15psi log vs. 10 psi.. help me out here

[myblack98gst]

15 psi

rpm_____timing___TP____o2 volt___air flow
2339____29_____18______.92_____2.86
2476____27_____29______.92_____3.96
2582____25_____37______.92_____4.69
2667____24_____44______.92_____5.31
2906____22_____58______.94_____6.20
3058____23_____64______.90_____6.48
3210____21_____70______.76_____7.19
3382____17_____75______.86_____8.30
3625____11_____78______.88_____8.94
3800____9______86______.86_____9.62
3992____9______97______.90_____10.18
4164____9______97______.92_____10.91
4554____9______97______.94_____12.09
4746____7______91______.94_____12.76
4972____7______91______.94_____13.24
5425____11_____91______.94_____14.78
5597____12_____91______.94_____14.67
5832____13_____92______.94_____14.89
5941____15_____92______.96_____15.20
6093____17_____93______.94_____15.53
6449____19_____96______.94_____15.53

I stayed out of the throttle so long to show how the timing reacts and WOT

10 psi

rpm____time__TP____02___Air Flow
4082 __24____97__.90____8.51
6023___25____97__.92____12.65

okay so I am not going to waste time on the 10 psi log but you get the drift. I was going to do a 20 psi but got into traffic, it looks basically the same but more air flow.

My question is why the hell is my timing soooo low.

engine set-up

6 bolt w/ 2g pistons
walbro 255 pump
Earls 6an fuel filter SS line up to rail
Denso 720cc injectors
AFC2 for control
Big 16g ported
Front mount

base timing is set right on 5* advance
the fuel lo throttle is -20% across the board
hi throttle 1,000 -20% 2,000 -25% 3,000 -40% 4,000 -45%
throttle points 15% 80%

 

[myblack98gst]

.get me on the mailing list!

 

[TURFNNSURF]

I think you are getting timing pulled due to knock around 3800rpm to 4900rpm, there is more load on the motor in that area as you approach the torque peak at 5250rpm. I would suggest you add some fuel between 3000 and 5000 rpm. Maybe set the afc to -30% @3000 and -35%@4000 then to -40%@5000 up. see if that helps..

 

[myblack98gst]

I will try that.

Also does the air flow number get adjusted by the AFC?? is it really 15.53 or is it 22.51
(15.53 x .45 (fuel correction))

 

[TURFNNSURF]

The air flow number you see on your logger should be the corrected air flow that your ECU is getting from the SAFC. I think the number displayed on the SAFC is the air flow before correction. But somebody anc correct me if im wrong. Most of my corrections with the SAFC are minor between -5%@1000rpm to -7%@6600rpm so I don't see that large of an air flow change..

 

[kpt4321]

You're knocking because you're damned lean.

Why are you using -45% on the hi throttle map? That's way too lean for you injectors. Add in some fuel and see what happens.

The airflow number gets adjusted. Airflow In * (100+correction) = Airflow Out.

 

[myblack98gst]

You're knocking because you're damned lean.

Why are you using -45% on the hi throttle map? That's way too lean for you injectors. Add in some fuel and see what happens.

The airflow number gets adjusted. Airflow In * (100+correction) = Airflow Out.

I used that number going off of 720cc is 37.5% larger than the 450cc stockers. so around 37-40 would just get it back to base fuel. I initially had it set to -20% and it bellowed out SOOO much smoke and ran like crap. it still smokes more that it should.