Maybe I’m overthinking this (being highly cautious before I jump in to anything), but when you see car makers with twin-scroll turbo diesel, are they using the exact same injectors and fuel pumps which are uprated to cope with extra pressure etc? I’m thinking 3.0TDI single turbo vs Bi-turbo, as seen on the Audi A6, and BMW 120d vs 125d.
Does anyone know if there are engineering differences to cope with the possible extra fuel system pressure for bi-turbo over the single turbo variants to pump more fuel in. I do wonder about the extra pressure that these tuning boxes apply and the potential effects it may have longer term on injector and fuel pump operation. If the Bi-turbo variants use the same fuel pump and injectors at a higher pressure rather than bigger injectors at same pressure as the single turbo systems then I would be confident we have nothing to worry about.
The difference between the 140CR and 170CR engines seen commonly on the MK6 Golf and Scirocco was seen in both injector set and turbo, as well as a few subtle difference with the cylinder head. I’d assume from the injection and turbo differences that VAG does scale up the fuelling system to get more fuel in by bigger injectors capable of spraying more per cycle at an unchanged fuel pressure rather than just ramping up the fuelling pressure.
How close to arbitrary upper pressure limits do tuning boxes which report 30% increase in output take the car’s fuelling system (assuming that these “safety” limits are known to anyone outside the VAG network)?
I know we have VW’s warranty to fall back on if something should go pop and we remove the traceless box before sending it back to VW, but I do wonder whether I’d be passing on a future ticking timebomb at part-ex time. I must admit that I can’t find many examples on the net where people have had a box and had their injectors, fuel pump or turbo knack and have had a tuning box fitted, not knowing whether they would’ve failed anyway (but there were a few). There do seem massively more people who are happy with their boxed car than who regret the decision later, which makes me think the injection systems are pretty robust (although looking into 30-50k of a car’s life that the box owner has the car for rather than the whole 150-250k miles of the car’s lifecycle might be a little short sighted).
