Well I bought some 625cc injectors from trickyrs (thanks man) and I was wondering what would happen if I put them in with my current setup. I have 2 ways to adjust fuel, my regulator, which is a 1:1 regulator and the safc. My question is, if I put them in, will my car run? And will it run well? I am thinking about doing it tomorrow but I want to make sure my car can handle the injectors. Thanks guys!

Rumor is the stock ecu can't handle the 625's, even with a s-afc. But then again, we've learned some things this summer about what the ecu supposedly can't handle. If you can get it to idle, the rest will be easy. Let us know if it works.

That is the problem, I do not want to put them in if it is not going to work. That is just a waste of time. So what are the odds?

bryden, why are you going so high of injectors? how much boost do you plan on running? what are you injector runnning now?

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Personally, I don't believe your car will idle right with the 625cc injectors with the stock ecu and S-AFC. At idle, there's too much fuel to be leaned out, but at WOT, I don't think you'll have much problem. I idle pretty rich right now, even with the Accel DFI set to the leanest possible number without the car cutting off. If I try to lean out any more, then there's not enough injector pulse to keep the car running. It's great when I gun it though :-)

I have 415's and I do not think they are big enough. I have a completly built motor (head and block) and a new fuel system. I want to run about 15 psi daily and then 20 on race gas at the track. I am having EGT issues (I think). It is either not enough fuel, or it is my EGT probe. I have a new one coming. As soon as I get it I am going to install it and see how my EGT's are. If they are still high then I will be putting in the 625's. Several people I talked to (4G63 guys) thought that I needed bigger injectors. I dunno.

Well 4G63 guys run different setup than we do since different engine and alredy turbo. They belive going with bigger injectors all the time becuase it is suppose to make the car run better and get better EGT. But 650 are more than enough man. All my friends down here in Miami DSM with 650 are running 20G and MUTT-32ETE at 20 psi daily. So they are generatiing a lot of power more than 300 hp to wheels. When i see their SAFC settings they are negativ 40 and more. Just wanted to let you kow how their settings are becuase remember we could not do that since we have a map sensor we want to keep it as close as possible to 0.

Since on previous post i have learned that the leaner the SAFC setting are the less volts the map will get, meaning bad reading and retard timing.
Guys Please correct me on this if I am wrong.



Laterz

if i rememeber right, someone or a few have 440cc injectors and run 15psi daily, and i think someone ran 20psi on race gas. well it just pop in my head. also i remember someone saying with some 550cc injectors on the dyno he keep on messing with there o2 sensor since he was running too rich with 550cc injectors.. i believe that was greg? oh yah chris is using the 515cc injectors stock ecu for now running 18psi, that should tell you something..hehe
good luck



Michael 99gs
HRC Stage 2
Stage 3 process begins gathering parts for rebuild

http://www.dreamwater.net/purplebeast

Well I believe that the 625's are too big for the safc to run. I've seen posts asking what will run them becides the accell dfi. Greg's setup is this:
Stock in-tank pump
HRC in-line pump
95 stock Fuel rail
HRC 625cc injectors
Accel DFI for injector control

I would imagine you could mimic this to a point. I believe that the 625's with the safc would still be way to rich, and it would alter your map sensor voltage and mess with your timing.(Especially since your stft and ltft would prolly me maxed trying to compensate for the left over fuel that the safc couldn't take care of. I believe the "celing" for the safc as I have always heard it is either 440's or 550's. Plus with that mammoth fuel pump that is going to raise base pressure with the 625's too won't it? The stock ecu is doing some great things though so it may be worth a try. With all these new fuel options my head is starting to spin thinking about wich way to go when I'm ready.
Shorty answer: I don't think that it will work but it may be worth a try....

I have to idle my 440's at 13psi fuel pressure to keep the trims from completely maxing out. Since you are running a 1:1 reg you probably idle at close to stock pressure right? Either way you'll have WAY too much fuel IMO.

so in my opinion it will probrably keep those injectors if you are going to run stand alone. If not go with something smaller IE like some poeple were saying here 550 or so.

I know some 4g63 guys that running 16G turbo at 20psi daily with the stock 450cc injectors. I believe if i am right that the SAFC settings were not plus they were still in negative%


laterz

So it sounds like no one knows what will happen, for that reason alone I am thinking about doing it. I can not hurt anything by dumping too much fuel right? It will idle like shit, or not stay running, is that all that can go wrong?

I believe that you can get detonation if running too too rich I THINK.

but i am not sure about that heheehh lolz
can someone back me up on this ???

I worked it out once where I believed a 550 to be the largest we can manage effectively. I chose to take that limit from some math I worked a long time ago and then scale it back one notch by using 525's on the stock ecu and 1:1. The e-manage will be used for fine tuning. I think to get your moneys worth out of you setup and if you ever want to make big power you will definitely need some large injectors. At this point, I would just put the 625's in and see what happens and play around with the fuel pressure. If you do get it running you will definitely need some way to manage your fuel to get the curves right as it should be pretty rich. Mine already is with 525's. Personally, I would guess it will not run, but that is just a guess.

And since a few here mentioned it, the reason for running larger injectors is to reduce strain. Lower fuel pressure and less heat plus better timing. The 2G 4G63 ecu loves big injectors on pump gas.

Thanks for the info Chris. I think I will just put my new EGT probe in and hope my EGT issues go away. Eventually I will put the 625's in, but not right now. I just don't want to put em in, and then have to put the 415's back in, too much work.

>So it sounds like no one knows what will happen, for that
>reason alone I am thinking about doing it. I can not hurt
>anything by dumping too much fuel right? It will idle like
>shit, or not stay running, is that all that can go wrong?

You could ruin your 02 sensor. But, as far as I know, no significant engine damage could occur. Your DP and cat (if you have one) might be covered with excess fuel as well.

i'd say try it out...at least at idle and see how it runs and lower the super afc all the way to -50% across and set the fuel pressure to 13psi and see what happens for at least 2 min. if you feel it's not idling well...forget it and remove them.

-50 on the SAFC, is gonna give you some hella timing advance just before you go into boost. You need to data log and make sure you do not go any higher than 30 degrees advance or you will be predetonating.

could probably fix that with some timing retard from an ignition, but that is really going to kill the big end.

just more info for thought.

It's too late for me to call HRC (their closed) but I think the 625cc that comes w/ our kit is a low impendence injector. Wouldn't fuck up the injector if you plugged them into the stock harness? I can't remember but Len was telling me about it. I just can't remember if they were a low impendence or high impendence. (Think its low) And he was telling me something about possibly hurting the injector if you plugged it into the stock harness and ran it like a normal injector.

I don't remember and I’m not too sure, maybe someone else will read this and correct me :-) I'm sorry I can’t remember what he said exactly it was a while ago.

I don't think you will be able to get your car to idle for shit if at all. Like Kon said even w/ the DFI it is super rich. My pulse width at idle is like ~1.3 and the A/F reads .98v lean it out anymore and it turns off.

no their 625 work on our cars. I know it becuase i was reading the page a lil while back ago and they had all of them. I believe even the 720 for our model. I was trying to find the page but their web site is having a lil problem and can't post the info.


sorry


laterz

No, 720cc injectors WILL NOT work on a stock ecu and I doubt that the 625cc injectors will work.

Yes, they are for our cars (they fit) but you can't run that large of an injector w/o something to help you. I.e. the DFI, Haltech, AEM, etc, etc, etc.

I use the 625cc w/ the DFI and it works fine but 625cc is a large injector and the stock ecu will probably not be able to handle them.

I think you are confusing the subject and discussion of this thread. The question is the issue of the stock ECU being able to control a large fuel injector like the 625cc. The Accell injectors fit our cars but have to be driven by some kind of piggy back or stand alone. He is wondering if he might be able to "persuade" the ECU into controlling them using a 1:1 and the AFC.

Brynden, are the 625cc injectors that you have HRC's (Accel)? If they are then JustOne is right; the HRC 625cc and 720cc injectors are low impedance (12 ohm) injectors, and the stock injectors that run on the stock injector harness are 14.4 ohms. So, if you install the 625cc's using the stock injectors, your injectors will eventually fail. The 625cc's and higher needs to be controlled by a piggy-back fuel management system, standalone computer, or other means, but not by the stock ecu alone (even with the S-AFC).

Also, if you lower your fuel pressure too much and/or if you lean out the larger fuel injectors too much with the S-AFC, then you are messing with the injector pulses, resulting in bad injector spray patterns because of the low fuel pressure. Most injectors are designed to work best with fuel pressure around 45 psi. If this is the case, then you are really hurting performance by altering the injectors' designed characteristics. I'm certainly no expert about all of this, but I believe this to be the case here ;)

I forgot about that. It is extremely difficult to find high imp in anything more than a 550 and those are pretty rare. The ones I have are high impedance and as large as you would normally see around. The injectors you have probably are low impedance. I think you should just buy an AEM ecu anyway. :) You would have one hell of a car if you did and sorted it all out.

if you run to rich for a period of time you could, burn your exhaust valves, cause dangerous backfiring, not the good kind;) foulage of spark plugs, and iver heard of damage to the piston, maaybe. and last but not least poor gas mileage;) good luck bro, imo the afc will not function the injectors properly and your best bet is to run em on stand alone or just get some 525s

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"PAID THE COST TO BE THE BOSS"

Fully built motor,Hrc stage 3, 19 inch rollers, Big Brakes, Targa top conversion, custom hood,supra taillights, trd wing with cf, kaminari widebody kit, air ride, autometer guages and all of Apexi Sacf, avc-r, rev/speed meter. interior fully glassed, tenzo r seats, pics soon to come!

if you had a s-fmu, and the afc, and either the new holley dis box or a msd programable dis2, and a dataloggger of course, I think you could get ti to work with 0 problems......with expierence. if you just put in 660 injectors (assuming either they are high impiedance, or you have a resistor pack to hook them up to), your car probably won't start at normal fuel pressures. you will probably have to lower your fuel pressure to around 10 psi at idle, lean out your afc out at idle a bit (maybe 20 or so %), replace the throttle input lead from the s-afc with the output from a 3 bar map sensor (probably the one from your ignition box) and use the low throttle setting at 1% and the high throttle setting at 99% and use the low throttle setting for idle. the high throttle setting will probably end up being around 0 (because that will be for 30 psi). doing that, with some experimentation, and careful monitoring of egt's, ignition timing, air/fuel ratio, and knock, I think you could get it to work.

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bring it on............