely obsessed with my own education and knowledge, this was my number one most powerful survival instinct and I WAS quite brilliant and an obsessed, if not gifted, problem solver. Since my disability began (decades ago) it has been a constant backsliding struggle to maintain the abilities that I once had which have been reduced by more than 50% (slowly coming back now, though). Thus the comparison to Alzheimer's, or the typical idea that when people get older they begin to forget things and are not as sharp as they once were.
I think the tendency is, with technical knowledge and math skills, if you don't use it you lose it.

SO, I do find myself very often writing things (such as in this topic and many others) to reinforce the fact that once upon a time I really was a very intelligent, perceptive and educated guy. I am very often trying to reinforce that for my own benefit and self esteem because I FEAR to loose it.

So, self esteem is an issue and for people who worked hard to earn that, it's not surprising to me that some people want to make it clear that they did work hard for it and are worthy of some respect for that.

Intelligence, education, perceptual abilities etc. are all relative to one's personal experience in this world, each being different so in my view every being is on equal terms, one being's personal experience is not more important than another's. The most can be the least and the least can be the most, it's all relative.

I think that a basic thing an intelligent person comes to understand is the incomprehensible amount of knowledge and information that one does not know and never will know so therefore we are as stupid as anyone else.

I am not a rocket scientist (although I did study that to some extent- really). I am just an old guy, low income with an old truck that I want to restore and this is the only way that I will have a nice 'new' looking truck.

THEN there are the far less educated in all of the technical mumbo-jumbo big words and smart talk, that come up with a simple one liner observation or thought that is BRILLIANT because it leads others to see the problem in a different perspective and may be (or) result in, a best solution!

Too much education and book knowledge, although great to have, can interfere with our abilities to perceive the problem from outside of that education box and perceive the problem as it actually really is rather than from a diagram and chart from a text book or reference book.

I hope that what I wrote helps people to understand part of what's going on in this topic thread and really, I don't like to see people get so stressed out from arguing.

 

That is a classic example of faulty logic. Like "Leroy" is a dog, and my friend is named "Leroy, ergo . . my friend Leroy must be a dog.

Since IH reported in their own corporate literature about building the 6.9 diesel from the MV-446 platform - I'll take them for their word. I find nothing strange about it. Not sure why you do. I've got two IH tractors here with the same basic engines in gas and diesel. BC144 in one (the gasser) and the BD144 in the other (the diesel). They share parts too - like the head gasket, main and rod bearings, wet sleeves. etc. But in this case - IH planned to offer them in gas and diesel formats right from the start. Seems with the MV-446 - it was outliving its usefullness as a gas engine and using existing tooling to produce it as a diesel made good business sense. Well - as least good by IH standards. They did almost go bankrupt from mis-management.

Saying "I wear a tin foil hat" does not change facts. I'm sure you wish it did. Maybe if you can conjure up some better ways to insult me - at least maybe it will make you feel like a bigger person.

Some of you people kind of surprise me. You don't have a clue how to work on an injection pump - so you lash out at someone who does. Same when someone states something you did not know. Like the GM 6.2 being designed by Detroit Diesel, or the the IH 6.9 diesel project. If you doubt the story about the genesis of the 6.9 - why not just research it on your own instead of trying to dispute facts by insulting me (like a little child might do).

 

My tin foil comment had nothing to do with hats....

Calling the 6.9/7.3 idi an IH is like calling aluminum foil "tin foil". Not an insult, but a good analogy.

You referenced the ih gasser to justify your labeling of the idis as IH. Talk about childish.....you could have written a few essays by now in a quest to justify your claims; claims of which were for what purpose exactly?

This has been so silly. You should start your own thread.

 

Stepping away from the tech stuff for a moment - some of my observations are as simple as this. My entire exhaust system fell off my F250 with a 6.9. Even part of the Y-pipe. It sounded like a garbage truck but not near as loud as a gas engine usually sounds with no exhaust. Driving that way for nearly a year ended up with exactly the same fuel mileage and I climbed hills the same speed. I.e. I observed NO gain at all.

Another first-hand example is the 1994 F250 turbo 7.3 I drive now. I took the entire stock exhaust off years back and got a custom system from Stan's Exhaust including a huge Donaldson muffler. Sounds a lot meaner. Absolutely NO gain in fuel mileage or power. Unlike my 6.9, my 7.3 has a built in restriction that is pretty hard to eliminate . That is - the exhaust driven supercharger. Turbos take away and add power at the same time. The point to having one is there is gain. Regardless - it is pretty limited with a 2 1/4" outlet on the turbo outlet.

There may be trucks out there that see a useful gain by just improving the exhaust. If so, I haven't had any. I heard the same claims for years with the GM 6.2 that came OEM with dual 2 1/2" exhausts (twice what my 6.9 Ford had). People were claiming they needed dual 4" exhausts to run. I kind of doubt it. Also installed a few Banks Powerpack exhaust systems that only showed a little benefit when the fuel was turned up. Those are my personal experiences. Your's may off course be different.

On a side-note. While working for a place that sold RVs back in the early 80s - we installed many parts that were supposed to give nice gains on gas engines. Crane RV cams, special intake manifolds, headers, large dual exhaust systems, etc. In reality - we observed very little gain from any of them except headers - and some higher RPM improvement with some of the cams. And with the headers - in the long run they weren't worth the aggravation. They throw off a lot of heat that can cause a problems, and they rot out. In fact - we had one customer who had "lifetime warranty" Blackjack headers that we replaced four times before the company went out of business. He eventually paid us to put his cast-iron exhaust manifolds back on.

Aftermarket turbo systems was where we saw huge gains. Only concern was engine longevity. But the ones we installed never had more then 8 PSI boost.
Only real issues I recall was when we installed a Banks turbo system on a Chevy truck with a 350 Oldsmobile diesel. It didn't last 20K miles. But many without turbos did not last 20K miles either.

Well - I'm going to take my "tin foil" hat off now.

 

You kind of lost me. But . . as I see it . . IH designed the 6.9 which is basically the same engine as the IDI 7.3. Just a diesel engine with the same Ricardo Comet precombustion-chamber IDI system like GM used in the 5.7s, 6.2s, and 6.5s. Until the Powerstroke DI engine came out- the engine was an IH design. The Powerstroke was designed under the new silly name . . i.e. Navistar. Same engine company. Just almost went belly up and shed a lot of other assets not related to engine and truck building.

By your reasoning - why do you call any Ford or IH engine a "diesel?" Rudolph Diesel had NOTHING to do with building these new engines. They just happen to share a compression-ignition system. So - to be fair - and for you to be consistent - you should not be calling any engine a "diesel" unless it was designed by Mr. Diesel himself - correct? Bad enough that Mr. Diesel did not invent the first "diesel" anyway.

 

I did not want to get involved in this but considering that you are a 'Post Guru' with well over 2,000 posts perhaps you are way too quick to write and way too slow to research to confirm that what you write is true and accurate.

It's not critical in this instance but misinformation can and does on occasion cause others to make costly errors, much added unnecessary work or expense which I have seen on occasion in Pre-Power Stroke IDI forum topics where I spend most of my time.

From the 'History' of Navistar International which is the history of International Harvester Company and it's truck and engine division, at Wikipedia:

I emphasized a series because these are the 6.9L/7.3L IDIs. The 6.9L IDI is without any doubt or question an International Harvester Engine and the 7.3L is the same engine with some modifications; larger bore, roller rockers, larger head bolts and a solid state GP controller and I suppose the turbo-charged IDIs are still the same series. That is based on what I have read in my studies and I am not an expert by any means. I believe that is why this history states a series of engines which are the 6.9L and 7.3L IDIs.

Secondly:
So technically you can call the 6.9L/7.3L IDIs a series of International Harvester engines and in my opinion that is essentially the most correct. However, for production after the 1986 name change these engines can be called "Navistar International" "Navistar" or "International" and also be correct. Keep in mind that those are just a name change for the original IH Truck and Engine Division.

In many other official ways, (stock exchange, SEC filings, etc.) Navistar International is still considered to be the same historic International Harvester company (truck division) under a different name since 1986.

You can read the whole thing here, including the relationship to Ford Motor company, just follow the table of contents at the 3rd paragraph:
https://en.wikipedia.org/wiki/Navist..._Motor_Company

Finally: That may be just trivia but I would like to say that after reading the posts of jdemaris I am in awe and very much impressed, to say the least, by his extensive knowledge and depth of his [very long term] first hand experience, not to mention his sacrifice of time and energies to bring some of that specialized knowledge and practical expertise into this forum topic.WOW! Unfortunately, some of that sacrifice was for nonsense like this name of the engine issue.

There are others who have shown extensive knowledge here too as well as throughout the forums and I for one greatly appreciate the time and energies that they all have sacrificed to bring that knowledge and information to everyone who reads the forums on Ford-Trucks.com. That is a very big thing (whatever you call it) as many thousands of people read these forum topics and will be doing so for a very long time ahead and I'm sure many will feel the same way.

Just THANK YOU VERY MUCH!

PS: However, don't let the internet rob you away from some of the most important things in your life, like taking the time to give your beloved pets the attention they deserve as you may deeply regret it later when they are gone

 

I suspect I do more hard research then the average wrench turner. I worked as a professional document researcher so have some training in that field. Anybody can write anything and there's no jury that's going to find them guilty or not guilty when it comes to accurate facts. That's why is important when doing research that "counts" to check the source citations used to write the book or article and see if the are primary or secondary documents- or just based on hear-say.

As I stated before - I never sat at the table of IH to see decision making going on. So I am just as reliant as anyone else here (that I'm aware of) of taking some other record-keepers word for things.

I have probably read every history in print concerning IH, Cyrus McCormack, et. al.,etc. I take everything I read with a bit of skepticism unless it is from a primary document - preferably straight from IH.

A few things I am sure of based on some primary info I've seen over the years.

#1 - the 6.9 diesel was built on the the existing engine platform of the MV-446 gas engine. That was stated many times in IH documents.

#2 the original name change was NOT originally to be "Navistar." It was proposed to be "Navigating the Stars." "Navistar" is a shortened version of that original name. Seems the longer original got dropped real fast and maybe was never adopted officially.

Now if you can show me anything taken from a primary "in house" document that states the 6.9 diesel was a totally new ground-up design - I'd like see it. Otherwise I'll stick with what I believe to be true taken from documents generated by IH and not a book writer.

Back to calling a 7.3 an "IH" or "Navistar" engine? Who the heck cares. I don't. I don't jump down someone's back if they call it a "Navistar." Why jump down mine if I see it as a IH product regardless of what name change evolved.n

In my world, the purpose of language and selecting words is so people can understand what is being talked about, in context. Does anyone here get confused when I call the 6.9 and 7.3 IDI an IH engine? I don't think so.

Like I said earlier. I don't see anyone getting upset calling the 6.9 and 7.3 a "diesel" even though they are both compression-ignition engines that Rudolph Diesel had little to do with. Now - maybe if Mr. Diesel had invented the first diesel engine - I'd be more understanding. But, he did not. Sir Harry Ricardo had more to do with what was used to build the 6.9 diesel then Rudoph Diesel did and yet he gets NO credit (Ricardo Comet precombustion system for IDI compression-ignition engines).

If not upset about using the diesel name - why so upset about me calling the 6.9 and 7.3 IDI an IH? That's a rhetorical question. At this point, I don't care anymore. I've kind lost respect for this forum. I've gotten jumped on for talking about how to repair injection pumps (taboo I guess)? Also for stating the fact the Detroit Diesel designed the 6.2 for Chevy and GMC. And of course the evolution of the 6.9 diesel as if creating a diesel from a gas engine was rare. It is not. Many companies have done it with great success and IH has done it with many engines.

 

This didn't occur to me at first but driving a diesel vehicle with a manual transmission is very much different than driving a gas engine vehicle with manual transmission.

When you shift the diesel and at what RPMS is going to make a significant difference in ones perception of "Performance" due to RPM, horse power and torque ranges being different than a gas engine. I can't cite those values off the top of my head but I think the best and most efficient RPM to shift this combination would normally be 1500 to 1800 (maybe up to 1900) empty and maybe a bit higher with a significant load or going up steep grades but don't allow the engine to go under 1400 RPM or you'll be lugging the engine which is not good for it. Some people don't seem to care and shift at higher RPMs.

People have different driving habits but for efficiency and optimum performance that is where I would start if I had your vehicle and modify that to your own perceptions of what's best. I almost NEVER romp on the fuel pedal because the engine can only efficiently burn as much fuel as the volume of air and heat of compression in each cylinder will allow. More fuel than that injected into the cylinders will be much wasted as un-burnt fuel and come out the tail pipe as black smoke with only a little extra power. There may be times when that is necessary for a little bit more needed power but it is not efficient.

Normally, in the 3 diesels I've owned and a few other's I've driven for work all of those manual shift except for my present F250, I've always let the engine decide how much fuel it likes- I just got used to driving like that and appreciate what a diesel does when all of these things are right and I LOVE DIESELS.

So possibly, your first diesel has better performance than you originally thought. Good luck, it sounds like you'll take good care of the vehicle.