RSR FUEL CALIBRATION

The most difficult aspect of tuning whether it is fuel injection or carburation is getting the fuel delivery curves exactly right for your application. In the case of fuel injection this means getting your base map exactly correct for the various combinations of manifold pressure and engine rpm. RSR provides you with the tools necessary to completely map your engine. We realize that you do not have a $200,000.00 computerized dyno facility or a $10,000.00 exhaust gas analyzer. Our AUTOCAL software gives you both digital and analog read-outs of air/fuel ratios and engine load factors to speed your developmental process. You can manually edit point by point your base fuel map using these digital and analog read-outs or you can use the autocalibration mode and let the electronics write your base map during actual driving or dyno runs. By using the autocalibration mode and fine-tuning individual points in the manual edit mode you will be able to make a fuel map perfectly suited for your particular application. If you are unable to use a portable PC while the vehicle is moving we offer an inexpensive portable onboard readout of real-time air/fuel ratios and a booklet showing you how to use this display to develop your base fuel map. Using this portable display while driving and a computer to program your ECU you will be able to fully develop your base fuel map without the need for expensive and difficult to obtain dynamometer time. If you have access to a sophisticated dynamometer you can shorten your development time simply by using the on screen displays shown in the AUTOCAL program which tell you exactly how much fuel to add or subtract at any given point in the base map. Fuel calibration is a difficult process which cannot be completed on a dynamometer alone. Actual driving cycles are necessary to adjust your programming to provide accurate transition fueling. Whether you use our portable air/fuel ratio meter or take a ni-cad powered portable PC along for the ride you will have to drive the vehicle to perfect the fuel injection program. RSR calibrates specific systems but we cannot develop the programming for every possible application. Our software and support instrumentation will allow you to quickly perfect the RSR system on your particular vehicle.
ON-BOARD DIGITAL AIR/FUEL RATIO METER
This is the best investment I ever made Powered by The vehicle's 12 volt system this meter is directly connected to the Bosch Lambda oxygen sensor located in The exhaust system. The meter has a 10 L.E.D. display consisting of three green, four yellow, and three red lights. These lights represent a digitized instantaneous readout of air/fuel ratios ranging from 16~8:1 to 10.3:1. I can instantly 'see' My airifuel ratio and make adjustments based on this information. There is no need to look at The spark plugs or to guess if the motor is 'rich' or 'lean' at any one point to include transitional fueling. On closed loop RSR fuel injection systems the display will show oxygen sensing as well as all other functions such as accelerator pump fueling and high speed fuel cut-out on deceleration. Using this on-board meter I can quickly develop A base map.
FUEL INJECTION COMPONENTS
FUEL INJECTION FILTERS: Fuel injectors and injection fuel pumps should not be operated without filters designed specifically for fuel injection. Gas tanks and in-tank filters cannot be trusted to provide the filtration necessary to guarantee trouble-free long term operation of pumps and injectors. The fuel pump must be prefiltered to a 70 microns or less and the fuel injectors to an even finer degree (5 microns). Do not use any 'billet aluminum' style filters that use sintered bronze or paper elements as these are too restrictive and do not provide the filtration capacity necessary.
FUEL INJECTOR SIZING: To select a proper injector for your application you need to know the intended peak horsepower and of course the number of injectors in the system. We use the well agreed upon Brake Specific Fuel Consumption (BSFC) figure of .5 lb fuel/hp. hour for most engines. For example on a 3OOhp 8 injector RSR system: 3OOhp x .5 lb fuel/hp hr.: 150 lbs fuel/hr. 150 lbs fuel/8 injectors : 18.75 lb/hr injectors @ l00% duty cycle. A conservative correction factor would be to run the injectors at a 70% duty cycle as you should never hold the injectors wide open or 'static'. To calculate the injector size divide the calculated static figure of 18.75 lb/hr by .7. This gives you 26.76 lbs/hr or a 25 lb/hr injector. In this application your injectors would be using a 70% duty cycle to maintain a constant 300 hp. A simple formula is
Horsepower x .5 lb/hr. = lb/hr per
.7(# of injectors)----------injector
If you wish to correlate cc's per minute to lbs/hr. lO5cc per minute equals 10 lb/hr. Thus an injector that flows 315cc per minute flows 30 lb/hr.
The RSR Fuel Injection System is calibrated at 51 psi of fuel pressure at 0" vacuum. If you use A Adjustable Fuel Pressure Regulator you can calculate alternative injector delivery rates, stated in lbs/hr by using the following formula: