Vms Fuel Pressure Regulator

[JHEIII874T5M]

For a daily driver, if one didn't have selectable maps, run a low boost setting... a fpr would be alright.

[Slater]

For a daily driver, if one didn't have selectable maps, run a low boost setting... a fpr would be alright.

There ya go. Someone that understands what an adjustable FPR can be used for.

I'm not saying they are junk and have no use. I'm just saying if someone's "plan" is to get a custom tuned Rica ECU, or a fully programmable standalone ECU, then there is no place for an adjustable FPR unless you don't know how to properly tune an ECU.

[Johann]

And this adjustability cannot be programmed into the ECU? Unless the Motronic ECU cannot properly idle and fully control the pulse width of injectors that large, which I doubt it cannot, then it is not needed.

In other words, what is the point of having a perfectly tuned ECU if you are just going to throw it out the window and override the ECU with an external fuel adjustment? Your perfectly tuned ECU isn't perfectly tuned anymore. If it's because you have made changes that require more or less fuel, then get your ECU retuned. This is why you got a programmable ECU in the first place is it not? If the ECU cannot make the appropriate changes then this is another story.

You are not going to find many professional race cars using true standalone engine management systems coupled with an adjustable FPR or other piggyback fuel hack products, unless used for temporary tuning purposes only. FPRs are called "band aids", as are piggyback controllers like MAF controllers, VAFC, etc. Band aids are generally used when the proper solutions are unavailable, like programmable ECUs. Since this guy is going Rica or standalone fully programmable mgt, he has no need for band aid fixes anymore.

Unless he wants the "wow" factor of having shiny red bits under his hood. Me, I'll take the programmable ECU.

You talk about "adjustable" but the key thing is rising rate up to a set point. The adjusting part is only needed in the innitial stages to set the fuel pressure to compensate for the desired boost. In most cases the stock FPR would be sufficient but it could be that in Michiel's case the pressure needs to be set a tad higher under full boost to stabilize the fuel system.

To reach his set goal of 500 engine HP minimum he needs to make something like 1.5-1.6 bar of boost or maybe even a bit higher. I think this suggests the fuel pressure to be upped at least to 4.5 bar instead of the stock 4 bar, which is already higher compared to the later T5 models by the way.

The injectors are rated 650 CC at 3 bar.

After all is set the ECU is programmed accordingly.. ;)

[Slater]

You talk about "adjustable" but the key thing is rising rate up to a set point. The adjusting part is only needed in the innitial stages to set the fuel pressure to compensate for the desired boost. In most cases the stock FPR would be sufficient but it could be that in Michiel's case the pressure needs to be set a tad higher under full boost to stabilize the fuel system.

To reach his set goal of 500 engine HP minimum he needs to make something like 1.5-1.6 bar of boost or maybe even a bit higher. I think this suggests the fuel pressure to be upped at least to 4.5 bar instead of the stock 4 bar, which is already higher compared to the later T5 models by the way.

The injectors are rated 650 CC at 3 bar.

After all is set the ECU is programmed accordingly..

True, if the stock FPR is not up to the task or cannot control fuel and a different unit is needed then you are totally correct.

The key as you pointed out is that you use the FPR to set your fuel up the way you want BEFORE TUNING the ECU. Not AFTER as is commonly misconceived. Another misconception is using one in place of a properly tuned ECU. It is no substitute for a tuned ECU.

I just think a lot of people think they need it when in fact there is actually very few people that need it. You have to have a pretty serious setup to necessitate an aftermarket adjustable RRFPR in the scenerio you described.