No post-compressor or post-IC temperature pickups are used unless the vehicle has been converted to use our custom Speed Density code. This is located in an "airbox" MAF housing from the factory or traditional "filter-on-a-stick" intake housing in the aftermarket. Mass Air Flow is measured by a traditional Denso-provided integrated intake air temperature and hot-wire mass airflow meter. Top feed conversions are common practice, even for otherwise-stock vehicles. Uprated side-feed injectors have proven to be particularly problematic even the factory side-feed injectors are known to have a high failure rate. The 2007-2014 STI, 2006-2014 WRX, 2006-2013 FXT and 2007-2012 LGT use ~565cc top-feed injectors (dark blue), though the part numbers and body coloring may have changed across a few years. The 2002-2005 WRX utilized ~440cc top-feed injectors (light blue). The elaborate speed control is presumably used to promote pump life, decrease fuel heating and lessen FPR overrun (the factory FPR has a short spring and small orifice) during periods of low fuel demand.įactory specified injectors vary, mostly along vehicle generation lines, though all are provided by Denso. The pump is triggered to "high" for a period after startup and falls to "low" (assuming state thresholds have not been wildly altered) after the "startup" or "hot-start" periods end. Switching between states is primarily controlled via IPW or IDC thresholds and sometimes RPM breakpoints, model dependent. The ECU can command three unique low-middle-high states, which are 33.3%, 66.6% and 100.0% from the factory but can be edited as necessary during fuel system calibration. Fuel starvation during right-hand turns is a known limitation of the design many track vehicles and fast street cars use an auxiliary surge tank to alleviate this issue.Ī PWM controller that is signaled by the ECU regulates fuel pump speed. Like other Japanese vehicles, this assembly also contains a "siphon" system operated by the returning fuel flow to sump the driver's side fuel tank reserves. A traditional in-tank hanger, located in the passenger side of the saddle-style fuel tank, handles fuel delivery from the tank. The factory fuel rails are in a series configuration. Ignition system upgrades are rarely needed as the factory hardware has been proven shown itself to not only be durable but also capable of supporting roughly triple the factory power levels with no meaningful degradation to spark energy or combustion quality.Īll turbocharged Subarus for USDM markets to-date (MY2002-MY2014) feature port injection, controlled a traditional 3 bar bypass fuel pressure regulator with manifold reference rate of 1:1. Spark and ignition control is straightforward on modern turbocharged Subarus crank and camshaft position are measured via reluctor and Hall-effect sensors, depending on model/year, and are then synchronized within the ECU, which operates four coil-on-pack ignitorless coils in sequential firing order. This page is maintained by COBB's Director of Protuning and includes web links for our Accesstuner Pro software builds, information about COBB-provide training options, links to various logos to use within your marketing materials, etc.
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