I Just have to add WOW!!! But u know wat........?? I would never sell my 7.3IDI for anything! i almost did but i know i would have regreted it. I respect all of the diesels and agree with fact tat the PSD are over rated. Dodge/Cummins made a really good point about his 6.9 and completely agree. I may be only 23 and new to the whole diesel thing and my 7.3IDI but u know wat?? I learned so much about my truck from this site its unbelieveable. And from learning wat i did from this site and the users on it i didnt sell my truck and didnt buy a PSD!!! Long Live My 7.3L IDI Diesel!!! Mechanicals Rock!!

 

23 years I have been hauling loads like this with my IDI.




I fully intend to still be hauling loads like that when the Power Stroke is actually 23 years old.
Wonder if any of the 94 Strokes will still be running in 2017?

 

What kept you Dave? I was starting to wonder....

 

Work has been killing me.
Seven days a week right now, and usually way to many hours every day.

I am taking tomorrow off, going down home to have a cook out from my nephew before he goes to Afghanistan.

Plus I get to meet his German girlfriend before he gets engaged if I drive fast enough tomorrow.


Look at all the knowledge about the IDI back in 2000 or 2001.
Is it any wonder there is not many people that know much about them today?

 

OMG, I have to laugh at this post, solenoid valves in a HD diesel engine?......I could say more, but I pobably shouldn't

Try and take it easy tomorrow, Dave. No pay check is worth killing yourself over.

 

Just a few quick things. After reading a few forums on this site, I had no choice but to join. I have learned so much about my PSD just from reading. In response to a few things listed above, the IDI vs. DI: I like the DI with the ECM because it really does increase the fuel mileage, maybe not a lot, but its the small things. The only downside is the Electronic components. I have nothing against any of them, but my ECM fried about 2 weeks ago and it was a $1500 replacement. I know rebouilding an injector pump is not cheap, but doubt that it approaches this sum (feel free to correct). Trying to "soup up" the electronic engines also cost more than I would like, granted it can be variable on-the-fly so it is not constantly burning more fuel until you turn the screw back to the stock position, but an IDI is just that; adjusting the screw to modify the fuel flow to a slightly more/less amount (once again, feel free to correct).

 

One thing that I forgot to ask. Why is it that the 94.5 -97 PSD's use dual mass flywheels? I had my clutch go out, and almost passed out when I learned how much it cost to replace. I then found out about the solid mass conversion for it. I saw that on the DMF the spring dampeners are on the primary flywheel and that the clutch plate actually contacts the secondary flywheel. There is also a minor slip point between the primary and secondary flywheels. On the SMF kit the spring dampeners are on the clutch plate. Is the reason for this that the SMF are lighter-duty. The mechanic told me that it should be able to handle the same loads, but that the Transmission growl would be a bit louder (I have a manual I believe ZF5). Is this the only reason for the spring dampeners other than to absorb the RPM difference between the engine and the drivetrain? Also, why the hydraulic clutch, the people that helped me replace the Master and Slave cylinder had never seeen such a thing? There have been a lot of "firsts" on my truck. Thanks for all your help.

 

Actually the DMF Flywheel was designed to absorb the shock of violent combution process of the diesel engine. And absorb some of the added shock of an ill running engine. Like when the Inj's wear out and the truck does not idle smoothly. Or extreme cold weather starts. The SMF does not absorb these shocks as well. Thats why you get gear rattle noise with the SMF conversion.

Some say the added rattle of the SMF can cause premature wear of transmission parts, others scoff at the theory. There are places to get the OEM Valeo DMF flywheel for $500, or so.
IME: I've gotten over 150K miles out of my OEM flywheel. A perfectly acceptable lifespan IMO. And will be replacing it with another Valeo DMF, when the time comes.

 

I'd be leary of anyone who doesn't know of hydraulic clutches.
They are BY FAR the norm nowdays.
these guys must be used to working on pretty old vehicles.

 

I think we got off the beaten path with this question. The idi is a completely different system than the direct injection of the powerstroke.. The older idi engines ran with a mechanical injector pump and injectors that opened at around 1750 psi of pressure.. The 93 year introuduced a turbo motor for factory that turned 190hp and upwards of 300 lbs of tourqe.. This engine used a wastegated turbo. It also had internal changes with hardened exhaust valves and larger wrist pinned pistons. These ran a compression ratio of around 21.5 to 1.. The following year the power stroke was introduced with the new huei system. These were also wastegated turbos but no mechanical injecton pump but rather oil pressure induced injection. The 94 turned 225hp and also 400 pounds of torque. It also had a compression ration of 18 to 1.. Thus running cooler than the idi.. They also introduced a computer system for this motor to monitor and alter mixers and sensor control. So the 2 motors are very different. The older idi was chimed the bulletproof because many could run well past 300,000 with no changes whatsoever but the powerstroke has proven to do the same. So really the choice is yours.. I have an idi im rebuilding right now and it is not cheap.. it has 325,000 on it and its getting the works (crank gound, bored, new heads).. So everything can be expensive its all on your taste..

 

robpreuss,
Welcome to FTE and the IDI forum.

This usually happens when posts from the graveyard come back to life from the original post date of 2/21/2001, so it is almost 8 years old.
I don't even remember any of the original posters, but it looks like they were regulars in 2001.

The IDI /Power Stroke debate is just like the Ford/Chevy/Dodge thing.
Some like this, some like that.
What I like in a truck is probably completely different than what the next 20 people want to see from a truck.
That is one of the reasons there are so many different brands and models.

If you read the entire post, then read some of the more recent threads, you will see that opinions about the IDI have changed and a few are still pushing the IDI envelope to places it has never been before.
83 thru 87 6.9 NA IDI was 175 HP and arounf 300 Ft Lbs @ 1400 RPM with 22.5 to 1 compression ratio
88 thru 94 7.3 NA IDI was 185 HP and 315 Ft Lbs @ 1400 RPM with 21.5 to 1 compression ratio
93 & 94 7.3 turbo IDI was 195 HP and 388 Ft Lbs
94 thru 96 the 7.3 Power Stroke produced 215 HP @ 3000 RPM and 450 Ft Lbs @ 2000 RPM compression ratio dropped to 18 to 1 to increase turbo boost levels
97 was the first year for 225 HP and 475 Ft Lbs.
99 the HP went to 250 and torque to 500 @ 1600 RPM

It has continued to climb from there.

As for the dual mass flywheel, that was standard equipment on the 87 6.9 with the ZF 5 which has an aluminum transmission case.
The intent was to dampen the power pulses from the low RPM diesel engine since max torque is produced well below 2000 RPM.

 

I'm pretty sure the '94.5-'97 PowerStrokes had NON-wastegated turbos, which would explain why my '97 is so sluggish off-the-line.

 

I wonder if the aluminum case was part of the reason to use a DMF. Aluminum is a much noisier material than cast iron.

 

I do believe the aluminum case was the main reason for the dual mass flywheel.

Aluminum transfers more sound and is also weaker and softer metal.

Peak torque at 1400 RPM, that does put those power pulses rather far apart when you compare them to a gasser engine.

Read through the early posts in this thread again, things sure have changed since '01.
Some of that info was funny.
Not what you would hear from someone that actually worked on an engine.

 

okay this has probably been said but here is the skinny on it all

idi:
the idi's are a much more simple design. They have a mechanicle injector pump and a mechanicle fuel pump. The ip pressurizes the fuel in individual lines opening the injector which injects diesel into a swirl chamber. The swirl chamber swirls the fuel in able to help the diesel burn better. Idi's generally can get better mileage but they will not be able to create the kind of power that i direct injected diesel can.

powerstroke:
The powerstroke is a direct injected turbo diesel that has no injector pump it uses a form of common rail. this system works by sending fuel into two rails in the head while a secondary high pressure oil pump pressurizes oil to a very high pressure in order to pressurize the diesel. on a powerstroke the cam position sensor reads the timing and tells the computer what it is then the computer sends a signal to what is called the injector driver module (idm) the idm then sends a shock to an injector on its power stroke in order to open it so the diesel can be burned. The big limitation on a powerstroke is that there is only a certian amount of oil available to pressurize in a reservior. if you increase that and the fuel then 1000 plus horsepower is possible.

My 2 cents
In my personal opinion i would take the idi. I have a 93 idi and a 97 powerstroke they are both good trucks and they can do whatever i may need to do with them. However an idi sounds smoother and has cheaper parts. The fact is that the powerstroke has alot more sensors some good some bad. if your cam position sensor goes out the truck dies so you better have an extra in your glove box. If you pulled em beside one another and raced em the idi would lose. Call me crazy but i still feel more power in my idi though, to me its kinda like drivin an 18 wheeler lol.

That pretty much sums it up i dont know if anyone has already posted how they work but that was my attempt. by the way the only part i know for sure is interchangeable is the shrader valve, but you hafto have a 93 or 94 idi. lol.

ps
there was one idi that made around 1200 hp it was a 7.3 idi sleeved to a 6.9 and if i recall the owner was blowing the freeze plugs out of it and i think he cracked the back half of the block off i dont remember