hey well im debating on and off about putting in dsm injectors in my ld9. For some read they just look like the clips or injectors are too fat or something for my rail. In the pic below are the blue top 1rst gen ones but the ones a guy might sell me are black top ones. Just wanna confirm if these are them or not because they look too big or something. Also they are the same length as the 2.4 ones right or shorter or longer?
BOOSTED wrote:hey well im debating on and off about putting in dsm injectors in my ld9. For some read they just look like the clips or injectors are too fat or something for my rail. In the pic below are the blue top 1rst gen ones but the ones a guy might sell me are black top ones. Just wanna confirm if these are them or not because they look too big or something. Also they are the same length as the 2.4 ones right or shorter or longer?
i cant tell you if they will fit or not. but there is a difference between blue and black top injectors. i may be mistaken (along time since i worked with stock inectors sorry haha) but the blue tops are 440cc injectors found in manual turbo cars, and i think the black tops are 390cc's found in auto 1g turbo cars, and i believe stealth/300gt tt cars as well. just wanted to let you know in case you need 440cc injectors and you think your getting them but instead he's selling 390's.
seeing I have them in my car i'd have to say yes they fit
Takes a little bit of ingenuity but yes they fit.
"Horsepower is the Ultimate Accessory"
First gen manual transmission DSMs came with 450cc injectors, auto trans (black top?) came with 380cc injectors.
BTW, tock fuel pressure on DSMs is 27psi.
Actually the black tops are 390cc.
Are the Dsm injectors Low or high impedence......
ive got 2.0 lsj from a cobalt in mine , they are fatties too
they plug right in but you need to adjust the height of the fuel rail , easier on the venom rail
but they have 36 and 42.5
2g turbo injectors are black tops and are also 440-450 cc's
the 2.0 lsj are high , just like the 99-05 cavs
im running lsj ones now and im at like 80% duty cycle.
80% duty isnt bad
im prob running lower than that with mine , i havent really loooked though
yeah 80% is nothing man... I was pushing 98-103% on my 370cc's on my old S/C setup and although it was really pushing them they never broke up on me. You need to get that new fuel pump in there this winter before you do those injectors
"Horsepower is the Ultimate Accessory"
Make sure you realize the 99 (mid year) J-bodies's are high impedance......
Anyway..... I have 2nd Gen Black DSM injectors on our drag car (450cc right?)...... I used the green rubber seals from under the coil packs to make sleeves to seal the injectors to the head. Worked pretty good.
Another note, while DSM's might run 27psi of fuel pressure stock, their injectors are rated at the same psi as ours. (from what I have read)
I have another set of DSM injectors out in the garage..... think they are blue or silver? IDK.
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
SpeedRacerZ wrote:Make sure you realize the 99 (mid year) J-bodies's are high impedance......
Anyway..... I have 2nd Gen Black DSM injectors on our drag car (450cc right?)...... I used the green rubber seals from under the coil packs to make sleeves to seal the injectors to the head. Worked pretty good.
Another note, while DSM's might run 27psi of fuel pressure stock, their injectors are rated at the same psi as ours. (from what I have read)
I have another set of DSM injectors out in the garage..... think they are blue or silver? IDK.
Would i need a AFPR to use these injectors? I dont think i should but never hurts to ask before i buy these.
Quote:
Would i need a AFPR to use these injectors? I dont think i should but never hurts to ask before i buy these.
Need = No... not as long as you have the injectors scaled down with HPTuners, which right now they def are not. But also like I told you last summer when we tuned your car... it certainly wouldn't hurt anything to have an AFPR. It would allow for more accurate tuning especially at idle. Here's my question though... if you really aren't planning on upgrading anything else on your engine then why bother? The injectors you have in there right now should be plenty enough once you get you new pump in and all your sensor issues straightened out.
"Horsepower is the Ultimate Accessory"
i was just leary of running out of fuel on the 50 shot and/or 75 shot.
if 99 and up j's use high impadence injectors then you cant use these anyways because dsm injectors are low.
Kyle Kurtz wrote:if 99 and up j's use high impadence injectors then you cant use these anyways because dsm injectors are low.
I'm guessing he didnt catch that the first couple times around.......
I'd search out some GTP injectors (99+)...... and if your adding N2O, I'd most deff go 'wet', then there is no need for larger fuel injectors...... (as long as the current are holding up right now)
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
Quote:
if 99 and up j's use high impadence injectors then you cant use these anyways because dsm injectors are low.
This isn't true... If you have high impedance injectors (usually tall and skinny) and want to go to the short and fat style injector, which is usually associated with low imp. it can be done. You will need to have the clips for that style spliced into your 99+ harness but the injectors them selves will work perfectly fine once this is done. What you cannot do is go the other way around from a low imp. to a high imp. injector.
"Horsepower is the Ultimate Accessory"
Its all relitive...... if you swap them out, one way its harmfull to the injector driver, the other to the injectors themselves.......
Look at the DSM's..... they use a High Impedance Injector driver, Low Impedance injectors, and a resistor box....... same with some Honda's.
Ohms Law calculator
I = E / R
In a High Impedance system, if the injectors(12ohm) see 12v, the system see's 1amp..... you swap in the Low Impedance injectors (2ohm), now that system see's 6 amps........ In most cases, a system is built for how its designed....... meaning if its built for 1 amp, its more then likely not made to with stand 6 amps.
Thats the driver part........ now here's some Injector info. (and more driver info)
MSD Ignition/Fuel Injectors
Saturated Circuit Drivers/Injectors
Most domestic OE production EFI systems use an ECU with 12 volt Saturated Circuit drivers. These are very inexpensive, simple, and reliable. This type of driver works by supplying 12 volts to the injectors and the ECU turns it on and off to establish a fuel injector pulse. In general, if an injector has a high resistance specification (12-16 ohms) the ECU uses a 12 volt saturated circuit driver to control it. This means that the current flow in the driver and injector circuit stays low keeping the components nice and cool for long life.
Conversely, a downfall of a Saturated Circuit driver is that it has a slower response time (and closing time) than a peak and hold type. This slower time can somewhat decrease the usable operating range of the injector energized by this driver. An injector operating on a saturated circuit driver typically has a reaction time of 2 milliseconds while a peak and hold driver typically responds in 1.5 ms.
NOTE: You can measure an injector's resistance with a Digital Volt-Ohm Meter(DVOM) by connecting it across the injector's electrical plug contacts.
NOTE: Ohm's Law can be applied to calculate the current in the injector and driver circuit when using a high resistance injector. Remember, Ohms's Law is I = E/R, where I = the circuit's current in amps, E = battery voltage in volts available to the injector, and R = injector resistance in ohms. So, for our 12 ohm injector being supplied 12 volts, I = 12v /12 ohms, which is 1 amp of current in the circuit to operate the injector.
Peak and Hold Driver/Injectors
These type of injectors and drivers may also be called current sensing or current limiting. They are more expensive and complex than saturated circuit drivers, and are not generally used with domestic production ECUs. They are primarily used in aftermarket high performance systems.
Most high flow injectors are low resistance (2-5 ohms) and use a peak and hold driver to activate them. The Peak current is the amount required to quickly jolt the injector open, and then the lower Hold current rating is used to keep it open for as long as the ECU commands. These require the extra kick from the higher current to keep the opening and closing time of the injector stable at the higher fuel flow rate.
With this type of driver, 12 volts is still delivered to the injector, but due to the its low resistance, the current in the driver circuit is high. How high? Using Ohms's Law we can calculate the current rating (12v/2 ohms = 6 amps). This is substantial current flow and a Saturated Injector cannot handle it.
The drivers also come in two values; 4 amp peak/1 amp hold, and 2 amp peak/0.5 amp hold.. Even though 6 amps may be available to operate the injector, the maximum it is allowed to reach is 2 or 4 amps, depending on the driver's current limit.
Thats why its not a great idea to mix and match. Can it work....... sure. But do you wanna be the one that has to replace the ECM when the driver fries?
***Edit***
Forgot to add, the shape of the injector does nothing to determine the resistance. The older V6 (2.8/3.1) injectors looke EXACTLY like the Quad 4/Twin Cam 2ohm injectors, but are in fact 12ohms. The change in injector shape is from one manufacturer to another. The new 'Slim Line' injectors are Bosch injectors....... I believe the older fat ones where Rochester injectors......
Edited 1 time(s). Last edited Friday, January 26, 2007 12:46 PM
SPD RCR Z -
'02 Z24 420whp
SLO GOAT -
'04 GTO 305whp
W41 BOI -
'78 Buick Opel Isuzu W41 Swap
Very interesting...
Thanks for all the info Brian. I used the low imp. Ford Brown Tops on my 99 for about 2 years with no issues and tuning worked perfect for me... this is just my personal experience though. I think if you have the option you should always buy what the car originally came with.
"Horsepower is the Ultimate Accessory"
SpeedRacerZ wrote:Its all relitive...... if you swap them out, one way its harmfull to the injector driver, the other to the injectors themselves.......
Look at the DSM's..... they use a High Impedance Injector driver, Low Impedance injectors, and a resistor box....... same with some Honda's.
Ohms Law calculator
I = E / R
In a High Impedance system, if the injectors(12ohm) see 12v, the system see's 1amp..... you swap in the Low Impedance injectors (2ohm), now that system see's 6 amps........ In most cases, a system is built for how its designed....... meaning if its built for 1 amp, its more then likely not made to with stand 6 amps.
Thats the driver part........ now here's some Injector info. (and more driver info)
MSD Ignition/Fuel Injectors
Saturated Circuit Drivers/Injectors
Most domestic OE production EFI systems use an ECU with 12 volt Saturated Circuit drivers. These are very inexpensive, simple, and reliable. This type of driver works by supplying 12 volts to the injectors and the ECU turns it on and off to establish a fuel injector pulse. In general, if an injector has a high resistance specification (12-16 ohms) the ECU uses a 12 volt saturated circuit driver to control it. This means that the current flow in the driver and injector circuit stays low keeping the components nice and cool for long life.
Conversely, a downfall of a Saturated Circuit driver is that it has a slower response time (and closing time) than a peak and hold type. This slower time can somewhat decrease the usable operating range of the injector energized by this driver. An injector operating on a saturated circuit driver typically has a reaction time of 2 milliseconds while a peak and hold driver typically responds in 1.5 ms.
NOTE: You can measure an injector's resistance with a Digital Volt-Ohm Meter(DVOM) by connecting it across the injector's electrical plug contacts.
NOTE: Ohm's Law can be applied to calculate the current in the injector and driver circuit when using a high resistance injector. Remember, Ohms's Law is I = E/R, where I = the circuit's current in amps, E = battery voltage in volts available to the injector, and R = injector resistance in ohms. So, for our 12 ohm injector being supplied 12 volts, I = 12v /12 ohms, which is 1 amp of current in the circuit to operate the injector.
Peak and Hold Driver/Injectors
These type of injectors and drivers may also be called current sensing or current limiting. They are more expensive and complex than saturated circuit drivers, and are not generally used with domestic production ECUs. They are primarily used in aftermarket high performance systems.
Most high flow injectors are low resistance (2-5 ohms) and use a peak and hold driver to activate them. The Peak current is the amount required to quickly jolt the injector open, and then the lower Hold current rating is used to keep it open for as long as the ECU commands. These require the extra kick from the higher current to keep the opening and closing time of the injector stable at the higher fuel flow rate.
With this type of driver, 12 volts is still delivered to the injector, but due to the its low resistance, the current in the driver circuit is high. How high? Using Ohms's Law we can calculate the current rating (12v/2 ohms = 6 amps). This is substantial current flow and a Saturated Injector cannot handle it.
The drivers also come in two values; 4 amp peak/1 amp hold, and 2 amp peak/0.5 amp hold.. Even though 6 amps may be available to operate the injector, the maximum it is allowed to reach is 2 or 4 amps, depending on the driver's current limit.
Thats why its not a great idea to mix and match. Can it work....... sure. But do you wanna be the one that has to replace the ECM when the driver fries?
***Edit***
Forgot to add, the shape of the injector does nothing to determine the resistance. The older V6 (2.8/3.1) injectors looke EXACTLY like the Quad 4/Twin Cam 2ohm injectors, but are in fact 12ohms. The change in injector shape is from one manufacturer to another. The new 'Slim Line' injectors are Bosch injectors....... I believe the older fat ones where Rochester injectors......
haha ive been looking for something like this for awhile now to explain to people that it isnt ok to use just any injectors haha. thank you
if your gonna be using dsm injectors in your car u might as well go with the ones from evo's coz they r the same but bigger cc's
regular setup - 689awhp/793tq @ 50 psi on race fuel
winter setup - 353awhp/401tq @ 25 psi on 93
1992 Mitsubishi Eclipse GSX - current
1991 Eagle Talon Tsi AWD - Sold
