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Discussion Starter #1
I was wondering how the ecu would react to the addition of a 5th injector. I know it's been done before and i've searched but nothing seems to justify my logical thought. If you add un-calculated fuel to the system doesnt the ecu say,"god im running lots of fuel here!" and then deplete the system of an amount proportional to the amount that the 5th injector injected? thx for any clarity on this subject.
 

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My guess would be that the ECU really wouldnt know any better. We have a pretty basic system not helped by our single wire o2 sensor that really doesnt know whats going on. I doubt the ECU would decrease fuel and you would just run rich from the extra injector.
 

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Possibly the O2 sensor output at WOT is not used, as the ECU would'nt be running closed loop?

Just a thought. I may be wrong.
 

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Discussion Starter #4
I don't doubt that the ecu ignore the o2's signal on WOT. But what about the rest of the time. You dont need to go WOT to be in boost.
 

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I don't think it's a good idea to just slap in a 5th injector (perhaps in parallel to one of the stock injectors to control it?) and raising your boost is the best idea...

But for that matter, if you're still on the stock turbo, it will never over-run your stock 4 injectors so why bother? What kind of upgraded turbo do you have?
 

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TR-mx6 said:
I don't doubt that the ecu ignore the o2's signal on WOT. But what about the rest of the time. You dont need to go WOT to be in boost.
But you wont need the extra fuel unless you're at WOT. And even then likely not above a certain psi that would be activated with a switch.
 

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I dont run a injector, but a seperate system. Its actually a NOS system with a extra nozzle only run fuel beside the main nozzle/shot. To fire of this solenoid I actually used a Hobbes pressure switch. It sends the signal to the solenoid to fire if it hits 10psi(you can get different) as long as I have WOT set by a microswitch. Works very good. And I can adjust my ratio by using different jets. Waiting right now for my wide-ratio and EGT setup to come. Preliminary tests show good on the dyno.

I basicly just wanted to recomend the pressure switch. Any parts house can order them. They come in lots of config. and are cheap. Set it up with a master on/off switch. That way you can shut it down.
 

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I just have 390's, Walbro 255lph, and a chip. So far my ARF's have been 11.8's and no higher at 20-21psi. Highest numbers were 12.4-12.5's and that was at 24psi.

I want to run meth injection, thats after my new turbo})
 

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I just have 390's, Walbro 255lph, and a chip. So far my ARF's have been 11.8's and no higher at 20-21psi. Highest numbers were 12.4-12.5's and that was at 24psi.
u have a jayb chip to run those bigger injector right? or do u just run sloppy rich when not boosting, oh and u wonder why u ruined your motor and head gastket arent our gaskets suposed to blow around 23psi. seems like u runnin a little much on that motor huh?
 

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mx6GT91 said:
I just have 390's, Walbro 255lph, and a chip. So far my ARF's have been 11.8's and no higher at 20-21psi. Highest numbers were 12.4-12.5's and that was at 24psi.
What kind of turbo do you have now.
 

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mx6GT91 said:
I just have 390's, Walbro 255lph, and a chip. So far my ARF's have been 11.8's and no higher at 20-21psi. Highest numbers were 12.4-12.5's and that was at 24psi.

I want to run meth injection, thats after my new turbo})
and water/methanol injection kits start at around 200 bucks..heheh

it's lovely what semi-concentrated windshield washer fluid can do for an engine in a fine mist...heh
 

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HotAss6GT said:
it's lovely what semi-concentrated windshield washer fluid can do for an engine in a fine mist...heh
Someone is doing that on a 2g! I forget who... :(

I'd do it if my intake temps ever hit 100F.. (well, probably way more than that ;))
 

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Discussion Starter #13
But you wont need the extra fuel unless you're at WOT(thats right, makes sense now.)

Hmm..i will try adding a saturated injector to my setup and dyno again. It will be set at 10lbs. At 10 the injector will shoot. And we'll see who was right about my car runnig lean.
Not like it matters but it makes things more interesting. haha. I probably will need a fuel pressure regulator with that. Or no 5th injector and a boost sensitive regulator. Damn, so many choices. I'm going to try all of them. lol
 

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just buy a walbro 190 fuel pump and get a wideband done. if you've done a wideband with that dyno run...what was your ratio?
 

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HotAss6GT said:
just buy a walbro 190 fuel pump and get a wideband done. if you've done a wideband with that dyno run...what was your ratio?
I don't know why you suggested either of those. Neither will help actually adjust fuel flow.

If the stock pump is on it's way out, I'd agree on replacing it. But otherwise, no point.
 

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I suggested the new pump if his is going bad. Getting the wideband done to see how lean he is running. And if he's running a little lean, wouldn't you hear some sort of ping?
 

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when i would ping i would get a puff of brown smoke out of the exhaust. you could always hook up a light to your knock sensor, so when you do start to ping, the light will turn on, and you could mount the light somewhere in your interior...like led sized light.
 

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that knock sensor idea is good hmm do a how to
 
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