93% Injector Duty

[chrisJDM]

Was having a blast around last night and checked the Power FC Commader and i managed to fit 93% Injector Duty at one point, ive heard before its not best to venture over 90% to be safe, so what do i do??? do i need to replace my secondaries with summit bit better?

[dubber91]

93% injector duty isnt favourable.....i always used to work up to 85% and thats it: it means your injectors arent closing (due to opening and closing time of the injectors) and are essentilly staying open each revolution.

Bigger injectors is the only way to go really. What is your AFR like at 93% injector duty?

[Jit]

as dubber says really...above 85 isnt really good as the injector response vs times gets non-linear as you go above 85

[jonrx7uk]

What is your AFR like at 93% injector duty?

Can you check the AFR using the PFC?

Jon

[Laeeq]

Mine goes up to 98% if i give it a full woot but not all the time i do that....Max @ Reworx mapped it and was told the AFR was ok at that point :2eek but i do run WI too that also helps...I am running 1.12 bar boost on high boost setting and low at .85 and at this boost setting the injectors are at round 85% + WI...  :2eek

[Ricco_04]

It doesn\'t help with the much colder air (please come back summer! :o )

You may have also have had a spike - what max boost did you hit (and what are you set to run at?)

I also go by the 85% rule.

[dubber91]

if your nicely rich at 98% Duty cycle you got no worries. As jitesh says, it becomes non linear: so fuelling is less predictable. BUT it should still remain fairly repeatable i.e. should deliver that fuel regardless no matter how many times you do it with those air temp/boost correction values.
So long as your rich, (depends where rev, boost, load wise as to HOW rich) it should be fine.

Steve

[gsb876]

93% is deffo high, either bigger injectors or a bigger fuel pump will do the trick.

What boost are you running too chap ?

[dubber91]

its not ESSENTIAL to do any of that if your not leaning out :2Rolleyes
despite a common beleif that injectors \'burn out\' if you run them at high pulsewidths/RPM (duty cycle) ive never experienced one having done so.
ESPECIALLY given that you only reached that duty once on a burn.
The problem with all these little electronic playstation gadgets is that you can end up worrying yourself: theres information in there dangerous if in the wrong hands.
All an engine needs is air and fuel (and in this case it likes boost too). If whats coming out of the exhaust contains too little oxygen then your chucking more fuel in than you need.
Too much oxygen and your lean.
ignore everything your little bleeping/flashing/scrolling/fiddling station tells you and so long as you arent leaning out then its fine.
High load and high boost conditions call for AFRs of down to around 12.5-13:1.

[royston1xx]

ignore everything your little bleeping/flashing/scrolling/fiddling station tells you and so long as you arent leaning out then its fine.
High load and high boost conditions call for AFRs of down to around 12.5-13:1.[/QUOTE]

Run that lean on a boosted rotary and you will get a nice big bill and will have to sell your flashing gizmos that were warning you in the first place to pay for your rebuild lol.:eek

[dubber91]

sorry mean 12:1 lower figure. it still depends on How much boost, what RPM and what load. At the end of the day a stock rotor running 12PSi boost aint gonna need to be as rich as a high-po motor running 1.5-2bar is it

[chrisJDM]

I have been having boost problems since i have the car and only recently have been getting it up to 0.7 bar at most although the other night went for a ragg and it hit 0.89 bar and the injector duty was 93% .  Standard fuel system, apexi power fc, im looking to in the near future uprate injectors, fuel pump, fuel rail, intercooler etc and also get the rats nest replaced with new tubing to sort out the ongoing boost issues.

[Ricco_04]

So (as I said above)  this duty was caused by a spike! :Thumbsup!

(possably maybe! :Ladys-man )

[chrisJDM]

yes you are correct im thinking :god

just ordered a GReddy FMIC, which is going to be followed by a new fuel system :Tongue1

[Ricco_04]

Sounds good! :cool

Would a boost controller help with this issue?