Fic 850s running at 87% duty cycle with fp green at 20psi???

[bsbllfit7]

So i was under the understanding that the fp green wouldn't be maxing out the 850cc injectors but they are already running at 87% with 0 timing gain or pull. I did have to add quite a bit of fuel to help with knock. My WOT SD cells are around 108-114 or so and this seemed to help eliminate the knock. Knock sensor is functional and i do have a wideband in the mail. I am just wondering why the IDC's are so high for a relatively small amount of boost. I was under the impression that you could get 23-25 psi. Also this is a 2.4l and i do realize that because of that it will require some extra fuel. Lets see what the experts have to say. I didn't save my log from tonight but will take another one tomorrow.

 

[PieEyedPiper]

What makes you think you can't get near 23-25psi before you run out of injector? You might be in the 90's but it's not a given that you'll be over 100%. Honestly, though, I would have expected maybe a flat 80% but that's just me and I don't know jack about speed density.

 

[bsbllfit7]

But aren't you not suppose to run injectors over 85% or so? Also I forgot to mention this is a 9:1 compression engine and 2.4l so it probably will require some extra fuel to suppress knock. Just want to hear what people have to say. And also what size injectors should I go to for e85 with this setup

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[snowborder714]

Post logs. A 3rd gear pull would be great along with an idle log.

 

[Black-Out]

But aren't you not suppose to run injectors over 85% or so? Also I forgot to mention this is a 9:1 compression engine and 2.4l so it probably will require some extra fuel to suppress knock. Just want to hear what people have to say. And also what size injectors should I go to for e85 with this setup

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Yea you're right you shouldn't exceed 85% because the injectors won't have enough time to close beyond that.....With your engine being a stroker 2.4 and 9.0:1 comp, your volumetric efficiency is probably 30% or more higher than stock....on a 2.0 liter 850's would more than likely suffice with a walbro pump or larger ......but with your set up you probably need 1000's for high octane and if your going E85 plan on going to 1600 or more for the 40% increase in fueling requirements.....It may seem drasticly huge at first but you'll appreciate the wiggle room later should you decide to use a turbo with a little more flow then what you already have....especially with a 2.4 liter....
Your best bet though is to calculate BSFC (brake specific fuel consumption) and go on from there to get the fuel requirements for your application....