ASNU Fuel injectors
We use ASNU's range of injectors on most of our builds now, where ever we have the choice to. We have found the data that ASNU provide for calibration, and their dedication to accurately matching them up into "matched sets", to make tuning much more straightforward.
ASNU name their injectors based on their flow rate at 3 bar of fuel pressure and 85% duty cycle. Remember this if you are comparing them with other brands, as usually people will give the rating for their injectors at 100% duty, or their total flow rate. If you wish to compare properly then use the graphs provided for the data you need.
The use of precision cut atomiser plates on the ASNU's also makes them much more appealing over the "hose pipe" style injectors that are simply a bare valve. They allow for the fuel to be properly broken up into small droplets before injestion in to the engine. Small droplets of fuel evaporate much quicker than large ones, meaning more of the fuel will be vaporised by the time it is in the cylinder. It is only the vaporised fuel which will burn in an engine. Any liquid fuel that cannot be vaporised will be left over, and will simply show up as black smoke out of the exhaust.
We have run a few sets of the 1050's on 2.0 4 cylinder Vauxhall Turbo engines with the standard Bosch ECU now, and to great effect! Idle, part throttle and cruise are all nice and smooth with them, showing good low speed, low pulsewidth, atomisation. The characterisation data that ASNU provide is spot on, and makes tuning them easy.
This is for a single plain injector.
Adapters are available for multiple different fuel rail sizes, and to adapt the bottom end of the injector in some applications. Electrical plugs with tails are also available, they use the square style Bosch "jetronic" or EV-1 connector. Please get in touch and let us know what you need them for, as we should be able to sort out the appropriate parts to fit them to your car.
To help you form your own opinion upon what size injectors you require, here is a simple formula for calculating it from your target horsepower;
Horsepower x BSFC
No. Injectors x Max Duty Cycle
Horsepower - at the crank
BSFC - use 5.7 for NA, 6.3 for low>med boost and 6.5 for med>high boost
No. Injectors - number of injectors to be used
Max Duty Cycle - the max. duty you wish to use as a decimal (0.8 - 0.85 max, preferably less)
This will roughly provide the required flow per injector in cc/min on petrol.