2002 7.3 Ford Boost Pressure?

[rx2tee]

We have a F-250 4X4 with a 7.3 Diesel and 6 Speed Manual.
I use a scan gauge to monitor engine data.
We bought the truck new and it seems to be in very good shape but I am wondering where I can find what the Turbo Boost should be at a given RPM and throttle position.
(The scan gauge displays 4 parameters at a time and can be configured to display RPM, %Throttle Position, Turbo Boost in PSIG, and induction temperature if I am not mistaken.)

Thanks for any help.

[cutty72]

1750 RPM under full load with an otherwise stock engine, you should be seeing around 7-8 psi. The stock turbo doesn't really light until about 1600 RPM. Drop a gear and hit 23-2400 and you will get closer to you max boost. Again stock, probalby not over 20 psi, likely 16-18.
The oil on the boots is from the crank case venting into the intake, and is "normal". Some delete it, others don't.
DieselSite has replacement boots that aren't affected by the oil residue.
RiffRaff diesel also has quality replacement boots.
Both also sell a billet compressor wheel that will increase your boost pressure, reduce or eliminate surge, and help with EGTs.

[rx2tee]

Thanks for all the input from everyone.

[Wiley75]

rx2tee wrote:
I was thinking that if I am pulling a grade at a steady 1750 RPM and 100% throttle the boost would be near maximum.

Thought that because that because peak torque 1750 RPM.

I am not sure I ever see 17 PSIG. I will check the boots and clamps.

Should my waste gate be in good shape at 90K miles with almost no trips of less than 50 miles and very little stop and go miles.

Hi. I used to have the same truck and as I recall you won't see 17 psi at 1750 rpm. Drop a gear and put the throttle on the floor however and you should see 17-18 psi.

If boost is low check hoses as people have suggested. Also investigate for signs of exhaust gas leakage where the up-pipes coming off the exhaust manifolds enter into the bottom of the exhaust turbine housing (black streaks on the pipes, etc). 7.3s are known to leak there, which causes less exhaust gas entering the turbine, which can lead to low boost pressure.

regards,
Wiley75

[stsmark]

As said here a healthy 7.3 should make 18 psi easily. Oily boots mean the stock boots are breaking down from breather residue. Dieselsite had better replacements but they are proud of them. The waste gate actuators are known to relax with age, there are multiple options, Banks Big Head ect.
Have fun

[rx2tee]

I removed both of the cold side boots and noticed "Pipe contains oil residue" printed on them. So oil inside must be normal.
The clamps and boots look fine to me after cleaning and inspection.
I put the cold side back together and then snugged up the clamps on the hot side. I used engine cleaner and water to clean up everything so I can see if the leaks are sealed off.

[LarryJM]

rx2tee wrote:
We have a F-250 4X4 with a 7.3 Diesel and 6 Speed Manual.
I use a scan gauge to monitor engine data.
We bought the truck new and it seems to be in very good shape but I am wondering where I can find what the Turbo Boost should be at a given RPM and throttle position.
(The scan gauge displays 4 parameters at a time and can be configured to display RPM, %Throttle Position, Turbo Boost in PSIG, and induction temperature if I am not mistaken.)

Thanks for any help.

As mentioned there are too many factors that determine boost with load being the major one. On a stock engine you should see around 15 to 18# max and you will set an SES light and go into a defueling mode for several minutes if you exceed 25#. My Van has a slightly different turbo than the F-series, but neither IIRC are designed to be run at more than 25# for any length of time.

Larry

[rx2tee]

My intercooler boots were oily the last time I had the hood open.
I think my boots and clamps need attention.

[wittmeba]

I dont know of any specific throttle speed to give a specific boost pressure but you wont see but a max of about 25# with a good motor. Mine is a 2001 and since I installed gauges the max pressure has dropped from 25 to about 22 just from age. 25 is with a tuner and running a 80 HP tune. Without a tune it would peak about 15# at its best.

[rx2tee]

I was thinking that if I am pulling a grade at a steady 1750 RPM and 100% throttle the boost would be near maximum.

Thought that because that because peak torque 1750 RPM.

I am not sure I ever see 17 PSIG. I will check the boots and clamps.

Should my waste gate be in good shape at 90K miles with almost no trips of less than 50 miles and very little stop and go miles.

[ScottG]

A quick Google search suggest's you will see about 17# max.
Link

[ScottG]

Nobody can give you exact boost at throttle position. There are just too many variables but there should be a maximum boost limit someone could provide.

[Turtle_n_Peeps]

If I read your post correctly there is no correlation between boost pressure and % or throttle.

IOW's I can have maxed out boost pressure at 1/2 throttle or I can have very little boost pressure at WOT.

Turbo's are very load dependent for boost pressure.