rrfpr vs afpr
- Thread starter adz_sportif_turbo
- Start date
Yes I know what he meant, but my statement still stands. Even if you only have ONE boost 'limit' or setting as you call it, you have to go through all the levels to get to that desired end value.
So it doesn't matter if your max'd at say 1 bar, your fuelling and boost have to go from idle to full tit (WOT).
You start and 0 and end at 100 so why is one PR better than the other at doing that. I have 0.5 bar and 1 set, however if I use low boost I only go to 0.5bar, but if I use high boost I go to 0.5bar and pass it all the way to 1bar.
When passing 0.5 bar I still need the same fuelling as the other time when I stayed at that level so what is having one type of PR going to change about that?
You could set high boost witha 1bar ceiling and only drive carefully, generally gettig to half of your desired limit. So irrespective of what you have set as the end result the fuelling must be controlled and supplied correctly.
A 1:1 PR would (with a base of 2.0bar fule pressure) supply 2bar at idle and when on boost at 0.5bar boost give 2.5bar fuel and when at 1bar boost give 3 bar fuel.
A RRFPR would give a never stable always increasing FP depending on increase boost? Would this then be harder to map for and if so why is it used?
The fuelling doesn't care if you have 1 actuator set limit on WOT, a switable (EBC) limit on WOT or foot controlled limit stopping you from hitting WOT, the fuel pressure is defined by the setting on the FPR giving it the initial fuel pressure and the boost produced and fed to the top of the FPR from the inlet manifold.
Would a RRFPR no give you a possible slightly lean supply at the get go then OK in the middle and rich at the top?
Would a RRFPR no give you a possible slightly lean supply at the get go then OK in the middle and rich at the top?
azerty
Supermoderator
you need a RRFPR if you want to boost over standard ECU boost cut which is 0.85 bar.
your ecu won't deliver more fuel over than that. So you need a RRFPR to deliver more fuel over 0.85 bar, the more boost you will go over that value, the more presure you will need to add to be able to deliver enough fuel at high boost. This needs to be setup on a dyno or Road tune with a wideband. if you run high boost you will end up with the car beeing very rich under 0.85 bar on WOT (as your ECU doesn't know you have raised boost pressure). Also, most of people who want to go over fuel cut buy a RRFPR and an FCD. most popular FCD is HKS which is a resistor type. which means it will trick MAP sensor signal (intake boost pressure) to a lower voltage so your ecu think you are actualy runing less boost, so you you can up the boost more than standard fuel cut. This trick will result with an engine running lean. and more boost you will want to reach, the more you engine will tend to run lean as you will have to use a stronger resistance on you FCD to trick your ECU.
Now there is the proper way to do things. Buy a good piggyback like EMU or go for a proper standalone ECU and never look back
in that case standard reg is just fine, as you will map your fueling from the ecu (as it has to be done !). That said, some fellas (ask Aga) use both RRFPR and Standalone, to have a bit of flexibility straight on Fuel reg.
I hope it has been clear enough
your ecu won't deliver more fuel over than that. So you need a RRFPR to deliver more fuel over 0.85 bar, the more boost you will go over that value, the more presure you will need to add to be able to deliver enough fuel at high boost. This needs to be setup on a dyno or Road tune with a wideband. if you run high boost you will end up with the car beeing very rich under 0.85 bar on WOT (as your ECU doesn't know you have raised boost pressure). Also, most of people who want to go over fuel cut buy a RRFPR and an FCD. most popular FCD is HKS which is a resistor type. which means it will trick MAP sensor signal (intake boost pressure) to a lower voltage so your ecu think you are actualy runing less boost, so you you can up the boost more than standard fuel cut. This trick will result with an engine running lean. and more boost you will want to reach, the more you engine will tend to run lean as you will have to use a stronger resistance on you FCD to trick your ECU.
Now there is the proper way to do things. Buy a good piggyback like EMU or go for a proper standalone ECU and never look back
in that case standard reg is just fine, as you will map your fueling from the ecu (as it has to be done !). That said, some fellas (ask Aga) use both RRFPR and Standalone, to have a bit of flexibility straight on Fuel reg.
I hope it has been clear enough
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Azerty,
That is exactly what I wanted. I have an eManage blue with enlarged injectors and a 1:1FPR. But so do others and they ran RRFPR and I couldn't understand why they did.
That was my confusing point.
Cheers for the detailed, specific and exact reply.
it appears I have the 50% choice of setup then
That is exactly what I wanted. I have an eManage blue with enlarged injectors and a 1:1FPR. But so do others and they ran RRFPR and I couldn't understand why they did.
That was my confusing point.
Cheers for the detailed, specific and exact reply.
it appears I have the 50% choice of setup then
ruggiero06
Member +
you need to fpr regardless if u have a piggyback or standalone because you need to up the pressure to supply more fuel.
azerty
Supermoderator
^ no you don't need... unless you have maxed out your injectors. keep in mind injectors have been designed to work at specific presure range (one of the reason is spray patern...) bigger injectors and EMS are here to work proper fueling. that said RRFPR add some flexibility on the tuning (I have both)
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