N/A IDI Turbo Conversion

[BlueHound]

So I’ve got a 1991 F250 4x4 with a N/A 7.3 IDI and an AOD 4 speed. I’ve been looking to turbocharge my truck but I need to know the specifics on a couple things:
-First do I need to get new pistons and rods. I’d heard that the N/A IDI’s had dome top Pistons and the turbo models had flat tops making it a death sentence to turbo the N/A’s.
-Second do I need to get a new injection pump to keep up with a turbo.
-Third do I need to get new heads and valve covers.

 

[Thewespaul]

Haha I don’t know where you read any of that but no to all of that. Only thing you may change over is the valve cover if you are using an ats style kit which relocates the cdr valve

 

[Hydro-idi]

So I’ve got a 1991 F250 4x4 with a N/A 7.3 IDI and an AOD 4 speed. I’ve been looking to turbocharge my truck but I need to know the specifics on a couple things:
-First do I need to get new pistons and rods. I’d heard that the N/A IDI’s had dome top Pistons and the turbo models had flat tops making it a death sentence to turbo the N/A’s.
-Second do I need to get a new injection pump to keep up with a turbo.
-Third do I need to get new heads and valve covers.

You heard wrong. That’s all a bunch of made up junk whoever you heard that from.
You can turbo an N/A engine without any problems. However, it is strongly advised that you replace headbolts (preferably ARP) & headgaskets when making the swap. These engines Achilles heel was definitely the headgaskets & 6.9 headbolts.
While heads are off, get them rebuilt by a reputable machine shop in your area.
You don’t necessarily need a new injection pump but if yours is old & worn out, your turboed engine will definitely benefit from a new IP and injectors. It’s also advised that you replace both the IP & injectors at the same time.
If you are going to use your old IP, you can increase the fuel output to compensate the extra air that the turbo will provide to your engine.

 

[BlueHound]

So there’s no need to worry about the Pistons?

 

[Thewespaul]

No need. The na idi internals are good for over 400hp

 

[BlueHound]

I’m not necessarily going to make lots of horsepower, but my concern is that the dome top Pistons with 22.5:1 compression combine with 8-10 psi will be game over for my old beast

 

[saburai]

It’s not necessary going to make lots of horsepower, but my concern is that the dome top Pistons with 22.5:1 compression combine with 8-10 psi will be game over for my old beast

I just finished the bulk of my ATS installation on my '90. Since my beast is older, I sincerely hope not

Seriously, there are many online this forum who have added a conservatively boosted turbo to relatively high mileage NA idi's with excellent results.

 

[typ4]

Good god where does this crap come from.
There are NO dome top pistons in these engines, all are the same compression ratio. 21.5-1
Turbo it, Run it.
Even a stock pump will feed a turbo engine without being touched and make a remarkable difference.

 

[Thewespaul]

You must be registered for see images attach

Here’s a 7.3 idi na block I have.
Hmm no domed top pistons here, must be something in the water...

 

[BlueHound]

Well that’s a relief. Thanks Guys.
Would any of you by chance have a recommendation on a kit that is easier to install or are they all about the same

 

[saburai]

Russ might be able to assist...

 

[Thewespaul]

Pretty much all the same, but the older they are usually more challenging. I have a kit for sale if you are interested.

 

[BlueHound]

I would be interested but I wouldn’t be able swing the cash right now.

 

[Thewespaul]

I would be interested but I wouldn’t be able swing the cash right now.

I hear ya there! I’m asking $700 for the kit since it is used so quite a bit cheaper than the new kits available

 

[Rossroams]

A used ATS isn't too bad, just make sure you can get the 2 piece up pipe apart before hand. I've already broken a rubber mallet and used a can of WD40!