How much boost on a journal bearing turbo?

[suprastroker88]

So I was talking to a guy at Turbo Power, a turbo rebuilding shop in Sacramento, CA about rebuilding my Turbo Concepts TC70mm bolt-on turbo. He told me that because it is journal bearing, it would not be advised or safe to run beyond 18psi. He said if I plan on ever running more than that, I need to either have it upgraded to a ball bearing or just buy a ball bearing turbo. Is this accurate information?

 

[87targa]

diesel turbos are journal and they boost 25+ psi. I think that dude is on crack.

 

[mecevans]

Guy must have been a salesman lol

 

[Nick M]

What does manifold restriction have to do with the oiling system?

 

[Suprapowaz!(2)]

If that turbo fails on you he may ask you how much boost did you run on it. If you say anymore than his advised 18psi he probably won't warranty it. Keep that in mind.

 

[suprastroker88]

What does manifold restriction have to do with the oilin system?

you lost me here. we're not talking about the manifold

 

[suprastroker88]

If that turbo fails on you he may ask you how much boost did you run on it. If you say anymore than his advised 18psi he probably won't warranty it. Keep that in mind.

he doesnt warranty his turbos at all. thats why i decided to look else where for a rebuild

 

[GrimJack]

So I was talking to a guy at Turbo Power, a turbo rebuilding shop in Sacramento, CA about rebuilding my Turbo Concepts TC70mm bolt-on turbo. He told me that because it is journal bearing, it would not be advised or safe to run beyond 18psi. He said if I plan on ever running more than that, I need to either have it upgraded to a ball bearing or just buy a ball bearing turbo. Is this accurate information?

No. I would look elsewhere for turbo work. Manifold pressure and turbo revolution speed are only vaguely related - there are several other large factors that should be taken into account.

 

[suprastroker88]

thanks. good to know since im still fairly new at this

 

[GrimJack]

Think of it like this.

Anyone who speaks to you solely in terms of PSI or pressure is likely clueless. What really matters is how much air is being pushed and to some degree at what temperature. How are these different?

Pressure is affected by quite a few things outside of the turbo itself - intake pipe size, cam size, manifold flow, and a whole bunch more. So, in real life, this means that 'safe' pressure levels for a turbo are different for every car.

Anyone talking in terms of how much air a turbo can provide - usually in pounds per minute or some similar term - is far more likely to at least have a clue how these systems work.

 

[Poodles]

Plus, he doesn't warranty his work at all...

 

[Nick M]

you lost me here. we're not talking about the manifold

Sure you are. If you ported the head and manifold with oversizes valve and kept the wastegate actuator the same, "boost" would go down as power went up.

 

[bioskyline]

So I was talking to a guy at Turbo Power, a turbo rebuilding shop in Sacramento, CA about rebuilding my Turbo Concepts TC70mm bolt-on turbo. He told me that because it is journal bearing, it would not be advised or safe to run beyond 18psi. He said if I plan on ever running more than that, I need to either have it upgraded to a ball bearing or just buy a ball bearing turbo. Is this accurate information?

hes on glue. from what i know the max psi on a turbo is based on the size of the compressor housing, and the size/angle of the compressor blades. a BB turbo will spool faster due to less static friction to overcome, but bearings have nothing to do with max boost