We are using the WHP Flex Fuel Sensor Kit, -6AN from ECU Master so our ECU can accurately control and blend the fuel, ignition, and boost tables according to the ethanol content and fuel temperature. The ethanol content and fuel readings kick on within a quarter of a second of start-up and each kit includes the ethanol sensor, a laser cut, CNC bent, and powder coated mounting bracket, hardware, and a connector with 8-foot harness.
We mounted the WHP Flex Fuel Sensor on the firewall with a 3D printed spacer, and ran the 3/8” (-6AN) Earls Super Stock return line from the Radium DMR fuel pressure regulator to the WHP Flex Fuel Sensor. From the sensor, the -6AN return line connects to the factory hardline that returns fuel to the fuel tank.
We removed one of the Radium Low Profile Banjo Swivel Fittings from the feed side of the primary fuel rail and ran a 0* straight fitting and ½” (-8AN) Earls Super Stock fuel line from the fuel hard line over the top of the transmission bell housing to the fuel rail.
Speaking of the stock hard lines, we removed the factory fuel line to be replicated in -8AN sized aluminum tubing.
A local aircraft shop bent a -8AN sized tubing in the same shape as the stock fuel hard line.
The new hard line is significantly larger in diameter than stock and will deliver significantly more fuel volume at the same pressure. The volume here is key. While FD RX-7s have been making 400-600whp for years with the stock fuel hard lines, they typically need two 460lph fuel pumps in order to accomplish this. When fuel flow is restricted, pressure needs to be increased to supply the demands of flow and pressure for the injectors. By going with a larger fuel line that provides more flow volume, the higher pressure and need of a secondary pump diminishes. We are very interested to see what the limitation of the 415LPH Deatschwerks DW400 fuel pump is with this larger fuel line.
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I am still here, consuming every FD update. This thing gets more awesome with every post!
Thank you 🙂
Great series. What’s the story with aluminium fuel hardline and ethanol-based fuel? My (limited) understanding is that aluminium needs to be anodised at minimum to protect it from the jungle juice.
Yes, ethanol can corrode aluminum, particularly when it contains water or in high-concentration blends The alcohol reacts with the metal to form aluminum alcoholate, causing white, chalky corrosion, pitting, and potential, severe damage to fuel systems.
Thank you. E85 is hygroscopic and will absorb water which can lead to aluminum corrosion only if it sits for long periods of time. Raw ethanol is generally safe for aluminum. Since we will not store or let the car sit with E85, running the aluminum hard lines will not be a problem. We will also be running drums of Ignite ethanol, so that further reduces this concern.
Very cool updates.
As part of the testing you’re doing for the single pump setup, how does the cost of making the larger aluminum fuel feed line compare to adding a 2nd fuel pump and using the stock feed line?
There are many solutions to a given problem. We wanted to find the maximum power the 415 LPH DW400 fuel pump can support on a rotary without fuel line restrictions. Once we reach that point, we will turn to a brushless single pump solution based on the layout of our fuel starvation solution in the previous article.