Hi Ben, it's been a while since I've had the time to check out the forum. Thanks for sharing some of the inevitable teething problems a turbo car ( especially a carburated blow thru ) can present.
I've got a couple more questions for you about your car if you don't mind. ( knowledge is like horse power, you can never have too much ). What is your turbo configuration ( compressor and turbine AR sizes, compressor and turbine trims )? What timing and fuel are you using, at what RPM doeswhen does the boost come in ?
Something else, something I noticed on alot of turbo cars, even OEM's. Nobody really talks about it much. I am wondering if perhaps you may have noticed this yet. If you take off the compressor discharge tube after a bit of low speed driving around town, have you noticed any engine oil pooled in the low points of the discharge plumbing. Not a whole lot of oil, usually a teaspoon or less, but it's almost always there.
I've talked to guys with ALOT of turbo experience and they have all seen it at one time or another.
The funny thing about it is it that it occurs on some installations and not on others. Myself and others have tried all kinds of things to prevent it ( it's not like it's a big problem, it's just technically not ...right ).
We've replaced the carbon compresser seals, increased the seals spring pressure, used sump pumps to suck the return oil out of the turbo, all with varying degrees of success. The one thing I'm trying now is to restrict the amount of oil to the turbo ( I've just changed the supply lines to AN-3 SS hard lines, .063 ID ).
I've described it as not a problem, but that perhaps is not totaly true. Some times after tooling around at low power settings for a while, when you jump on it, the revs and boost will built then all of a sudden the engine will briefly hiccup, you'll get a puff of blue then every thing continues on as normal,( I am assuming that the air velocity and mass rise to the point were the oil slug finally just gets sucked into the engine ) it wont do it again until the next tooling around session sometimes not even then. Not a big deal but annoying in that it's not perfect.
Let me know if you've talked to anyone else about this or experienced this for yourself and if anyone has come up with ideas as to a solution. Thanks