Fuel System

Fuel Cap

Aero-style fuel filler cap This is the Mocal 2" locking 'Aero' cap (part no. CAP3SF) locking fuel filler cap I used on my Fisher Fury R1. It's worked really well and has an in-built restrictor for unleaded fuel. For IVA I added the lead-free flap kit (part no. MOCLFK1). This needs a fuel hose with a 51mm internal bore to connect to the tank and two stainless-steel, 50-70mm hose clips to fix it.

Fuel Tank

I've learnt a lot about car and bike fuel systems whilst designing and building the fuel system for my Fisher Fury R1.

I want a properly baffled fuel tank. This video shows a cut-away view of the fuel tank in a Sauber F1 car, including the horizontal baffles (at about 2 minutes 30 seconds) and the fuel flaps to allow fuel down through the tank but not back up again. This keeps the centre of gravity lower.

The above video shows the kind of custom tank I have in mind. It will be made from aluminium. It also makes much more sense if the fuel return feeds into the lowest part of the tank.

The fuel tank has to sit with a 'firewall' between it and the passenger compartment. For this reason, I plan to mount it behind the main tub and low down, sitting on/between the rear subframe and in front of the engine. This keeps it central too.

In the Fisher Fury R1 I'm using a 25 litre tank and this gives a fairly short range (165 miles is the best I've managed). I'm planning to use a tank about this size again, to keep the weight low.

Fuel Level Sensor

In the Fury, I used a mechanical fuel level sensor but I'm not sure there will be space for something like this in the new tank, especially with baffles in place. This sensor has a resistance that varies depending on the position of the float (100% = 11 ohms, 0% = 260 ohms). There is a Eurpean standard S5-E-sensor specification which should be zero ohms when full and 180 ohms when empty.

Electronic fuel level sensor This electronic fuel level sensor in the centre of the tank may be the best solution. Because the tank is a complex shape, the sensor will need to be calibrated across it's entire range.

Fuel Vent

Initially, I fitted a vent valve in my Fisher Fury R1 but, it created more problems than it solved and I've not used one for the last three years. The filler cap enables any excess pressure to be released.

Fuel Filter

The fuel filter sits between the tank and the fuel pump, to protect the pump from contaminants in the fuel. I plan to make it easier to reach this time! It is a consumable item after all.

Fuel Pump

My preference is for an external fuel pump, purely from a maintenance/replacement perspective. It typical Colin Chapman fashion, I'm planning a compact, light-weight pump running for its life. Some bike engine ECU's require the OEM 'in-tank' fuel pump to be used though.

Fuel Pipes

There is a lot less pipe work with a mid-engined car! This move alone will save around 2 kg in fuel pipework and fixings. Having the fuel tank close to the engine also helps a lot.

Top • Last page update: 04 Jun 2013