Keeping Fueling In Check

[jrubio96]

I've recently upgraded the turbos on my 2015 S7 to Pinnacle Stage 1 BBs, and I'm curious what range I should be looking for in the logs to determine if we're keeping the HPFP/LPFP/Injectors within a healthy range.

If you have logs for reference, that'd be awesome as well. Figured forming a thread on what is considered a healthy HPFP Bar, LPFP kpa, and Injectors MS data range might also be useful for others to reference, not just myself.

[IllusionalTA]

Above 500 is safe for LPFP pressure, as you start suckin down fuel you'll start seeing the actual not keeping up with the requested values, you can get to 475 and be "ok" but, i wouldn't play below 1/2 tank, they will suck the bucket dry in a hurry any lower..

[THCarpenter]

the 4.0 for the C7/7.5 with the EA824 engine runs the LPFP at 6-6.5Bar constant. We are a returnless system.

when you start adding boost, the LPFP and HPFP transition is a drain on the system and you see that in the logs. Im at work, and not near my PC with my logs/screenshots to help describe this in depth.

as Steve said above......with higher boost numbers and the demand on the fuel system, playing catch 22 with less than 1/2 tank is not in the cards.

You should look at getting the RS7 LPFP drop in unit as a bare minimum as it has a second pickup tube to help keep the basket and pump primed, but our issue is as said above the transition from LPFP to HPFP as the pump struggles when the floodgates open up.

We have a full on Telegram chat that has work arounds and access to the manuals saved on our dropbox. If you look at the chatbox sub forum you'll find the link.

I agree that making threads on the forums is the best way forward to retain information, but with the onset of Facebook, forums are a dying breed and the information is lost quickly.

I have a few detail oriented posts here for just data collection and straight forward information.....attempting to remove as much bias or favorable information as possible...like this company is best or that.....just raw data....let the user decide.

[jrubio96]

Thanks for the info guys. I'm looking to finally install my walbro 525 as a secondary pump to help keep up. I'm definitely seeing it dip below 500 at the top end of the rpm band. What should I be seeing the request set to? Since it'll fall off anyway at the top end, should I see the request set pretty high so it works the lpfp harder?

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[IllusionalTA]

In my experience with my Hellcat pump, set to come on at 5psi, my lpfp will hang about 620 or so, the oem pump will actually slow down, in order to try to maintain the 600 "setting" and surprisingly the hellcat pump can mostly support the power level to go 137mph that my car does, and my oem lpfp will be requested to do almost nill at full throttle. The request is inverse of pressure, so as pressure drops off due to pump limitations, the car is goin to request more infinitely, i've seen 900 on a log before, but obviously your pump can't, so the car's gonna open up the injectors more, to try to save the afr, if it gets to the point where the car cannot keep itself happy, then you'll experience fuel cut, and youre teeth will hit the steering wheel, your wgdc will plummet as well..

[IllusionalTA]

Here’s a screen shot of my fuel pumps off
My btres, you’ll see actual that’s the top line and requested is the one diving .. IMG_7519.jpg

[jrubio96]

Interesting, but also reassuring that the hellcat lpfp will be sufficient for me since you're obviously quite high power. Right now my request near the top of the RPM with my oem lpfp is 520ish, I wonder if setting it higher for now until I get in my hellcat will help at all. I've hit fuel-cut a couple times but it hasn't been a super jarring experience. We've got the fuel cut under control for now, slowly ironing the car out within the limitations we're working with since I'm on stock gates/map/lpfp for now.

[IllusionalTA]

the request isn't goin to magically add fuel, the pump has, what it has, and anything over Rs7's will tap them out if wringing the car out. the hellcat is a good addition, for sure and a fairly inexpensive one at that..