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dual injector

Posted: Sun Mar 22, 2009 5:00 am
by chewyikai
Hi

can it be possible that i use 2 injector at the same time for 1 piston. my engine is a mercedes 190e 2.3-16v which the head is design 1 port per valve intake.

Below is a pic of my plenum.
Image

so its 2 runner for 1 piston and i need to use 8 injectors.

Re: dual injector

Posted: Mon Mar 23, 2009 6:54 am
by Matt Cramer
You could probably use an injector in only half the runners and get away with it, but there's no reason you can't use two injectors per cylinder. A lot of high boost turbo setups do this, often with separate maps for each injector set.

Re: dual injector

Posted: Mon Mar 23, 2009 7:12 am
by chewyikai
how do i make the injectors inject to gather rathen than making it squirt at a later stage?

and how to wire it?

Re: dual injector

Posted: Mon Mar 23, 2009 7:33 am
by Matt Cramer
chewyikai wrote:how do i make the injectors inject to gather rathen than making it squirt at a later stage?
I'm not sure I understand this question, but I think the answer might be to use dual table mode.
and how to wire it?
Wire the primary injectors to injector bank 1 and the secondary injectors to bank 2.

Re: dual injector

Posted: Mon Mar 23, 2009 7:35 am
by fury fan
How was the original intake configured? Was it port EFI or throttle-body?

I don't want to disagree with Matt, because he has significantly more practical knowledge than I do.

However:
I'd hesitate in injecting fuel/air in 1 valve and then air only in the other. The combustion chamber was surely designed for both ports to have wetflow. Homogeneous mixtures are required best for power, fuel efficiency and emissions - not to mention detonation resistance. You'll have a lopsided intake charge if you use only one injector. Also, you'll need to inject all the required fuel in one side, so you have 2x the fuel near a cold cylinder wall, which could lead to washing oil from the rings in that area (and carbon buildup).

I'm not saying it won't work, I just don't think it will work well, for the above reasons.

Overall, 'rebuilt' injectors are fairly cheap on Ebay, and it looks like you'll be needing a custom fuel rail anyway, so there shouldn't be much more expense to add 4 more holes. If it were me, I'd throw a little more $$ at it and have a balanced system to prevent wierd tuning issues or long-term durability issues later.

Re: dual injector

Posted: Mon Mar 23, 2009 4:34 pm
by elturbonitroso
i would said that size the injectors for the h.p that you think that the engine its going to make and run the 8 injectors at the same time.(one inj,per runner) cyl.1 and 4 to channel 1 and 2and 4 on channel 2.

Re: dual injector

Posted: Mon Mar 23, 2009 8:38 pm
by chewyikai
fury fan wrote:Overall, 'rebuilt' injectors are fairly cheap on Ebay, and it looks like you'll be needing a custom fuel rail anyway, so there shouldn't be much more expense to add 4 more holes. If it were me, I'd throw a little more $$ at it and have a balanced system to prevent wierd tuning issues or long-term durability issues later.
i was thinking of that too but how to make 2 injector squirt at the same time in 1 port???

elturbonitroso wrote:i would said that size the injectors for the h.p that you think that the engine its going to make and run the 8 injectors at the same time.(one inj,per runner) cyl.1 and 4 to channel 1 and 2and 4 on channel 2.

Sorry for my stupidity, but can you elaborate with some simple diagram?

All of your help is very appreciated :D

Re: dual injector

Posted: Tue Mar 24, 2009 5:05 am
by Matt Cramer
chewyikai wrote:i was thinking of that too but how to make 2 injector squirt at the same time in 1 port???
Wire them to the same driver output pin.

Fury Fan, I haven't really worked on an engine of this type. Some 4AGEs are somewhat similar but the ports are a bit more siamesed, not completely split like this.

Re: dual injector

Posted: Tue Mar 24, 2009 7:58 am
by chewyikai
Image
This is the head of my engine
as you can see it has 8 holes

Re: dual injector

Posted: Tue Mar 24, 2009 2:43 pm
by elturbonitroso
all you have to do is wire them in pair to the same inj. output as matt said.