8 cylinder front engine iconic vehicle
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By Crumpler
#123020
Pretty arcane subject for me as a pre ‘87 guy.

The actual mission is to link installed Bosch sensor to VEMS.
Back story is that there is one sensor now on the 86.5. It is placed in the most forward position ahead of the TB assembly. That’s really the only place I had that worked with the S3 layout. But also interesting that the sensor holes and plugs are there in that model year and not used, obviously they were headed in that direction.
Currently the sensor is wired directly to a Link brain that self calibrates noise on start up and comes with a signal light in the cabin. I had an issue with it picking up false readings with the lower timing belt idler clicking on the the block but that’s resolved (don’t ask), now it seems to give honest knock events at appropriate times.

The pin layout to wire this sucker directly into VEMS is well documented. My more specific questions are knock properties on the 928.
When would you program start window and window length in relation to timing degrees? The generic recommendation is start 12 and window length to 60.
Then there are frequency settings based on bore — I think. Um, I can do some math there.
Also with one sensor reading all eight cylinders, that probably will have different signatures because of distance to sensors right?

Then, I might be making this up, but didn’t I read somewhere that S3 pistons are noisy(er) to begin with.
Any advice appreciated.
Dave.

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