3 or more injectors

edge · Post by **edge** » Tue Jul 04, 2006 8:36 pm

not really because i was tolt the later model injectors on later cars all fire at the same time i really dont see why this wont work ill let you know when i get the manifold on will .may be a mounths time though i want to remove the ignition module and put on a commodore one give me more
room under the bonnet also making some strut braces have got the plates made for the top of the shocks

jakobsladderz · Post by **jakobsladderz** » Tue Jul 04, 2006 10:44 pm

If you're using the JA computer you can hook up 2 MPI injectors to each TB circuit as both JA injectors are the same size and fire alternately. I think the later models used staged injection and different sized injectors so this may not work. Does anybody have any better info than that? That will reduce fuel pulsations and reduce the load on each ecu pin.
You really will want to hook up a mixture gauge though, otherwise you'll have buckleys idea whether you are helping Arabs buy sterling silver supras or helping your pistons find the way to the bottom of your sump..
The ignition module is more of a complete ignition system, with build in knock sensing and so forth. Hooking a commodore ignition module is no mean feat, you'll need an aftermarket ECU for that to sequence the spark, along with an optical dizzy from a sonata 8V to sync the ECU with the crankshaft.. quickly moves away from a budget system, though perhaps you could use the spare coil as part of an alarm system or a jakob's ladder...

RiceThief · Post by **RiceThief** » Tue Jul 04, 2006 11:34 pm

As i said the only thing i can think of when using the JA computer is you wont know when the injectors will fire in relation to the engine. The last thing you would want is the injectors firing at the wrong stage in the combustion cycle or when the inlet valve is closed.

I think running two injectors per bank would work, but as mention you would have to reduce the number of times the computer pulses the injectors, by a factor of 4 or 2 depending on how many times the injectors are fired in a combustion cycle.

You can get a commodore ignition module to work instead of the starion ignition module. The starion module is basically a dumb unit with only timing retard in relation to the knock sensor. All the timing is within the dizzy with the weights and mechanical advance and retard with the vacuum unit connected to it. You wont need a optical dizzy and it wouldnt really work if u use one as the timing would be locked. I've gotten the commodore ignition module to work with the starion dizzy but you wont have any knock timing retard. If you want to do it, i've got a diagram that Merlin drew up to get it working with a commodore igniton module.

jakobsladderz · Post by **jakobsladderz** » Wed Jul 05, 2006 8:41 am

The injector phasing it not a problem. Plenty of cars have their injection running off two circuits with the injection behind a closed intake valve. Despite what logic may dictate, there is very little change in engine performance with changing injector opening location.
Realistically you have to inject behind an open valve as soon as the engine is at full load because the intake valve is opened only 1/4 of the time (give or take a bit) but you need the whole time to get enough flow. At full load and full revs the injector is opened four times longer than the intake valve.
Having the fuel sit in the intake for as long as possible gives it time to properly evaporate before being drawn into the cylinder. Sequential setups are often set up to inject with closed valves until full load.

In short, there's no problems injecting whenever in the cycle, so long as it's at least one injection pulse per cycle.

edge · Post by **edge** » Sat Jul 22, 2006 4:30 pm

hi guys i have bolted the manifold up and had it all running revs up good and runns smothly will post up a pic 2morow

Junkers · Post by **Junkers** » Tue Jul 25, 2006 2:54 pm

So hows this going? does it perform any better? pics?

edge · Post by **edge** » Tue Jul 25, 2006 4:24 pm

it runs ok havnt taken it for a drive yet no licence (speeding in the starion)

ill do picks later the manifold is off a frount wheel drve so i still have to move the throttle body may do that next week when i get my licence back its been a long 3 months

edge · Post by **edge** » Tue Jul 25, 2006 4:35 pm

Junkers · Post by **Junkers** » Wed Jul 26, 2006 4:16 pm

Keep us updated

logik · Post by **logik** » Wed Jul 26, 2006 5:53 pm

im glad someone has just hopped in and started mucking around with it, instead of just saying no.

will be very interested to see how this pans out.

im sure if you used bigger injectors per bank (assuming you set up two injectors per single injector circuit), you could probably refine it by playing with the fuel pressure?

im assuming all starions came with twin 850cc inj in the hat?

would this directly translate to the equivalent of having one 425cc inj per cyl?

edge · Post by **edge** » Wed Jul 26, 2006 8:45 pm

na i have wired all the injectors to one wire from the computer but im only running the wire with the black stripe to the smaller wires from the injectors and straight to positive on the other wire to the injectors will have more of a play around on the weekend

Junkers · Post by **Junkers** » Thu Jul 27, 2006 10:47 am

I have just bought a eci multi manifold to play around with aswell. Does that wire with the black stripe control the duty cycle? Is it a + or - input?

What I'm curious about is how the eci multi's are setup for adjusting the fuel mixture as they may have differen't resistance ranges so I might try and use the original pots off the TBI manifold.

edge · Post by **edge** » Thu Jul 27, 2006 4:55 pm

i think it is a - input. glad to see someone else interested in this every one says no it cant be done.you should have four wires to the injectors two of them have a black stripe you should be able to use one of these i tried both ways it didnt seem to matter it still ran and just to see if it whent i put 12 volts straight to the injectors

jakobsladderz · Post by **jakobsladderz** » Thu Jul 27, 2006 7:46 pm

The injector wire from the ECU is switched to ground. one side of the injector is connected to 12V, the other is grounded at the appropriate times by the ECU to complete the circuit. Injectors are not polarised so it doesn't matter which goes to + or -, they'll open either way. if you're using a cut-up factory loom one side of the injectors will be joined anyway, so you can stick to their scheme and not have to make too many extra connections.

If you're using a JA ECU, you could hook half the injectors to bank A and half to bank B, unless I'm mistaken the JA was not staged, each injector opens in turn.. correct me if i'm wrong on that anybody. the advantage of sharing the pulses between two banks is less fuel pulsation and less load on the ECU. it'll work OK though the way you have it.

The other (somewhat related) thing is the assumption of the 50% max duty cycle. if this is the case then the two 850 ish cc injectors on the starion are working at best as one 850cc injector (or 4 212cc injectors) giving at best (using 550cc ~= 100HP - probably a bit generous for a turbo) 154HP. Starions are supposed to be ~170Hp from the factory and that's at 7PSI. They don't run out of fuel until 13PSI intercooled and that's only because mr bishi said so, so there has to be more than 50% duty cycle available or the injectors have to be bigger than 850cc :x

Keep us informed... This could become a good cheap mod for some..

logik · Post by **logik** » Fri Jul 28, 2006 3:43 am

if i have 4 550cc injectors installed on a mpi manifold, running from starion ecu... if i find a way to reduce the fuel system base pressure from 36 to 22psi, this should match the 1700cc total fuel rate?

http://www.witchhunter.com/injectorcalc1.htm gave me the idea, or is there more to it than that?

Austarion

3 or more injectors

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