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Dry Nitrous and Injector Duty Cycle

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Old 06-16-2017, 09:19 PM   #1
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Default Dry Nitrous and Injector Duty Cycle

Brought my stock motor, trans & converter 2k SS to the track last week and ended up running a better time than expected. [email protected]
Only spraying a .55 jet through the MAF sensor. Here's the odd part. Stock injectors and efi live only shows about 82% duty cycle. Shouldn't I be close to 100% with 120ish shot?? How can I tell if it's a false reading ?

Thanks for any ideas,
Shawn

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Old 06-18-2017, 01:14 PM   #2
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No thoughts ?
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Old 06-18-2017, 01:46 PM   #3
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Default Injector Duty Cycle

Hi NX20, yes you have the BEST CORRECT DUTY CYCLE for DRY NOS.
Could this be the reason ?

I manufacture/design Fuel Injectors.

MY REPORT is the most common, BEST, Duty Cycle is from 60-85% with my preference of 80-85%. (NON GDI)

WHEN the Duty Cycle is past 92% the Fuel Injector may STAY OPEN, may operate at x % or other, NOT GOOD.

When at 100% there is NO ACCOUNT for RPM changes, NOT GOOD.

WHEN you state "through the MAF sensor" this could cool the Hot Wire ?

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Old 06-18-2017, 03:34 PM   #4
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Originally Posted by 2000ssNX20 View Post
Brought my stock motor, trans & converter 2k SS to the track last week and ended up running a better time than expected. [email protected]
Only spraying a .55 jet through the MAF sensor. Here's the odd part. Stock injectors and efi live only shows about 82% duty cycle. Shouldn't I be close to 100% with 120ish shot?? How can I tell if it's a false reading ?

Thanks for any ideas,
Shawn
so the duty cycle is calculated based on how much fuel is being used. But you need something to check it against.

My assumption: Lower duty cycle than expected equals not all incoming air/nitrous being captured by MAF.

Advise: Add a wideband. That will tell you where you are from a fueling perspective. Adjust spray nozzle position to achieve optimum g/cyl calculation.

On a dry set up, nozzle location and angle can have a huge impact on how MAF registers it.
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Old 06-18-2017, 05:57 PM   #5
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I wonder if the fact I Mixed VP Unleaded Extreme 110 octane with a specific gravity of .845 could have richned it enough to cover up lack of injector ? Of course I guess it possible that a previous owner had they opened up some as well...

Definitely going to get a wideband and install it before playing around anymore.
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Old 08-24-2017, 08:43 PM   #6
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On a dry set up, nozzle location and angle can have a huge impact on how MAF registers it.
Is there any "common" way that is best, or does it vary based on how the intake track is setup? I have been "kicking around" throwing a small (say 50hp) dry shot on my truck, out of site, just to run a # from someone.
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Old 08-28-2017, 06:51 PM   #7
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Default NOS = 10% HP/ Fuel = 10% increase

Hi NX20, good tech, your report of a 10% N20 HP "shot" AND a 10% fuel increase.

SPOT ON

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