Colonel

P.S., lowering the reported load from the MAF sensor, such as by porting it or by going negative on the MAFT, also has the side effect of raising the timing advance somewhat. This is because the PCM uses the MAF reported load to determine timing advance. Lower the load and timing advance goes up. Increase it and timing advance goes down.

BullSSeye

OK, the gray area for me was where the closed loop reported to the open loop tables. I assumed they were at 1:1.So I couldn't understand how the WOT could adjust using a closed loop table that's going to eventually become stoichiometric anyway. But in reality they are not 100% connected. It's not exactly wideband dyno tuning, but it does get you in the ballpark I suppose. And they are quite a bit less expensive than Edit or a Predator.

Well, I might copy your post and forward it to a friend of mine if that's OK with you. He's an ASE cert. diagnostician and has taken numerous classes to remain up to date. He's also an avid SBC tuner, but 95% of his experience has come from LT1's and older carbed motors. So he and I have discussed this a few times and he has some doubts about the MAFT's (as did I). Anyway, I'd like to see if your explanation can answer his questions. Thanks again for the info. <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

Colonel

Sure, that would be fine. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

You can reassure him that the MAFT does indeed work and it can make permanent changes to the WOT mixture. That is not in question. It has been everyone's experience that has ever used one (myself included.)