fast injection

F. A. S. T.   X F I   Fuel Injection   vs.   C A R B.

Actual Test Results---Oct 2008

fast xfi

Knowing that tune-able fuel injection systems are the wave of the future, we were interested in trying a unit that was very complete, with no guess work on what plugged into what, and narrowing the choice down to the FAST XFI ,(xtreme fuel injection), we then needed a car that was consistent, carbureted, and well tuned, that we could try the injection on, so we chose my son's 80 Camaro 350 small block which previously had run consistent 10.40's at 127mph with a well tuned 750 carb going thru the traps at 7000rpm. After installing the FAST XFI injection, we made it to a test session and on the 2nd run we were at a 10.25 and by the 5th run of the day we had run a 10.12 at 133.50mph going thru the traps at 7500rpm. Although we were finished tuning for the day, I'm sure we only skimmed the surface. Our objective was to make the engine more efficient thru the entire RPM band and basically, when you can see the parameters on a screen, you can easily make adjustments to improve performance getting you to the end faster and with an infinite amount of tuning possibilities at your fingertips, you will be capable of doing the same.
You also have a couple of new innovative self learning FAST EFI systems to choose from: check out the original 1st generation FAST EZ-EFI 1.0 self learning, tune as you drive,easy replacement of 4150 carb applications up to 600HP non boosted applications with a FAST throttle body-- or-- for self learning applications up to non boosted 1200HP applications and has the ability to control ignition timing The New FAST EZ-EFI 2.0 should serve the purpose very nicely--or--see MultiPort EZEFI for engines that already have multiport injection--all the EZEFI Systems have self learning capabilities and tune as you drive.

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FAST XFI Operating System: or ----Go to the Installation

The FAST ECU can operate in either of two operating systems:

Alpha-N --- which is commonly used in situations where the engine has low manifold vacuum caused by a large camshaft for racing (our test car used this system)--Alpha -N uses the TPS and RPM to determine fuel requirements and changes are made to the base pulse width of the injector which you can increase or decrease to keep you at your desired A/F ratio thruout the entire RPM band. Another strong feature about this system, after you've made a few passes, you'll begin to see that the system is taking away fuel at some point in the upper rpm inorder to keep the engine at the desired A/F, and that is telling you at what RPM the HP curve is beginning to decline, so now you can gear the car to hit the traps at that particular RPM.


Speed Density--- which is used primarily by street performance vehicles, turbo or supercharged applications--this system will use the readings from the MAP, ATS and RPM to determine the fuel requirements --by constantly calculating the volume of air passing thru the intake it can determine the density of the air entering the engine and from there, the ECU looks up the desired air/fuel ratio (entered by the user in a manifold absolute pressure vs. engine RPM table) and determines the correct amount of fuel required to achieve that target A/F ratio. Finally, the ECU uses the number of injectors and the injector flow rate (both entered by the user in the Fuel Calc Parameters screen) to arrive at the required injector pulse width.

Although neither operating system produces more power than the other, there are a few differences:
1. Speed Density will allow for much better driveability tuning than Alpha-N and therefore better for street performance.
2. Any turbocharged or supercharged engine MUST use Speed Density. The boost level in a forced induction engine is a critical part of the fuel calculation and the location of the ATS will differ from N/A applications. N/A applications (using speed density) can locate the ATS in front of the throttle body (possibly somewhere in the airpan to measure air temp entering engine), Boosted applications, however, want to measure the air temp under boost which will be hotter, so mounting the ATS behind the throttle body in the plenum is suggested.
3. For Alpha-N, the ATS can be located in airpan or aircleaner to measure the air temp coming in.

The FAST ECU can also operate in either of two modes:

Bank to Bank mode--where the injectors on one bank all fire simultaneously (I still have a hard time when I think about this situation, but it obviously works because our test car also used this mode in the Alpha N operating system)


Sequential mode--where you can tune each cylinder individually, by the amount of fuel or the amount of timing each cylinder needs to maximize your efficiency thru the RPM band. (we hope to give this a try this year, time permitting--we'll keep you posted)

To operate in sequential mode, you will need, either a dual sync FAST distributor, which can set the injector firing and ignition timing (comes in complete kit or sold separately-see CUSTOM KITS ), or a crank trigger to set the injector timing and an IPU (inductive pick-up) distributor to set the ignition timing--also suggested is an adjustable rotor, so you can phase in the ignition timing correctly.-(see Crank Trigger for purchasing a crank trigger and also installation tips when installing a crank trigger when used with an XFI Fuel Injection System)
To operate in bank to bank mode, the dual sync isn't required, you can use an IPU distributor and with the balancer positioned at 50° BTDC on #1 firing, align one of the 8 contacts of the reluctor in the distributor with the magnetic pickup (in distributor) and lock distributor down (that sets your injector timing), next, move the balancer to your preferred total ignition timing (36° or 40° etc.)and phase in the adjustable rotor to line up with the #1 rotor contact in the cap.

The FAST ECU can operate in both open loop and closed loop:

Open-loop----With the engine running in open-loop, the ECU collects and records all data from the sensors to describe engine operation but does not use data from the O2 sensor to adjust fuel requirements. There will be temperature parameters on the disc you load to provide a good cold start and fast warm-up, and this will stay in effect until it reaches a certain temperature, 120° or 140°, whatever you find to work best, and then it will go into
Closed-loop--With the engine running in closed-loop, the ECU collects and records all data from the sensors and fuel delivery is continually corrected to a specified target air/fuel ratio based on feedback from an O2 sensor. Most of the adjustments you make for performance will be used during closed-loop cycles.

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