Radium Engineering Flex fuel sensors measure ethanol content. They can be used in the FPR return line. But for improved accuracy and faster response times, the sensor should be plumbed upstream of the fuel injectors in the feed line. In this case, expect to see up to a ~10psi pressure drop if multiple pumps are used with a high-powered engine.
As shown the Radium Engineering adapter splits the fuel flow into an auxiliary passage parallel to the sensor. Because the flex fuel sensor is directly inline with the fuel flow path, it will read the incoming ethanol content at high and low engine demands. Traditionally this additional flow path could be accomplished with hose and y-adapter fittings. However, the Radium Split-Flow Flex Fuel Sensor Adapter is less complicated, considerably compact, and provides a mounting solution for the popular GM 13577429 flex fuel sensor (shown below).
1. GM P/N: 13577429 NOTE: This sensor is the same found in AEM 30-2200 / 30-2201, ECU Master WHP, MaxxECU 1282, Fuel Tech 5005100353 / 5011100354, and Cobb Tuning kits. Compatible with included mount 2. GM P/N: 13577379 This sensor already has 3 useable mounting holes. The provided mount cannot be used. 3. GM P/N: 13577394 NOTE: This sensor is the same found in the Haltech HT-011000 kit This sensor already has 3 useable mounting holes. The provided mount cannot be used. For assembly, this sensor (shown above) requires a minor modification described in the instructions. FEATURES -4pc billet 6061 aluminum construction -Black anodized and laser engraved -10AN (5/8") equivalent flow rate -Can be used on fuel feed or return line -8 double FKM O-rings (primary and backup) -Stainless steel metric hardware