Offered in 1.2L, 1.3L and 1.5L variants, these VTEC equipped inline four cylinders have garnered quite a following. Honda launched their L-series platform alongside the Honda Fit city-car in 2001. If urgent, please email or contact the manufacturer directly" * For this reason, we have decided to halt the current development on a catch can solution for the car to focus efforts elsewhere.* Due to national supply shortages, piston orders may have unforeseen delays. In stock longblock form we have found that the L15B7 found in the 2017+ Honda Civic Si PCV system works very well, and operates well beyond what we expected when beginning the testing. More remarkable is at the 400whp level (35psig), the turbo inlet is able to pull the crankcase pressure down to -1.5psig – way below atmospheric pressure! This is impressive because it shows the added crankcase pressure caused by increased piston blow-by is not proportional to the suction increase from the turbo inlet- quite impressive at double the horsepower on an engine that is stock from valve cover to oil pan.Ĭonclusion: Does your 2017+ Civic Si Need A Catch Can? Further, the more boost more mass flow through the turbo inlet (read: higher boost/power levels), the more crankcase pressure is able to be pulled from the crankcase and through the valve cover.įor reference, at the 300whp level (20psig), the turbo inlet is able to pull the crankcase pressure down to -.6psig. The turbo inlet is a very, very effective supply of low pressure and therefore the flow rate of the mass and volume of Crankcase Pressure is extremely high. One can also use a chest drainage management system, which typically enables vacuum to be applied along with quantifying the effluent. There are three large "ports" which connect the area under the valve cover to the crankcase, evenly spaced along the engine. A flutter valve (also known as the Heimlich valve after its inventor, Henry Heimlich 1) is a one-way valve used in respiratory medicine to prevent air from travelling back along a chest tube. The only non-perfect behavior is on a bench when pressure is very slowly increased to the valve, in which case it doesn’t seal until 5-6psig. Upon the Intake Manifold seeing positive pressure, the check valve between the intake manifold and crankcase closes, making the only ventilation source the turbo inlet.ĭuring normal conditions/transient changes in pressure, the Check Valve closes and seals almost instantly. It’s compact, powerful and can out perform the last generation’s K24 powered Civic Si. We got our hands on a turbo 1.5 liter from a 2017 Civic and it’s radically different from Honda’s engines of the past. **It is unclear/untested so far as to how much fresh air, if any, is pulled into the crankcase via the boost/turbo inlet channelīoost Operation: What is happens internally to my 1.5T L15B7 while under boost? The New L15B7 Turbo from Honda: We take a close look a the L15B7 that comes in the new Civic EX Turbo. It is likely that this is because a significant flow rate under vacuum is not necessary, and by doing so they would also need to introduce additional/larger fresh air sources to the crankcase system. The port goes through the cylinder head, but does not pull from the area underneath the valve cover.ĭuring the vacuum operation the sole check valve is open, however it only allows an extremely low flow rate. Positive Crankcase Pressure is pulled into the Intake Manifold (vacuum) via a sealed port that connects the intake manifold directly to the crankcase. The stock system appears to do a very good job at air/oil vapor separation, as there are minimal traces of oil film on the intake/inlet tract, the compressor inlet, compressor outlet or charge system. No cyclonic separators only baffled channels molded into the valve cover to separate oil vapor. There is only one check valve in the entire system, which is located in the tract between intake manifold and crankcase. It is not confirmed at this time the amount of ventilation the turbo inlet tract provides whilst the manifold is under vacuum and with minimal low pressure provided by turbo inlet. Two sources of ventilation for the crankcase: the Intake Manifold whilst under vacuum, and the turbo inlet tract whilst manifold is under boost. Performed dyno test with turbo inlet PCV hose disconnected to observe crankcase pressure without a source of ventilation vacuum This pressure data was overlaid with general engine conditions to correlate differences in crankcase pressure (inferred from pressure underneath valve cover) with changes in power output. No concerns of localized pressure pocket or High/Low pressure zones. That pressure sensor recorded pressure in a zone/position where there was minimal fluid velocity, so as to get a proper reading of pressure underneath the valve cover. Testing Procedureĭyno testing performed with our 2017 Honda Civic Si at various power levels, with a 1 bar pressure sensor installed in the oil fill cap on the valve cover. Objective: To understand operation and measure performance of 2017+ Honda Civic L15B7 OEM PCV and Air Separation systems to determine need for external catch can system. Honda L15B7 1.5T PCV System Testing and Observations
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