I mean couldn't you just set the fuel pressure to 58 psi unhooked from a vacuum/boost source so when you hook it up it will drop to around 45 psi while at idle? That would let you go up to 58 psi at 0 and still yield a 1:1 ratio while in boost. Then wouldn't pulling fuel up top with the map clamp lower the pressure back down due to the map sensor not seeing the voltage for the amount of boost you are actually running? Someone chime in and correct me if I'm wrong.
i thought stage 3 fuel system was 80psi or 75psi something like that....ive seen big turbos here on the forums on stock injectors with a return line so im shure with the stg2s you would be fine
Right, but you see setting it to a 58 PSI pressure @ 0 psi the 1:1 ratio would raise the boost enough so that you would be at 75 psi at 17 psi. That is as high as the stage 3 setup goes. I figured I could clamp out the rest of the fuel for whats not needed.
there is too big of a fluctuation in how much fuel needs to be taken out and certain rpms with big turbo's......so an safc or dtec will be needed.....but in thought why can't you turn the static lower than 58?.......you can.......even if you hooked the vac source to after the throttle body so the reg would see vac at idle it would still run the same max psi......yu need to just hook it directly to the tip vac line on the cold pipe and keep dropping the static pressure till its a safe afr........but driveability might suffer
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sorry guys but the car is for sale....all out first gen is in the works
I mean couldn't you just set the fuel pressure to 58 psi unhooked from a vacuum/boost source so when you hook it up it will drop to around 45 psi while at idle? That would let you go up to 58 psi at 0 and still yield a 1:1 ratio while in boost. Then wouldn't pulling fuel up top with the map clamp lower the pressure back down due to the map sensor not seeing the voltage for the amount of boost you are actually running? Someone chime in and correct me if I'm wrong.
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the fuel system im running on a s3 turbo is walbro255, boomba rail w/ redstar return line, 650cc DW injectors with a base pressure of 50psi, referencing with boost to a max of 75psi fuel pressure
tuning with afc neo, pulling approx 20-22% across mid to top end
i suppose i should drop my base pressure to approx 45psi and retune from there as to avoid excess timing at high boost
this is basically my plan.
just installed the s2 injectors last weekend (throwing a #3 misfire now), guessing its a bad plug..
next weekend the rr-fpr, base pressure will probably be closer to 50lbs.. depending wide-band reading
no matter what you tune the fpr to the afr's will always back down to the factory settings at idle...somewhere around a 14.7-15.0.....
yes, the pcm will pull back fuel, but then if the injector size isnt matched to the what the pcm thinks it is running the short term/long term fuel trims will be a bit off, resulting in pulled timing IIRC. scaling back the injectors at idle should correct this IIRC
Just put the return line in before the S3 Rail & dial back the fuel pressure to say...70psi. S3 runs at a constat 75psi from the tank to the rail where the pcm then tells the rail how much fuel to pull out. By reducing the pressure before the rail the pcm still thinks it's getting the same 75psi & does it's usual thing when in reality you leaned it out some.
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John Ruckman
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is this a good setup for fuel on stage 3 turbo?
Linear Mode
