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REQ_Fuel Calculator air fuel ratio assistance

Posted: Wed Feb 11, 2009 9:09 pm
by Maggott
Hi

This is probably a stupid question but I have searched a lot and not found the answer, even though searching this forum and the megamanual.

In the engine constants it asks for engine displacemnt, injectors, injector flow and air-fuel ratio.

My problem is I have no idea what to set my air-fuel ratio at.
Is this a calculated guess for every car ad how do I find this ratio out??!!

I am especially confused because no one else seems to have this problem!!! :cry:

Any Help would be awesome!

MS1 V3.0 029 code Megatune 2.25p3
1990 B6ZE turbo, 320cc injectors, tdo4h

Re: REQ_Fuel Calculator air fuel ratio assistance

Posted: Thu Feb 12, 2009 6:01 am
by Matt Cramer
The idea behind Required Fuel is that it is the pulse width that would give you the air fuel ration shown in the box at wide open throttle if the engine had 100% volumetric efficiency. Some tuners will set this to the ratio they want to target at full throttle (usually around 12.5:1) and others set it to 14.7:1. There aren't any wrong answers as long as the engine runs well, though your map is going to look really weird if you put in a value less than 10 or more than 20.