Inj Duty And Gt35/40

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01-14-2004, 10:17 PM

#11

IGY

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Join Date: Dec 2001

Location: Okinawa Japan at McDonalds

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Quote:

Originally Posted by Badog' date='Jan 15 2004, 12:37 PM

Where are you? What was the temperature? Temperature correction factors are in play, I am sure.

Just as a side note: 93% inj duty on 4100cc of inj would equal about 460RWHP at 12 psi. That does not fit the behavior of a mild port engine with a GT3540.

Regards

But he doesn't have 4100cc of inj because he is running 40 psi of static pressure. We also don't know what exactly his port looks like, and the last time I checked .9 was closer to 13psi. 400-425 is very doable at that boost and that inj duty. I do not call having to turn up fuel pressure or get bigger injs a problem. If the car feels good, and has a good steady AFR it is probably right.

01-14-2004, 10:38 PM

#12

Badog

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Quote:

Originally Posted by IGY' date='Jan 15 2004, 10:17 AM

"But he doesn't have 4100cc of inj because he is running 40 psi of static pressure."

Huh?

850+850+1200+1200=4100 total inj, or did I miss something in my math?

Good old Max Cooper has a good fuel calculator on his site. Plug in the 40psi and the other values and see what you get.

Okay, I thought I saw boost reported on the PFC, which would have been Kg/cm and would have equaled boost in the 12's. Based on my AVC-R and PFC, they both run spot on with each other so I would wonder if the boost was much into the 13's. You have a AVC-R and a PFC, IGY?

He said mild port. Who the heck knows what any of our ports flows? Too bad it's not as precise as it is in the pissdon world.

Igy, you doubting it's the temperature correction factors pushing the duty cycle up? I'm all ears if you know better.

01-14-2004, 11:14 PM

#13

IGY

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Join Date: Dec 2001

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Quote:

Originally Posted by Badog' date='Jan 15 2004, 01:38 PM

I used the same fuel calculator, but I used a BSFC of .70 (don't ask me to get this # scientifically) because with this fuel calculater it gives #'s closer to actual dyno #'s I have seen and compared with. Not everyone's setup is the same and it is very difficult to predict, without seeing the car in person any of the 50 billion things that can be different. If he dyno's his car and gets 425rwhp at 13psi and 93% inj duty it would be totally acceptable and very likely in my experience.

Yep got a pfc. Yes .9 is 12.8 psi which is "closer to 13". Isn't funny how changing one little # can make you go from 477 to 422 on that hp calculator? I'm not telling anyone their idea is wrong I am just saying that it is possible that there is nothing wrong with the car.

Could be temp correction, but that would still mean there is nothing wrong with the car. 11/1 afr at 93% duty on 4100cc of fuel and drives smooth = fast car.

01-14-2004, 11:22 PM

#14

IGY

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Join Date: Dec 2001

Location: Okinawa Japan at McDonalds

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Some off the wall probs that it could be;

850's are flowing less than 850cc (dirty/old)

fpr is not 1 to 1 and is more like .9 to 1(seen this on a SARD fpr)

pump is falling off (not likely with the Apexi gtr pump)

could be bad wiring to pump (low voltage=lower output)

Just a couple off the top of my head.