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Discussion Starter #1 (Edited)
Help with fuel controller

First of all I have the HKS AFR.
after reading both the HKS AFR and the Apexi AFC manual, I think they perform the same fuctions. I can increase throttle response % and fuel curve at selected 11 RPM points, -50%+50% 1 pt increment.
So is there a recommended RPM points that I should dial in more fuel to accomodate 18psi?
I wanna dial in more fuel after 4000RPM to provide the engine with more fuel to see if it will lower my EGT a bit, I think my engine is running lean so I am in the process of finding out why.



thanx

Jonas
 
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Discussion Starter #3
if you don't know what you are doing, you shouldn't be tuning your a/f. a/f tuning is a science and if you are good at it you will reap many rewards, one small miscalculation however and you can kiss your engine goodbye. and yes, it can happen that quickly.

also, if you are having other problems (ie abnormally high egt's) you should get that problem figured out before you start playing with your fuel mix. the afc will more then likely compound your problems.
 

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The above is correct.

If you are stock MAF and stock fuel at only 18psi, you should not be leaning out.

You might be able to richen up the car with an SAFC, etc. However, you will be hiding the problem, not correcting it.

For example, lets say an injector is somewhat clogged... that cylinder is running lean, throwing off your EGT's... by richening up all the other cylinders, your EGTs will drop, however your lean cylinder will not get any better.

The false sense of safety that the lower EGT's are giving you may prompt you to raise the boost, and finally, lean out the cylinder to much and go boom.

You need to find the problem, and make sure everything is working great before you modify the fuel curve.

Once you do that, you can predict when things arent running properly because you will have had a solid base line to adjust from.

I'm on a small single with stock fuel. I'm actually pulling out 7% fuel from 4000 RPM+ and my EGT's still never get above 800.
 
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Discussion Starter #5
hey Ekool,

are you running stock fuel pressure regulator with your small single too? if so, does it still runs rich? I thought with more boost we would need more fuel.

Jonas
 

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The fuel system is completely stock. Yes, it still runs PIG rich. Like i said, i'm actually pulling out 7% fuel, and the EGT's peak out ~780 usually.

It needs to be leaner, but i'm afraid to pull out more. Most people run like -5%.

When i crank up the boost, i peak real high but the boost drops down with RPM (the turbo is too small to hold it) -- so it works out real well on the stock fuel system. I can actually peak the turbo at 1.8 bar, however, it is short lived... and since you are taxing the fuel system more with RPM, i could probably MAX the turbo and never overrun the stock fuel system.

Thats something that will have to be corrected when i go to a larger turbo tho.
 
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