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pbp1 · 08-07-2013, 10:45 AM

Sorry, you are correct, my comments were focused on SS. As far as the speed at which commands are given from the ECU. I can only speak with authority about the system we make but we use dual 25mhz processors in our ECU so that gives us a potential of 50,000 commands per second. I seriously doubt any engine has a need for more than 50,000 different commands before you get past the 60' mark. LOL. Most modern ECUs have at least this much capacity. As for the injectors going static, that is a simple matter of running out of injector capacity. If your engine needs 288 pounds of fuel per hour and you are running eight 36 pound per hour injectors, the ECU cannot get any more fuel out of the injectors. Most injectors are not linear in their fuel delivery above 80% duty cycle. The ECU controls the injectors as to deliver the requested amount of fuel based on the injector flow rate you have defined in your tuneup. The ECU cannot know or account for inconsistencies in the injector flow characteristics (as you have above 80% duty cycle) so when you injectors are above 80%, the engine is not actually getting the fuel that you (or your ECU) thinks it is. He can turn the fuel pressure up effectively making his injectors "bigger" but there are limitations to that as well.

08-07-2013, 10:45 AM	#75
pbp1 Junior Member Join Date: Mar 2013 Posts: 78 Likes: 11 Liked 18 Times in 5 Posts	Re: Which is faster carb or Fuel injection? Sorry, you are correct, my comments were focused on SS. As far as the speed at which commands are given from the ECU. I can only speak with authority about the system we make but we use dual 25mhz processors in our ECU so that gives us a potential of 50,000 commands per second. I seriously doubt any engine has a need for more than 50,000 different commands before you get past the 60' mark. LOL. Most modern ECUs have at least this much capacity. As for the injectors going static, that is a simple matter of running out of injector capacity. If your engine needs 288 pounds of fuel per hour and you are running eight 36 pound per hour injectors, the ECU cannot get any more fuel out of the injectors. Most injectors are not linear in their fuel delivery above 80% duty cycle. The ECU controls the injectors as to deliver the requested amount of fuel based on the injector flow rate you have defined in your tuneup. The ECU cannot know or account for inconsistencies in the injector flow characteristics (as you have above 80% duty cycle) so when you injectors are above 80%, the engine is not actually getting the fuel that you (or your ECU) thinks it is. He can turn the fuel pressure up effectively making his injectors "bigger" but there are limitations to that as well.