peak to peak periodic cycle (a few redundant words here , so the maximum an injector can stay open is 10ms. If it stays open at 9ms, then it is 90% duty cycle. If you divide that by half and say that you can only have a 5ms max duration, then a 240cc injector * 4 will only give ample fuel to supply about 120 hp peak.

 

Divide the duty cycles by half (the percentages), which means the max time is multiplied by two (not divide by two), so your 10ms example means the injectors would fire every 20ms.
You have to remember that the intake valves are probably going to be open for longer than one stroke (which is the 10ms in your example)

 

for the purposes of my calculation.


RPM.....Engine..Inj.....MAF....Throttle..Ignition. ..O2S....Duty....Boost (psi)
...........Load....Time........................... ..................Cycle

1700....5.30....10.94....27.36....85.1....-13.50....0.555....16%....-0.4
1875....6.30....10.56....37.43....84.6.....-6.80....0.680....17%.....3.0
2180....8.20....15.10....55.69....84.6.....-4.50....0.765....28%.....8.0
2580....9.75....16.32....78.12....84.6.....-6.00....0.815....35%....12.2
3300...10.05....16.32...111.94....84.6....-10.50....0.815....45%....15.4
4040...10.00....16.32...129.51....84.6....-17.30....0.820....55%....13.8
4540...10.00....16.32...122.50....84.6....-17.30....0.835....62%.....9.3
5060...10.00....16.32...161.87....84.6....-17.30....0.855....69%....13.7
5560...10.15....16.32...180.97....84.6....-16.50....0.855... 76%....14.2
6060....9.80....16.32...187.08....84.6....-16.60....0.835....83%....12.7
6420....9.20....16.32...187.11....84.6....-14.30....0.805....88%....11.2

That looks better now. Thanks. No wonder my lawn mower runs so slow ;P

 

This chip trails off to 11psi at redline, hence the low MAF readings

 

well at least my fudging provides close numbers to you boost gauge Have you decided what to do?

 

it is not 100% duty cycle at 16ms, but more like 85%, which is "supposedly" safe for the injector.

Are you sure Marren said 14ms was max safety limit for this injector?

 

What were the conditions of your run - what gear, outside temp?

What kind of Fuel Pressure Regulator are you using? Stock Injectors?

I noticed that our MAF readings were real close up to about 5200 RPM, when my K03 runs out of air. Since the MAF readings are close, then the O2 sensor readings should compare too, but they don't, mine are much higher.

If you notice, the O2 sensor readings fall off when the MAF readings stabilize. I presume this is because the boost pressure starts to drop, and so does the fuel pressure.

Is your FPR adjustable? Seems you should tune it so it runs richer on the top end, then adjust the low and middle range via the software. Of course, this is assuming the stock fuel pump is capable of sustaining this amount of flow.

Here's my little comparison:

Mike O._________________John B.

RPM______MAF____________RPM______MAF
2580_____78.12__________2600_____86.3
3300____111.94__________3240____109.7
4040____129.51__________4000____134.1
5060____161.87__________5120____170.3
5560____180.97__________5560____170.5
6060____187.08__________6080____172.8
6420____187.11__________6400____173.9

RPM_____MAF___________RPM_____MAF
2180____.765__________2205____.150
2580____.815__________2579____.880
3300____.815__________3361____.885
4040____.820__________3962____.890
4540____.835__________4618____.890
5060____.855__________5026____.865
5560____.855__________5557____.850
6060____.835__________6031____.845
6420____.805__________6495____.840

 

...the increase in injector timing is not linear to an increase in flow. Therefore, a Bosch injector, when run at below 14ms, is easier to program the ECU for. When programming over 14ms, if you know how much below the additional flow degrades compared to additional timing, then you are OK up to a point.

In addition, a 16ms signal at high RPMs (6500+) may indeed be over 100% of duty cycle.

Mike O.

 

bosch manual doesn't even talk about the closing times. So you're right, for a 16ms on time, might as well leave it open at high RPM. 14ms sounds about right.