Datatek
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I've got a book on the Bosch diesel pump and can look it up for you. PM me.
As regards why no-one has asked before, you've answered your own question: for £100 you can get a plug-in chip that's proven safe, works, improves driveability and economy and takes 5 minutes to fit. Why would anyone in their right mind think that that is more expensive than anything you can DIY
I can totally understand your quest for knowledge and I've no doubt you will eventually succeed to get some small improvements but do it at theoretical level where there is no risk to your motor.
And I can tell you already that its not as simple as adjusting a single sensor. The Bosch EDC works on a 3D fuel map. The chips work best by removing the dips in the fuel map surface which correspond to the revs and loadings the emmision tests are done at. By changing one sensor statically you will only change one facet of the fuel map. If you're lucky you might lift the full surface a few percent but it will still have the same dips.
I have the analogue powerbox plug-in which physically uses the MAP sensor so that tells you one input the box uses. It gives a big burst at 2000rpm when the turbo comes up to full boost. The digital models don't use the map sensor using an adjusting 3D fuel map instead and give a much smoother improvement.
Absolutely. Fuel mapping is not a simple single dimensional thing. eveything is taken into account from atmospheric pressure, manifold pressure, fuel pressure, engine revs, throttle opening, intake air flow and so on. From these signals injector timing and duration are calculated. The best way of improving the performance is a re-map which takes out the artificial dips introduced for the emmisions tests plus modifying the fuelling to increase power.
If you are really interested, get yourself an old ECU and download the firmware into a computer, disassemble it, work out where the fuel map is and then try tweaking it. Lots of people have done it so it can't be too hard
