View Full Version : SR20 injector duty cycle

03-14-2012, 09:48 PM
question about SR20 injector driver parameters... was wondering if each injector duty cycle is actually different between each other... from my understanding... factory tuned computers... each cylinder should be getting the same amount of fuel through out the rpm range and vary upon load correct??

03-15-2012, 04:38 AM
There are 4 injector drivers but only 1 command, and it commands opening time depending on load and rpm (mainly - it does corrections depending on temp and knock too)

Beware though, there is a threshold where it goes from semi sequencial to full group; and when in full group, they will be opened twice per cycle.

Thing is, if one of your injector is cleaner than the others, it will give more fuel for the same opening duration; and depending on headers, manifolds and so on you may need a bit more fuel in a cylinder than its neighbour.

What is the point of your question exactly ?

03-16-2012, 01:17 AM
the reason for my question is... i just came up on an old school apexi multichecker. and to read injector duty, it is wired in to one of the injector drivers. and was questioning the theory if the reading off one injector driver would differ from the others.

03-16-2012, 05:29 AM
Then no, readings are the same. I dont know how it works, but i doubt it accounts for the double injection system in full group. If it shows an unusually short duration or duty on load, it means you have to double it to have the real one.

03-18-2012, 10:23 PM
oh i see... no, it didn't show "unusually low" readings. when i did 4th gear pulls at 12-13 psi t25 with 370s it showed around 90 percent duty cycle... so im guessing its pretty accurate? lol. i mean, the apexi multichecker is the aftermarket of the oem nissan jecs power meter. works the exact same way and wired in the same i believe. unlike the tectom thats pluged in through the consult.

03-19-2012, 03:32 AM
that looks accurate yes :D