>>Can someone do this for this thread.
>>It looks like neither Armond or I can.
>>At the very least, can someone please
>>clarify what-it-is that dictates the
>>loop state(open or closed) on our ECU?
>
>Ok today I did data log it for partial throttle and,
>
>45-55% throttle
>6-10psi
>18-22 deg advance
>EGT 1250-1300
>

Interesting in deed. Looks like when MAP reading get maxed out, regardless of being in closed loop, timing comes down to 18-22 degrees.

>I did this several times and always got the same result.
>The advance would go right to 22 and then drop down to
>19.5-18. A few times it would drop lower to around 16 deg.
>But everytime it would go to 22 deg for a moment right away.
>
>I never saw it higher than 22 deg. under boost
>
>WOT and 18psi I get 18-20 advance.

Still seems just a bit high for that much boost pressure, but if you got no detonation, than thats awsome. That much timing without detonation makes some good power.

>What do you mean by clarify what dictates the loop state?
>
>Throttle position is how the ECU knows when to go close and
>when to go open loop.
>
>Brian

Ditto. From your tests, looks like the ECU retards timing back from almost 30 degrees under vacum conditions, to around 16-22 degrees advance at WOT. The MAP most def controlls this. I would *think* that if you ran the missing link, that you would get just a tad bit higher timing advance at WOT, around 18-22 degrees max. This is because it keeps the MAP at its max voltgage of 4.5 volts (at 0 psi). If you use the VC2 or other, it can keep the voltage a tad bit higher (4.7 volts or so, compared to the missing link max voltage of around 4.5 volts). This means that with a slightly higher map voltage under boost, that the ecu will pull just a bit more timing, closer to 16-18 total degrees of advance. Make sense? Theoretically, it would be *safer* to use the VC2 or other device to get a bit higher voltage from the map other than 4.5 volts, as less voltage from the map will make for a bit more timing advance. If we go with armonds advice, just run it a tad bit richer if you use the missing link, to help avoid detonation. This *could* be why i detonated at 10 psi, that along with a slightly lean A/F ratio. Makes sense anyway.. I use the missing link. Our stock maps are supposed to read about 4.5 volts at 0 psi, as the missing link keeps any boost pressure from the map sensor, which is why the missing link makes the map see an exact 0 psi all the time under boost.

I'm REALLY interested to know at what exact MAP voltage does it make the ecu go into fuel cut. If we knew this, then maybe we could adjust our WOT timing advace acording to map voltage AFTER 4.5 volts on up to the max voltage the ecu can accept. It would be interesting to see if we can get more timing retarded after 4.7 volts on the map. I think this could be very useful to do for people running 18+ psi. This way, we wouldnt have to use ANY timing retard units. Just raise the map voltage slightly, and the ecu pulls a tad bit more timing. Any thoughts??