Why the 7.3L NA
 

I don't want to insult the owners of these trucks but why did Ford & IH/Navistar build the 7.3L motor/engine. It seems the 6.9L is better in everyway. I know every change Chrysler/Cummins did [intercooler '91.5, catalytic converters in California (and later evrywhere else), computer controlled 24V '98.5 and the new 6.7L (w/ particulate filters)] was always because of emissions requirements. Was it the same deal here? If it was I must be missing something, it looks like a typical case of change for the sake of change.
Maybe the bump in displacement made more power to compete against the up-coming Dodge CTD???????????
Also it would be cool to have the HP and torque ratings of the different engines and years of the IDIs.
After '94 Dodge's canged with the transmission type even so it gets complicated. I have a feeling Ford didn't do that, smarter.

Really, there isn't that many changes with the Dodge/Cummins or the 6.9 to 7.3 Fords.
Cummins went to the 24V for fuel efficiency and emissions requirements. The CRD was introduced to build a quieter engine to compete with the Ford and Duramax. The 94 transmission change was made because they couldn't make the available auto and Getrag survive behind the 5.9.

Ford's bump to a 7.3 was simply a displacement increase. There were no major engine changes to go along with it. They've had a few changes in the years. Not just for the sake of change, but to try to improve on what they have and get the edge on their competitors. Like Dodge and Chevy, some of the changes were good, some were not.

Jason

Some clarification on the Dodge side of things, I guess were getting into another brand here but I like the correct info to be perpetuated.
One the late '93 manual Dodge CTD trucks already had the New Venture NV4500, not because the Getrag was as terible as it's reputation but because the NV4500 is the best. I don't know a lot about the Dodge autos after the 727 Torqueflite because I will never have an auto equiped diesel unless it's a swapped-in REAL Allison like my two 545s. As far as I'm concerned they all should be sticks or REAL Allisons, not the kinda' Allison in the Chebbies. If you have an auto and like it and it shifts faster than I can that's great! I am only speaking for my self but I still don't think any of them have REALLY made a transmission worthy of their powerplants. I think the TF727,C-6 and TH400 with a few upgrades and an awesome torque converter were the best. If they neede an overdrive (which they did) slap on a GEARVENDORS and raise the price.
Second the "94 trucks had EXACTLY the same power rating as the "89-"93s had 160/400. BUT they had a much better (wastegate) turbo and a better Bosch IP.
Third the Common rail diesel doesn't appeal to me because I'll never have a computer controlled diesel and I really only care about diesels I can afford but, they were the quietest for a year or two.
Fourth the fuel effeciency increase of the 24V ,I believe, was a very beneficial byproduct of the computer controlled motor and the doubling of the valve count, but that's just what I surmised by interviews with the engineers @ Cummins (not by me personally). BUT I can tell you for a fact if it weren't for emissions requirements there would still be an inline Bosch 7100 IP and a 12V head on that motor today because everyone knows that was the epitome of reliability, simplicity tunability(mechanically) and power, especially the engineers thet desighned it and then had to change it because of gov't regulation.

There is a lot to be said for media hype and marketing. There has been no real change in engine design for 100 years. Its still based on the principle of using compression to slam chunks of metal back and fourth thousands of times per minute to get the job done. Emissions and power have improved, but efficiency has not. Changing the design of an engine is a way to get buyers interested. How many times have you heard the phrase "introducing, the ALL NEW [name of car/truck/suv]". There is no such thing as all new, and commercials that treat me like I'm some sort of idiot are one of may reasons why I will never buy a new vehicle. End of rant


This article is by Jim Allen, a member that chimes in on this forum for time to time, cool guy, anyway he has a good write up on the relatively recent diesel engines including the 6.9.

http://www.oramagazine.com/archive/2...-finesse-2.asp

Yeah, everyone is all hyped up about what vehicle is going to have a diesel next, I guess that's good but I DON'T CARE! They have too many particulate filters and computers and sensors for me- I like mechanical stuff.
They should have been building Jeeps, compact and mid-size SUVs years ago and they kind of tried but they didn't sell enough of them to keep them in production.
The Europeans, Australians, Africans...well I guess everyone but us, had figured it out a long time ago. I guess they had to be better at something.
I'll read that article by Jim Allen and see if I haven't already, I can't remember. His Old Iron articles are the first thing I turn to. And kudos to Fourwheel Parts for publishing it.
I try to spend my money with the little guy, because I am one! But I always throw 4wpts some too because of the mag.

Subaru has made the first diesel boxer its a 2.0 4 cylinder

93's already had NV4500's? Really... I've been shopping for one, and I sure haven't seen one with a 4500.

Ah well. The change from the 6.9 to the 7.3 was solely an emissions related change. They re-located the injectors slightly for a cleaner burn.
I don't have torque ratings on hand, but, most(not all) low altitude 6.9's are 175 HP, and low alt 7.3's are 185. The 7.3's torque peak is a good bit lower in the rpm range, but, that's solely a change in the pump tuning.

Hoven't worked on many of those Getrag trucks, huh? :) I've rebuilt a few of them. In the early years, they couldn't keep the Getrag's from coming apart behind the 5.9. Yes, the 4500 was the best, but that wasn't difficult given the reliability issues of the Getrag. I had a good friend who was the local dealer's Cummins tech from 89-95. So I got to see a bit of the carnage first hand.

I'm not one to be intimidated of technology and computer controlled engines (obviously the wrong forum to say that in). More precise fuel control, better mileage, cleaner air. Its win, win all the way around. In 1980, if you were to tell me that there would be an OEM car with 500+ horsepower that is capable of 20 mpg and be very driveable and mild mannered, I wouldn't have believed it. Variable turbos and computer control of diesel engines have given the same results. You can have the big turbo top end power without sacrificing torque where it is needed. 350 horse and 650 lb/ft of torque is hard to deny.
I think they made a huge step backwards with the '07 regulations, but that is government control. Not what the manufacturers wanted to do.

Jason

Here's a interesting opinion from a third party on the NV4500. I particularly like the quote "herd instinct" in the side bar on the right.
http://www.novak-adapt.com/knowledge/nv4500.htm

I don't think Getrags are that great but neither are ZF 5-speeds. They are both just OK as far as I'm concerned. Everyone has there own opinion. My ZF sounds like a miniature concrete mixer but it keeps working, granted it might have more miles on it I don't know as I don't know the history of the truck, but my Getrag has had Mobile 1 synthetic in it and a "slinger" filter since about 65K and it ackts like it's brand new. It is now in the mileage range where a lot of them go bad so we'll see what happens but for now it's perfect. I am also still on my orig. clutch but Dodge did put a better clutch in the Getrag equiped trucks than the NV4500 ones, doesn't make any sense.
Yes they absolutely did put some NV4500s in '93, they are hard to find. Greg Whale who owns I believe a '92 Club Cab and occasionally writes for off-road mags, Truck Trend and Turbo Diesel Register might have some info on when and how many. I don't think they are very common, as you have discovered. of course a lot of people have swapped them in place of their Getrag when it went south so you might find one in any year of truck. Obviously it's not the same trans. but A LOT of high-end cars especially Porche (which I also don't particularly love) have used Getrag transmissions/transaxles.

I still think the NV4500 is the best HD 5-Spd. it does have an O.D. retaining nut problem and obviously it's more complicated than a 4-spd. but all 5 and 6 speeds are.

I'm not "afraid" of computer controlled vehicles as almost every gas rig I drive on a regular basis is fuel injected and I like multi-port better than throttle body. I just like the reliabilty of mechanical diesels. I don't want a "brain box" stranding me in the Central Oregon desert, it's happend to others. Nobody has to like the same things I do, and they obviously don't. I'm just stating my opinion.
Another opinion: I'm full of them, or IT depending on who you ask, I think the emissions regulations are getting out of control, we've had cars for years that were actually CLEANING the air in some locals. I guess it's because I grew up in a conservative logging community but I'm tired of tree huggers trying to ruin everything I enjoy.

Poorly educated tree hugger at that.
Most of the same morons yelling about nuclear power are now yelling about co2 emissions.

It's unclear (at least to me) who that was directed at...

I'd be the last one to say that any of the recent implementations of pollution controls and such stuff makes any sense.

However, when I go outside today, the air is much cleaner than when I was a kid. It feels good. Also, we haven't cut down all the big trees. Logging is big, even today, but regulation has forced it to become sustainable. You can't deny that there is some good mixed in with all the crappy regulation nonsense.

Not everyone who is concerned about the environment we live in is a total wacko ;)

I just think they went a little TOO nuts with the diesel emissions.

I mean, light trucks have so much crap on them now and they get WORSE mileage than they used to. I still don't understand how using more fuel at the expense of lower emissions is so much greater?

Plus, how much particulate pollution are light diesels REALLY responsible for? Seems to me like trains, trucks, and construction equipment produce the majority, and nobody's making them meet these super-strict requirements.

Looked at a lot of cars all over the world in the past 8 years doing field service. I can tell you even though they use a lot of deisels in Europe they are getting just as tough on emisions as the US is. Not a lot of difference between how they build them there and how they ship em to the US. When I was in Australia last year for 2 months, you can't buy high sulfer off road deisel anywhere. It's all super clean Highway looks almost clear and we were running it in all the mine equipment and generators. You live around the more populated areas and they do smog checks there on cars and trucks. Talked to a road train driver and the company had to switch to Volves because of emisions and he hated them, missed his old Whites and Macks, the Volvo lost to much power in the heat. Africa sucks. You go to large population centers and it's just like LA was back in the 70's and the commercials are about air pollution. Lagos has tis brown haze year around, gets worse in the winter due to Hamatar, that's when they add the dust from the Sahara but I've been here 3 times and it's always bad as far as I'm concerned. They run their vehicles through the gears so fast they just lug them down so far. I had to tell my driver to down shift to 2nd at 20 MPH because he was in 4th in the land cruiser. What morons.

Actually they are tightening the noose on off road and heavy industry diesels as well. But since there are more diesels on the highways, thats what is focused on, since that will make the biggest difference for particulate emissions. Urea injection is on the way too (yes, thats not a typo). The cost on MPG will have repercussions later on when fuel shortages become more apparent. But seeing the big picture is not the mandate of any one government organization, like the EPA for example who only regulates air quality based on inhalable particles. So hang on to those old non emissions integrated diesels for god's sake! you will need them in the years ahead.