Is a RRFPR Really Needed...?
- Thread starter AdDaMan
- Start date
Starlet_Sam
Moderator, Regional Area Reps Supervisor & Gay Car
I'd say yes, just get it all checked over and spot on.
ChrisGT
Member +
Well yes...you need some way of increasing fuel pressure beyond stock levels to compensate for the higher boost and an uprated fuel pump isn't necessarily going to do that! The pump will be providing fuel to the fuel system at a higher pressure but not into the fuel rail. Thats the job of the FPR; to allow the correct amount of fuel into the rail. The pump will be delivering either too much/too little fuel and the FPR will allow the correct amount through.
Last edited:
dantheman
Member +
you wont need one if you got a ecu of some kind to increase the duty on the stock injectors to squeeze abit more juice out of them. if not then yeah you need one ideally, as you wont have any way of increasing the fueling to compensate for the extra air being drawn in.. plus its always good to have one as it gives the tuner the option to fiddle with it if need be..
although saying that some cars are different and seem to have sufficient fueling for the raised boost without the need for raising the fuel pressure.
best thing to do is get one, and get the fueling checked, if it needs raising over standard then you will have the option.
although saying that some cars are different and seem to have sufficient fueling for the raised boost without the need for raising the fuel pressure.
best thing to do is get one, and get the fueling checked, if it needs raising over standard then you will have the option.
ChrisGT
Member +
you wont need one if you got a ecu of some kind to increase the duty on the stock injectors to squeeze abit more juice out of them. if not then yeah you need one ideally, as you wont have any way of increasing the fueling to compensate for the extra air being drawn in.. plus its always good to have one as it gives the tuner the option to fiddle with it if need be..
although saying that some cars are different and seem to have sufficient fueling for the raised boost without the need for raising the fuel pressure.
best thing to do is get one, and get the fueling checked, if it needs raising over standard then you will have the option.
I think the lad only has a fuel pump and BCC so yeah, hes gonna need a FPR!
If you want a better tune you could always fit the FPR and get a SAFC and let a tuner trim the fuelling down so its spot on throughout the entire rev range...or you could just buy an eManage!
ChrisGT
Member +
Yeah the HKS sends lower voltage signals to the ECU which makes it think its running lower boost so it will run lean. But with a JAM/Greddy unit (clamp type FCD's) the car will run OK under fuel cut levels as the ECU will see the right boost but at fuel cut point the ECU will keep seeing the 12Psi~ish and fuel for that but in actual fact you may be running 16Psi - so it will also run lean.
Just out of interest, its the HKS FCD that doesn't work well with a SAFC right?
starbogt
Member +
I know of 1 person who ran the jam fcd and a hks actuator ran 1 bar was giving perfect fueling at 1 bar so it is possible but every car is different and his was checked on rolling road. my car I ran a fpr with hks actuator and FCD and needed to raise pressure to compensate the fcd I was using.
a bcc at 1bar would normaly be ok but you absolutly must get it checked before boosting it.
If you are going to use an fcd it's ideal to use an rrpfr as it would have been leaned out over the complete rev range and the rrfpr will bring it back over the complete rev range.
A bcc is better when useing something like a safc as you will then only need to make adjustment to fuelling over fuel cut. If you use a rrfpe you will be rich until you go over fuel cut.
If you are going to use an fcd it's ideal to use an rrpfr as it would have been leaned out over the complete rev range and the rrfpr will bring it back over the complete rev range.
A bcc is better when useing something like a safc as you will then only need to make adjustment to fuelling over fuel cut. If you use a rrfpe you will be rich until you go over fuel cut.
sx_turbo
Lifer
no the safc works fine with either type of fcd
sx_turbo
Lifer
a safc wont raise the fuelling past fuel cut.
you need an rrfpr, and then trim it back down with the safc
ChrisW
Lifer
I never ran a FPR when I ran 1bar on my hybrid, and Nick Jones, who maps my car, has said I won't need one when running 1.4bar on my soon to be TD04 set up!
I do run an emanage though with injector harness so I believe he must adjust through this, not too sure though, but I know I never had one!
I do run an emanage though with injector harness so I believe he must adjust through this, not too sure though, but I know I never had one!
sx_turbo
Lifer
Is it not tuned against revs, never used one so have no idea.
ChrisGT
Member +
It is tuned against revs; it has 16 adjustable positions in the rev range at which you can trim down fueling. But like Ricky said, you can't use a SAFC to raise fuel pressure on its own - needs to be paired with a RRFPR.
And my comment about it not working with a HKS FCD is only if you don't wire the FCD in before the ECU, so never mind that!