minimum pulsewidth measured
Thread Starter
Teching In
Joined: Dec 2003
Posts: 32
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From: Pleasanton, CA
minimum pulsewidth measured I built this setup to measure the minimum pulsewidth for various injectors. By minimum pulsewidth I mean the shortest pulsewidth that results in enough fuel flowing through the injector for an engine to idle.
http://para.noid.org/~lj/InjectorPulseTest.jpg
I've only looked at three part numbers so far, all made by Siemens-Deka, and all tested at 43 psi fuel pressure. Here's what I found:
60 lb/hr high impedance: 1.5 ms (this injector has a "Mototron" part number in ink)
72 lb/hr low impedance: 0.8 ms
83 lb/hr low impedance: 0.9 ms
As expected, the high impedance injector had a fairly broad transition from no flow at all to a reasonable stream, whereas the low impedance injectors had a sharper cutoff. I'm convinced that is why guys have a hard time getting the big high impedance injectors to work well at low loads.
http://para.noid.org/~lj/InjectorPulseTest.jpg
I've only looked at three part numbers so far, all made by Siemens-Deka, and all tested at 43 psi fuel pressure. Here's what I found:
60 lb/hr high impedance: 1.5 ms (this injector has a "Mototron" part number in ink)
72 lb/hr low impedance: 0.8 ms
83 lb/hr low impedance: 0.9 ms
As expected, the high impedance injector had a fairly broad transition from no flow at all to a reasonable stream, whereas the low impedance injectors had a sharper cutoff. I'm convinced that is why guys have a hard time getting the big high impedance injectors to work well at low loads.
Thread Starter
Teching In
Joined: Dec 2003
Posts: 32
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From: Pleasanton, CA
Originally Posted by RedHardSupra
sweet setup! thanks for sharing the data. are you able to do more testing for other popular sizes, like svo 30/42s?
ahhhhhhhh i should have sent u mine out, i am having troubles low load getting my racetronix 38's to idle, i threw the cam in to try and make it need more fuel. but if i get to low levels of fuel needed the car has a hard tiem running. awesome man!!
nice work.
Your values for 60's are very close to some I have for those injectors as well.
I don't know why people have trouble making them work, I use them for fords all the time with no real issues, but I have full batt comp tables as well.
Ryan
Your values for 60's are very close to some I have for those injectors as well.
I don't know why people have trouble making them work, I use them for fords all the time with no real issues, but I have full batt comp tables as well.
Ryan
Yes this is why for years guys go to a low Z injector with big pound hour stuff. Factory cars (german stuff etc) have been running lowZ stuff form the facotry even for years
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Verdad Gallardo Thread Starter
Teching In
Joined: Dec 2003
Posts: 32
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From: Pleasanton, CA
Originally Posted by CHarris
I've got the Motron 60's running well at 1.8-1.9 ms on my combo listed in my sig...
BTW, CHarris, do your injectors say Mototron on the body? Or Motron?
