turning down fuel pressure to compensate for larger injectors?

[240shawty]

ok in a pickle. long story short as an xmas gift my friend and girlfriend took my car to a shop without my knowing to find out y i had a dead cylinder. it was injectors. so they order new ones. stock injectors for an rb20 is 270cc, now i have 440cc!:bash: i dont have the money for a good tune right now so i was wondering if turning down fuel pressure to compensate for larger injectors will work an if anybody has tried this before? what should i set the fuel pressure to? an what not....

thanks

[rb25_s13*CHUKI]

should still be good, The ecu wont detect bigger injectors and automatically send max fuel, it will still be running the same.

[240shawty]

it wont run rich as hell?

[rb25_s13*CHUKI]

it wont run rich as hell?

I don't think so, It shouldn't run any more fuel than it use to.

[budlite]

No, ur car wont run worth of dick! It will be flooded nonstop. Either get stock injectors or a tune.



Thread/

[240shawty]

what about a apexi safc? could i use that to help the problem?

[240shawty]

i kno im going to have to get it tuned sooner or later but im jst looking for short term solutions till i can come up with some money for that....

[Huntsman2007]

I don't think so, It shouldn't run any more fuel than it use to.

This is the worst fucking input ever. If you have 270cc injectors, and pull them out and put 440cc injectors in their place, the ecu will send the same signals, but the amount of fuel being delivered will be much higher. You will load that thing up on fuel. No no no. Safc might work. I'm not sure about turning down fuel pressure, but in theory that should work.

[jamg]

you're going to need a tune. the duty cycle between those injectors are different.

[rb25_s13*CHUKI]

This is the worst fucking input ever. If you have 270cc injectors, and pull them out and put 440cc injectors in their place, the ecu will send the same signals, but the amount of fuel being delivered will be much higher. You will load that thing up on fuel. No no no. Safc might work. I'm not sure about turning down fuel pressure, but in theory that should work.

You need reading comprehension, I said I don't "think so" and It "shouldn't".

I didn't say I know so and It wont

[Kingtal0n]

If you are in a jam, and need to simply drive the car, then yes: You can turn down the fuel pressure AND use a SAFC to adjust for the larger injectors.

NO this is not a permanent fix. You should either find a set of OEM size injectors or supply the engine with a new tune.

If you pull out too much fuel using afpr or safc you can damage the engine. Likewise, using a SAFC to adjust fuel can affect timing, which can also damage the engine. Use these components at your own risk!

[budlite]

If you are in a jam, and need to simply drive the car, then yes: You can turn down the fuel pressure AND use a SAFC to adjust for the larger injectors.

NO this is not a permanent fix. You should either find a set of OEM size injectors or supply the engine with a new tune.

If you pull out too much fuel using afpr or safc you can damage the engine. Likewise, using a SAFC to adjust fuel can affect timing, which can also damage the engine. Use these components at your own risk!


I was to lazy to type that..

+1

[240shawty]

ok cool thanks alot for yalls help

[Taylor008]

How hard is it to find used ka injectors in Georgia? Apparently really hard.

[240shawty]

How hard is it to find used ka injectors in Georgia? Apparently really hard.

i guess it isnt easy to understand what u r reading if ur from utah.. (everyone else seemed to understand without criticizing) if u read the post i didnt kno my car was takin from my house (im stationed in ft campbell and car is in ga) an since i already have them installed i was seeing if i could use them without paying for a tune. but thanks for the input

[jamg]

240atlanta dot com

are you a member?

[fliprayzin240sx]

You need reading comprehension, I said I don't "think so" and It "shouldn't".

I didn't say I know so and It wont

If you didnt know, then why post? Go slap some 555cc on your RB25 without any kind of correction it, what do you think will happen? Cranking your FPR down wont do jack and shit.

Back to the OP, go find another set of stock injectors. Somebody is bound to be selling stock top feed injectors for an RB20 for less than $80 for all 6.

[240shawty]

240atlanta dot com

are you a member?

yea "project s14.5" is the username

[codyace]

RC Fuel Injection (http://www.rceng.com/technical.aspx)


Plug and play and estimate. Sure you can globally trick it, but just keep that in mind.

[240shawty]

If you didnt know, then why post? Go slap some 555cc on your RB25 without any kind of correction it, what do you think will happen? Cranking your FPR down wont do jack and shit.

Back to the OP, go find another set of stock injectors. Somebody is bound to be selling stock top feed injectors for an RB20 for less than $80 for all 6.

can i calibrate the new ones to run at stock cc or no? i mean these r new injectors id hate to jst sit them on the shelf till i get around to using them...

[steve shadows]

ok in a pickle. long story short as an xmas gift my friend and girlfriend took my car to a shop without my knowing to find out y i had a dead cylinder. it was injectors. so they order new ones. stock injectors for an rb20 is 270cc, now i have 440cc!:bash: i dont have the money for a good tune right now so i was wondering if turning down fuel pressure to compensate for larger injectors will work an if anybody has tried this before? what should i set the fuel pressure to? an what not....

thanks

Usually you use Adjustable fuel pressure regulator to turn the pressure up just slightly to get the maximum out of certain injectors. Turning it down is possible within 1-3 psi but I wouldn't do much more than that. You need to be using a wideband and have a good clear AFR data readout, not just stabbing in the dark. Tuning is the easiest, most cost effective way to get more power, it also makes the biggest single difference in how the car runs but it's a specific and tedious art form which can also be very dangerous if it's not done properly. Get a wideband or take it to a dyno if you're not sure of your ability. Otherwise you'll do what I did when I first started 11 years ago, you'll just keep going through Long Blocks until you teach yourself everything the hard way. Don't regret it but I could afford it back then :rofl:

[240shawty]

Usually you use Adjustable fuel pressure regulator to turn the pressure up just slightly to get the maximum out of certain injectors. Turning it down is possible within 1-3 psi but I wouldn't do much more than that. You need to be using a wideband and have a good clear AFR data readout, not just stabbing in the dark. Tuning is the easiest, most cost effective way to get more power, it also makes the biggest single difference in how the car runs but it's a specific and tedious art form which can also be very dangerous if it's not done properly. Get a wideband or take it to a dyno if you're not sure of your ability. Otherwise you'll do what I did when I first started 11 years ago, you'll just keep going through Long Blocks until you teach yourself everything the hard way. Don't regret it but I could afford it back then :rofl:

i have no ability when it comes to tuning. never got to a point where i had too to b honest.. but thanks i guess ill jst have to suck it up an get a tune. if it isnt one thing its another with this car

[brndck]

It would be much much much cheaper just to get a new set of stock injectors. You most likely only have ONE bad one. I have never in my life seen an entire set of injectors all go bad at once. Honestly I've never even seen more than ONE go bad at the same time.

[240shawty]

It would be much much much cheaper just to get a new set of stock injectors. You most likely only have ONE bad one. I have never in my life seen an entire set of injectors all go bad at once. Honestly I've never even seen more than ONE go bad at the same time.

i had 2 that shit out on me i wish i still had the orignal 6 but the shop kept them for some reason or another.

[Croustibat]

I don't think so, It shouldn't run any more fuel than it use to.

You are fecking stupid, dont answer BS when you dont know anything. How the hell did you come to that conclusion ? Did you just throw a coin and play tail or head ?

Dont believe you can get away from that with a "but i wrote i dont think so". STOP answering things you have no clue about. This is not a computer game, people will spend money based on answers they get. Stick that in your damn head.

The ECU has no way to know the injector size, it will command them open for the same amount of time, making it overfuel badly. :duh:



@OP > wont work, fuel pressure has more to do with fuel atomization than fuel quantity. changing pressure will change fuel quantity of course, but there is a square root relation between the two. That and injectors have a latency time, which you need to tune too. Basically you are screwed.

You need a tune, or an SAFC -which will cost more or less the same and wont give better results. Or get used injectors to replace your new ones.

go back to the shop and get your injectors back, the reason they kept them is surely because they wanted to sell them. Maybe it was just a connector problem... no "ifs" or "buts", they are yours.

BTW how the hell did your gf reach your car keys ? Car 101: dont let a woman drive your car. :D

[RedTopKA-T]

You can adjust it to get target afr's while cruising and idle if you have to but do not boost it with low fuel pressure and or big injectors you will break something

[RedTopKA-T]

I had my car tuned a while ago and 2 of my 550's shit out on me after the tune,I got new injectors and its running pig rich ,I don't have $ for a retune right now so i have to adjust the fuel pressure to either be good at idle and cruising and lean when I hit boost,or be pig rich at idle and perfect in boost.I just keep the pressure @ 43psi with Vac @ idle let it run rich and change the oil very often untill I get it tuned again..

[fliprayzin240sx]

You can adjust it to get target afr's while cruising and idle if you have to but do not boost it with low fuel pressure and or big injectors you will break something

I had my car tuned a while ago and 2 of my 550's shit out on me after the tune,I got new injectors and its running pig rich ,I don't have $ for a retune right now so i have to adjust the fuel pressure to either be good at idle and cruising and lean when I hit boost,or be pig rich at idle and perfect in boost.I just keep the pressure @ 43psi with Vac @ idle let it run rich and change the oil very often untill I get it tuned again..

You're another dumbass...read what he has and what he's trying to do. How do you propose he adjust his "target AFR" when he has nothing but a fucking adjustable FPR and he's trying to toss in injectors that are almost double the size of the stock one? :picardfp:

[KendallH]

You're another dumbass...read what he has and what he's trying to do. How do you propose he adjust his "target AFR" when he has nothing but a fucking adjustable FPR and he's trying to toss in injectors that are almost double the size of the stock one? :picardfp:

Sometimes I think 240 owners legitimately think these cars are carbureted.

[cotbu]

Wow just wow!
Ok no attacking any stupid posts just giving a scenario of why you shouldn't turn down the fuel pressure. you'd probably have to run something less than 2bar.
Most likely case is the injector won't atomize the fuel correctly and ejaculate fuel or piss it out. That is the worst case, because fuel doesn't compress and you'll probably bend a valve or rod before the cylinder gets washed. You'll probably have hard starts too, that is a good thing. Don't start it until you have away to correct the over fueling problem.
No body can really say without having hands on with the car, those injector might not flow correctly and might just work like stock 270's, fat chance! A band aide fix could turn into surgery. You could just source some 270's and that would fix your problem and then you'll have upgrade injectors for later.

[jholman]

Get the right injectors. You could possibly work it out with and safc or something like that but it's a gamble.

[240shawty]

ill c what i can find.

[Kingtal0n]

Most likely case is the injector won't atomize the fuel correctly

iirc most sequential fuel injection systems spray the fuel directly onto a closed intake valve, where it may puddle regardless of injector pressure.

[cotbu]

iirc most sequential fuel injection systems spray the fuel directly onto a closed intake valve, where it may puddle regardless of injector pressure.

Not if timing is correct!

And also I'm talking about hindering the process with too much fuel, if you can't see what or know what happens when there is liquid gas in the combustion chamber, head over to the chat section... look for the small question thread!

Kr_xiusqtUM

[budderigs]

you can tune up to 550cc injectors with a safc you can go bigger if you have a larger maf. but you need basic tuning knowledge as well as a wideband to use as a tuning reference.

trying to turn down the fuel pressure is a very bad idea. the injectors are designed to run 35-55 psi. to get them to flow 270cc your going to be down to 20psi. that is way under what is needed for an efficient spray pattern. it will run horrible.

I have a set of stock redtop rb20 injectors laying aroud. I was planning on saving them to convert my daily to run on e-85. but if you need them I will part with them. $80 shipped.

[Croustibat]

He needs money first and foremost, so dont tell him to go and buy an SAFC and a wideband afr sensor and gauge ...

[Kingtal0n]

Not if timing is correct!

And also I'm talking about hindering the process with too much fuel, if you can't see what or know what happens when there is liquid gas in the combustion chamber, head over to the chat section... look for the small question thread!

Kr_xiusqtUM

Just because theres a video online that shows injectors spraying fuel into an open valve doesnt mean thats how it actually works;

why not pick up and read the user manual for a few stand alone ecu? for instance,

http://data.prestoliteperformance.com/documents/instructions/DFI/pdf/ACCEL-DFI_Instructions_gen_7.pdf


"23b. Target Injector timing (sequential fuel mode only)
This table contains fuel injector target timing values for all possible engine speeds
and engine loads. Enter a number between 0 and 720 degrees. This value,
displayed in crank angle degrees, designates the end of inject point of the fuel
injector. Using the injector target timing we are assured that the injection event will
not coincide with the intake valve, opening event, unless the duty cycle of the
injector overlaps the event. Typically, end of inject point should occur before the
intake valve opens. Under light load conditions, if the intake valve is open during an
inject cycle, poor atomization, or improper mixing of fuel will occur. This could
cause driveability and exhaust emission related problems that can not be tuned out
by the operator."

It helps to read the manuals

[cotbu]

Go to your car and fucking look how it works, meth or nitrous spraying with gasoline into a closed valve would be so stupid, fuck what you heard man up! Go to you're car with the f'd up rack and get a good look into the cylinders rotate the crank makes sure the koeo position and look come back with video!

Fuel atomization is key, why spray fuel for it to settle back to a liquid? if that was the case then everything venom says about their injector not being the problem is true!
please get that video up!

The only time you would get fuel sprayed on a closed valve is during start up, when the injectors are batch firing, or limp mode.then again that's not normal operation.

[240shawty]

ok so i found 2 sets of ka injectors an picked those up for 50 bucks so i guess ill b running those for awhile and found an intake idea its on the top thread what yall think?

[240shawty]

thanks for all yalls input too by the way its been very helpful

[cotbu]

You gonna learn today!:eek: alright, alright!!

Sent from my S3 pumping Darth Stalker v7

[Kingtal0n]

ok lets just ignore what the ecu manufacturer says about fuel injection and go with the video on youtube for our information instead.

[cotbu]

No!!! go to your car and make a video!;)

Sent from my S3 pumping Darth Stalker v7

[Kingtal0n]

No!!! go to your car and make a video!;)



A video?
P1130736.mp4 video by Kingtal0n | Photobucket (http://s23.photobucket.com/albums/b378/draglarry/?action=view&current=P1130736.mp4)

[cotbu]

OK, you win! xd!!
Just for reference, i won't describe what I see here just, but there is no pool even though the injector leaks, you can clearly see when the injector fires.
Iz31eCym2iQ

Sent from my S3 pumping Darth Stalker v7

[fliprayzin240sx]

ok so i found 2 sets of ka injectors an picked those up for 50 bucks so i guess ill b running those for awhile and found an intake idea its on the top thread what yall think?

Umm...why did you pick up KA injectors? Last I checked, RB20 injectors are top fed while KAs are side fed.


Wait, KA24e's top fed?

[cotbu]

Wait, KA24e's top fed?
yes
Last one
aQV2NGRl6RI

[Kingtal0n]

how can you tell if the injector wasnt done firing before the valve opened?
Like you said, it leaks, so fuel keeps going in regardless of what the ECU says.

Looks to me like most of the fuel was sitting on top of the intake valve, waiting for the valve to open.

high temperatures and high inlet velocities (among other things, such as "swirl characteristics") are what helps to vaporize the fuel as it enter the chamber. That is why large intake ports/manifolds on carburetor engines tend to have fuel puddling problems- due to low port velocity, the fuel falls out of suspension. Its not a big deal if it sits on the valve. It is a big deal if the fuel condenses onto the walls of the intake manifold, or on the floor of the intake manifold.

[cotbu]

If I have to point it out to you, then what did you pay for(meaning education), mr electron mass : 9.11x10^-31 kilogram
electron charge: 1.60x10^-19 Coulomb

The last video explains why gas is atomized

[Kingtal0n]

your new video does not really detail or show anything useful. You sure you got the right one?

Gas is atomized because it should be atomized for proper combustion. If a carb can deliver a fairly adequate mixture of fuel and air to the cylinder, at 0psi (no fuel injector) that will burn well, then apparently you do not need a fuel injector to atomize fuel, eh?

Fuel injectors/injection is more about precisely measuring the amount of fuel that enters each cylinder.

also,
please repost the other video it was much better than the next one.

[cotbu]

Your gonna compare carb to fuel injection, then say fuel injection is about the precise amount of fuel being injected, why are we having this conversation in a thread were someone is running larger injectors than tuned for and want's to fix it by turning down the fuel pressure. Are you saying that it doesn't matter if he runs larger injectors, because on a carborated engine fuel isn't atomized like it is a fuel injected engine but it still runs.

They are two different animals, fuel is mixed with air differently. which is more efficient!
And blah blah blah.

If you where actually correct, I wouldn't even be posting to your replies. let's just say your right!

[ka-t]

does anyone have a 270cc injector to give this guy lol

[rb25_s13*CHUKI]

You are fecking stupid, dont answer BS when you dont know anything. How the hell did you come to that conclusion ? Did you just throw a coin and play tail or head ?

Dont believe you can get away from that with a "but i wrote i dont think so". STOP answering things you have no clue about. This is not a computer game, people will spend money based on answers they get. Stick that in your damn head.

The ECU has no way to know the injector size, it will command them open for the same amount of time, making it overfuel badly. :duh:



@OP > wont work, fuel pressure has more to do with fuel atomization than fuel quantity. changing pressure will change fuel quantity of course, but there is a square root relation between the two. That and injectors have a latency time, which you need to tune too. Basically you are screwed.

You need a tune, or an SAFC -which will cost more or less the same and wont give better results. Or get used injectors to replace your new ones.

go back to the shop and get your injectors back, the reason they kept them is surely because they wanted to sell them. Maybe it was just a connector problem... no "ifs" or "buts", they are yours.

BTW how the hell did your gf reach your car keys ? Car 101: dont let a woman drive your car. :D

So I don't know anything because I answered something wrong? you act like you never answered a question wrong Your a very close minded person. Maybe car 101 with you is to not let your stupid whore drive your car but my girl can drive my car just fine.

[Croustibat]

So I don't know anything because I answered something wrong? you act like you never answered a question wrong Your a very close minded person. Maybe car 101 with you is to not let your stupid whore drive your car but my girl can drive my car just fine.

When i dont know, i dont flip a coin; and i dont call other persons GF "a whore".

It also seems that you are taking some uneducated guess; i am a knowledgeable person, meaning i took the time to learn, unlike you who randomly write idiotic stuff. That really is the difference between us: i know my stuff, and you dont. If someone follows your ideas/advices, he will lose his time and money; if he follows mine, he wont.

That is called "being constructive". You arent, so keep your strong words to yourself and learn before posting and showing the zilvia world how much of a moron you are again.

I am harsh, yes, and i really think you deserve it for being such an idiot and an ass. Final words; learn to read, the GF talk was
1/not destined to you
2/a joke

If you cant tell, stop posting on forums :zzz:

[Frank_Jaeger]

So I don't know anything because I answered something wrong? you act like you never answered a question wrong Your a very close minded person. Maybe car 101 with you is to not let your stupid whore drive your car but my girl can drive my car just fine.
You're embarrassing yourself so hard right now.

[Kingtal0n]

because the internet is so serious
http://i23.photobucket.com/albums/b378/draglarry/moss_s15/10554.jpg
http://i23.photobucket.com/albums/b378/draglarry/moss_s15/DSCN0514.jpg