Project Lexus SC300 Road Racer: Part 1 – Intro and Fuel Cell

,

Here’s one example of the fun stories I have about this car. Zip ties holding the fuel pump onto the bracket? Sure, why not. #SEEMSLEGIT

Getting boxes of car parts delivered always makes it feel like a fun holiday. But I wonder what could be inside these?

Radium Engineering and Fuel Safe have partnered to produce Radium fuel cells.

They combine Radium’s Fuel Cell Surge Tank (FCST) with your choice of Fuel Safe cells. This particular example is cell 00000001 – the first one EVER! Well, Fuel Safe has been building cells for more than 30 years, so that’s a bit of an overstatement. But it is the first cell that Radium and Fuel Safe collaborated on, and MotoIQ got to be the first to use one. What’s so great about a fuel cell? What’s the surge tank for? Time for a TECH BREAK!

A factory fuel tank is designed with a very wide range of characteristics in mind. Engineers have to look at factors like range and capacity, crashworthiness, keeping the car from being stinky, emissions, and many other things. From a safety perspective, the fuel tank is made of pretty tough coated metal. That also makes the tank heavy. It’s designed to survive a collision, and is located in a place that helps to minimize the odds of it being severely damaged during one.

A fuel cell is made of a lightweight outer shell (20 gauge powder coated steel, in the case of the Pro Cell) and has a bladder inside. This bladder is what holds the fuel, and, on the Pro Cell, meets FIA FT3 certification. The FIA certification has to deal with puncture, tear, deceleration and other resistances. A street fuel tank is designed primarily for highway-speed incidents. Racing incidents can happen at much much higher speeds and, therefore, involve much much higher forces.

As you can see from the earlier picture, the fuel tank is located up and in between the shock towers. This keeps it safe, but isn’t optimal. The specific gravity of unleaded gasoline is generally around .755 kg/L. A 20.6 gallon SC300 fuel tank holds 77.98 liters. 77.98 x 0.755 = 58.8749 kg, or approximately 123lb. That’s a lot of weight to have well above the center of gravity of the vehicle. Heck, it raises the center of gravity of the vehicle. And that doesn’t even include the weight of the tank itself!

The factory baffling in a fuel tank is good, but not great. I’ve experienced starvation issues with Damnit during cornering even with several gallons of fuel in the tank. Fuel starvation, especially on a turbo car, is not a good thing. A proper racing fuel cell is full of fuel-compatible foam baffling that helps prevent sloshing and helps to keep fuel near the pick-up.

This is also where the surge tank comes in.

This is the underside of the Radium Engineering FCST.

It combines a lift pump and a primary pump in the tank. The lift pump lifts fuel out of the cell and pushes it into the 2.2-liter surge tank. The primary pump then pushes the fuel from the surge tank out to the engine. Whether you are pulling high Gs from hard drag launches or high-grip cornering, the surge tank helps to ensure that fuel flow to the motor remains constant – no more starvation!

The “Fuel Cell” part is the fact that this setup is integrated into a top plate that fits standard racing fuel cells, like Fuel Safe’s PC122, the 22-gallon tank we are using. The top side of the FCST has -AN ports for hoses and our FCST came with the optional fuel filler neck and a rollover/vent tube.