There's
another thread on here where the supplier joined in the discussion although not a lot was said.
I've just read through their technical reference and while they talk mostly common sense, there are some things that don't quite gel - for example a statement along the lines of "If you reduce the CO2 emissions, you'll increase the NOx emissions". Not really - you don't get a lot of NOx created with lower combustion temps. But that's being picky.
It would seem that their unit concentrates on injector duration and fuel pressure. Their particular trick is to shorten the injector pulse duration while increasing the rail pressure. This has the effect of squeezing the same amount of fuel into the chamber in a shorter amount of time: in reality, this should equate to what feels like more horsepower. The cost ought to be reduced torque and higher combustion temps which increase NOx production and EGTs.
Higher EGTs will drive the turbocharger harder (hotter gas expands more creating a higher velocity of gas through the turbine aperture). However since the D40 turbo is VNT, the ECU will regulate boost by adjusting the vanes and while you'll spool a little quicker, you won't get as big a bonus as you could have. I don't think this chip fiddles with the turbocharger like Unichip does so there's a bit of waste there - they could have done more!
I'm not sure I'd want one in my car. Shorter, faster burns are fine with a high revving motor but in a diesel that produces most of its power (and thus cruises at) relatively low RPM, perhaps less fuel in a longer burn is called for (unless the RPM increases, and I'm sure you could map that). Particularly when towing - having a downward force for longer on the piston is something like a cyclist pushing his foot on a pedal. Having a rapid, short combustion is more like a hammer blow on the cyclist's pedal instead. It'll spin the wheel over alright, but power delivery per engine rotation is reduced this overall torque should be reduced. It makes sense in my mind like that anyway.
My money would still be on the Unichip. Increasing the rail pressure represents a risk I don't want, with the new CRDs already running 1700BAR (1800BAR for the V9X).
