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Rb20 Running Lean

aahh32

By aahh32,
in South Australia

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Race__24 Experienced

Race__24

Posted
Posted (edited)

Isn't an AFR of 13 more rich than an AFR of 12. I thought it was the lower you go the leaner it gets and there for the graph looks about right, starting at 13 and getting richer.

Correct me if I'm wrong.

Edited by Race__24
D_Stirls Veteran

D_Stirls

Posted
Posted (edited)

you are wrong

Air/Fuel ratio; You always refer to the air mixed with 1 part fuel in the ratio and if you have 14 parts air (i.e. 14:1) then you will have more air than if you have 12:1. Lean means that you have less fuel and rich mean that you have more fuel.

It depends on the engine but generally 12:1 is what is looked for under load 12.5 is starting to get dangerous. Under light load (closed loop)the ECU aims for 14.7:1 as this is the correct amount of air to balance the Fuel oxidation reaction (If you have done chemistry you will know what this means).

As the AF Ratio gets leaner the cylinder temps begin to rise, if they get too lean then that is where you start getting detonation problems or you start melting pistons or damaging turbine parts.

What the extra fuel does is lower the combustion temps by producing a cooler burn and the extra fuel also removes some of the heat from the cylinder.

Edited by D_Stirls
aahh32 Community Regular

aahh32

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  • Author
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i replaced the fuel filter yesterday and started it up and it ran a hell of alot smoother but still going to replace the injectors aswell before i put it on the dyno to check the AFR's if anybody has any gtr injectors let me know.(might aswell replace them with something a little better than stock if im doing it anyway)

D_Stirls Veteran

D_Stirls

Posted
Posted

you can't just fit GTR injectors and expect it to run, you will need to wire in the dropping resistor from a GTR as well and it will need to be tuned, and when i say tuned a proper tune (changing the fuel maps) not just whacking it on the dyno and playing with the CAS. Expect to pay $450-$600 for a proper tune. So with injectors and resistor your looking at around $900.

aahh32 Community Regular

aahh32

Posted
  • Author
Posted
you can't just fit GTR injectors and expect it to run, you will need to wire in the dropping resistor from a GTR as well and it will need to be tuned, and when i say tuned a proper tune (changing the fuel maps) not just whacking it on the dyno and playing with the CAS. Expect to pay $450-$600 for a proper tune. So with injectors and resistor your looking at around $900.

yeah i realise i have to wire in the resistor thats not a problem and i was planning on getting it chipped when i take it in for a tune and a dyno check.

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