fuel injectors??? so confused>??

[turbo2nr]

i purchased 52lb msd injectors hi impedance.

i was under the impression that i needed hi impedance but heavythrottle said i need low impedance..

they said i need to wire in resinators in and it should work..

how do i wire in resinators? what kind do i need? any spific way to wire them in? how safe is it?

also being to feed injectors i need to re plumb the fuel lines. that doens seem to hard. i really wana use the 52lb but it seems like soo much of a headack. a small project turned out bigger then i expected. should i just sell these and get some 370cc and call it a day?

[j-z]

so i believe i made out that theyre top feed? that means you have to get a top feed rail. replumbing the fuel lines is nothing. youll probably have to extend the feed line, but thats no biggy. you will have to get an external fpr though. youre gonna want an adjustable regulator anyways if youre running a walbro or other high pressure pump. the resistor part is simple as well. jgs has individual resistors that you wire into each injector wire. OR you can go grab a resistor box off a honda like an accord or prelude and then take the wires off of that and wire into each injector. i dont know exactly the specifics on the wiring of a resistor box, but i know theres a write up of it on here. its real easy nonetheless. do you have to get new harness plugs for the top feeds? deatschwerks=plug and play.

[rotorimp]

For the resistors/resistor---Common practice is to wire the resistor(s) to the common side of the injector. on the ecu there will be four wires coming out--each going to a injector. the other side of the injector is a common wire between all injectors--wire your resistance there.

[turbo2nr]

so do i need the resistors for the hi impenance top feed? of can i just plug and play.

the guy supplyed me with the clips for the msd injectors.

thanks for the info im not that scared about the whole process anymore

[KATwo40]

I'm so tired of reading these posts that say "You have to use an adjustable FPR if you're running a Walbro pump." It's simply not true. His parts list shows SAFC as one of the components (in his signature). If the pressure is slightly high as a result of the larger pump, it can be tuned out with the SAFC. I have been running a Walbro255 for over 2 years now on the stock regulator and 370's.

Now, to answer the question at hand, NO, you do not need resistors if the injectors are high impedence (saturated). You will need the topfeed rail, which will probably require an adjustable fuel pressure regulator (by design).

Not to solicit or anything, but I have 370's currently in my car. They're a direct drop-in on the stock rail. If you'd like to work a trade, I'd be interested, as I'm stepping up my system. However, this should be done in private, not in the KA-T forum. If you wish to discuss, contact me via email.

[email protected]

[j-z]

afc doesnt tune fuel pressure! using a high pressure pump will change base fuel pressure. now in the situation i am using 560s (averaged flow of all 4) deatschwerks and a safc i HAVE to use an adjustable fpr. fuel pressure changes the amount of fuel flowed out of the injectors. without the afpr id be running too rich because the afc can only compensate for so much. i dont know what the 52lbs equate to in cc, but i know it will be close to the afc limit of compensating. in his case it would be wise to run one and anyone else running 550s with a afc. he def has to run one with a top feed rail.

[KATwo40]

I wasn't implying that it tuned fuel pressure, but that he could reduce the pulsewidth to compensate.

However, you pointed out something I overlooked, in that the SAFC will probably be maxed out and won't be able to reduce the PW enough.

Sorry for the confusion, I didn't think long enough on your statement.

[turbo2nr]

thnaks for all the helpful info guys. so can some one recomend a cheap good fpr? how good is the e-bay stuff? crap? i was thinking about a megan or something.

[j-z]

yeah the megan is good. i have one and it works perfectly fine.

[jae_rex]

What do you have the Megan Racing FPR set to? I am running 460's at 40 lbs, it idles fine, but when I hit the throttle, it's seem like its getting flooded.

[j-z]

you should set it at 43.5 psi with the vacuum hose unplugged. when you plug it back in it will be around 38 psi. is yours at 40 psi at idle? if so do what i said and see what happens. it should drop to around 38 psi at idle. that should also cure your problem too because for every pound of boost you run, you up the fuel pressue by one psi.

[turbo2nr]

with the megan does the Fuel pressure rises on a 1:1 ratio with boost? as with the aeromotive?

[j-z]

it sure does. same goes for your stock regulator as well.

[jr_ss]

afc doesnt tune fuel pressure! using a high pressure pump will change base fuel pressure. now in the situation i am using 560s (averaged flow of all 4) deatschwerks and a safc i HAVE to use an adjustable fpr. fuel pressure changes the amount of fuel flowed out of the injectors. without the afpr id be running too rich because the afc can only compensate for so much. i dont know what the 52lbs equate to in cc, but i know it will be close to the afc limit of compensating. in his case it would be wise to run one and anyone else running 550s with a afc. he def has to run one with a top feed rail.

J-z, I have to disagree here. Your ECU controls the flow of fuel out of the injectors. The fuel pressure reg, is just that, it regulates the pressure in the line. Your ECU changes the pulse width/duration the injector is open increasing your fuel. The longer the injector is open, well you get the point. That's why you have to get a tune, because a stock ECU will simply not be able to add enough fuel for the correct mixture.

The SAFC just modifies what the ECU see's, leaning or richening up where needed by the imputs you select on the unit. If a regulator were to increase fuel flowed, everyone would be doing the regulator and not getting an ECU tune, not to mention it would be way cheaper to have a reliable turbo'd Ka.

[turbo2nr]

is this one ok to use is a megan fpr, its cheap and comes with a gauge.

http://cgi.ebay.com/ebaymotors...wItem

also can i use steel braided lines with the fpr?

[j-z]

J-z, I have to disagree here. Your ECU controls the flow of fuel out of the injectors. The fuel pressure reg, is just that, it regulates the pressure in the line. Your ECU changes the pulse width/duration the injector is open increasing your fuel. The longer the injector is open, well you get the point. That's why you have to get a tune, because a stock ECU will simply not be able to add enough fuel for the correct mixture. The SAFC just modifies what the ECU see's, leaning or richening up where needed by the imputs you select on the unit. If a regulator were to increase fuel flowed, everyone would be doing the regulator and not getting an ECU tune, not to mention it would be way cheaper to have a reliable turbo'd Ka.

whaaaaat????? what exactly are you disagreeing with? we need the afpr to keep the fuel pressure at the stock pressure to keep from running to rich. from what i got out of what you said is that fuel pressure doesnt change the amount of fuel flowed? if so, thats totally WRONG. they make something exactly what you were talking about instead of going with a tuned ecu. its called a fmu and they raise fuel pressure in different ratios to increase fuel flowed out of the injectors. my deatschwerks flow chart says that at 50 psi my injectors flow an equivalent to 600cc as opposed to 560cc at the stock 43.5 psi. and no its not more reliable to use a fmu as opposed to a ecu tune as you cant tune out specific points on the rev band where needed. fmu just increases fuel pressure as boost increases. it works, but using a safc is way better than that. have no idea where that post cam from ?.yes you can use ss braided lines, but its not needed. if you want the bling then you have to use AN fittings if youre gonna go with the SS line.

[egan]

i dont see why you need a afpr. i put in my 255 walbro and 370 injectors on stock fpr and the fuel pressure is same as stock. 38 at idle.

the only reason you would need an afpr is if your fuel pump outflowed the stock rail and the stock fpr couldnt put enough fuel past it. therefore bumping the pressure. OR simply if you wanted to adjust your fuel pressure as a tuning method.

im really not sure what you two are arguing about, but i can tell you this:

-using a base fuel pump will NOT change fuel pressure. put an inline gauge on your feed line and start the car. youll see. the stock fpr is mechancally set to keep 38psi in the fuel rail and return line at idle. (untill it is overloaded, which with 255 it is not)

-regulator DOES increase fuel flowed through injectors. some people DO do the regulator and skip the ecu tune. its called a fuel management unit (FMU) or rising rate fuel pressure regulator(rrfpr) both are the same thing. there are just so many more reliable and safer options at such a great cost now compared to 3 years ago when it was FMU, safc, or hacked mafs!!! FMU is straight thuggin! 6:1 for 8psi on z31 t3!!!! hehehe

edit: on topic, turbo2nr; go to murrays and just buy fuel line for fuel injection that fits on the megan rail if thats what ur goin with for fpr

[jr_ss]

whaaaaat????? what exactly are you disagreeing with? we need the afpr to keep the fuel pressure at the stock pressure to keep from running to rich. from what i got out of what you said is that fuel pressure doesnt change the amount of fuel flowed? if so, thats totally WRONG. they make something exactly what you were talking about instead of going with a tuned ecu. its called a fmu and they raise fuel pressure in different ratios to increase fuel flowed out of the injectors. my deatschwerks flow chart says that at 50 psi my injectors flow an equivalent to 600cc as opposed to 560cc at the stock 43.5 psi. and no its not more reliable to use a fmu as opposed to a ecu tune as you cant tune out specific points on the rev band where needed. fmu just increases fuel pressure as boost increases. it works, but using a safc is way better than that. have no idea where that post cam from ?.yes you can use ss braided lines, but its not needed. if you want the bling then you have to use AN fittings if youre gonna go with the SS line.

I'm disagreeing with the concept that fpr does not increase fuel flow. They simply put the fuel pressure where you need it. I understand that at a certain fuel pressure injectors flow a certain amount but, it's not actually the regulator itself that is flowing the fuel. The ECU uses the injectors to increase the amount of fuel injected into the cylinders at a given fp by way of the pulse width. The pulse width is what changes the major amount of fuel injected into the cylinder. A long pulse (injector opened) the more fuel. When the fuel pressure is at a higher than stock rate, sure more fuel will flow, but it's not the fpr that does this....

[egan]

I'm disagreeing with the concept that fpr does not increase fuel flow. They simply put the fuel pressure where you need it. yes, where you need it for desired flow

I understand that at a certain fuel pressure injectors flow a certain amount but, it's not actually the regulator itself that is flowing the fuel. huh?

The ECU uses the injectors to increase the amount of fuel injected into the cylinders at a given fp by way of the pulse width. correct!

The pulse width is what changes the major amount of fuel injected into the cylinder.correct again!

A long pulse (injector opened) the more fuel. almost there!!!!

When the fuel pressure is at a higher than stock rate, sure more fuel will flow, but it's not the fpr that does this....ooooh...fail. the fpr DOES force more fuel through the injector per given pulsewidth. explain how a fmu works then... maybe ur trying to say its not the fpr that raises fuel pressure to make more fuel flow? thats true. but fp can be raised manually;afpr (or by boost;FMU) through the fpr to make more fuel flow per given pulsewidth.

edit: my previous post may also have helped the arguement to get you two on the same page

[j-z]

thanks for making that clear as day post egan. im with you on every single thing you pointed out especially on the 'HUH' part of what he wrote. ive been on the correct page from the start. i just dont even know why he made his first post as i said nothing for him to start this. plain and simple what i was saying from my first post is that change in fuel pressure will change amount of fuel flowed. not once did i say anything about pulse width, so i have no idea where that one got pulled from.

[jr_ss]

thanks for making that clear as day post egan. im with you on every single thing you pointed out especially on the 'HUH' part of what he wrote. ive been on the correct page from the start. i just dont even know why he made his first post as i said nothing for him to start this. plain and simple what i was saying from my first post is that change in fuel pressure will change amount of fuel flowed. not once did i say anything about pulse width, so i have no idea where that one got pulled from.

It was just a statement but, I believe we weren't arguing, just debating. Either way it's all sorted out...

[j-z]

totally agreed we wernt arguing. carry on folks!