NY Twin Turbo
All the good stuff.....Times 2.
- Joined
- Dec 10, 2014
I always thought I was clear on this. But I feel I have to double up on the info.
When XFI gives you the current AF number as read from it's wide band, it only gives you AF as most people know it to be with gasoline. Correct? So it converts the Lambda number into an AF number for the average dumby who has no idea that a perfect burn is not always with gasoline and that means it's not always 14.7 to 1. In actuality, it doesn't make a calculation based on the physical amount of fuel being introduced into the calculated air mass. Right?
What I'm getting at is this...... If I put my fuel energy constant at .680, and leave my AF map alone, and add true and tested E-85 to an empty tank.........why can't I tune using the old AF numbers for rich/lean reference, since this is what I'm used to doing? Lambda is what the computer really sees anyway. Now all I should have to do is add 3 or 4 degrees of timing globally to the entire spark table. No?
If I used to run an 11.4 AF (also known as Lambda .78) at 20 psi and now I change the FEC to .680, I should still leave the AF at 11.4. This will still give me Lambda .78. Because if I change the AF to 7.6 I'll drown the motor and it won't be at Lambda .78. And this is the real number I'm looking for.
I understand there may be a bit more to the actual tuning. Maybe warm-up, cranking and starting, ect.... But, all things being equal (except for timing) nothing should change. I easily have the fuel system for it.
Of course I can just use the XFI in lambda mode, but since I'm more familiar with AF numbers why can't I just keep using it this way.
Am I way off here. Or is it nearly this simple.
When XFI gives you the current AF number as read from it's wide band, it only gives you AF as most people know it to be with gasoline. Correct? So it converts the Lambda number into an AF number for the average dumby who has no idea that a perfect burn is not always with gasoline and that means it's not always 14.7 to 1. In actuality, it doesn't make a calculation based on the physical amount of fuel being introduced into the calculated air mass. Right?
What I'm getting at is this...... If I put my fuel energy constant at .680, and leave my AF map alone, and add true and tested E-85 to an empty tank.........why can't I tune using the old AF numbers for rich/lean reference, since this is what I'm used to doing? Lambda is what the computer really sees anyway. Now all I should have to do is add 3 or 4 degrees of timing globally to the entire spark table. No?
If I used to run an 11.4 AF (also known as Lambda .78) at 20 psi and now I change the FEC to .680, I should still leave the AF at 11.4. This will still give me Lambda .78. Because if I change the AF to 7.6 I'll drown the motor and it won't be at Lambda .78. And this is the real number I'm looking for.
I understand there may be a bit more to the actual tuning. Maybe warm-up, cranking and starting, ect.... But, all things being equal (except for timing) nothing should change. I easily have the fuel system for it.
Of course I can just use the XFI in lambda mode, but since I'm more familiar with AF numbers why can't I just keep using it this way.
Am I way off here. Or is it nearly this simple.