Injector questions.
13-10-2008, 01:53 PM
#1
Injector questions.
I have been look at injectors to use with my OFAB set up and i have a few questions to see if i am correct in what i am thinking.
They have different OHM`s, CC, Pressure (LB/HR)
(701s) 15.8 OHM`s, 226CC, 22LB
15.8 OHM`s = Power
226cc = Injector Flow Rate, Fuel amount
22LB = Injector Flow Rate, Fuel Pressure
(803s) 4.7OHM`s, 370CC, 35LB
So i would need to use a resistor to lower the OHM`s.
How about fuel pressure? 803 have a higher fuel pressure would i just use a higher pressure fuel pump? What about the fuel pressure regulator?
The above is purely an example as they run at different pressure and require different power, Its just to find out what i would need to do if i chose to use injectors above the 701s i have.
Cheers Stu
PS Hope i made sence
They have different OHM`s, CC, Pressure (LB/HR)
(701s) 15.8 OHM`s, 226CC, 22LB
15.8 OHM`s = Power
226cc = Injector Flow Rate, Fuel amount
22LB = Injector Flow Rate, Fuel Pressure
(803s) 4.7OHM`s, 370CC, 35LB
So i would need to use a resistor to lower the OHM`s.
How about fuel pressure? 803 have a higher fuel pressure would i just use a higher pressure fuel pump? What about the fuel pressure regulator?
The above is purely an example as they run at different pressure and require different power, Its just to find out what i would need to do if i chose to use injectors above the 701s i have.
Cheers Stu
PS Hope i made sence
13-10-2008, 04:08 PM
#2
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they would all run at the same pressure.
the CC of the injector is simply another way of describing the flow rate which is often given in lbs. use one method or the other in order to compare two injectors.
the resistance is not a reflection on power directly but if you're using low resistance injectors then your ecu must be able to run low resistance injectors properly or you will need series resistors which is botch up way of doing it.
the CC of the injector is simply another way of describing the flow rate which is often given in lbs. use one method or the other in order to compare two injectors.
the resistance is not a reflection on power directly but if you're using low resistance injectors then your ecu must be able to run low resistance injectors properly or you will need series resistors which is botch up way of doing it.
13-10-2008, 04:36 PM
#5
they would all run at the same pressure.
the CC of the injector is simply another way of describing the flow rate which is often given in lbs. use one method or the other in order to compare two injectors.
the resistance is not a reflection on power directly but if you're using low resistance injectors then your ecu must be able to run low resistance injectors properly or you will need series resistors which is botch up way of doing it.
the CC of the injector is simply another way of describing the flow rate which is often given in lbs. use one method or the other in order to compare two injectors.
the resistance is not a reflection on power directly but if you're using low resistance injectors then your ecu must be able to run low resistance injectors properly or you will need series resistors which is botch up way of doing it.
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13-10-2008, 04:51 PM
#8
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What sort of BHP are you after?
The IW 31 are good up to 280bh. You will need the IW 58 up to 320bhp. And then bigger for up to 400.
Ollie
PS I will have a set of IW 058 for sale in about 2 weeks time.
The IW 31 are good up to 280bh. You will need the IW 58 up to 320bhp. And then bigger for up to 400.
Ollie
PS I will have a set of IW 058 for sale in about 2 weeks time.
13-10-2008, 05:16 PM
#10
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There is no "botch" at all about resistors in the earth line to each injector, that'sd complete crap, the only difference is it happens externally instead of internally in the ecu.
tabetha
tabetha
13-10-2008, 07:17 PM
#13
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which ecu that is designed for low ohm injectors has internal resistors then?
if it has resistors then it was NOT designed for low ohm injectors but has been frigged to make them work.
the fact is that low impedance injectors (peak and hold injectors) are designed to be low resistance to allow for higher power at the instant they are commanded to open = "peak" and then the drive power is reduced for the "hold" part.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
many people apparently do use series resistors successfully but it would appear that the greater the size of the injector, the greater is the potential problem
13-10-2008, 07:26 PM
#14
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....which ecu that is designed for low ohm injectors has internal resistors then?
if it has resistors then it was NOT designed for low ohm injectors but has been frigged to make them work.
the fact is that low impedance injectors (peak and hold injectors) are designed to be low resistance to allow for higher power at the instant they are commanded to open = "peak" and then the drive power is reduced for the "hold" part.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
many people apparently do use series resistors successfully but it would appear that the greater the size of the injector, the greater is the potential problem
if it has resistors then it was NOT designed for low ohm injectors but has been frigged to make them work.
the fact is that low impedance injectors (peak and hold injectors) are designed to be low resistance to allow for higher power at the instant they are commanded to open = "peak" and then the drive power is reduced for the "hold" part.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
many people apparently do use series resistors successfully but it would appear that the greater the size of the injector, the greater is the potential problem
Agreed 100% and I have designed a few ecu's in my time
13-10-2008, 08:51 PM
#16
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Use high impedance injectors (high ohms)
You cant live map OFAB yourself so I would recomend you asking your tuner/chip supplier for proper advice.
Doing this DIY is NOT the way to go unless you change the managment to an after market type
You may save a few quid by getting injectors cheaper but in the long run it will cost you money !
You cant live map OFAB yourself so I would recomend you asking your tuner/chip supplier for proper advice.
Doing this DIY is NOT the way to go unless you change the managment to an after market type
You may save a few quid by getting injectors cheaper but in the long run it will cost you money !
13-10-2008, 08:54 PM
#17
the fact is that low impedance injectors (peak and hold injectors) are designed to be low resistance to allow for higher power at the instant they are commanded to open = "peak" and then the drive power is reduced for the "hold" part.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
13-10-2008, 08:57 PM
#18
Use high impedance injectors (high ohms)
You cant live map OFAB yourself so I would recomend you asking your tuner/chip supplier for proper advice.
Doing this DIY is NOT the way to go unless you change the managment to an after market type
You may save a few quid by getting injectors cheaper but in the long run it will cost you money !
You cant live map OFAB yourself so I would recomend you asking your tuner/chip supplier for proper advice.
Doing this DIY is NOT the way to go unless you change the managment to an after market type
You may save a few quid by getting injectors cheaper but in the long run it will cost you money !
13-10-2008, 09:02 PM
#20
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RS Stu,
If you deviate away from a standard conversion, It will need custom mapping and cost you loads extra !
There are very few who can do this properly on OFAB.
If you intend to keep the standard ECU, you really need to talk to someone like MSD or Collins about what they can do for you.
When I say standard conversions, proper tuners will probably have something near to what your engine spec needs but you will have to use the correct parts for the job in order to be correct.
Bigger is not always better !
Sorry !
PMSL @ jim Galbally
If you deviate away from a standard conversion, It will need custom mapping and cost you loads extra !
There are very few who can do this properly on OFAB.
If you intend to keep the standard ECU, you really need to talk to someone like MSD or Collins about what they can do for you.
When I say standard conversions, proper tuners will probably have something near to what your engine spec needs but you will have to use the correct parts for the job in order to be correct.
Bigger is not always better !
Sorry !
PMSL @ jim Galbally
13-10-2008, 09:12 PM
#21
RS Stu,
If you deviate away from a standard conversion, It will need custom mapping and cost you loads extra !
There are very few who can do this properly on OFAB.
If you intend to keep the standard ECU, you really need to talk to someone like MSD or Collins about what they can do for you.
When I say standard conversions, proper tuners will probably have something near to what your engine spec needs but you will have to use the correct parts for the job in order to be correct.
Bigger is not always better !
Sorry !
PMSL @ jim Galbally
If you deviate away from a standard conversion, It will need custom mapping and cost you loads extra !
There are very few who can do this properly on OFAB.
If you intend to keep the standard ECU, you really need to talk to someone like MSD or Collins about what they can do for you.
When I say standard conversions, proper tuners will probably have something near to what your engine spec needs but you will have to use the correct parts for the job in order to be correct.
Bigger is not always better !
Sorry !
PMSL @ jim Galbally
engine spec atm
2.0 16v Blacktop
low comp pistons
701s
OFAB ecu
Cossie T3
Adj cam pullys
piper valve springs.
Will a ofab chip run this ok? or will it need custom mapping regardless?
13-10-2008, 09:17 PM
#22
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When you say OFAB chip do you mean any chip ?
The chip MUST match the injectors and engine spec exactly or it will need a live map.
Looking at you spec, it certainly isnt a standard although the companies I mentioned above may have something near enough but I think to stop it melting and get the best performance, a live map is what you need !
Will be worth it in the long run.
The chip MUST match the injectors and engine spec exactly or it will need a live map.
Looking at you spec, it certainly isnt a standard although the companies I mentioned above may have something near enough but I think to stop it melting and get the best performance, a live map is what you need !
Will be worth it in the long run.
13-10-2008, 09:25 PM
#24
So, as long as i get high impedance injectors ill be ok, As it going to be live mapped any way. So lets just say i am going down the live map route it OFAB ok? or will it be better and cheaper to change to cossie mangement or an aftermarket unit?
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