we're dealing with an s4 na ecu, although i guess this works for the s5's and turbos to an extent.

we are concerned with timing ONLY at full throttle.



couple of questions:



1. how does it finger out the timing? afm? tps? pressure sensor?



2. i assume it uses the load and rpm to come up with a base timing number, and the temp sensors to add corrections, but mostly these are retards, yes no?



ideally i'm looking to set wot timing to about 26btdc, and it would be easiest to do it satationary in the stall, and not having to simulate a load somehow

 

We've done it on a chassis dyno. It doesn't cost much and is a controlled environment. We had the dyno operator confirgue the dyno to hold our engine at 7000rpm (mid-point of our usable power band) at WOT. We then dialed in the desired timing. That way you get full load advance. If you don't mind torching a set of brake pads the same thing can be done with the car on jackstands. We've done it that way too. Standard, I'm not responsible, disclaimer applies. I've been told by a fellow that's cracked the ECU that the S4 TII ECU begins pulling timing at 95*C and has pulled about 5* by 115*C. I'd guess that would be fairly common across the range.



FWIW we found about 1hp per degree of advance over 15* across the board up to 25*BTDC full advance @ 7000rpm. Over 25* didn't make any more or less power.

 

yeah we found with the haltch the car made best power @26btdc, which +/-, might as well be the same as your 25btdc....