injectors maxing out

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triple j

Member +
my injectors are maxing out, at 5000rpm the are at 80% from there to 7000rpm the reach about 110% total duty cycle, my afr is around 10.8/11.0 on wot, should i fit 370s or some thing like that.
 
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triple j

Member +
Its td04 with emanage blue, the pump is a 255lph 6 months old, i will get a new fuel filter i never changed it
 
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AdamB

Member +
This the one you mapped yourself mate? Yeah lean it out to around 11.8 at WOT, you'll prob find you will pick up better throttle response and more torque up higher in the rev range. Stock injectors should be fine upto around 260bhp mate. You may want to try get hold of a fuel pressure regulator as it allows much more scope for tuning. Don't increase beyond 4 bar though as it will be very difficult to control the injectors.
 
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triple j

Member +
Yeah this is the one alright, i will trim it back to 11.8 and see how the poor injectors are doing then, i feel 11.8 would be as far as i would like to trim it back to.
 
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AdamB

Member +
Try 11.6 mate, 11.8 is still pretty safe for 1 bar.
If that doesn't change anything, swap the fuel filter and check the feed voltage at the pump, generally around 1 volt lost loses around 10% of fuel flow from the pump.
 
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triple j

Member +
just checked fuel pump strong 12 volt constant there so thats ok, i will go with new fuel filter tomorrow then trim a little fuel if the roads are good.
 
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AdamB

Member +
No probs mate. Let us know how you get on.

I don't know what other tuners do when using the likes of EMB/EMU, at a guess they ensure the engine is fitted with a fpr which allows the stock injectors to flow much more than at stock pressure. Stock fuel pressure is 2.3/2.4 bar. Increasing this to 3.0 bar will prob give a healthy gain in flow rate and you'll be able to reduce the duty cycle.
 
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SalmanGT

Fresh Recruit
its always batter to use, bigger injector, i have seen people using 120% duty cycle.

low fuel pressue=>higher flow of fuel==>higher life span ==>low amp draw by fuel pump=> safer tune.

ur current fuel pressue with stock fpr is going till 50psi (35psi+14.7)
 
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AdamB

Member +
Not necessarily true, if you run too low a fuel pressure the fuel doesn't have enough force to atomise into the air charge, leaving you with poor running conditions and hard to control combustion at the right time. It's advised fuel pressure does not drop below 2 bar before this starts to happen.
 
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Rev

Member +
I have seen tests showing better torque with higher fuel pressure which is a big plus .

Re fuel pressure how does that work with the starlet which Ive seen stock fpr base pressure is 27.02 psi which is less than 2 bar ( 29 psi ).
 
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