Lizard928

Does anyone happen to know the injector opening time in ms for 85/86 24# injectors?

TIA

blown 87

It changes with load.
What are you trying to figure out?

Shane

i was looking at the users manual for the sharktuner and one of the pages listed it at .93ms but I don't know if that is actually the real value or something put in there for illustration.

blown 87

It (the MS) changes, it is how long the injector is open.
Not much at idle, a lot at WOT, this will change with with size of the injectors (LBS/ hour).
You do not want a injector that will be to big for idle or one that is to small and maxes out and can cause the engine to run lean.

FlyingDog

blown 87, He says opening time, not open time. I had to read it twice to catch that.

blown 87

You sir are 100% correct, so much for me PUI.

I would think that the time it takes for a injector to open would be insignificant between the injectors that we use on a 928 regardless of PPH.

Lizard928

Yes I am looking for the opening time, not the PW of the injector running.

and the opening time of the injector can have a very large effect on how many PW it runs.

I am needing this to help me smooth out the idle alittle.

If I dont find/get answers by the morning I may just take a spare injector to a rebuilding shop and have them test it for me and tell me.

John Speake

Around 1mS for a pintle injector appears to be the accepted figure. The minimum total injector pulse should be greater than 1.5mS to get reliable fuelling.

karl ruiter

John's number seems reasonable, I usually assume somewhere in the 1 to 4 ms range for most solinoid valves. I expect some variation from unit to unit also. You can see it with an oscilloscope. You put a switch to turn on the voltage, then a resistor, then the injector and connect the other side to ground. Hook your scope between the injector and the resistor. When the injector stops moving you can see a shift on the voltage as the back EMF goes away. The time between when you throw the switch and when the injector stops moving the the opening time.

Lizard928

Karl, anything higher than a 1.5-1.7 opening time is not good, and likely to overheat the injector.

I am needing to know this for my standalone to get the absolute best idle, and off idle performance/responce that I can.
I am giving the Bosch service center that "the guy" made a post about here awhile ago, to see if they can answer my question. I have run it with 1.0ms before John and it is ok but the afr does jump around abit, where I should be able to get it so stable that the afr should only move +/- .1 of an afr.
I found at around .7ms opening time that the afr (granted it was much richer 12.5:1) was very stable.

All in the fun of getting it dialed right in, for the absolute best settings.

PorKen

People say the disc type (Ford four hole) injectors have a bit less mass, and can open faster, for a smoother idle.

Everyone says that the four hole are superior, but then I came across articles like these:

http://zdyne.com/forcedfactory.html (bottom of page)

http://www.automotivearticles.com/12...n_Setups.shtml

I was going to buy some (Accel pintles), but ended up (buying Fords), because they were tan, which matches the stock 85-86 color.

RngTrtl

+1 for this approach. If you must know the opening time, then it must be measured and measured for all the injectors. When talking about times in the 1 ms range, then rules of thumb got out the window.

blown 87

It might be different in a 928, but the some of the supercharged Corvette folks have had real problems with the Acell's. For what it is worth, I have had no dealings with these injectors.