I've gotten my hands on a 7.3 IDI with turbo from a '94 250 with 119K mi on it. I'm swapping it into my '94 F350 to replace my 7.3 turbo with head problems and 360K mi. Everything looks good except for the output from the turbos.

My original 7.3 turbo has a flanged connection with stainless steel clamp on the downtube to exhaust and muffler. The 250 turbo looks like it has some kind of slip joint. Both turbos have the same part number on the plates.

Looks to me like the easiest fix is to unbolt the output housing with the waste gate valve from my 350 turbo and swap it over to the 250 7.3 allowing me to keep the turbo with 119k miles on the engine and not having to fool around with exhaust pipes? Does anyone see a problem with this other than getting those 12 point bolts out. Anything else I should look out for?

Both engines are out and on stands so access is not a problem.

 

BTW - thanks in advance. This list has been a great!

 

You have a stock Ford 7.3 turbo engine in your F350.
The F 250 has an ATS turbo system on it.



ATS outlet flange left, stock Ford right.

The stock turbo is a 2.25" ID downpipe.
The ATS turbo is a 3" ID downpipe.

Your stock downpipe is also flattened out down by the bell housing area right picture.
The ATS is a 3" round pipe all the way down left picture.



ATS was the system that Ford used on the stock turbo engines, but they redesigned the turbo outlet and downpipe.
The ATS system is much better than the Ford system.

There is a possibility that the 250 engine was a factory turbo, someone just upgraded the turbo outlet and downpipe to the ATS system.

The Ford system costs you about 50 HP, spools slower and runs hotter.

 

Nothing is easy I guess - Thanks for pictures Dave- helps a lot.

I'm confused now - What exactly is ATS - is it a manufacturer or a design or what. Both of these turbos have a little metal tag that says "Garrett" on them and they both have the same part number.

Based on your reply and looking my situation over here is where I think I am.

My F350 7.3 has a stock Garrett turbo on the aluminum intake manifold side and a cast iron side with a 2.25" flange and has the flattened downtube.

The replacement F250 7.3 has a Garrett turbo on the aluminum intake manifold side and maybe the cast iron side also but it definitely has an ATS 3" flange on it and no downtube.

My options as I see them are:

A: Move the stock ford 2.25" flange over to the 250 7.3 and lose the 50 HP I never had and not have to deal with exhaust downtube issues

B: Keep the 250 IDI turbo as is and get a new downtube

But - 1.) If I do that don't I lose all the advantage of the 3" flange and downtube when I connect it to the rest of the exhaust system that looks to be 2.25" diameter all the way to the muffler.

and

2.) How do I fit the new 3" downtube in a space big enough for a flattened 2.25" tube.

I've been without this truck for months now and trying to get it running as cost effectively as possible. I'm kinda leaning toward option A

Sorry for the novice questions. I really appreciate it.

 

Advanced Turbo Systems is what ATS stands for.

http://www.atsdiesel.com/ats_new/

When Ford decided to add a turbo to the 7.3, they went with an ATS designed system.
But they did redesign the turbo outlet and downpipe.

Some say for clearance issues, some say because the ATS system made the IDI turbo more powerful than the soon to be released Power Stroke engine.

The ATS system can get you around 250 to 260 HP, the 94 Power Stroke only had 215 HP.
In stock trim, none of the Power Strokes exceeded 225 HP until 1999.

So in 94 when both motors were available, which would you choose.
A less expensive IDI turbo that was putting out 250 HP or a Power Stroke that cost more and was only putting out 215 HP?

Installing the ATS system as it came from ATS would have been a bad marketing decision for Ford.

In 99 Ford finally scrapped the flattened out downpipe on the Power Stroke, same one they were using on the IDI turbo, and the HP on the 99 Stroke jumped to 250 HP and the torque jumped from 450 ft pounds to 500 ft lbs.

You have to fold over the cab seam on the firewall for the 3" pipe to clear or install a body lift.

Yes if you connect the 3" downpipe to a stock exhaust, all gains will be lost.

The stock exhaust Ford used has been to small for a diesel engine from day one in 1983.
It took until 1999 for them to wake up and unleash the diesel power with a decent exhaust system.

Same can be said for the intake system.

Diesel engines need air, all they can get both in and out.

 

I have the 3" down pipe on my 91 f250 and it fits good...

 

Thanks for that reply Dave - it cleared up many questions. Whew!

Do you have any picture of how and where the body seam was folded over to make room for the 3" down tube?

While the engine is out I'm going to change the rear seal while it's easy to get to. I've already changed the valve cover gaskets. Can you think of anything else I should change while the engine is out.

A buddy suggested I change the front seal in the tranny (automatic) since the converter has been hanging on it for a couple of days already and it's easy to do now.

Thanks again

 

I went the body lift route.
A 2" lift was more than I needed.
I actually could have only raised the cab an inch and would have had plenty of room.