i have a 1991 f250 with a 7.3l IDI and i currently have a ATS turbo on it... i dont know what size it is i was wondering if anyone knew how to find that information out....
also i am looking to upgrade my turbo (reason i want to know what size it is) and also my fuel.
if anyone has any ideas for me that would be greatly appreceted.
money isnt really a problem but im a do it yourselfer and this is the second diesel i have had and i dont really know that much about it. (my first was a dodge used for pulling a horse traler not modified or anything like that) but im looking for speed and i want smoke but i know smoke is just more fuel. i know that the air fuel ratio is 18-1 but i dont really know where to start.
a shop in the area told me that my turbo bearings were bad and the previous owner told me the same thing. another reason im looking into replacing the turbo.
thanks everyone!!!!

 

rebuild the current turbo it has more than enough boost capability to blow the heads clean off.ya dont wanna go to far past 10 psi without headstuds.i have heard you can hit 15psi without studs but i dont know how long it would take it.for upgrades rebuild the turbo and install headstuds then turn up fuel and adjust wastegate

 

91ford250,
Welcome to FTE and the IDI diesel forum.

What size is the downpipe (exhaust pipe) and is your turbo wastegated?

ATS has 4 IDI turbo systems plus the stock Ford system was an re-engineered ATS system.

 

the downpipe is 3in. and my turbo is not wastegated.

 

thank you vary much for the info. my turbo is pushing about 9psi of boost now and i heard about studing the head, but wasnt sure (the guy who told me that has not been able to keep his truck together more than a week.) is that a hard job to do??? and i dont have a wastegate but i already have my fuel turned up all the way.
also is it hard to rebuild the turbo or would you recommend taking it to a shop to do... i have a vary reliable shop near me that alot of my buddys go to and have nothing but good things to say about them. (East Coast Diesel)

 

from what i hear swapping the bearings out isnt too bad.i have never done it so i couldnt tell you.im thinking david85 has done a few.headstuds are not hard to do but take a while because its best to torque them down in sequence 4 or 5 times.dave s. will tell you all about it.he probably had popeye arms when he did it.

 

The bad thing, if your truck has A/C the easiest way is pull the engine.

There are two head bolts on the passenger side that can not be removed with the head in place.

Also the bolts have to be in the head when it is installed on the engine in the truck, which makes torquing the head studs a real pain.

The only place I know of that has 7.3 studs is DPS, and thay are proud of them.

The ARP studs I used in my 6.9 stated run up to torque 4 times in 4 steps before the final install.
When I did mine I was watching the turns of the stud nuts as I did it.
The final install had about 1 more turn on every nut that I had on the first install.

A wastegated turbo let's you build boost at lower RPM without blowing the heads off at higher rpm and is adjustable for boost pressure.
With a non wastegated turbo, the only way to regulate the boost is with fuel settings and RPM control.

 

would he be able to loosen or take the cab mounts off and jack the cab up to give him a better angle instead of pulling the motor?

 

Head studs are almost 5" long if I remember right.

Check out the rear head bolts on the passenger side and see what you think.

The back bolt behind the rocker cover and the lower bolt below the rocker cover are two bolts I am sure you have to have in place when you do a head install in the truck.
And I think the lower rear inside bolt has to be in place as well.

After that you need to run it up to 100 foot pounds and remove them 4 times before the final time to 100 foot pounds.

Torquing them down alone would make it worth pulling the engine.
34 bolts installed 5 times to 100 foot pounds and removed 4 times from 100 foot pounds is like running 306 bolts up to 100 foot pounds.
Four steps each way, now you are looking at 1224 steps to torquing the heads down with studs.
My arm was tired after I installed my heads.

But I am old and sitting on an engine is not how I like to work anymore.
I want my feet flat on the ground when I am lifting heads and torquing bolts down.
Better for me and the job comes out much better.

PS oil contamination of head gasket surfaces will cause gasket failure with high boost.
Acetone wipe of the head and block surface right before gasket installation is critical.
Extra care to prevent surface contamination with the stud lubrication is also critical.

When you build a hot rod, extra care at every step is required.
You basically use the same parts as stock with a few mods, but every step is exactly right, not just close to how it should be.