Real Fiero Tech

It's about time you're done with this thread Shaun. Has it occurred to you that BMW reads, and logs, fuel pressure before and after the HPFP? You think I haven't checked this?

I cannot overdrive the OEM pump, for 2 reasons. First, I wouldn't want to given the questionable reliability of the pump even at OEM speed. Although they have a lifetime warranty, they're a pain to change, and aren't completely free.

Next, overdriving them is nearly impossible at this point because it screws with the electronic control. I'm not sure how, but the tuner friend of mine said that is out of the question.

As for that link, that's no bueno. First, to date, I think they have 1 of those shipped, and it has never functioned properly because the electronic control cannot be done through the OEM computer when it's overdriven. Their pump is turning roughly 8 times OEM pump speed. If they ever do figure out the electronics, I'd question the pump's reliability turning that fast all the time.

Lastly, their company has a history of less than optimal warranty support.

Shaun41178(2) wrote:why can't you supply what the lp pump flows? I asked a simple question. do you not know? what did you upgrade it to?

if the hpfp can't keep up, then you are sol. Why not go hit up the m boards for help? Or did you call them all stupid there so now everyone laughs at you?

step it down to e47. its a much easier solution than what you propose.

Because it's not a feed pump issue, as he said. From the sound of it, the HPFP is a community wide problem that NO ONE knows how to solve yet.
I @$$ume there's a common feed pump upgrade that is the defacto standard upgrade path, like BPU used to be (still is?) for MkIV Supras. If he has that and it's enough for everyone else in the community pushing the limits of the HPFP, what does it matter what it's capability is?

Also, chill the F out.

Aaron wrote:As for that link, that's no bueno. First, to date, I think they have 1 of those shipped, and it has never functioned properly because the electronic control cannot be done through the OEM computer when it's overdriven. Their pump is turning roughly 8 times OEM pump speed. If they ever do figure out the electronics, I'd question the pump's reliability turning that fast all the time.

Lastly, their company has a history of less than optimal warranty support.

What does the electronic control do? Just give pump RPM so that the DME can estimate fuel flow volume and command the appropriate duty cycle for the pressure control solenoid? Are the HPFP's output pulses synch'd to injection events so that the pump is always discharging when an injector is open?

Understanding the DME's needs from the pump RPM signal would help a lot in understanding how we go about achieving more fuel flow.

I spent more time looking at the diagram. The unit is a 3 cylinder swash plate pump. It also appears to be huge compared to GM's HPFP in the LT1 & LT4. Maybe you could drive one of those from a cam lobe?

The Dark Side of Will wrote: What does the electronic control do? Just give pump RPM so that the DME can estimate fuel flow volume and command the appropriate duty cycle for the pressure control solenoid? Are the HPFP's output pulses synch'd to injection events so that the pump is always discharging when an injector is open?

Understanding the DME's needs from the pump RPM signal would help a lot in understanding how we go about achieving more fuel flow.

I spent more time looking at the diagram. The unit is a 3 cylinder swash plate pump. It also appears to be huge compared to GM's HPFP in the LT1 & LT4. Maybe you could drive one of those from a cam lobe?

To be honest I have no idea, as I'm not involved or educated in any of the electronics side of this project.

The pump is also larger than the newer BMW HPFP's, which are smaller and driven off cam lobes. But our DME cannot control them, or the GM unit.

Getting fuel isn't the issue really, as there are more than several HPFP options out there (Diesels). But again, it comes down to electronic control.