Soot on compressor wheel?

Well, I have a slight exhaust leak between the ats manifold and the 1/2" spacer plate. The air filter hasn't been oiled yet, and is a new replacement with about 10k on it. The 3b starts to light around 2k. I'm thinking its got to be the exhaust leak?

Thanks for the help guys.
 
Why thank you, Chris. I had forgotten about this thread.

Big Blue, an analogy for ya: Charge your air compressor, hold the blow gun with your anus, pull the trigger, rip a fart. Will the rancid stench migrate to the air tank? Don't think so. Not till your skills for guttural discharge approach the pressure of the air tank. Most likely you'll taste fart for the next few days.
(For the love of gawd, nobody try this. Save it for Mythbusters.)

Works the same way with your turbo when drive pressure is much higher than boost. Overspun 35 pinwheels with a tight housing fed by 3B and 35 compressors makes it a distinct possibility for a turbo to taste diesel fart from time to time.

May not be the silver bullet in this case, but as I insinuated, and Chris stated; it's possible.
 
Amish Elegance said:
Works the same way with your turbo when drive pressure is much higher than boost. Overspun 35 pinwheels with a tight housing fed by 3B and 35 compressors makes it a distinct possibility for a turbo to taste diesel fart from time to time.

May not be the silver bullet in this case, but as I insinuated, and Chris stated; it's possible.
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:umno: unless you have a mechanical problem like valve float, the VALVES are kinda in the way here guys. A gasser has valve overlap and even with a carb force fed by a turbo nothing flows backward for more than 100th of a second.
Our motors push out on the exhaust stroke and then the exhaust valve SHUTS. as the piston starts to travel down then the intake valve opens and air is forced in from the turbo(s). There is no way the minute amount of exhaust left in the chamber can over come the incoming charge. What most folks see on the comp wheel is residue from aluminum when polished by dust @ 50,000 rpms. If this residue seems excessive, you have a bad filter (or hole in the intake), or you have an exhaust leak the filter is pulling soot from, or a minor oil seal leak. $.02
 
TURBOLVR said:
:umno: unless you have a mechanical problem like valve float, the VALVES are kinda in the way here guys. A gasser has valve overlap and even with a carb force fed by a turbo nothing flows backward for more than 100th of a second.
Our motors push out on the exhaust stroke and then the exhaust valve SHUTS. as the piston starts to travel down then the intake valve opens and air is forced in from the turbo(s). There is no way the minute amount of exhaust left in the chamber can over come the incoming charge. What most folks see on the comp wheel is residue from aluminum when polished by dust @ 100,000+ rpms. If this residue seems excessive, you have a bad filter (or hole in the intake), or you have an exhaust leak the filter is pulling soot from, or a minor oil seal leak. $.02
Click to expand...

Fixed it for ya :Cheer: I totally agree!
 
And you're both totally wrong....

Sounds like both of you need to plot out a cam profile on paper sometime. Yes there's overlap, and with enough drive, YES it will push back across the intake valve. Get a sh*tty cam..... you can push soot out into the intake manifold with even tame boost/drive ratios.

HOWEVER......

While that is certainly true, on a compound setup it would be nearly impossible to push soot up the runners, into the manifold, through the colde side CAC tube, through the intercooler, through the hot side CAC pipe, through the second stage compressor, through the intermediate cold pipe, and finally through the first stage compressor where it was detected by the OP.

Just not..... gonna..... happen.


The first stage compressor is literally snagging the soot from the exhaust leak the OP mentioned. Mine did this once as well, it wasn't until a dyno pull with the hood up that I could actually see a stream of soot leaving a leaky pipe that shot straight out the front of the truck at about a 45* angle before hooking a 180 and getting sucked straight in the air filter. Made it pretty clear why I was having such a time keeping the filter from looking like ass.
 
TURBOLVR said:
What most folks see on the comp wheel is residue from aluminum when polished by dust @ 50,000 rpms. If this residue seems excessive, you have a bad filter (or hole in the intake), or you have an exhaust leak the filter is pulling soot from, or a minor oil seal leak. $.02
Click to expand...

I agree with that possibility as well.

Charles said:
And you're both totally wrong....

Sounds like both of you need to plot out a cam profile on paper sometime. Yes there's overlap, and with enough drive, YES it will push back across the intake valve. Get a sh*tty cam..... you can push soot out into the intake manifold with even tame boost/drive ratios.

HOWEVER......

While that is certainly true, on a compound setup it would be nearly impossible to push soot up the runners, into the manifold, through the colde side CAC tube, through the intercooler, through the hot side CAC pipe, through the second stage compressor, through the intermediate cold pipe, and finally through the first stage compressor where it was detected by the OP.

Just not..... gonna..... happen.
Click to expand...

Thanks for noting overlap the overlap present in all Cummins cams, varying and minimal as it may be, I neglected to mention that.

As you stated it, I agree. Two bad assumptions I made towards the setup would have made this much more possible:

First, I asked what wheel we were speaking of blissfully cruising right past the "primary" in the post. I plead retard. I agree with you to the extent of soot on the primary. I assumed secondary.

Second, with this being a conversion, the possibility exists for eliminating the CAC for ease of installation. I missed the "twin ram" in his sig that eliminates that possibility. The probability of that occurring in with a CAC in line is greatly reduced but not eliminated.

Bottom line, without further input from the thread starter and oil and exhaust leaks being thoroughly restated, chumming the waters with a long shot seemed like a good idea to spice up an afternoon.

Thanks for your post, Charles. As usual you have stated your opinion bluntly and with sound reasoning, one of the reasons why I have thoroughly enjoyed all of your 190 posts here. :Cheer:
 
You guys are a hoot, you could probably argue....er....comment on the color of George Washington's white horse.
 
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