It all started when I put my car on a dyno. At the end of each pull a puff of oily smoke would waft out from the valve cover vent on the passenger side.
I never liked disconnecting the stock tube from the valve cover to the turbo, but like everyone else I didn’t want any oil going through the intercooler. I have been plagued by oil leaks and I find more oil comes out the more I get on it.
I performed an experiment on my car today. I put a ¾” heater hose on the turbo inlet bell opening. I ran it into the car and went driving. At idle there was no noticeable flow into the tube and the BLM value didn’t change whether I plugged the line or not. As soon as I stepped on the gas the tube began sucking in a lot of air. At 10 psi the tube was whistling with air going into the engine. The BLM numbers adjusted only a minor amount. My “thumb over the end” vacuum gauge tells me the suction pressure is about 0.5”-1” of Mercury. With the restrictive stock air cleaner the suction would have been greater. The cool thing was holding the tube when the turbo farted; it’s a pretty loud sound when it’s in your hand. You can really feel the air push back out while the flow reverses out the compressor.
Next, I connected a tube to the valve cover vent hole. At idle the flow was being sucked in by the PCV valve. Plugging the tube, the crankcase pulled a vacuum of about an inch or two. As I rolled into the gas, the inflow increased. At medium-low throttle the flow stopped and at medium to high throttle considerable blow by was pushing out of the engine. I made the mistake of plugging the hose a couple of times while it was blowing smoke and managed to blow a lot of crap out of the dipstick and onto exhaust manifold.
The turbo inlet has the potential to flow a lot of air, and it does so at the right time too. I am planning to figure out some sort of filtered catch can between the engine and the turbo inlet to keep things clean. The Buick engineers hooked it up for a reason; they just didn’t put enough capacity in that little black sponge thing.
Anyone else tested this? I am curious if my engine is typical or not in the amount of blow by.
I never liked disconnecting the stock tube from the valve cover to the turbo, but like everyone else I didn’t want any oil going through the intercooler. I have been plagued by oil leaks and I find more oil comes out the more I get on it.
I performed an experiment on my car today. I put a ¾” heater hose on the turbo inlet bell opening. I ran it into the car and went driving. At idle there was no noticeable flow into the tube and the BLM value didn’t change whether I plugged the line or not. As soon as I stepped on the gas the tube began sucking in a lot of air. At 10 psi the tube was whistling with air going into the engine. The BLM numbers adjusted only a minor amount. My “thumb over the end” vacuum gauge tells me the suction pressure is about 0.5”-1” of Mercury. With the restrictive stock air cleaner the suction would have been greater. The cool thing was holding the tube when the turbo farted; it’s a pretty loud sound when it’s in your hand. You can really feel the air push back out while the flow reverses out the compressor.
Next, I connected a tube to the valve cover vent hole. At idle the flow was being sucked in by the PCV valve. Plugging the tube, the crankcase pulled a vacuum of about an inch or two. As I rolled into the gas, the inflow increased. At medium-low throttle the flow stopped and at medium to high throttle considerable blow by was pushing out of the engine. I made the mistake of plugging the hose a couple of times while it was blowing smoke and managed to blow a lot of crap out of the dipstick and onto exhaust manifold.
The turbo inlet has the potential to flow a lot of air, and it does so at the right time too. I am planning to figure out some sort of filtered catch can between the engine and the turbo inlet to keep things clean. The Buick engineers hooked it up for a reason; they just didn’t put enough capacity in that little black sponge thing.
Anyone else tested this? I am curious if my engine is typical or not in the amount of blow by.
