Injector duty cycle.

[neil_jdmr]

Where is the percentage level of duty, where it starts becoming dangerous for detonation.
 
Iam running pretty much just bolt-ons, Full exhaust inc downpipe/decat etc, arc smic, hks pods and pfc mapped by pip, boost set at 0.8 bar.
 
Power is somewhere between 300-330hp depending on boost
 
Usually my inj duty reads around 85-90% on full throttle(0.8 - 0.86) but as the pfc doesnt regulate boost very well on occasion i have seen over 0.9bar and the highest ever recorded duty i have is 93.8%.
 
Is this level still ok??
 
I do not plan on anymore power, but i do want it to run happily for a while yet.

[SiH]

I\'ve always been told that 85-90 is the most you should push it. I was running 343 on stock fuel and hitting 94, which is why i upgraded.

It worried me putting that much strain on the injectors, so i went for 1680 buckets for peace of mind

[Bobbit]

Would an uprated fuel pump help with this?

[hairyhoover]

nope.. higher fuel pressure or bigger injectors plus a remap would

[Bobbit]

So uprated fuel pump, a pressure reg, and a remap would work on standard injectors? Or would you need large injectors? I\'m getting a remap soon and want to make to most of it. Sorry for Hijack Neil :Thumbsup!.

[Kash_]

An uprated pump, fpr and standard injectors should be fine for upto 380bhp

[neil_jdmr]

So back to the question, Do i need a fpr and fuel pump or am i ok as i am.
 
is duty in the 90\'s too much, even if it only creeps into it on very cold mornings.

[Bobbit]

I was told 85% was about the limit bud, anything over runs the risk of the injectors being open all the time but then i\'m obviously no expert lol. Dont think Pip would have mapped it without a safety net, so to speak, tho.

[BlitzBoy]

The ones that sometimes stick open or shut are the bored out 850 > 1300s.
When I ran on stock injectors I used to hit 95 to 99 percent quite frequently.
85-90% will do no harm to the injectors themselves, the reason for the 85% limit is to allow some degree of safety in regards to the tune when you hit certain conditions where the ECU will use some of the fuel correction settings eg in regard to air temp,oil temp etc .

The first upgrade to any fuel system is the pump which will make the afrs richer if the map is not touched, you will need to remap then you will see injector duty go down to some degree.

[Prof]

The two biggest problems with running Injectors to close the their limit are:
 
1) Heat - the coil being driven on for such a long period will cause a lo of heat dissipation and possibly reduce the life or reliability of the injector.
 
2) At duties close to 100% the injectors become non linear - and it\'s possible that at very high duty below 100% the injector can\'t operate fast enough and enters a much more dangerous half on and half off - as the valve cannot open and shut fast enough - it effective sits half open which gives a serious fuel drop right when you are on boost, if the injectors then hit 100% they will lock open - so you get your fuel back, but the damage will already be done.
 
I\'ve heard that 85% is a good limit to work to, you can hit higher percentages for short periods of time - as you won\'t be driving the car on full boost all the time I would have thought.

[m1tch]

Im going to aim for about 85% max on mine, its always best to not max any componant out, which is why im upgrading to bigger injectors, to run a lower duty cycle, but the same sort of flow, and also means it can be upgraded in time