Batch or Sequential firing?
05-10-2013, 04:42 PM
#1
Race Car
Thread Starter
Batch or Sequential firing?
Has anyone reprogrammed the 944 to do sequential firing vs. batch firing of the injectors? I wasn't sure if the new MAF kits from Rogue or Vitesse do this?
05-10-2013, 04:49 PM
#2
I believe to do this requires a trigger wheel and sensor on the camshaft. I know to do sequential I would need to add those to my car so that the TecGT knew cam position. I'm running in batch because I didn't feel like having to set everything up.
05-10-2013, 05:21 PM
#3
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As Darwin stated, to do sequential injection you need a cam sensor. However on the 951, the DME hardware and wiring would need to change in addition to the software.
When the injectors duty cycle drops too low, below a certain level, the injectors become uncontrollable. Causing bad idle and bad low load running conditions.
When the injectors approach the low or minimum controllable duty cycle, the Vitesse MAF software operates in semi-batch mode causing the injectors (all 4) to fire half as many times, but for a longer duration to keep their duty cycle above the "uncontrollable" low duty cycle.
When the duty cycle is back up to controllable levels, the software automatically switches back to full batch mode.
We ran 120# injectors with good idle. I have been needing a reason to try the 160#, maybe one day.
When the injectors duty cycle drops too low, below a certain level, the injectors become uncontrollable. Causing bad idle and bad low load running conditions.
When the injectors approach the low or minimum controllable duty cycle, the Vitesse MAF software operates in semi-batch mode causing the injectors (all 4) to fire half as many times, but for a longer duration to keep their duty cycle above the "uncontrollable" low duty cycle.
When the duty cycle is back up to controllable levels, the software automatically switches back to full batch mode.
We ran 120# injectors with good idle. I have been needing a reason to try the 160#, maybe one day.
05-10-2013, 06:25 PM
#4
Race Car
Thread Starter
As Darwin stated, to do sequential injection you need a cam sensor. However on the 951, the DME hardware and wiring would need to change in addition to the software.
When the injectors duty cycle drops too low, below a certain level, the injectors become uncontrollable. Causing bad idle and bad low load running conditions.
When the injectors approach the low or minimum controllable duty cycle, the Vitesse MAF software operates in semi-batch mode causing the injectors (all 4) to fire half as many times, but for a longer duration to keep their duty cycle above the "uncontrollable" low duty cycle.
When the duty cycle is back up to controllable levels, the software automatically switches back to full batch mode.
We ran 120# injectors with good idle. I have been needing a reason to try the 160#, maybe one day.
When the injectors duty cycle drops too low, below a certain level, the injectors become uncontrollable. Causing bad idle and bad low load running conditions.
When the injectors approach the low or minimum controllable duty cycle, the Vitesse MAF software operates in semi-batch mode causing the injectors (all 4) to fire half as many times, but for a longer duration to keep their duty cycle above the "uncontrollable" low duty cycle.
When the duty cycle is back up to controllable levels, the software automatically switches back to full batch mode.
We ran 120# injectors with good idle. I have been needing a reason to try the 160#, maybe one day.
05-10-2013, 06:54 PM
#5
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When you are at WOT and higher RPMs, it's not going to make a huge difference economy wise.
In theory, and it depending on injectors size, sequential helps economy and maybe drivability at idle and low load.
There are ,many opinions on this. In my opinion, if you have the capability to go sequential, then go for it.
One benefit, sequential injections gives you the ability to trim individual injectors (assuming the engine management has this capability). So if you have unequal air flow to the head, you can compensate (or band aid) by adjusting fuel per hole. Of course you'll need a way to monitor each cylinder by itself. With batch mode, you can band aid by using an injector with a bit different flow (same size injector just with a +/-% in flow)...
Engine managements with per cylinder trim (fuel & Ign) and knock detection gives you the tool to address knock per cylinder..
Batch is simpler to implement, and cheaper. Sequential requires additional sensor(s) and someone to properly program it.
The bottom line, once you identify your requirements for an engine management, you can determine which solution is best for you.
In theory, and it depending on injectors size, sequential helps economy and maybe drivability at idle and low load.
There are ,many opinions on this. In my opinion, if you have the capability to go sequential, then go for it.
One benefit, sequential injections gives you the ability to trim individual injectors (assuming the engine management has this capability). So if you have unequal air flow to the head, you can compensate (or band aid) by adjusting fuel per hole. Of course you'll need a way to monitor each cylinder by itself. With batch mode, you can band aid by using an injector with a bit different flow (same size injector just with a +/-% in flow)...
Engine managements with per cylinder trim (fuel & Ign) and knock detection gives you the tool to address knock per cylinder..
Batch is simpler to implement, and cheaper. Sequential requires additional sensor(s) and someone to properly program it.
The bottom line, once you identify your requirements for an engine management, you can determine which solution is best for you.
05-11-2013, 12:55 AM
#6
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I have sequential on the FL car along with stand alone EMS & COP, you need pretty deep pockets and lots of knowledge, for minimal benefits. You will need lots of patience and constant tweaking/fiddling/testing/monitoring!
I would not spend the money to go this route again. Very satisfied with my CA car running a reasonably priced system from Rogue. Basically plug and play, drive and enjoy. No stress and cussing.
I would not spend the money to go this route again. Very satisfied with my CA car running a reasonably priced system from Rogue. Basically plug and play, drive and enjoy. No stress and cussing.