it's a possibility that the fuel pump is playing up! but surely if the pump was lazy you would suffer fuel starvation at the upper end of the rev range?

When my pump was faulty it was most obvious at around 3.5k when the engine was hitting peak torque.

When my pump was faulty it was most obvious at around 3.5k when the engine was hitting peak torque.

normally the place where the most fuel is used is at peak hp rpm, but i guess quite a lot of fuel is used at peak torque too:)

another toguht on fuel supply... the fuel pressure regulator has a hose which connects to the intake manifold. and the pressure of the fuel is referenced to the depression/boost in the manifold, so the fuel pressure is always either 2.5 or 3 bars(depending on engine code) abouve the manifold pressure/vacuum. so if your turbo is making less boost, therefore your fuel pressure is going to be less right?? but the pulse from the ecu will still open the injector for the same period of time hence you get less fuel??? hence less power.

some people are going to say. "ah yes but the ecu can compensate for that" the answer is yes it can, but it only does if a reading from one of the sensors is out of range or the emmision are all gone wonky.

maybe a new pump and remap is in order

if you fit a 4bar fpr does the map need to take account of this? i assume it does but unsure.

maybe a new pump and remap is in order

if you fit a 4bar fpr does the map need to take account of this? i assume it does but unsure.

not suitable for turbocharged engines i'm afraid, unless you remove the manifold vacuum hose! with the bosch-type fuel injectors that the 20v engine has the injectors suffer from fuel metering/ovheating issues when used at pressure as high as 4 bars and they become unstable when used like that for long periods. besides i doubt your fuel pump would be able to keep up without the addition of an auxillary pump/and catchtank.

but the asswer to your question is yes... every time you adjust your fuel pressure you need to change the map slightly to compensate.

further to this, you would probably be better off sticking with the standard fuel pressure regulator and going for some injectors with a higher static flow rate. i've seen the cosworth green inectors being used on the 20v before.

loads of people run 4bar fpr's tom, i think they are standard on some 1.8T's

well if it were factory fitted they would ceratinly have uprated injectors which were capable of this. the agu coded 20v engine has a 2.5bar regulator

the only ones that would have the 4bar possibly are the 210/225 engines which do have bigger injectors and a better pump

the only ones that would have the 4bar possibly are the 210/225 engines which do have bigger injectors and a better pump

i've just looked on etka and the tt is listed as having the same regulator for the ajq(180bhp) and apx(225bhp) engines..

also the mk4 golf has the same regulator (with the same part number) on many engines

including 1.6, 2.0, 1.8 20v n/a, and 1.8 20v turbo

but my version of etka only goes upto 2002 so i daresay later ones might have different regulators fitted.