Fuel - "GoGo Juice"
A couple of things about the evolution of the Commodore fuel system.Fuel Tanks
The car originally came with a custom fuel tank; black thing made out of rather thick steel plate. It was rather heavy, but did the job. At some stage, we decided to replace it with a lighter ally tank, and include a fuel sender and scavenging tank in the redesign. We supplied some ally sheet to the guys at Rotomotion, and they managed to turn it into a reasonable tank. The unit was externally braced and allowed for foam filling (used for two reasons; firstly to minimise fuel movement within the tank and secondly to minimise the chance of an explosion if the tank were to be ruptured).
In hindsight the tank ally was too thin (the stresses of offroad really required something a bit beefier), and the fuel sender was a waste of time (it's easier and more reliable to dip the tank to figure out what you've used and fill accordingly; of course some/most engine management computers nowadays monitor fuel usage and could probably be used/modified to indicate when fuel is running low - based on litres left and k's to go).
Foam
On the subject of foam; the stuff has a habit of releasing small foam particles into the fuel system which need to be filtered out somewhere. Unfortunately the design of our system had the Holley scavenging pump first in line from the tank, and as a result the particles filled the pre-filter (in the pump) and restricted/stopped the flow of fuel. Once we had figured this out (yes; this is another reason why we've had to pull into the pits during a race), it became a simple matter of regular maintenance.
Fuel Tank Breather
It's a good idea to get the fuel tank breather below the level of the tank, so that in the event of a roll-over you don't have fuel pouring out. Unfortunately a single low breather can became clogged with mud and will result in the engine starving for fuel and the tank possibly being crushed. The fitment of two breathers in protected locations can alleviate this problem, however it's a good idea to keep an eye on them during maintenance.
Fuel Pumps and Filter
Scavenging pump was a Holley Blue (from the 1600 when it passed on), which fed a truck fuel filter (also from the 1600) and custom swirl pot. A high-pressure Bosch pump then pushed the fuel towards the front. The standard fuel regulator on the quad-cam was used to limit fuel return to the swirl pot. We never had a problem with this setup, even though we suspected the Holley had given up the ghost when we ran out of fuel the first time...
The Engine Side of Things...
We never really had any problems with the Rochester carby, and certainly none with the quad-cam fuel injection system. The single complaint I can think of was the ol' 308's habit of dying coming into a corner. I'm guessing this was due to a bad fuel mix (too lean or rich due to the deceleration), however we never got to the bottom of this.
