7.3 questions

[sandman116]

I recently bought a 1992 f350 2wd with the 7.3L with the waste-gated banks turbo. I have a few questions. First off am curious why my truck gains ALOT of power if you drive it after you first start it? If you cold start it and go it runs really good for like 3 seconds and then it wont ever run that good again until the next day. Second i want to know if I can make more than 10 psi on the turbo. Last but not least I want my truck to have more turbo noise from the exhaust side. I have 4" strait pipe up to a single 6" stack but i want more noise haha. I would like it to sound like a 6.0L but i don't know if that possible. Any help is much appreciated, thanks.

 

[gatorman21218]

the power gain is the cold timing advance. it adavances the timing when the high idle is on
You can make more than 10 psi on the turbo, its the head gaskets that you want to worry about. With factory headbolts, 7-10 psi is the limit.

My factory turbo sounds like an F-18. ive never messed with any other turbo set up so sorry cant help you there

 

[OLDBULL8]

That 6" stack is gonna act like a muffler. Check the wastgate for actuation, might be stuck. Ya might get another 4-5 PSI boost depending on intake air, volumn and intake air temp. As as running better hot or cold, that's anyones WAG.

 

[sandman116]

SO the stack is going to make it quieter? and how do i check the wastgate for movement? Im not new to working on trucks, im just new to the world of turbos.

 

[icanfixall]

The wastegate operates off the boost pressure made by the inlet of the turbo. It pushes the valve open. In that can that the pressure hose attaches to is a spring that keeps the gate cloed. Pressure overcomes it so the gate opens and exhaust slips by the hot wheel in the turbo.. Running stock head bolts limits your boost to maybe 11 at the most. Boosting any more is a sure way to see the insides of the heads when you replace the blown head gaskets. Never attempt to replace head gaskets in the truck alone for sure. Thats a three man job. One to watch and two to lift off the head with a 10 ft piece of 2 inch pipe. The reason for the feeling of more hp on a cold engine is the cold advance acting in the injection pump. Its not supposed to shut off till the coolant reaches 120 degrees. So I'm thinking your sender behind the thermostat housing is gone bad..

 

[79jasper]

Go way smaller on the stack diameter. Like 4 inch.

I put dual 4 inch stacks on my brothers 94 with the banks turbo, whistles like crazy, and sounds like a real jake brake when engine braking.

His was from grand rock, IIRC.

 

[sandman116]

Is there a way to advance the pump timing so it always runs that good haha

 

[79jasper]

Well you may need to have your engine timed anyways. Just from normal wear.

 

[sandman116]

idk if it matters but it still runs fine, just not alot of power. How would i check the timing?

 

[79jasper]

Specialized timing equipment for an idi.
There's a few options. But someone else will have to give you better details (I haven't timed one myself, just read about it) or just search on here. (There's tons of threads on it)

 

[icanfixall]

The eay way to time these engines is by the pulse timing method. The other method is the luminosity probe timing. The lumi probe replaces the glow plug on number one cylinder is is a much more difficult way to time the engine. To do it correctly you need a hydrometer to know what the diesel cetane is. Then the timing is set to a negative setting like -4 or -5 degrees after top dead center. This negative timing is just a reading done by the type of timing your useing. If you redo the timing with the pulse type timing method you will see the timing is reading on the positive side now probably 8.5 degree before top dead center. The differances are how the timing is done using the meters. Many here like the Ferrit meter but that instrument rewuires a timing lite thats adjustable. But it works very well. I like using the Kent Moore J33300-A meters. Those meters are very accurate and will split the single degree into a tenth of a degree.