Yeah, totally agree... injectors are cheap in general, so simple/easy/wise to replace in the long run. But I do know there are a lot of people who try to do a budget 200 horsepower... so for them it would matter a bit, but in general for a build up I usually recommend to run 550's. We sell our kit with all hardware, connectors, etc for in the same neighborhood... they are low impedance so only work with a Haltech or AEM or Microtech. And also a good/simple trick on your part for the stock FPR to get more headroom when needed.
Larger Injectors For Forced Induction
- Thread starter LinuxRacr
- Start date
Maxx Mazda
Contributor
- :
- Stock P5
Why run a low impedance injector? My Haltech can do both, but is there a specific advantage to any one type?
Nope... just what is available/cheaper. There may be some advantages but I'm not familiar enough to know what they might be. Just happens that the 550's we use fit okay and are pretty cheap. We sellt he full kit for 255 with 4 injectors, clips, mounting hardware etc.
Maxx Mazda
Contributor
- :
- Stock P5
That's a prett sweet deal. THat's why I went with the STi's. Direct PnP, so all my wiring mods were done under the dash at the Haltech.
Can you elaborate more?
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
a little late to the game there, coach...
Peak/Hold = Low Impedance (high current)- these are faster in response but generates more heat.
Saturated = High Impedance (low current)- these are slower but run colder.
Typical Reaction Times:
Saturated = 2ms
Peak/Hold = 1.5ms
Typical Current flow (Ohm/Voltage):
Saturated = 1 Amp
Peak/Hold = 4-2 Amps
Saturated = High Impedance (low current)- these are slower but run colder.
Typical Reaction Times:
Saturated = 2ms
Peak/Hold = 1.5ms
Typical Current flow (Ohm/Voltage):
Saturated = 1 Amp
Peak/Hold = 4-2 Amps
Also...I didnt wanted to add to the flamewars because it was a little off. But just for the record.
We all know that most, if not all dont rev the engine over 8000rpms, that is why we could run 100% open time on the injectors without risk. Its over 8k rpms when the response time becomes critical and thats why we can run big HP with small injectors...we make peak HP at low rpms.
Once you start working the head, cams and stuff, more fuel flow will be needed which can be obtained by just raising fuel pressure or with longer open time.
Moving the peak HP to a higher rpm will require even more flow obviously. But then you add the response time criticality to the graph.
By the way, you can use Peak/Hold injectors with stock ecu. The inverse will not work. (you cannot use saturated in a peak/hold circuit)
We all know that most, if not all dont rev the engine over 8000rpms, that is why we could run 100% open time on the injectors without risk. Its over 8k rpms when the response time becomes critical and thats why we can run big HP with small injectors...we make peak HP at low rpms.
Once you start working the head, cams and stuff, more fuel flow will be needed which can be obtained by just raising fuel pressure or with longer open time.
Moving the peak HP to a higher rpm will require even more flow obviously. But then you add the response time criticality to the graph.
By the way, you can use Peak/Hold injectors with stock ecu. The inverse will not work. (you cannot use saturated in a peak/hold circuit)
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Maxx Mazda
Contributor
- :
- Stock P5
Idgrasil is right. My dyno sheets showed peak power at only 6200 RPM. I revved it out to almost 8K too to see, and it just dies up there.
did you have any head work done? custom valves and such?
There is a PM feature?
Thats my point....You along with many others..don't give much info...do you know how many 440cc injectors are out there.....?
I know you are referring to the WRX..but the next guy may not.
Someone with some good solid info need to make a sticky on injector info...WITH PICS!
Hell...I'm not sure I even know what you are trying to say here.
