Pressure Regulator

I converted the fuel rails from a deadhead-return-style to a flow-through-return-style configuration to better support my power levels. While doing this I replaced all of the barbed fittings with AN fittings. Most SL-C builders mount the pressure regulator to the firewall or chassis, but I decided to mount it between the fuel rails on the supercharger. This results in less hose and I think it looks cool because it fills in an otherwise empty space which is visible in the rear window. That said, it was a lot more work than mounting it to one of the standard locations with the provided bracket.

The primary challenge was figuring out how to securely mount the regulator so that I could use hard fuel lines. There are two casting holes in the intercooler which I tapped for 1/4”-20. I then used 1/8” aluminum to fabricate the mounting plate which provided an opportunity to use my dimple dies. Yeah, I know they’re more commonly seen, and often overdone, on hot rods, but I think they’re cool. Both the aluminum monocoque and the dimple die originated in the aviation industry, so they aren’t out of place. Abe did a nice job welding it together.

Self-adhesive 1/4” rubber was used to pad the plate above the cast boss for the vacuum reference port and to help dampen vibrations. This finalized the height of the plate and two aluminum spacers were turned on the lathe to fit between the holes tapped into the intercooler and the plate. The two extensions at the back of the plate are wedged under the supercharger and are intended to help keep the plate in place.

Abe had two pressure regulators from Fore Innovations; a F1i which is two tone (raw aluminum and black) and a F2i which is all black. I prefer the appearance of the former, but the latter has superior internals, specifically a ceramic/stainless valve and a fluoropolymer coated spring. After confirming with the manufacturer, we swapped the internals.

Fuel pressure gauges are bulky. This normally isn’t an issue, but mine is on display in the window so I spent several late nights looking for a thinner one (see comparison picture below).

I wasn’t able to remove the 1/4” NPT plug from the vacuum reference port. Worrying about stripping something in an important part is one of the most stressful parts of building a car… and the supercharger is both important and expensive. I tried using a hex-bit socket and a 3/8” impact gun to no avail. I then made a simple heat shield (a hole in scrap aluminum) to protect the paint, heated the plug with a torch and tried again to no avail. If it was going to strip, I wanted Abe to be vested so I let him deal with it ;-) He heated and wailed on it with the 3/8” gun and it didn’t budge. The last attempt before pulling the super charger off and drilling it was more heat and a 1/2” impact gun. Fortunately, that worked! I replaced the plug with a stainless steel barbed fitting.

The fuel lines were fabricated out of aluminum. I’m going to look for a thinner vacuum line, but this part of the car is done until final fit up. The next step is to install the surge tank, high-pressure pump, E85 sensor and fuel filter between the fuel rails and the low-pressure fuel system.