Anybody know the flow rate of the OEM injectors?
Flow rate
- Thread starter 4AU4LIFE
- Start date
I believe that DanO had his stock injectors cleaned and flow tested by RC Engineering. I searched for the topic but was unable to find it.
92NSX said:
do a search in the nitrous & forced induction section. i believe bad carma has posted that info previously.
good luck.
I thought they were rated at 270cc/min at a nominal pressure of ~45psi. However, from my experience they respond well to higher pressures, so at 90 psi you should be able to get ~380 out of them.
Here's the link:
www.danoland.com/nsxgarage/injector/injector.htm
shows the flow-test results of my '92 injectors. I had them test them to 100psi and the results are hand-written at the bottom of the page.
DanO
www.danoland.com/nsxgarage/injector/injector.htm
shows the flow-test results of my '92 injectors. I had them test them to 100psi and the results are hand-written at the bottom of the page.
DanO
Well it looks like my memory sucks, they must be rated at 240 not 270. Funny how clear that memory was. Perhaps 270 is the largest commonly available (in the US) Honda injector? Oh well, I'll write it off to age. 
Thanks DanO!
Thanks DanO!
BryanZublin said:
I think I will just send them there(RC) and have them taken care of.
Taken from www.mrgasket.com/hondainj.html
If it is 100% accurate is up to you.
According to the P/N from accel
The C30 uses 325cc (low ohm), basically the same injector as the H22a Prelude from 1992-1996.
The C32 uses 275cc (high ohm), basically the same injector as the H22a Prelude from 1997-2001.
-Ray
If it is 100% accurate is up to you.
According to the P/N from accel
The C30 uses 325cc (low ohm), basically the same injector as the H22a Prelude from 1992-1996.
The C32 uses 275cc (high ohm), basically the same injector as the H22a Prelude from 1997-2001.
-Ray
Very interesting, but it sounds wrong. However, both are for late model OBDII cars, the C30 listing is for the automatic. They don't list any for the '91- '94 cars. And why larger for the 3.0 automatic?
You know i do think the listing is flawed, but also correct in a few ways. I have done alot of work on the prelude motors, especially with the fuel injection and i can verify the injector sizes for those OBD1&2 motors.
They originally started with the 325cc injectors on the prelude, instead of taking the 240cc injectors and ramping up the injector pulsewidth, and cranking up the fuel pressure like they do with the civic & integras. People trip when you tell them that the basic civic DX is the same injector as the B18C Type-R, the difference is the fuel pressure & computer programming for pulse width. The type-R being almost maxed out in injector duty cycle, firgure a motor with a lot fatter torque curve, which translates into a larger thirst for fuel. Enter the larger injector. NOW, with the newer Preludes, and increased emission standards enter the problem..... so Honda has reduced the injector size to just small enough to meet the targeted power output, but be as small as possible to have better control over idling emissions when pulsewidths are extremely short & sensitive. Trust me about this one, try to get a Integra motor to idle for street use with 1000+cc injector, what a b*tch. LOL!
Ok, enough of my rambling...... basically the C30, when honda was building it decided to use the larger injector route figuring in later itterations of the motor if they increased power output they would have extra room with those injectors, but in the second version of the motor (C32) emissions played a more important role for injector selection.
Now mind you i have never taken my injectors out to have them flowed so i cannot guarantee that my 91 injectors are 325cc. I have taken what i know and have observed with honda sharing the "parts bin" and applied it. Now after the 550cc 's go into the motor, I'll get the injectors service for the h*ll of it, and we'll see then for sure what they are.
Aynways, this is just my little rant about the subject.
Why are we debating about this anyways??? LOL
92NSX, what are you needing the flow rates for? are you trying to calculate something??? Maybe i can help....
-Ray
They originally started with the 325cc injectors on the prelude, instead of taking the 240cc injectors and ramping up the injector pulsewidth, and cranking up the fuel pressure like they do with the civic & integras. People trip when you tell them that the basic civic DX is the same injector as the B18C Type-R, the difference is the fuel pressure & computer programming for pulse width. The type-R being almost maxed out in injector duty cycle, firgure a motor with a lot fatter torque curve, which translates into a larger thirst for fuel. Enter the larger injector. NOW, with the newer Preludes, and increased emission standards enter the problem..... so Honda has reduced the injector size to just small enough to meet the targeted power output, but be as small as possible to have better control over idling emissions when pulsewidths are extremely short & sensitive. Trust me about this one, try to get a Integra motor to idle for street use with 1000+cc injector, what a b*tch. LOL!
Ok, enough of my rambling...... basically the C30, when honda was building it decided to use the larger injector route figuring in later itterations of the motor if they increased power output they would have extra room with those injectors, but in the second version of the motor (C32) emissions played a more important role for injector selection.
Now mind you i have never taken my injectors out to have them flowed so i cannot guarantee that my 91 injectors are 325cc. I have taken what i know and have observed with honda sharing the "parts bin" and applied it. Now after the 550cc 's go into the motor, I'll get the injectors service for the h*ll of it, and we'll see then for sure what they are.
Aynways, this is just my little rant about the subject.
Why are we debating about this anyways??? LOL
92NSX, what are you needing the flow rates for? are you trying to calculate something??? Maybe i can help....
-Ray
Maurice, I told you from the get go they are 240 cc peak-hold on a 92 NSX. I tested them myself on a digital meter, 2.5 on the dime. they can increase up to 250 cc after cleaning calibrating at RC. I guess you didnt trust me?
For those of you talking about whats in your car because of whats in your other Honda be careful. even oem honda injectors of the same size can be peak-hold (2.5 ohms) or saturated (12-16 ohms)and you cant mix them but you can use saturated on peak-hold ecu but not the other way around.
NA1 #2853 your injectors are not 325 CC unless they were swapped out.
91-96 PEAK-HOLD 97+ SATURATED on NSX
For those of you talking about whats in your car because of whats in your other Honda be careful. even oem honda injectors of the same size can be peak-hold (2.5 ohms) or saturated (12-16 ohms)and you cant mix them but you can use saturated on peak-hold ecu but not the other way around.
NA1 #2853 your injectors are not 325 CC unless they were swapped out.
91-96 PEAK-HOLD 97+ SATURATED on NSX
NA1 #2853/Ray - excellent points, regardless of the absolute OEM values.
BadCarma - sounds like you have some insight here and it is consistent with DanO's tests. I'm running an AEM on a '93. Now that I've been through emissions again I have two more years to tinker without that hassle. I've been running stock injectors at high pressures (and before the AEM had auxiliary injectors) but obviously need to get something larger. I happen to have a set of new OEM units from a 2000 C32 but I assumed they were the same as what I'm running. Do you know for sure what they should be? I suspect still too small, but now I'm curious about what I have. One more think, so long as they don't lock up, what's wrong with running say 90psi? Never mind fuel leaks and such. Perhaps the injector will wear out faster, but other than that? Has there been a study about the impact of higher pressures on spray pattern and atomization? Or perhaps the way it hits intake walls etc?
BadCarma - sounds like you have some insight here and it is consistent with DanO's tests. I'm running an AEM on a '93. Now that I've been through emissions again I have two more years to tinker without that hassle. I've been running stock injectors at high pressures (and before the AEM had auxiliary injectors) but obviously need to get something larger. I happen to have a set of new OEM units from a 2000 C32 but I assumed they were the same as what I'm running. Do you know for sure what they should be? I suspect still too small, but now I'm curious about what I have. One more think, so long as they don't lock up, what's wrong with running say 90psi? Never mind fuel leaks and such. Perhaps the injector will wear out faster, but other than that? Has there been a study about the impact of higher pressures on spray pattern and atomization? Or perhaps the way it hits intake walls etc?
Needed that info for price on getting them flow tested and blueprinted from RC. Thanks for the offer though.
BadCarma
You got PM.
sjs said:
Steve, I dont believe I have any special insight into the matter but here is my opinion.
Has there been a study about the impact of higher pressures on spray pattern and atomization? Or perhaps the way it hits intake walls etc?
This is my take on spray patterns. On high REV high HP motors you dont want a nice mist pattern. I saw a post some time back were someone had posted a pic of a lucas injectors tight pattern and it was criticized by several members. a tight water hose is what you want for big power(lucas) type pattern.I know it will not atomize in the intake but will atomize well in the chamber.you want that hard hitting tight pattern to keep the fuel delivery blasting, that nice even spray pattern is designed for just what you indicated in your post 'emissions and economy' and admittedly a good burn efficiency.so if you are going for HP, F/I or nitrous the tight pattern is better (my opinion), if you are stock the OEM injectors are fine, increase your air flow by more then 1/4 across the power band and its time to think about larger injectors.
This is a VERY simplistic comparison but your injector is an electric selonoid akin to a nitrous selonoid. us NOS guys 'flutter' are selonoids much like an injector pulse, thats the base for progressive controllers.these are known to wear out the selonoid much faster.I believe the same about the injector and know you are knowledgeable about that already...just an FYI for the other guys.
This all leads into duty cycle, put to much pressure on it and run at above 85% duty cycle on Honda injectors (Pintle type) and they can (injectors) have an overlap, the injectors has X amount of time to open and close,walk on that and go completely lean you can get a complete failure and a hole in the side of your block much like a supercharged engine(NSX) I saw posted pics of.
For Me, if I have the need to exceed 80-85% duty I think it is time to move on to bigger injectors. with your AEM it should not be a problem.
I discussed spray patterns but dont have an answer for you on the effect of the high PSI on the pattern just duty cycle.I am sending off a set of high flow JDM Prelude injectors to be calibrated and cleaned at RC and intend on picking their brains on the effect of pressure on pattern.
What are the rating for the 2000 injectors on the 3.2 powerplant?I only know the ones I have dealt with and have not messed with a 2000 yet.I will know next week when I pull them out of an NSX that I am building a three stage NOS system for, I insisted on the injectors being calibrated even with low milage because of the NOS. I really doubt I posted anything here you did not all ready know but it may be of some help to the forum.lastly I guess it comes down to knowing what your duty cycle is at with any given pressure and if it exceeds what the PRO'S indicate (RC in my book) is safe step up to bigger.
Guys heres some stuff that might be helpful:
N/A motors are around .50 BSFC ,thats the amount of fuel you will uses per hour per HP produced
To know the limit of your injector use this formula:
Horsepower =
flow rate x % duty cycle
________________________
BSFC
want to know what it will do at higher pressure
F2= �ãp2/p1 * F1 (EDIT...ASCII for the formula didnt come out correct) I will fix it later) disregard for now
F2 = new fuel flow rate
F1 = Original flow rate
P2 = New pressure
P1 =old pressure
hope this was accurate and helpful, remember that this is only an opinion on what I feel is correct.I am sure their are others that disagree with my position
Best Regards David
Badcarma: I cant argue with having them testing, the numbers dont lie, so i guess i was wrong. I guess i'll have to recalculate a few things i was working on, i was going on the data that the C30 used the larger injectors.
Do you happen to know what peak duty cycle on the c30 is? I just bought one of those oscelloscope moduals for my PDA, but i dont really feel like disassembling the paneling to tap in the ECU right now, LOL.
I would be interested in the rates you get back from RC on the 2000 injectors, to see if they are really 270cc like Accel & Neuspeed say they are.
-Ray
Do you happen to know what peak duty cycle on the c30 is? I just bought one of those oscelloscope moduals for my PDA, but i dont really feel like disassembling the paneling to tap in the ECU right now, LOL.
I would be interested in the rates you get back from RC on the 2000 injectors, to see if they are really 270cc like Accel & Neuspeed say they are.
-Ray
injectors
Perhaps the OEM for these injectors may help:
http://www.keihin-us.com/injsi.html
I found this awhile ago. It lists some of the common OEM injectors made for Honda. If you look at the drawings, you will see that KN1 type was used on earlier NSX without air-assist and later NSXes uses air-assist injectors KN1-AA (primarily OBD2 cars). They come in different flow rate. The common ones are high impedence (saturated) and rated around 250cc/min (15L/hr) and some 445cc/min (26.73L/hr).. But they come in both flavor and flow rate doesn't depend on the impedence. Note that flowrate depends on the working pressure. If you look at the part numbers, they resemble Honda part numbers so you can kind of correlate them to a particular family of cars.
Now for our cars, according to Honda's parts database:
97-02 MT 06164-PBY-A00
95-96 MT/AT + 97-02 AT 06164-P0A-A00
91-94 MT/AT 06164-PT3-A00
We established from DanO's test that PT3-A00 are about 245cc/min@43psi. According to Keihin P0A-A00 should flow 248cc/[email protected] and has low impedence. We just need to have someone test the PBY-A00 or if we take a wild guess, the KN1-AA high impedence version flows 14.88L/[email protected] which is equivalent to 248cc/[email protected].
Interesting enough, the cross reference also shows that 91-94 injectors are used in 97 CL 2.2, 97-95 Legend and 92-94 Vigor.
Btw, Keihin's web site also has technical info on Honda fuel regulators and pumps!
HTH,
Eddy
Perhaps the OEM for these injectors may help:
http://www.keihin-us.com/injsi.html
I found this awhile ago. It lists some of the common OEM injectors made for Honda. If you look at the drawings, you will see that KN1 type was used on earlier NSX without air-assist and later NSXes uses air-assist injectors KN1-AA (primarily OBD2 cars). They come in different flow rate. The common ones are high impedence (saturated) and rated around 250cc/min (15L/hr) and some 445cc/min (26.73L/hr).. But they come in both flavor and flow rate doesn't depend on the impedence. Note that flowrate depends on the working pressure. If you look at the part numbers, they resemble Honda part numbers so you can kind of correlate them to a particular family of cars.
Now for our cars, according to Honda's parts database:
97-02 MT 06164-PBY-A00
95-96 MT/AT + 97-02 AT 06164-P0A-A00
91-94 MT/AT 06164-PT3-A00
We established from DanO's test that PT3-A00 are about 245cc/min@43psi. According to Keihin P0A-A00 should flow 248cc/[email protected] and has low impedence. We just need to have someone test the PBY-A00 or if we take a wild guess, the KN1-AA high impedence version flows 14.88L/[email protected] which is equivalent to 248cc/[email protected].
Interesting enough, the cross reference also shows that 91-94 injectors are used in 97 CL 2.2, 97-95 Legend and 92-94 Vigor.
Btw, Keihin's web site also has technical info on Honda fuel regulators and pumps!
HTH,
Eddy
Re: injectors
DanO's injectors flow rate was AFTER cleaning-calibrating. the nsx injectors 91-96 ALL 240 CC peak-hold low draw 2.5 ohms, cant speak for the 97+ injectors until next week. their is alot of sketchy info out their and alot of asumption. cold hard facts are lacking.also many sites-vendors are offering injectors sized for the NSX with a 5 to 10% increase in flow rate as it will not effect idle or cause washdown so you cannot use those numbers as OEM.
Good info Eddy! I will peruse the site and see whats up with their numbers.BTW I have seen a half dozen report sheets direct from RC after calibration of 91-96 cars all were 240 p-h until cleaned calibrated, also this is not due to age.some were a little above 240 some below when they came back all were better then 240 and calibrated to about .8 (thats freaky) but maybe thats what RC shoots for.stock injectors dont normally need cleaning calibrating until 100k unless F/I then it would be around 50k.
the ones they offer as 250 cc saturated 12-16 ohm's will work fine on 91-96 cars but are you sure they say they ar OE? I will look for myself. also remember the cars in Japan can have different flow and impedence then those in the states. the ECU is also setup to run higher octane in Japan.make sure you are pulling US car OE rates
Best Regards David
P.S. I am done posting on this unless we start a new thread as the answer to 92 NSX'S question was answered correctly.if anyone starts a new thread that covers injectors and the fuel system in general that would be great. we need more serious dialog on here and less fluff.
Maurice, I owe you a public apology, I reviewed our emails and PM'S and I never stated the flow rate only that the injectors I sent you were stock OEM for your car...sorry bro
Eddy said:
DanO's injectors flow rate was AFTER cleaning-calibrating. the nsx injectors 91-96 ALL 240 CC peak-hold low draw 2.5 ohms, cant speak for the 97+ injectors until next week. their is alot of sketchy info out their and alot of asumption. cold hard facts are lacking.also many sites-vendors are offering injectors sized for the NSX with a 5 to 10% increase in flow rate as it will not effect idle or cause washdown so you cannot use those numbers as OEM.
Good info Eddy! I will peruse the site and see whats up with their numbers.BTW I have seen a half dozen report sheets direct from RC after calibration of 91-96 cars all were 240 p-h until cleaned calibrated, also this is not due to age.some were a little above 240 some below when they came back all were better then 240 and calibrated to about .8 (thats freaky) but maybe thats what RC shoots for.stock injectors dont normally need cleaning calibrating until 100k unless F/I then it would be around 50k.
the ones they offer as 250 cc saturated 12-16 ohm's will work fine on 91-96 cars but are you sure they say they ar OE? I will look for myself. also remember the cars in Japan can have different flow and impedence then those in the states. the ECU is also setup to run higher octane in Japan.make sure you are pulling US car OE rates
Best Regards David
P.S. I am done posting on this unless we start a new thread as the answer to 92 NSX'S question was answered correctly.if anyone starts a new thread that covers injectors and the fuel system in general that would be great. we need more serious dialog on here and less fluff.
Maurice, I owe you a public apology, I reviewed our emails and PM'S and I never stated the flow rate only that the injectors I sent you were stock OEM for your car...sorry bro
Last edited:
.
Last edited:
I hear the "don't exceed 80% duty cylce" quote so often and have yet to hear a reasonable explanation. Does anyone remember CIS mechanical fuel injection that was popular in the 1980's on many millions of European engines (VW, Mercedes)? CIS is "Continuous Injection System" where the fuel is injected into the manifold ALL the time.
80% duty cycle
It takes certain amount of time for the injector to fully pull open, and then takes time for it to recover into the closed position again. If you take injectors past the 80% mark, and then rev up into the higher RPM, there is very little time inbetween every rotation of the motor, so you will be asking the injector to open, then close, but before it fully closes, yuo ask it to open again, and then you will cause the spray partern to turn into a dribble.
[RPM - 1 Rotation Cycle--------------------------][Next Rotation----->
[Open Time][Pulse Time----------------------][Close Time----]
......................................................................[Next Open Event]
......................................................................(See The Overlap!)
See you are asking the injector to open again as it just begins its close swing...... partially choking off the spray, and then opening again, so the spray patern flutters.
-Ray
It takes certain amount of time for the injector to fully pull open, and then takes time for it to recover into the closed position again. If you take injectors past the 80% mark, and then rev up into the higher RPM, there is very little time inbetween every rotation of the motor, so you will be asking the injector to open, then close, but before it fully closes, yuo ask it to open again, and then you will cause the spray partern to turn into a dribble.
[RPM - 1 Rotation Cycle--------------------------][Next Rotation----->
[Open Time][Pulse Time----------------------][Close Time----]
......................................................................[Next Open Event]
......................................................................(See The Overlap!)
See you are asking the injector to open again as it just begins its close swing...... partially choking off the spray, and then opening again, so the spray patern flutters.
-Ray
CIS was interesting. Yes, it had ~40 psi on the injectors at all times, but they only opened during an intake stroke.
When the intake valve was closed, this was not enough differential between the fuel supply and the manifold to overcome the injector spring mechanics. When the valve opening, the added vacuum the piston created allowed for higher differential pressure, which opened the injector.
Mechanical injection...YUCK!!
When the intake valve was closed, this was not enough differential between the fuel supply and the manifold to overcome the injector spring mechanics. When the valve opening, the added vacuum the piston created allowed for higher differential pressure, which opened the injector.
Mechanical injection...YUCK!!
Last edited:
