wastegate opening pressure

[Smithereen]

Have been trying find a low boost problem for awhile. Pulled turbo and found exhaust leak at the pipes. Thought I would check the wastegate and found it starts to open at around 10psi. I can only get around 9-10 psi boost. Is the wastegate bad or is it ok?

 

[dpantazis]

How are you testing this to determine 10 psi of opening pressure?

 

[Smithereen]

I am using air pressure on a regulator. I am just going off the regulator guage.

 

[dpantazis]

i am not sure what/how you are doing thisbut i don't think that you are going to find out anything like that. and i would not force the turbo to spin without any oil pressure to lube the bearings.

unless you KNOW that you are suffering from low boost its jousting at windmills. if you have low boost then you have a leak from somewhere.

check the boots on the IC pipes, there are 4 of them, the sheet metal intakes there are 2 of them, your turbo, the IC, etc..
you already said that you have an exhaust leak, start with that. the truck will NOT make boost unless it is working hard. like pulling a trailer uphill.

DO NOT mess with the wastegate pushrod adjustment. it will not change the boost pressure, only the blow off pressure.

make sure you understand how the turbo works and what the function of each of the components are before you mess with things.

these pages are pretty good:

Wastegate - Wikipedia, the free encyclopedia

Turbocharger - Wikipedia, the free encyclopedia

and look at the ford diesel tech society webpage for a coffee table book pdf on the turbocharger.

 

[BIG JOE]

What DP said.

Joe

 

[Smithereen]

I think you misunderstood me with the regulator. I am putting regulated air to the wastegate diaphram, not to the turbo compressor wheel. All I was asking was , at what boost pressure does the wastegate, on a stock turbo, open. I did pressure check the intake piping and there was no leaks. I have been a highway truck mechanic for 21 years, so I think I know how a diesel engine works.

 

[BIG JOE]

I think you misunderstood me with the regulator. I am putting regulated air to the wastegate diaphram, not to the turbo compressor wheel. All I was asking was , at what boost pressure does the wastegate, on a stock turbo, open. I did pressure check the intake piping and there was no leaks. I have been a highway truck mechanic for 21 years, so I think I know how a diesel engine works.

Yer right, we misunderstood what you were saying & doing. I don't think either one of us meant any harm, nor foul.

Now.. Off the Top.. I'd say, if your WG is opening @ 10 psi (Static, engine not running).. useing you testing method.. it's Okay.

On a 7.3. At [about] 10 psi of boost, the MAP sensor begins to sence the boost.. and [slowly] starts to acuate the WG actuator.. Sooo if yours is opening @ 10 psi.. no load.. follow me ?

Joe

 

[Smithereen]

No problem Big Joe, sometimes when I explain things ,it makes sense to me but not to others. I understand what you are saying, so I`ll get the piping to the turbo sealed up and check it again when I put the truck back on the road this fall. Thanks.