While towing a heavy load today - appx 12,000 lbs - with my 1994 IDI that has a recent rebuilt engine with 4" exhaust and downtube, appears to be stock Garrett turbo, I noticed that the max boost I'd see was about 8-9 lbs. and that was only breifly and while getting up to around 70mph. It seems to run at 5lbs most of the time. Is that low? Could / should I do something to increase that? I will be towing this 44' gooseneck trailer with 2 x 3000 lbs cars and extra wheels, tools, etc. quite a bit and I'd like to make sure I am not doing anything to hurt the truck.
EGT and Tranny temp seemed to do very well for me. Also, my fuel usage was around 7 mpg with that heavy load, driving from the SC coast to inland NC.

Thanks,
Tom

 

You can increase the boost, but will probably have higher EGT's.
What are you running for the intake to the air cleaner?

 

Right now intake is stocck, but I am going to do something very similar to what you have done, with HVAC ducting parts from Lowes / Home Depot.
Yesterday while towing my EGT's maxed out at about 900, and that was pretty brief.
I have not messed with the engine at all, other than putting in some GP's to fix starting problem. My tranny guy says that there is a PIP code that can't be cleared, but not sure if that is an issue. Also, that the allen bolts for the IP are a bit mangled and he suggested that I not mess with it because he got it adjusted as good as it will go. No idea how the wastegate is set. The truck run well so I hate to tinker too much and risk doing any harm - yet at the same time I want to start learning more about the engine and how to maximize performance, as I'll be doing as much of the work on the truck as possible.
Thanks.

 

8-9 PSI is really as much as you want to go on an IDI, maybe a little more, I don't know. The IDIs have around 22:1 compression, while the newer powerstroke and other turbo motors have around 17.5:1 compression, to accomidate the higher boost. If you set your boost to high, you'll blow the motor, or headgaskets.

 

Yes, that's what I want to avoid. The engine seems to be a factory remanufactured unit that is only just over a year old. The previous owner told me that he replace the tranny with a factory reman and rebuilt the engine - but I think he meant to say it the other way around because the tranny case is original and the previous rebuild was a botch job - it was done correctly 2 months ago so its good to go - althought it still seems to shudder occassionally with that 12,000 - 14,000 lbs load behind it.
A Ford tech saw the engine and told me that he is quite sure its a factory motor and that they cost around $3600 - he was impressed with that.
Is it worth considering a turbo upgrade? Or what about intake plenum upgrades? This all of coarse after getting the air intake squared away (replace stock under-hood assembly I mean).

 

On a 7.3 I wouldn't think twice about running 12 pounds or so.
15 is about max for a stock 7.3 engine.

 

How do you turn up the boost?

 

OK, at the bottom of the picture I posted the can with the hose connectoed to it is the waste gate actuator.

It has a spring and a rubber diaphram inside it.

The hose is hooked to the turbo discharge, so it sees the pressure the turbo is producing.

The rod into the waste gate actuator must not turn or the waste gate diaphram will be torn and the waste gate actuator will be junk.

Now follow the rod out of the actuator till you see the nut, which is a lock nut.

Loosen that nut while it is still all hooked up.

Now as you follow the arm across the nut, follow it until it ends.

At the end, it goes over a pin on the waste gate arm and is held there with an E clip.

Remove the E clip.

Now you have to overpower the spring in the waste gate actuator to remove the arm from the pin.

Once it is removed, on stock Ford and some ATS turbos the waste gate actuator rod is staked so it can not be adjusted.

If it does not turn easily, remove the female end of the rod.

Count the turns it takes to remove the female end so you can get back to the same place easily.

Now run a tap with the correct thread down in it to clean the threads.

Do the same with a die to the rod so it will turn to adjust easily.

The rod gets shorter to increase the boost, mine was a bit over 1 PSI per complete turn, but my turbo was also new.

So if you want to increase the boost 4 PSI, I would start with 4 complete turns in.

Now put everything back together and go for a drive.

Pay close attention to the max boost with you foot on the floor at upper RPM's, with a stock engine keep it under 15 PSI.

Fuel delivery also affects how much boost you can make.

The max will be when the exhaust starts to turn black.

 

Okay, sounds easy enough. Sounds like the rod going into the wastegate regulator can should never be turned - so changing the length of the rod is all done at the pin end(?)

 

Right at the very top of that picture, where the waste gate arm hooks to the rod there is an E clip.
Remove the E clip and remove the rod from the arm.
There will be spring tension on it so be careful.
Also after you make the rod shorter, the tension will be higher when you go to reinstall it.

And if you drop the E clip, good luck finding it.
Don't ask how I know that.

 

I copy that. Thanks.

 

I recently went through this, I was getting 7 PSI on a Stock 94' 7.3 with ATS downpipe and a 3" straight pipe. I shortened my Wastegate rod by 1 1/2 turns and now Im running about 9 PSI max boost.

I noticed a slight but effective difference in the towing performance. especially getting into traffic up the on-ramps.

I actually removed my entire Wastegate to do this procedure and found it very easy to work on at eye level instead of sprawled out across an engine. It also went together easy by putting the rod on the turbo first before screwing the two screws that hold the wastegate on the turbo. This removed the step of TUG-O-WAR with the wastegate diaphram to reconnect the rod.

But when I did remove the wastegate, oil came out of the pressure line. Not an excessive amount but I'd probably say 1-2 oz. Can anyone confirm if this is normal?