AFR Ratio Help to understand (log)

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AFR Ratio Help to understand (log)

Postby c00l » Sat Mar 24, 2018 6:59 pm

Hi,

is there anyone that could help me to know how much is A/F ratio of this log?

I'd need the formula to calc it. I had it but I didn't find it anymore :-(
Engine is 1.9 4 cyl


sec giri mm³/i mm³/i mbar mbar %

Time RPM Fuel inj Fuel req Pressure Pres targ Throttle

481,51 2644 97,542 103,383 2406 2351 42,27
483,06 2813 106,326 110,547 2576 2790 53,46
484,61 2986 110,496 110,547 2737 2800 43,49

Thank you!

Fiat Multipla 1.9 120CV ---> 190CV
GTB2056V Turbocharger, downpipe and straight defap, Ecu remap, Clutch kit stage 2 SMF, 5th gear 33/43.
Next step: 8lt FMIC intercooler, sided exhaust, water-methanol injection, water cooler system for intercooler.
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Re: AFR Ratio Help to understand (log)

Postby jurebv » Sat Mar 24, 2018 8:52 pm

Depends on many things like your exact engine code, altitude you are driving at...many more...etc but I would say around ~ under 15 AFR

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Re: AFR Ratio Help to understand (log)

Postby c00l » Sun Mar 25, 2018 11:11 pm

I found it: (engine displacement/n° cyl)*(1.15 o 1.2) * 0.8 * turbocharger pressure= mm3 intake air.

Intake air/458,40=turbocharger pressure to have optimal AFR

:thumbup:

Fiat Multipla 1.9 120CV ---> 190CV
GTB2056V Turbocharger, downpipe and straight defap, Ecu remap, Clutch kit stage 2 SMF, 5th gear 33/43.
Next step: 8lt FMIC intercooler, sided exhaust, water-methanol injection, water cooler system for intercooler.
c00l
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Location: Italy

Re: AFR Ratio Help to understand (log)

Postby jurebv » Mon Mar 26, 2018 6:48 am

Its not fixed values like you posted- 1.15 or 1.2 reffers to air pressure which depends on altitude,temperaturr, humidity...0.8 would be VE (Volumetric efficiency) which also varies from engine to engine and rpm

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Re: AFR Ratio Help to understand (log)

Postby c00l » Mon Mar 26, 2018 11:01 pm

jurebv wrote:Its not fixed values like you posted- 1.15 or 1.2 reffers to air pressure which depends on altitude,temperaturr, humidity...0.8 would be VE (Volumetric efficiency) which also varies from engine to engine and rpm


not fixed, true. But the calculations are correct and the variations are not so significant. it's a good indicative calculation. :ugeek:

Fiat Multipla 1.9 120CV ---> 190CV
GTB2056V Turbocharger, downpipe and straight defap, Ecu remap, Clutch kit stage 2 SMF, 5th gear 33/43.
Next step: 8lt FMIC intercooler, sided exhaust, water-methanol injection, water cooler system for intercooler.
c00l
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Joined: Sun Feb 25, 2018 7:05 pm
Location: Italy

Re: AFR Ratio Help to understand (log)

Postby chli1976 » Tue Mar 27, 2018 6:01 pm

For VAG i do it as this, but not sure if it is the right way

engine size (ccm) / cylinder * turbo pressure / AFR = mg injection qunatity

2000 / 4 * 2,3 / 17 = 67,65

So you should inject 67,65mg when you have 1,3bar boost.

Comments are welcome

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Re: AFR Ratio Help to understand (log)

Postby jurebv » Tue Mar 27, 2018 9:55 pm

Any car not just VAG : (cylinder ccm * boost pressure *engine efficiency * air density ) / IQ = AFR. Engine efficiency varies on rpm, air density varies on temperature,humidity and altitude.

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Re: AFR Ratio Help to understand (log)

Postby c00l » Mon Apr 02, 2018 8:22 am

chli1976 wrote:For VAG i do it as this, but not sure if it is the right way

engine size (ccm) / cylinder * turbo pressure / AFR = mg injection qunatity

2000 / 4 * 2,3 / 17 = 67,65

So you should inject 67,65mg when you have 1,3bar boost.

Comments are welcome


Tho only one I think relust is mm3 not mg.

engine size (ccm) / cylinder * turbo pressure / AFR = mm3 injection qunatity

However the way is right for me :thumbup:

Fiat Multipla 1.9 120CV ---> 190CV
GTB2056V Turbocharger, downpipe and straight defap, Ecu remap, Clutch kit stage 2 SMF, 5th gear 33/43.
Next step: 8lt FMIC intercooler, sided exhaust, water-methanol injection, water cooler system for intercooler.
c00l
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Location: Italy

Re: AFR Ratio Help to understand (log)

Postby jurebv » Thu Apr 05, 2018 9:59 am

are you sure AFR is the same when calculating in mm3 and not mg? i think AFR in mg is not the same as AFR in mm3, also VE is not included in your formula

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Re: AFR Ratio Help to understand (log)

Postby DW1976 » Sun Apr 15, 2018 9:52 am

there is a difference
regards

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