MED9 HPFP & LPFP Control
BenR:
Hi Guys,
Ive seen a bit of chat around regarding this but no solid information supporting it so thought id start something.
HPFP
When a bigger pump is used we bump up the rail pressures under HDRPSOL. There are rail pressure maps for Homogenous Operation, Knock Protection, Lean Protection, Cat heating.There is also a maximum rail pressure limit map. X axis is RPM and Y axis is 'indexed Driver torque limit before change" which i dont fully understand but it seems to work like most other load vs rpm scaled maps.
There is also VHDP which is pump volume. For example the OEM on a 2.0tfsi is 251mm^3. Many tuners change this map when the HPFP is upgraded. Ive heard of 300mm^3 for an APR pump. Whats the formula behind this?
LPFP
Generally you dont need to touch this but once you're using bigger turbos you have 2 choices. Either change the hardware to something that is hardwired to flow more or change the software. It seems the hardware option is easier.
Maps i have found are:
KFNTBKS "Target pressure as a function of temperature HDP"
KLPSKRMX "Characteristic set pressure fuel low pressure system maximum"
I am about to do some testing on these maps and will report back my findings.
So if anyone is using the OEM LPFP module on a bigger turbo (2867, 3071, 3076) you will see your lpfp drop to 2.5bar once you start making half decent power. The question is how can we demand more fuel? Im confused in how the above to maps will help that as they're not requesting a certain pressure. I will however report back when i have more info, or if someone else does. Feel free to chime in.
Cheers
RaraK:
Your stock controller of mk5 gti and similar will usually overheat if you demand much out of a pump.
You must hardwire or upgrade to a better lpfp controller of the TTRS maybe.
mec:
I'm running an rs4 lpfp controller on my a4, with stock pump and so far it has been way more than enough. When I installed it I did nothing to the lpfp maps, and I was seeing 6.1bar at idle, high 5's even at WOT. Then I adjusted the target pressure maps, now I Idle at 4.1bar and at WOT at 6000 RPM I am around 3.3-3.4bar. Not sure if you can use it. Otherwise the Boost Manager plus is also a cool solution, my friend had it on his car and you can program the lpfp maps, manage boost profiles, and control meth all from one device.
BenR:
I currently use a TTRS HPFP on smaller turbo cars. Say GTX2867. It seems to hold well at 25psi to 7000rpm. Even after requesting higher pressures through the correct maps the TTRS pump is ok for 30psi on GTX3071.
I use the RS4 controller and TTRS pump but i believe you do not need to controller and it can be done through the correct maps. Has anyone done this?
RaraK:
BenR -
Controller is needed for upgrade, it will overheat on road race or high speed runs for sure at high duty. I have done this on multiple setups and had to use an uprated rs4/ttrs lpfp controller to resolve the issues.
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