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Old 04-13-2014, 02:30 PM   #1
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Default Req fuel constant question

Im confused about the req fuel setting on the engine constants page. I always hear people complaining that it is too low when they are at 7 ms but with my calculations im at 5.8 ms. i read on another thread that on stock injectors you should run 13.2 ms. Am i wrong in assuming with bigger injectors your req fuel goes down? I have a 1.6 turbo running 11 psi and i use rx7 460cc injectors.
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Old 04-13-2014, 05:14 PM   #2
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..What?

Set required fuel with the built in calculator and then leave it be.


1800cc or 1600cc x 4 cylinders x 460cc injectors (in your case)

Should be 5.8 or 6.6 depending on 1.6 or 1.8.
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Old 04-13-2014, 05:41 PM   #3
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The dead time (injector opening time or injector lag time) has to be set right or your car wont run right with the correct req_fuel. My ms1 had a base map for rx7 460s when I got it and the req_fuel was 7.4 and it ran fine. The reason it ran fine is because the injector opening time was incorrectly set at 1.1 or 1.2 millisecs. The VE map was close and autotuning compensated for the req_fuel and opening times being off.

Opening time on rx7 460s should be about 1.6ms, iirc.
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Old 04-13-2014, 09:25 PM   #4
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Quote:
Originally Posted by sixshooter View Post
Opening time on rx7 460s should be about 1.6ms, iirc.
Are you positive about the 1.6ms? That goes against everything that I've searched and came up with.. Brain uses 1.2 some other guys go as low as 0.75. I'm currently sitting at this, but couldn't tell you where I actually got them from..
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Old 04-14-2014, 09:28 AM   #5
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1.6ms? I idled at 1.6ms.

deadtime for rx7 460cc injectors is around 1.0-1.2ms.




The req_fuel is just a multiplier.

PW = REQ_FUEL * VE * MAP + Injector open time

Req_fuel could be 10 or 5 or 69 for all it matters, so long as the VE table is scaled accordingly.
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Old 04-14-2014, 11:26 AM   #6
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I could be wrong.
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