stu8v said:
Regardless of mods they are a bodge.
When the ecu is mapped it is mapped throughout the rev range for a given (std) fuel pressure. If you then increase your fuel pressure to say gain a few bhp top end after and exhaust and inlet mods your car will overfuel low end. Its not a proportional thing, it needs to be mapped to be correct.
YOu've just contradicted yourself. One minute it's 'regardless of mods they are a bodge', the next minute 'it needs to be mapped to be correct'. So unless you don't count remapping as modding, there can be some value in using a pbv. Depending on the extent of your mods, and your fuelling requirements, a PBV gives you the adjustability to work with a remap better. I don't claim that on its own it makes any difference at all, and in fact may actually be worse. I would not recommend it on its own.
But in conjunction with other serious mods such as head and cam work, bigger injectors or higher flow fuel pumps, turbo conversions etc etc, I would not hesitate to use an adjustable regulator like a PBV.
And apart from anything else, going back to the situation of using it as a standalone mod, surely if we're talking about an ECU controlled, fuel injected car, the higher fuel pressure will momentarily allow more fuel through than mapped for. Then the lambda sensor will detect that the AFR is richer than expected and will lean the mixture accordingly - by closing down the injector duty cycle. This would be within the parameters of ECU control unless you had increased the fuel pressure by huge amounts. The only time when the ECU won't do this is when it goes to open loop at WOT under which overfuelling at low revs is totally irrelevant because you're caning it and almost certainly at mid-high revs.
IMHO.
