MAF tuning and ignition timing

[Martijn]

Hello You all.

Last year I installed a AHP 116 cam in my LS7. Becausse it is hard to find a experienced LS tuner overhere (The Netherlands) I decide to tune my ecu myself.
Last fall I did some runs on a dyno with good results, but this also give me some questions. Maybe some off your more experienced tuners can give me your opinion.

After the runs I analyzed the data, off the MAF frequency. What I found was that between 6000 rpm and 7000 rpm the MAF freq is about the same (9000hz).
Max HP is around 6000 rpm (525 whp), after 6000 rpm it drops.
What this means is that between 6000 rpm and 7000 rpm the motor pumps the same amount off air. But also that at 7000 rpm the cil air mass is lower than at 6000 rpm.

The commanded PE AFR is 12,7. After tuning my MAF freq in HP tuners the AFR at 6000rpm was 12.8 but at 7000 rpm the AFR was 12.2.
This is annoying becausse at 6000 rpm and 7000 rpm is the same maf freq. So when I make the freq slightly richer at 9000hz so the afr is spot on at 6000 rpm (12.7) it means that at 7000 rpm the afr will also be richer while it is allready to rich (12.2).

Would this be something I can correct with Ignition timing? Or else?

Please your advice

Martijn,

[jsllc]

Need to post tune and log for better help.

[Hib Halverson]

I am going to bet 50/50 that the problem is not all calibration, but that you don't have enough airflow above 6000 for that cam work well. If that's correct, then you need at least an aftermarket air intake kit or better yet, as set of ported heads.