Im learning how to monitor my AFR better now and im trying to understand the cause of some things.. just wanna start a discussion as the AFR are so important....

So i just replaced my walbro 255 fuel pump with a denso (supra tt) fuel pump.

now my AFR read richer, which is understandable (bigger/better fp getting more flow) but i dont understand how come my transition into boost richens up to mid 13.x to 14.x

also is it okay if my AFR are rich 13.x-14.x when im accelerating but remaining in vacuum?

whats the average AFR during cruise?

 

13-14 vacuum accel , cruise is ok .. in boost .. no way ... in boost u should have a 10-11 which ideally stabilizes in to an 11.3-4 ...at high rmp peak boost

 

you don't need to drop to 11:1 as soon as you hit 1 or 2 psi in part throttle. In open loop conditions, factory fuel curves tend to get progressively richer as boost increases.

 

Here is a chart (which I believe is from Chuck) that contains some pretty sensible FD AFR targets:



There are many threads on this topic in the ECU specific forums.

 

damn that is an awesome chart! thanks, ill check out the ecu section... always forget that even exists

 

Here's mine, similar to the chart posted by moconnor:



Max boost is 12psi, btw.

 

^ so ur at 12 AFR at WOT at 12psi ?

 

The AFR is boost dependent, not throttle. There is an additional factor that richens it up with decreasing effects, so it is richer for much of the power band. At about 5800rpm, you can see the real time 10.8 AFR start to approach the target 12 AFR. See graph:

 

are you running closed loop for high load operation?

 

Closed loop for all operation (within limitations) after warmup. It can only deviate + or - 10% from the fuel map. See the 02 Sensor FB window in the first pic I posted.

 

looks like your map should be reversed.
14.7 AFR for max RPM and boost doesn't sound right.
Nor does 11 AFR at idle.

 

^ read it again.

 

:+1:

 

I'll post more later but raced my FD this weekend and think it should have blown up. LC1 WB says 11.5-13.5. 4-5 min runs like this...

 

Subscribed because I need to learn about this

 

I really need to take tuning courses

 

This is stock injectors, fuel pump, and regulator. Engine has large street port with stock turbocharger system. Exhaust is M2 down pipe with RB single cat-back. Induction is M2 Medium IC with Greddy elbow. ECU is PFC with Datalogit. First chart is AFR Log and second and third charts are the injector pulse widths. These AFR's pretty much max out the stock injectors at 92% DC.

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This log puts it all together. For the high load cells the knock count is the indicator for adjusting AFR. Note this knock count is reasonable; I could probably remove some more fuel and still be OK. For the cruise cells lean as far as possible and still obtain a stable ride with good throttle response. For the idle cells (these were the hardest for me to tune) the key is a good stable idle with the IAS set at it's midpoint and throttle tip-in without stalling. My combination tends to enjoy a rich (12.4 - 13.0 AFR) idle which is probably due to the port work.
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I'm not a mechanic, nor am I a tuner, But I did most of the tuning by myself on a WOLF V4+EMS.
I have a 13B turbo with large street intake and exhaust ports. Car idles 700 -900 RPM. Does not smoke or idles "rich" either. I used to run with high compression rotors with no problem HX50, 4X 1000cc Delphi injectors. Car made 380 RWHP @12PSI.
Normal driving in in the vacuum ranges up to 1PSI boost:
Idle 15 degrees adv. 12.7:1 AFR in the idle ranges 650rpm - 1000 rpm low vacuum.
Off Idle (blip the throttle) immediately timing advances to 38 degrees and increases linearly to 43 degrees @9500RPM step by step as RPM increases. This is good for all loads in the VACUUM ranges up to 1 o2 PSI boost. Beyond that I will not give advice or my opinion...

To get a crisp throttle response you will have to understand the acceleration pump feature by increasing the full delivery percentage. I increased my acceleration enrichment between 400%-600% (this is just the additional fuel that you get as you would if you were to press the accelerator (gas pedal) in a carbureted car.

The AFR values that I observed is as follows:
I keep it around 12.8 up until 2000 rpm. Then I slowly adjusted my fuel tables to obtain about 14.1:1 - 16.:1 for driving around.

On the highway I run the mixture leaner 17.9:1AFR at steady state cruise . 60MPH to 90MPH highway.

Car gives me between 19 -22MPG all day.