[ike84]

Michael,

Very nice writeup about the tuning. I can't stand when people talk about all the power you get out of custom tunes, and how tunes are written for specific "parts" like catless headers. There may be some room for advancing spark in this motor but as soon as you knock the dme will pull the timing. You can alter the AFR target in closed loop operations, as it looks like yours has been, but your gonna pay for it one way or the other (either with more heat or more fuel).

A huge barrier to tuning is the ME 7.2. Even on the nefmoto site, which is probably the internet's best group of euro tuning junkies, the consensus is to not try to mess with it. Too complicated, no aftermarket support, no technical education. All guess work, and lots of risk. FVD claims that their tuners are trained in ME 7.2 but amazingly enough I could never get one of these guys on the phone.

Im surprised that you managed to get any bump out of a tune with fabspeed. I spoke with them directly about developing a tune last fall and let's just say I was fairly convinced they didn't know they first thing about tuning.

There is another thread where Pedro's plenum was dyno test and showed nearly identical number to yours. The theory with both of these plenums is that the Y shape helps to improve laminar flow around the split, but clearly this is not the case.

There is always the interesting war between CAI and short ram fans. One thing that I think is true that some engines do better with one over the other, and I think that the M96 may like short rams.

The reason I say this is because of my fuel trim data on my base 986. I run a 996 tune with a 996 plenum, 82mm TB, and short ram 3.5" dual filter intake that runs straight into my trunk. It's about as short and fat as you can make it.

My long term fuel trims are -17% on both banks. What's interesting here is that a 2.7L is 20.6% smaller than the 3.4. But my setup (which in closed loop runs at 14.7+-.2 at all times, I have a WB sensor installed) is managing to pull more air. By my calculations, I'm getting 4%ish more air than what I should proportional to displacement. And that's actually with my intake temps running hot because of the heat in the trunk, about 100F. I have no idea if this has translated into more power but I found it interesting.


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