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recalibrating an fmu for injectors

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Old Jan 27, 2008 | 04:22 PM
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recalibrating an fmu for injectors

I have 325CC injectors and a rrm magnum fuel rail.

As of right now i am using stock injectors with my magnum rail.

I will be using ecuflash to tune it with new injectors.

My initial thouht was to replace my fmu 12:1 with a adjustable fpr. but now i think i may buy a recalibration kit for the fmu and turn it down to maybe 6:1 or 8:1

I was wondering if anyone use a recalibration kit and also how hard it is to install??

which one do u think i need for 7psi with 325cc?

any help would be great. thanks.
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Old Jan 27, 2008 | 10:16 PM
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From: boostville
325cc injecotors is good for about 240whp. I would just install them and remove the fmu and not worry about the adj fpr until i wanted to run 10-12psi and then install one and a guage and increase the fuel pressure .5bar (7-8psi). This will make the be more like 380cc injectors.
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Old Jan 28, 2008 | 01:43 AM
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so u dont think i will need to have more fuel pressure with the bigger injectors?

I guess i could install the injectors and then just tune with ecuflash with those in there. I am worried about blowing up though when i do my test runs.

will just putting the injectors in make me run much richer?
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Old Jan 28, 2008 | 01:18 PM
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^Yes, installing w/o fuel mgmt will result in a rich condition and washed rings...not good. The injectors don't know any better...they'll just open the same amount of time as prescribed by the ecu; but they're larger, so much more fuel is entering the cc. Install, and tune with ECUflash like you suggested.
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Old Jan 28, 2008 | 01:22 PM
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he probably wouldnt even get that far. The car would probably not even idle. It may start and then stumble and stall.

You have more than enough fuel for ~180-90whp
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Old Jan 28, 2008 | 02:41 PM
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I want to run 7-8 psi, i think this is a very subtle advance in injector size, only being 50cc larger.

I know that people who have 440cc's have idle issues, so i am wondering how to have this setup.

I want to be able to use ecuflash to pull fuel or add it where i need, I am wondering if people think i need the added fuel pressure still and it seems i won't.

the more i read about the fmu use the more i feel like it is a silly way to add fuel to a turbo setup...
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Old Jan 28, 2008 | 09:05 PM
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people have idle issues do to either the wrong type of spray pattern or there is to much fuel at idle and they need to lean it out. 440cc injectors at 45psi base is good for ~325whp. Bit overkill. 380cc would be perfect to keep duty cycle low and not have to much injector.
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Old Jan 29, 2008 | 12:43 AM
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thus why rrm uses the rc 370's i think.

Is spray pattern adjustable?

Also, cincy so i understand you clearly i don't need any added fuel pressure to keep my car rich enough for 8 pounds?
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Old Jan 29, 2008 | 09:52 AM
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with 440s yeah the idle is up and down. but it really isnt that bad.
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Old Jan 29, 2008 | 12:57 PM
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Originally Posted by kungfugirl
thus why rrm uses the rc 370's i think.

Is spray pattern adjustable?

Also, cincy so i understand you clearly i don't need any added fuel pressure to keep my car rich enough for 8 pounds?
No, the spray pattern is fixed. You need injectors that match the stock ones and be the same impidence. Stock base fp is plenty depending on the size of the injectors. If you use the ones you have, base is fine for 8psi and you may need to add 7-10psi for 10psi of boost.

to the person above, you need to have someone remove fuel at idle. You are to rich.
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Old Jan 29, 2008 | 09:00 PM
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yeah..im lazy
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Old Jan 29, 2008 | 09:40 PM
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Why not get rid of the FMU altogether and just get some sort of tuning equipment/software to handle the new injectors?
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Old Jan 29, 2008 | 10:06 PM
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what is a fmu? im not sure of what it is
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Old Jan 30, 2008 | 01:44 AM
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tree pm me any questions regarding turbo i can expedite many and help u gain knowledge.

I have ecuflash and tractrix cable. I have yet t use it yet. I also have zeitronix wideband and logging software.

I may just ditch the fmu atogether, my fear is when creating a base tune i blow somehting.
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Old Feb 5, 2008 | 04:12 PM
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your adding larger injectors, you will need to subtract fuel. The time they are open should be the same, that would cause rich conditions, not lean.
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