Fuel Pressure Reg

[hbkuk1]

what benefit will i get from one of these i mean know what they do but would my VR4 benefit from having one?

[Nick Mann]

My understanding (and don't take this as gospel, I haven't investigated enough to feel certain of this) is that uprating the fuel pump and FPR is something done for two reasons:
1. You have modified your engine to the point that you need more fuel than the current system can take.
2. You want to get more fuel through your stock injectors.

As I understand it, reason 2 was employed by a lot of VR4 owners, because when doing that and running a piggy back ecu of some kind you could effectively offset fuel cut. More fuel in than the ecu thinks means you can intercept and reduce the airflow signal from the maf, meaning the ecu doesn't see fuel cut conditions until later than it would have done.

So, I also believe that an FPR and a fuel pump is not necessarily required when tuning the VR4 - it appears that the turbos will peg back the performance at a similar time to the fuel system. If you intend to push your turbos past well pst their efficient range or you have bigger turbos, then we could be back into reason 1 above.

[hbkuk1]

ok i wont bother then

cheers

[Nick Mann]

Sorry, just re-read this and the only reason I think FPR's are no longer as useful on a VR4 as they were is that there are now ways of offsetting the fuel cut through the stock ecu's. Therefore the higher fuel pressure method of fooling the ECU is no longer the easy way.