Those are Ford's stock numbers with the tiny restrictive air intake over the battery, small turbo outlet flange, smashed turbo downpipe, and a small very restrictive muffler and exhaust system.

An ATS system with a better intake, 3" turbo outlet and a free flowing 3" exhaust was capable of much more.
Same can be said for the complete Banks Stinger system.
Both of the aftermarket systems had numbers closer to 50% power increase with the correct fuel system mods.
50% would put an IDI around 277 HP.
Even a conservative 35% increase would put it at 250 HP.

As you consider this, remember Ford was introducing the Power Stroke 1.5 years after they installed a turbo on the IDI.
So if you went to the dealer for a new truck which would you buy?
An IDI turbo putting out 275 HP or would you spend more money for a Power Stroke putting out 215 HP?

In my opinion, that had a lot to do with Ford re engineering the ATS turbo and only advertising a 5 HP power increase.
And if you look, the Power Strokes from 94.5 thru 97 used the same smashed downpipe the IDI had, and the max power by 97 had only increased to 225 HP.
In 99 that downpipe was gone, and HP increased to 250.
It took until 2001 for the manual tranny 7.3 Stroke to get to 275 HP from the factory, the auto tranny stayed at 250 HP..

 

I can attest to the head gaskets.

My engine saw about 14 PSI on one hill climb when I first put the turbo on just to see how high it would go (hey, it was the honeymoon). But when I tore it apart there was erosion that happened behind the fire ring of the head gasket on two different cylinders. Not the end of the world and I still had good compression, but the damage was still done. I would say 10 PSI is as high as any 6.9 should go with stock head gaskets.

I only hit that high boost once, and the rest of the time 7-8 was the average maxumum boost, with 10 psi being the absolute max.

When I rebuilt my engine I dropped the compression slightly, added ARP head studs as well as manifold mods. Now I can't go above 10 PSI because of a minor boost leak on the intake (can't find that darn O ring for the intake snail chamber) and the injector pump being a little old. I'll probably add more fuel/turbo upgrades eventually because my engine could probably survive 20 PSI now.

Although it still does all I need as is and with the tall gearing I can cuise as fast as I want when empty.

 

That's exactly why I asked that, I didn't want anybody to think they could run 25# on their STOCK motor.

 

David is your truck a 6.9, and what PSI did you torque the head bolts to. Did you install 1/2 inch headbolts. Just curious.

 

Yes its a 6.9, and I think I torqued the studs to 90Ft/lbs (I know I went slightly higher than the instructions called for, but memory is getting sketchy). The bolts I used were an ARP aftermarket head stud kit that was purpose assembled for the 6.9. cost about $225. The diameter of the bolts were the same as stock and they simply thread into the factory threads, but the studs are over twice the strength of the stock head bolts.

 

Thanks for the reply

 

1/2" bolts use 13 threads per inch
7/16" bolts use 14 threads per inch

So going from a 7/16" bolt to a 1/2" bolt is not an option.
There is no way you could get enough thread to hold anything if you tried.

My ARP studs are torqued to 105 foot pounds.
Since the studs have fine thread nuts on top versus the course threads on head bolts, there is a lot more clamping force on the head gasket now.

 

Thanks Dave, I just keep asking dumb questions. Just got a mechanical autometer boost guage on ebay. I'll talk to the mechanic, he may want to change the head bolts. He is a great mechanic and I'm lucky to have him help me. He is also a certified aircraft mechanic (a&p) from a piper cub up through a boeing 707. He doesn't do much on aircraft anymore, because he is 75 yo, But he did some work on a buddy's cesna 150 the other day and he maintains his certification. The problem is he hates turbo's, LOL.
However he has a 350 powerstroke. He rebuilds and tests injectors for the IDI, and now is rebuilding and testing injectors for the 7.3 powerstroke.

 

The only dumb question is one that is not asked. Thats why we're here, ask away!

 

THAT'S RIGHT!!!!!!!!!!!!!!!

 

so how about another question i know dave and dodge/cummins have been helping me with info on the turbo setup i obtained so the real question is can you put together head studs because with the cost of everything so far with the turbo i won't have the 225 layin around to stud the heads my dad was a fabricator/machinist for dow for forever so i can obtain his help on this subject

 

If you are suggesting making your own studs, no you can't. Even if your Dad could get some high strength steel rod, machined and cut threads are not as strong as the factory threads which are rolled and formed.

 

Just keep the max boost in the 7-8 psi range and it will hold up for years. That doesn't sound like a lot of power, but trust me, even 5 psi will make the truck feel completely different.

 

Well now You've got Me scared I've been putting 14# of boost to the 6.9 for most of a year. Oh don't worry I wont turn it down it's way to much fun! But if it pop's I'll let You know. LOL

 

14 # on a stock motor?? I hope it never pops, but you are braver than I am.