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Are IDI's worth my time and money

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
Ive been thinkin lately about gettin a 80-86 diesel and im wonderin if there any good or should I just stick to my gas motors. Ive never owned a diesel before but have enough sense to know that they dont rev as high as a gas motor unless its a detroit. Im kinda gettin tired of workin on the same thing and want to try a diesel out.
 
The IDIs are strong motors and you can put on a turbo for alot more power. They have alot more torque than a gasser and are a whole nother experience to drive.
 

polarbear

just growing older not up
12,878
607
Boring, Oregon
We got any IDI owners on the forums? Won't hear me say much bad about them- didn't have th epower the later PSD's did, but they seemed durable enough.
 

LEB Ben

Arrogant A-hole At-Large
34,919
1,124
outside your house
The IDIs are strong motors and you can put on a turbo for alot more power. They have alot more torque than a gasser and are a whole nother experience to drive.


x2...I hear nothing but good about IDI's, except for the fact that they were waaaaaaaaay underpowered. But nothing a turbo can't fix right?
 
x2...I hear nothing but good about IDI's, except for the fact that they were waaaaaaaaay underpowered. But nothing a turbo can't fix right?

And really with trucks it can be argued that torque will win over power in the majority of applications anyway. ;)
 

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
I was figurin on gettin one with the banks turbo already on it. Ive seen a couple of em in the local classifieds with the turbos on em. My dads buddy has a 7.3 without the turbo but he went to a junkyard and found one and put it on there. Whats the difference between the 6.9 and 7.3? Could I just do this instead of banks?
 

Fellro

Moderator
Staff member
Somehow I overlooked this... Anyway, it all depends what you want it to do as to whether you will be happy with it. If you like torque that keeps giving, but isn't the fastest vehicle on the road, you will be fine. These motors will pull down a bit, bit set up right, will do just fine. I won't claim they are fast, but then, when these motors were built, reliability mattered more than racing the lights, and the insane torque/hp numbers were but a dream. It takes a bit more to get the kind of numbers that the powerstrokes get by plugging in a chip, but the injection system is so much more simple, reliable,and cheap to maintain in relation to the PS's. I don't currently have a turbo on my 6.9, but I have no issues pulling a 7000 pound horse trailer through the mountains of southern West Virginia. Doesn't do it fast, but I hang right with the semi's. Of course, my load wasn't included in that number. All done and said, my total weight was closer to 20,000, and only two times did it make me pull down to 30 mph, most of the time was 45. Not fast, but it did it all the same. With a turbo, it obviously would have been better yet.

Out here in the midwest, I don't have those nasty slopes so much, so I run loads like my two car trailer which weighs in at 7000 + 2 cars that were around 3-4000 each and got down the road fine. Overdrive on my truck would be nice, but if you are chasing after 87-94, you should be able to get a ZF or E4OD. Personally, I think these motors respond better to a manual trans, but that is my opinion, not a proven fact.

As far as the turbo goes, you can add a turbo to a 6.9 from a 7.3 just fine, it will bolt up. The differences between a 6.9 and 7.3 are internal. Head bolt size, valve guide style, and a little more cylinder wall are the main differences. Otherwise, everything will trade between the two. Some believe the thicker cylinder wall makes the 6.9 a better motor choice, as there is possibility of the 7.3 cavitating through or cracking, while the 6.9 doesn't tend to have those issues. The later style glow plug controller is more desirable, but the older style can be dealt with.
 

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
Thanks for the replies guys. I really dont care if its fast if I want fast ill drive my 76 or 85. What other mods can you do to em besides a turbo?
 

F 150Cobra

"Wild HoRsE" Got Torque?
3,642
104
Aruba
btw a detroit doesnt rev high.. when its at 2500 it sounds like its at 5000 becuase its a 2 stroke diesel engine..
 
Thanks for the replies guys. I really dont care if its fast if I want fast ill drive my 76 or 85. What other mods can you do to em besides a turbo?

Exhaust? Intake? Intercooler + turbo? Forge the internals for higher boost from the turbo? :p :rofl2: 'smiliedoh'
 

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
Well I mean other than exhaust and turbo I was figurin on that anyways. What exactly does an intercooler do? I saw somethin about marine injectors. Do I just find a boat with a diesel? Not lookin to spend a ton of money on stuff that dont need to get done.
 

Fellro

Moderator
Staff member
You can get marine injectors without having the boat... the idea is that they deliver more fuel. Once again, it depends how much you get carried away with it
as to what you need to be doing. First, I would get the fuel turned up, a simple adjustment on the pump, get the exhaust to be as large as you can get away with, open up the intake, and see what you think at that point before going any further. You can get a factory exhaust from someone that is upgrading their powerstroke as an upgrade.The factory put on pretty small pipes...
 

Fellro

Moderator
Staff member
Didn't literally mean the engine itself, but rather the intake hose into the air cleaner. If you get a look, there is a 4" hose from the air cleaner to a plastic pipe that runs under the power steering pump. That pipe flattens out to what many call the pancake section, which is about maybe 2" by 4", a heavy restriction. Then it sits right behind the rad support, which does a good job of blocking airflow... What many do about this is to put some kind of piping through the rad support to draw off the grille area, a bit of forced induction. I used 4" exhaust pipe, cut a hole through the rad mount, and fastened it to it. I also put a screen out in front to catch bugs and debris. I have no pyrometer to tell me anything, but have seen claims that EGT's went down with that simple mod. I'll have to get pics some time... I have the 4" intake and 3.25 exhaust... the factory pipe size was 2.25".
 

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
I see I dont have the truck yet gotta sell some parts from moms totalled 99 first but I know what your talkin about. I was readin the other posts in this section and came across some guys talkin about a "soup bowl" what is this?
 

Fellro

Moderator
Staff member
The debate rages on whether removing the soup bowl makes a difference or not... I should maybe throw one on mine just to see if it makes any difference.

It is the extension of the air cleaner lid down toward the intake. I believe it's main existence is noise reduction, and not sure it makes a restriction as claimed. My 86 came without such on the lid, but did have the hole at the bottom of the air cleaner restricted to about half the size. I cut that out, because that was an obvious restriction. My dad's 84 has the soup bowl on the lid, so I should experiment sometime to see if it makes any difference...
 

Fellro

Moderator
Staff member
It doesn't matter, and if you go turbo, it won't be there anyway. If it had the bowl, you could cut it off if you didn't want it.
 

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