By adding a lot of air into your engine through the use of a turbocharger, you require additional fuel to match this additional air. An ideal air/fuel ratio, would be 14.7 units of air, for one unit of fuel. So in a 2000cc engine, with 4 cylinders, one cylinder is 500cc. The engine would suck in about 468cc of air, and 32cc of fuel in a single intake cycle. This is under a perfect chemical conditions, with an engine having 100% volumetric efficiency. An A:F (air to fuel ratio) of 14.7 would read 1.00 on a lambda meter, these meters attach a probe into the exhaust system and measure how muc oxygen remains in the exhaust. Lambda is an industry standard for measuring the fuel mixture of an engine.. A perfect burn, or 1.00, would (in perfect chemical conditions - with gasoline) be 14.7. However since engines never burn completly, and they run hot, the fuel ratio is changed - esspecially on performance engines, away from economy and emissions, to cooling and performance. More fuel is called "rich," too little fuel is called "lean," and a perfect 1.00 on a lambda meter is called "stoich." By adding more fuel, the engine temperatures can actually be lowered, using the aditional fuel as a cooler. Turbo cars esspecially require "rich" A:F ratios, since turbo intake temperatures are much higher than N/A cars, and the high compression forces from compressing already compresed air creates a ton of heat. They also need to cool the exhaust with additional fuel. Running too lean is EXTREAMLY dangerous. Ratios like 14:1 and up on a turbo car under hard load starts to become dangerous, with the possibility detonation and burning a hole in a piston or valve. Adding more fuel to a system can be done using larger fuel injectors, or additional fuel injectors. Fuel is controlled by the ECU, and can be modified by electronics controllers, for more on this go to our electronics section. We have setup a number of custom fuel setups to ensure the fuel system can supply a stable and consistent fuel pressure to the injectors at all states - be it cornering, braking, low on fuel, low on battery voltage or whatever. Once fuel pressure is lost, the injectors cannot supply the required fuel, and engine damage is sure to follow. Please contact us to help you with your fuel system needs.


Fuel Pump:

Many stock fuel pumps, esspecially older ones, need to be replaced for higher flowing units to pump the required fuel pressure, when making high HP. When dumping a lot of fuel into the engine, a stock fuel pump may have trouble keeping the fuel pressure constant, and this could cause a lean condition in the engine, possibly causing failure. There are many types of fuel pump upgrades, internal and external pumps (in and out of the fuel tank) are options. For street cars we prefer the internal fuel pumps, since they pump more than enough fuel, and do not have the cons of external pumps. Cheap external pumps can overheat, and are extreamly noisy. High flow, high pressure fuel pumps can be had for cheap now, and are definatly a must when building a high output turbo car. External fuel pumps are great for high horsepower custom builds with fuel cells - and often two or more fuel pumps are used in combination wtih a swirl pot, to reduce the chance of fuel starvation.


Fuel Injectors :

The fuel injectors are little devices that inject precise amounts of fuel into the intake manifold at specific times. Fuel injectors work on "pulses," basically opening and closing a valve into the intake manifold at preset times, determined by the ECU (The fuel injector is simply a solenoid). There is usually one fuel injector per cylinder, however some cars have primary and secondary injectors such as the FD3S. Stock injectors usually flow 250-550cc of fuel, depending on what type of car you have. A stock SR20DET has 370cc injectors, and a 2JZ-GTE has 550cc injectors, stock. Larger injectors require re-tuning of the ECU, since a normal injector pulse would let in say, 35cc of fuel on a 350cc injector, but a 550cc injector opened for the same amount of time, at the same fuel pressure, would let in 55cc of fuel. Obviously you can see the problem here, more fuel, for the same amount of air, would cause a rich condition. The car may still be driveable, however it will not perform proporly, and would require tuning. When upgrading your injectors there is no need to go overboard. Figure out your HP goal and then buy injectors so that at peak power the injectors never go over 80% of their maximum flow capacity. Running an injector above 80% is where they are most likely to be inaccurate and fail, which is why it's not reccomended.

Fuel Pressure Regulator :

The fuel pressure regulator, keeps the pressure in the system constant, and returns excess fuel to the fuel tank via the return line. It is possible to upgrade the fuel pressure regulator to an adjustable pressure unit, or rising rate type. A rising rate will allow pressure to rise a set amount, as boost pressure increases, and a set rate unit will keep a constant fuel pressure at all times. By raising the fuel pressure you can squeeze a bit more fuel through your injectors, and by tuning, unlock some more HP if atomization of the fuel is better. Make sure you don't raise the fuel pressure too high, as it can overwork the fuel pumps, fuel lines, injectors and even the regulator itself. You can imagine what would happen with a fuel line failure.