Soot on compressor wheel?

you sure its not oil getting sucked out of the seal by the secondary before the primary lights.
 
I have soot in mine, but it's because my WG cover leaks. I think it could be oil and soot maybe.
 
before the primary lights the secondary is sucking air through it causing a good amount of vacuum in the cold pipe.
 
Rollin Coal said:
before the primary lights the secondary is sucking air through it causing a good amount of vacuum in the cold pipe.
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only if the primary is a pig. I've built/run many combos and ran a boost/vac gauge in the cold pipe. it never showed more than a hint of vacuum, even with a 35/12 over a 3B/32.
3B's do have a tendency to "breath" through the comp shaft seal at low boost if the crankcase venting is not adequate.$.02
 
What about a 35/12 over an S480, do you think there would be significant vacuum in that situation?
 
My wastegate cover was leaking and sooted up the side of my BHAF and the comp wheel turned dusty looking..... just something to look at.
 
the only way soot will get on the compressor wheel is if there is an exhaust leak. If there is a leak the air intake has access to this leak it can potentially 'suck' in the sooty exhaust.. soot is too small to be captured by the air filter..
 
There should NEVER be vacuum in the cold pipe...just because the big charger isn't making boost, doesn't mean there is vacuum there, at least not on any of the 6 or 7 sets of twins I've ran/built.

The big charger is still moving air, and I don't know how much the little one can "suck" around the compressor wheel...I don't think that actually happens.

Chris
 
Signature600 said:
There should NEVER be vacuum in the cold pipe...just because the big charger isn't making boost, doesn't mean there is vacuum there, at least not on any of the 6 or 7 sets of twins I've ran/built.

The big charger is still moving air, and I don't know how much the little one can "suck" around the compressor wheel...I don't think that actually happens.

Chris
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x2..
 
Soot on the compressor wheel? Is it soot or oil? Which wheel, the 35 or the 3b?

With a 35 secondary I'd be leary about reversion. That's a tiny turbine side when pushed to the limit. What does the rest of your intake tract look like? Is there soot on any of your charge air plumbing?

If your drive pressure is higher than your boost pressure, when the intake valve opens pressure differential will force exhaust gases back up the intake tract. If the difference is great enough it can make it all the way to your compressor wheel.

Measured drive pressure lately?
 
Amish Elegance said:
Soot on the compressor wheel? Is it soot or oil? Which wheel, the 35 or the 3b?

With a 35 secondary I'd be leary about reversion. That's a tiny turbine side when pushed to the limit. What does the rest of your intake tract look like? Is there soot on any of your charge air plumbing?

If your drive pressure is higher than your boost pressure, when the intake valve opens pressure differential will force exhaust gases back up the intake tract. If the difference is great enough it can make it all the way to your compressor wheel.

Measured drive pressure lately?
Click to expand...


Do you really think this is possible?
 
The clamp on my down pipe leaks a little and there is always soot on my compressor wheel. Just power brake the truck and see if its leaking exhaust that is getting sucked into the turbo.
 
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