Quote:
Originally Posted by prebordao
This post by Loren is really an oversimplification almost on the edge of "malicious intent".
First, reprogramming an ECU is not that simple if done properly. Even old systems like the Motronic used in 3.2 rely on 3D maps tying several variables simultaneously. So, you dont change a value here and there, you have to change many at the least, then you have to verify on the dyno (and road) and repeat...
Second, it should come as no surprise that sometimes the gains are significant. Porsche, like any manufacturer, tunes the engine to accept a broad range of gas quality, and always with emissions control in mind. When you're tuning, usually you can afford to forget about that, so with much less constraints, it's no wonder you get better results.
Third, dyno tests (for power and torque) are not everything. Something that can be improved (and usually is) over the factory spec is engine response / "revability". Specially in the older days, quick throttle response meant more emissions. If you care less about emissions, this too can be improved.
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True enough! Tuning any engine is 3D...old geezers that would jump the timing up and enrichen the mixture in hopes of finding more power rarely were successful. Well made DME performance chips are more sophisticated than that.
Dynos can be misleading too. We campaigned a Laverda 1000 3c back in the day. Out of tune it would make about 70hp on the dyno (factory claimed 90hp). A well tuned Kawasaki 1000 (factory claimed 90hp) would make about 78hp on the same Dyno.
On the drag strip..the same out of tune Laverda was near on a second faster vs the Kawasaki with the Laverda's taller gearing and a slipping clutch.
A Charlotte Motor Speedway the Laverda (once tuned, we backed the ignition timing down from factory specs and went with some slightly leaner jets, and the clutch repaired) was 10mph+ faster and clocked 10 seconds faster on an average lap. (better brakes and handling)
My point is that it is not just dyno results as the dyno is only a base to start your tuning. It is thoughtless to advancing the timing and throwing extra fuel in an engine to try and find increased performance. I doubt SW uses this tuning technique.
Some track time comparing the before and after would be interesting.
The maps in DME chips are a wonderful place to refine the tuning of a 911 engine.
