That's very interesting. So it makes me really wonder if we can adapt 6.6 Duramax parts to do this? In theory they should have done this when designing the Duramax trucks.

And when you said matching cfm of motor to cfm capability of the muffler, did you mean to say cfm of the turbo compressor?

 

So I took the wastegate back out and put the heavier spring back in and tried it and zero change. So this makes me think either I have a big boost leak somewhere that I just haven't found for whatever reason (I have smoke machine tested all my charge pipes and intercooler), or my BOV is leaking. I took the BOV apart and inspected the diaphragm and it looked fine. I inspected the sealing seat and took off the o-ring and they both looked ok, although I think I punched a hole in the o-ring trying to get it out, looking in my o-ring kit I don't have a good match to replace it with. Also the o-ring that seals the v-band flange has a crink in it, and unfortunately don't have a good size match in my kit for that one either. So these issues didn't show a leak on the smoke test, but I have lost confidence in my smoke tester, it's very difficult to see the smoke when there is a leak. Not to mention it makes a horrendous smell burning constipation/baby/mineral oil haha. I should have saved my money and just kept using the good ole plug it up to a shop vac with a bunch of electrical tape method. Maybe I am using it wrong or there is maybe a better method or a special black light or something to make the smoke show more...not sure. It may be made for testing tighter leaks, I noticed if I use it by putting it in the very end of the tailpipe at the back of the truck, it seems to only show a good leak indication at the muffler weep hole but dosen't seem to make it down the front of the truck to the rest of the exhaust, maybe just because its not a very tight leak and no pressure builds up.

Anyway I guess I can just remove the whole BOV and go out and test drive it and see what happens, but that's easier said than done trying to figure out how to block it off or make the pipes connect or try to find a plug for it. Turbosmart sells a very convenient blanking plug that says its for a BOV and looks to have a flange on it, but its unfortunately a 32mm and mine is a 50mm. Maybe I can just use one of those plumber plugs with the wing nut on them.

 

Doest the wastegate have the fire ring installed?

 

Yes it does. Has both the fire ring seat thing and the stainless gasket installed.

I will admit I know where some very small boost leaks are where I braised the MAF bung to the intercooler tube which I've been meaning to go back and try to seal up with RTV or maybe try JB weld or something like that, the leak is so small you can barely see smoke coming from it but I can feel a little air escaping.

I am just not sure how much boost leaks it takes to make a difference.

 

A small leak can cause big problems.

 

Yeah I have been fighting these leaks because I can't weld haha, but exhaust sealant, the stuff that turns crusty, works surprisingly well for exhaust and seals water tight and seems to keep rust away since I a mig welding it with C25. But I have been trying to use low temperature aluminum brazing for the intercooler pipe which will resist melting the brazing rods even when it get past 800-850 degrees which is when the brazing rods are supposed to melt, so it is very difficult to torch it hot enough without melting something, and its usually the other piece of aluminum that melts first and not the pipe. So bascially I can't get any fusion or penetration and the braze just kind of lays on top of the intercooler pipe. It is cheap Chinesium intercooler pipe though and not polished and I do go over it with sandpaper to try to get the oxide layer off but dosen't seem to do much.

 

Finally found a picture.
I used 4" alum tube and ran it inside the airbox and put a bead of silicone on the inside of it and black RTV on the outside.
It worked.

 

Thanks for the picture that's a good idea I didn't even think to just cut it out and add a metal tube I was thinking plastic, do you know what kind of elbow you used? From the picture it looks like one of those basic silicone elbows but I'm not sure if you would need a reenforced one since this one is pre compressor and could suck in?

My main goal is just to get the stock air filter working again. I think all those thin cone air filters, even the name brand ones (k&n etc) are crap and have basically zero filtering efficiency. I want to see if I can get the silicone content in the oil back to normal since it's like 10x the normal levels although it could be do to RTV or something like that but it seems it's from crappy filters letting dirt in.

 

is a cast aluminum short radius elbow.

 

Thanks, Ill probably go ahead and order that one and couple it with silicone couplers. But I might order a 4 in short raidus silicone elbow as well. I wonder if its pushed in at both ends good enough if it might be enough to keep it Un collapsed.

Maybe if I had to, I could tack up some rings with a brace to put in the unsupported parts of the coupler.

I did buy a U-bend 4in aluminum "intercooler" tube. My problem is I don't have anything to weld the aluminum, but I have tried low temp aluminum brazing rod on the intercooler pipe before. You almost have to melt the pipe before the brazing rod will melt and penetrate since if you try to help the brazing rod get hot with the torch it won't penetrate at all. It is very difficult, and the pipe ends have to be perfectly concentric and flat but hopefully since I ordered this expensive intercooler 4 in u-bend tube and not the cheap chinesium one then maybe it will braze better.