Quick question PSI and Stock injectors
07-14-2003, 10:15 AM
#11
you have conving me I got a Vafc....
Now I need to resolve this:
I will use a 10 psi pulley with a Comptech SC which injectors size?
should I usethe Vafc to increse the fuel or I also need to regulate the fuel preasurre pump?
thx
Now I need to resolve this:
I will use a 10 psi pulley with a Comptech SC which injectors size?
should I usethe Vafc to increse the fuel or I also need to regulate the fuel preasurre pump?
thx
07-14-2003, 11:10 AM
#12
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raising rate FMU with larger injectors combined with a 10PSI pulley and use the VAFC to pull fuel out as needed. The vafc only has 8 adjustment point settings at low and 8 adjustment points at high.
The VAFC may not offer enough adjustment points, I could be wrong on this.
You will still have to hit a dyno. The vafc can only pull fuel out with our car, from what I have read + values freak the ECU out and it doesn't know what to do with + fuel values.
I am going with Vortech and I have been reading as many threads regarding this issue.
More current in put would be nice. The threads that I read are all too old.
The VAFC may not offer enough adjustment points, I could be wrong on this.
You will still have to hit a dyno. The vafc can only pull fuel out with our car, from what I have read + values freak the ECU out and it doesn't know what to do with + fuel values.
I am going with Vortech and I have been reading as many threads regarding this issue.
More current in put would be nice. The threads that I read are all too old.
07-14-2003, 12:27 PM
#14
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Originally posted by derryck
I ran 10-12 psi on stock injectors for around 20K miles before selling my car.
I ran 10-12 psi on stock injectors for around 20K miles before selling my car.
Kevin
07-14-2003, 12:29 PM
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Derryck if im correct you had the speedcraft kit right? If so the reason you could do it was the vortech fmu you used.
07-14-2003, 04:04 PM
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Do a search on 440CC injectors and you will find comments that you will need to use the FMU, then fine tune with the VAFC and pull out fuel. There are only 20 threads on the 440cc injector. The raising FMU sounds like it is the way to go, especially at idle. 440CC imnjectors will keep the duty cycle from maxing out, which is what sounds like will happen with stock injectors.
Jenner and Wesmaster seem to have a good amount of experience in this category.
Jenner and Wesmaster seem to have a good amount of experience in this category.
07-15-2003, 08:25 PM
#20
440cc injectors theoretically should affect idle. I say theoretically cause I haven't actually seen it done to see results, B U T if you found a way to lower fuel pressure at idle they could perform exactly like stock.
A FMU doesn't affect idle fuel pressure it only raises fuel pressure when boost is added to give the stock injectors more flow, of course you have to experiment to see how much pressure is needed to give the right flow. The same thing would need to be done if you found a way to lower the pressure at idle.
Right off hand I don't know any way to do it other than a different regulator. But, on paper, you could make 550's work.
A FMU doesn't affect idle fuel pressure it only raises fuel pressure when boost is added to give the stock injectors more flow, of course you have to experiment to see how much pressure is needed to give the right flow. The same thing would need to be done if you found a way to lower the pressure at idle.
Right off hand I don't know any way to do it other than a different regulator. But, on paper, you could make 550's work.