TrickerZ

iTrader: (6)

Yes, make someone else do it for you
Yes
Shouldn't change as far as I know. Injection time just changes, not the amount. Someone else more knowledgeable please confirm/deny.

richyvrlimited

iTrader: (1)

1) nope
2) just the CAS is fine assuming you're using both signals from it
3) Sequential won't effect your Duty Cycles i.e. you won't have to go larger because of it

EDIT: TriggerZ, Chris doesn't need an additional crank trigger when there's already a crank (and cam) trigger coming from the CAS.

Chris Swearingen

iTrader: (1)

Still confused on #3. Why won't my duty cycles double when I only inject half as often?

richyvrlimited

iTrader: (1)

doesn't work like that.

you injecting once per cylinder per engine cycle, whereas with batch it's twice per cylinder per engine cycle.

So injecting less often, but more fuel, it balances out.

Matt Cramer

Half as often and twice as long is still the same ratio. Well, it may change a bit when you factor in injector dead time, but not that much.

Also note that 2 squirts alternating, which is what many Miatas run, fires each injector only once in an engine cycle anyway.

Chris Swearingen

iTrader: (1)

Sorry this isn't sinking in for me.

If I currently inject twice per cycle for 10 ms, won't I need to inject for 20 ms if I do it once per cycle? Assuming ( I know its a big assumption) that is correct, if I was at 50% Duty cycle won't I now be at 100%?

Matt,
How do I tell if I am on 2 squirts alternating? (found the setting that says Injector staging, but the selection above it in tuner studio says squirts per engine cycle = 2)

What I ultimately want to accomplish is individual cylinder fuel trim. Would that be possible with only two injector drivers? (something tells me that is wishful thinking, but you gotta ask to learn)

richyvrlimited

iTrader: (1)

exactly.

twice per cycle is 2x 10ms

versus once per cycle 1 x 20ms

so the DC is identical (or near as damnit due as Matt says to injector dead time)

In Engine Constants, there's two selections, one is for number of squirts and the other is for simultaneous/alternating injection

Only possible with full sequential. If you think about it if you tried to trim for one cylinder with batch injection you'd actually be trimming from two...

Joe Perez

iTrader: (8)

When you are squirting each injector twice per engine cycle, or once per crankshaft revolution, the displayed duty cycle is based upon the time of one crankshaft revolution.

So, let's say you're turning at 6,000 RPM, or 100 revs per second, your injector cycle time is 10 milliseconds (1/100 sec.) The injector squirts for 5 ms each time the crank comes around, so your duty cycle is 50%.

Now we'll say you've gone full sequential. Each injector is squirting once every two revs of the crankshaft. The injector cycle time is now 20 milliseconds (two crank revs) and, to deliver the same amount of fuel, the injector squirts for 10 ms. Still 50%.



Nope. Individual trim requires one driver per injector.

Ben

iTrader: (33)

As already answered, the NA CAS is capable of sending both the crank position and cam position signals. However, a trigger wheel at the crank will provide more accurate information to the PCM than a wheel mounted at the cam shaft. This is do to timing belt slop and flex in the cams. Many people call this solution good enough, but it does leave a bit on the table.

However, if you go with the NB super weird 4 tooth trigger wheel for crank position, you will also need to use the weird NB cam position as well, as it is also an unusual pattern, unless you want to write some custom code.

Chris Swearingen

iTrader: (1)

Lucky for me I left that sensor in place to plug the hole in the front of the valve cover. That is the one right?

Ben

iTrader: (33)

Yeah. Did you leave the original cam gear in place too? The cam gear has the weird pattern.

Chris Swearingen

iTrader: (1)

Sure did.

Ben

iTrader: (33)

Then you can use the NB triggers (with the Jason/Abe Schmitt circuit) which will be more precise than the NA CAS (in fact you can remove it), and you will be able to run fuel and/or spark sequentially.