injection question
05-03-2013, 10:25 AM
#1
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injection question
High I have a 85 z31t and have already searched and found answers I am just triple checking, is it ok to run high impendence injectors on my low impendence ecu? Because a 85 z31 is a low impendence ecu right? I need to run these injectors with my pc tuning secret box! And high impendence works great with it. Now I know that I have heard that a high impendence ecu can not run low impendence unless u use the resistors! but anyways thanks to who ever helps and have a good summer peace.
05-03-2013, 11:00 AM
#2
Awesome coincidence!
I was talking w/ FricFrac about this the other day. I'm running an 85 Z31T ecu / maf in my 280zx and am upgrading to an o-ring fuel rail for more injector options... Long story short, it should be fine.
I was talking w/ FricFrac about this the other day. I'm running an 85 Z31T ecu / maf in my 280zx and am upgrading to an o-ring fuel rail for more injector options... Long story short, it should be fine.
Originally Posted by NismoPick
I want to run slightly larger cc o-ring injectors on my setup, and there are plenty to choose from, but most modern cars run high impedance (saturated) injectors which [some say] are less effective for turbo applications because they don't have the "snap open snap closed" precision of low impedance (peak and hold) injectors.
This summer I'm going to try out a few different sets of injectors & probably dyno them, but I have some concern about running high impedance injectors on a low impedance ecu. As I have researched, most people are trying to do the opposite & are advised that low injectors on a high ecu will burn out the injector coils. I have found several posts of people saying high injectors on a low ecu will be ok, because the high require less power (like in this thread: High Impedance vs. Low Impedance Injectors, why, not what? - Turbobricks Forums )
Do you see or foresee any electrical problems running high impedance injectors on a low impedance ecu?
This summer I'm going to try out a few different sets of injectors & probably dyno them, but I have some concern about running high impedance injectors on a low impedance ecu. As I have researched, most people are trying to do the opposite & are advised that low injectors on a high ecu will burn out the injector coils. I have found several posts of people saying high injectors on a low ecu will be ok, because the high require less power (like in this thread: High Impedance vs. Low Impedance Injectors, why, not what? - Turbobricks Forums )
Do you see or foresee any electrical problems running high impedance injectors on a low impedance ecu?
Originally Posted by FricFrac
I high impedance injector will work just fine with a low impedance ECU. It will not burn it out. The low impedance ECU is capable of handling more current - it can't force more through. It's simple Ohms law - the voltage dropped across the injector is the same and the resistance is the same then the current has to stay the same. By adding another resistor in series with the injector you limit the current (thus the resistor is called a current limiting resistor). So the '81 turbo had a current limiting resistor pack because the ECU couldn't handle that much current. In 82-83 the ECU was capable of handling the current and didn't need the resistors to limit the current. The injectors are all the same between the years - low impedance. If you ran those low impedance injectors and the 82-83 ECU AND added in the resistor pack it would run fine (eg low impedance injector + resistor = high impedance injector).
Now the switching on and off with low impedance injectors could be faster because they draw more current and the magnetic field is stronger with more current. It's also stronger with more winding which a low impedance resistor will likely have. I think typically it's the current that has the largest effect so if I was to make an educated guess I'd think the low impedance would be the fastest. That being said in real life I think it will have a negligible effect. It's not really precision chemistry we're talking about here in the combustion engine. Personally I do take that into consideration with the MS3 setup and I find out what the turn on time and turn off time of the injectors are but it's also half art half science. I actually took the injectors and went into test mode and listened to the injectors and adjusted the delay while listening to them change pitch. When the pitch didn't go up significantly I figured that was the sweet spot and it was very close to the calculated value.
In the end it's how much fuel you're getting in and there is plenty of time with slower injectors to work just fine. For the ECU you can't tune it's so archaic and coarse it doesn't matter. For something tuneable like MS you can tune the delay in no problem.
Trust me - I deliberated about that one for hours already
Now the switching on and off with low impedance injectors could be faster because they draw more current and the magnetic field is stronger with more current. It's also stronger with more winding which a low impedance resistor will likely have. I think typically it's the current that has the largest effect so if I was to make an educated guess I'd think the low impedance would be the fastest. That being said in real life I think it will have a negligible effect. It's not really precision chemistry we're talking about here in the combustion engine. Personally I do take that into consideration with the MS3 setup and I find out what the turn on time and turn off time of the injectors are but it's also half art half science. I actually took the injectors and went into test mode and listened to the injectors and adjusted the delay while listening to them change pitch. When the pitch didn't go up significantly I figured that was the sweet spot and it was very close to the calculated value.
In the end it's how much fuel you're getting in and there is plenty of time with slower injectors to work just fine. For the ECU you can't tune it's so archaic and coarse it doesn't matter. For something tuneable like MS you can tune the delay in no problem.
Trust me - I deliberated about that one for hours already
05-21-2013, 07:27 AM
#4
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high rpm rev limiter i want one
I own a z31zxt and have a piggy back system I have control of ignition :timing. It does not have a rev limiter. It might but I don't think so! I want to make my car rev limit at a high rpm like above 5000. Does any body have a good idea? I seen that 2 step thing that they use on the s13 but isint that only for launch control? And will this rev limiter mess with my piggy back or will they like each other?
05-21-2013, 08:50 AM
#5
Without any info on your "piggyback system", it's pretty hard to know what setup you have / need.
Rev limiters are tied to ignition... it cuts spark to keep the rpm's under the set limit. There are several rev limiter options, depending on what you want.
I'm using a Mallory Hyfire 6AL with a Z31T ecu on my 280ZX Turbo. I have the rev limiter set to something like 5800 rpm because it still pulls hard above 5k (peak hp is ~5200 rpm).
Rev limiters are tied to ignition... it cuts spark to keep the rpm's under the set limit. There are several rev limiter options, depending on what you want.
I'm using a Mallory Hyfire 6AL with a Z31T ecu on my 280ZX Turbo. I have the rev limiter set to something like 5800 rpm because it still pulls hard above 5k (peak hp is ~5200 rpm).
05-25-2013, 05:35 AM
#9
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Well that's good to know, and I run the greddy blue. It allows me to use my atmospheric blow off valve. And I am going to run bigger injectors and it will control them. In fact I tune the airflow map right now and run a 2 stage boost controller and try to put the power down low, that's why I run it. I also might throw in 2 additional injectors and use my sub injector map and break the light speed barrier, OK!
05-25-2013, 05:59 AM
#10
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Well that's good to know, and I run the greddy blue. It allows me to use my atmospheric blow off valve. And I am going to run bigger injectors and it will control them. In fact I tune the airflow map right now and run a 2 stage boost controller and try to put the power down low, that's why I run it. I also might throw in 2 additional injectors and use my sub injector map and break the light speed barrier, OK!
05-25-2013, 06:37 AM
#11
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I also forgot to mention that I don't care if there high impendence. Really I just need a high impendence 330 to 550cc injectors of any car do you guys have any recomondations on what car I could retrieve these from? It doesn't have to be ford lighting i shouldn't of said ford lightning. I will be keeping the stock rail.
Last edited by turbotim; 05-25-2013 at 07:51 AM.
05-25-2013, 01:31 PM
#12
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Injector fitment
Can I use Volvo 30pound ev1 injectors they look like they have a plastic tubing around them I would have to attach the hose to, there not metal like ours would they work or green giant ford 42pound work? I have way to control them and would like them to be high impendence.
05-25-2013, 02:13 PM
#13
Merged threads. Please do not make a new thread for every "Can I use this injector?" question. 
If you can tune your ecu for any injector, you can use any injector. BUT... most of the injectors you're mentioning are O-RING injectors. Yours are BARB injectors. You need O-RING fuel rails if you want to use O-RING injectors.
If you can tune your ecu for any injector, you can use any injector. BUT... most of the injectors you're mentioning are O-RING injectors. Yours are BARB injectors. You need O-RING fuel rails if you want to use O-RING injectors.
05-26-2013, 06:17 AM
#14
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Understand about making the 2 threads wont happen again, And thanks for the reply's. I found the perfect injectors, they are high impendence 460cc out of 89 to 91 rx7 non turbo. If anyone is interested 86 and 87 were low impendence 460cc!
05-29-2013, 06:26 AM
#16
Before I answer, I have a question to you... Where are you finding this info about RX7 injectors? I'm just wondering how you find "some" of your info.
Depending on the year, some RX7 injectors have slightly larger pintle caps than the stock Z31 injectors, so you either need to shave them with a dremel or replace them with ones that will fit. You would use the Z31 o-rings.
Just an FYI... there are two basic pintle caps for your application: the long skinny ones (like stock), and the short hats. Searching GOOGLE IMAGES is a quick way to see what the injectors look like.
I've also been junk yard hopping lately to look for o-ring injectors with varying cc's. Unfortunately, most EFI cars use >200cc injectors. Some turbo applications and V8's are higher, but are more rare.
Depending on the year, some RX7 injectors have slightly larger pintle caps than the stock Z31 injectors, so you either need to shave them with a dremel or replace them with ones that will fit. You would use the Z31 o-rings.
Just an FYI... there are two basic pintle caps for your application: the long skinny ones (like stock), and the short hats. Searching GOOGLE IMAGES is a quick way to see what the injectors look like.
I've also been junk yard hopping lately to look for o-ring injectors with varying cc's. Unfortunately, most EFI cars use >200cc injectors. Some turbo applications and V8's are higher, but are more rare.
Last edited by NismoPick; 05-29-2013 at 06:28 AM.
05-29-2013, 01:03 PM
#17
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So, can I take my pintle caps off my stock injectors and put them on the rx7 ones? Or do I order new ones? and then when I get the rx7 injectors I check wether to use the long skinny ones (like stock), or the short hats? I am changing to all oval connectors too! They have square ones though from different years, but I opted for the ovals cause there cheaper! And if you want o ring injectors what about the ford green giants 42 pounders, And I got that injector info from googling z31 injector upgrades and then its one of the post that I think redz31 made if you cant find it let me know! And google it in google not in this forum!
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