How to scale the HPFP pressure sensor

[cpolly69]

i say they upped the pressure, made a different im, and they tuned with it that way - can't be anything else

[Realgib3]

pulse width is the only other thing I feel like they could have touched...Idk and at this point I don't care what it is I just wanna know!!!

[jhershorin]

So many smart guys...this thread was fun to read.

[djuosnteisn]

You and your bag of tricks are making apes out of us... lol.


It is a damn fun game though! I kinda like it.

[SpeedSixxx]

jhershorin.....lets be friends

[cld12pk2go]

Originally Posted by JumpingJackson The high pressure line that goes to the fuel line fails around 2400-2500 psi by the way, so i wouldnt go any higher than ~2250 or so.

Dang, so it cannot be very thick walled then. It doesn't take much thickness to hold obscene pressure on small dia tubing.

So by failed, do we actually mean that the hoop stress in the line exceeded the material yield strength? Or was it a connector failure?

[06Speed6]

Supposidly a connector failure, probably a seal.

[djuosnteisn]

I think just a leak.

I'll find out..... wait a min... i hope i don't find out. hahaha.

[cld12pk2go]

Originally Posted by 06Speed6 Supposidly a connector failure, probably a seal.

Good, that should be cheaper/easier to resolve.

[djuosnteisn]

"take 2 pills and call me in the morning"

Pills are in my possession.

...but i'm also a turtle dick and didn't realize the bore in the fuel rail wasn't threaded all the way down. Sigh, this is why i'm an electrical guy. So i'll either have to cut one of the pills down a fair amount, or grind the threads off one so it will slide all the way down.

Also, i'm starting to have doubts about the hole size, especially considering the feed hole on the hard line from the pump is only like 2mm (79 thousandths). But no worries, if i need to go smaller, or even more, try completely blocking it off, this pills are made out of stainless and i can just weld the hold shut.

More info tomorrow if i have time. Things are finally starting to calm down around here, and i almost have my spare block tore complete down .

[SilverDemon]

Sorry to hear, When I have the fuel rail and relief valve in my hands maybe I can come up with something a little different......I can go smaller on the orifice size if need be.

[Lex]

Looks like you'll have that motor done before too long. Tearing down is always fun and quick

[djuosnteisn]

Originally Posted by SilverDemon Sorry to hear, When I have the fuel rail and relief valve in my hands maybe I can come up with something a little different......I can go smaller on the orifice size if need be.

No worries at all! These will definitely work one way or another. And thanks again man for making them. I agree, once you get the rail, things will be much much smoother. I should have sent it to you a long time ago, lol.

Originally Posted by Lex Looks like you'll have that motor done before too long. Tearing down is always fun and quick

Tear down is soooo damn fun actually. I was able to pull an exh mani in 6 minutes, hahahaha. Now i just need some 12 point sockets to pull the head studs.

[superskaterxes]

lol thanks again silverdemon for making these!!!! go dustin go!!!!

[djuosnteisn]

Okay, so i have one ground down and slides right in, muhahahha.


Probably install it tomorrow i guess.

My only doubt at this point is that the hole in the restrictor is gonna be too big, considering it's not much smaller than the feed hole.

Opinions?

[mkriebs]

Better to start with a small difference then to blow something by going with a large difference.

[djuosnteisn]

your so rational.... ha!

[mkriebs]

I know... I don't like breaking stuff lol.

[SpeedSixxx]

i is gettin massive hard on..keep it up

[djuosnteisn]

I've finally swallowed the pill. What a pita to get to that valve.

First take off protection bracket (at least that's the only purpose i see for it, protect the hpfp stuff)



(i didn't take the bracket all the way off, just loosened it, the second pic is a spare i have)

Undo the small coolant hose (sorry no pic), not the big one. And put a cap of some sort on it so it doesn't spew coolant every time you bump the big coolant hose.

Now you can painfully wedge your fingers into the connector release, and use some stupid tool you make out of wire to wrangle the release off:


Undo the wire bundle clip so you can move it out of the way:


Cut a wrench in half:


Break the valve loose, and then it'll come out with your fingers. Be careful not to drop anything, esp the pill when install it. Pretty tough reach.


Re-install everything back to normal:




My only thought now:
- The valve, and all hpfp connections for that matter, are covered with a white paint like stuff. Almost like a liquid sealant. Do you think the valve is leak prone now? Anyone want to postulate what the stuff is?

I guess i'll fire it up maybe later tonight or drive it to work tomorrow. I hope to shit it doesn't blow up lol. Though i honestly don't think the hole is small enough to restrict flow enough. We'll see!

[SSinstaller]

Without seeing a picture it's hard to say for sure, it could be sealant, or it could just be an assembly marking so the techs know that the parts are torqued properly and that part of the assembly process is finished.

[SilverDemon]

I believe the white is to help a quick installation from the factory, maybe something like a dry lubricant to ensure proper torque specs. It just does not look like the typical thread sealant, but again nothing on this car is typical.

[djuosnteisn]

Just snapped a pic of the white stuff on the main feed connection. This stuff was on all hpfp high pressure side connections:

[superskaterxes]

lol wtf dustin you go through this whole install and then dont drive?!?! ahhhh the suspense is killing meeeeeeee!!!!!!!

[m4tic]

Originally Posted by superskaterxes lol wtf dustin you go through this whole install and then dont drive?!?! ahhhh the suspense is killing meeeeeeee!!!!!!!

^

[SilverDemon]

That white is just a verification paint, what SS said, those parts have been checked for proper torque.

[djuosnteisn]

Sweet. Relief valve is a straight thread and has a washer that is used for sealing surface. Silver, i don't think the valve i sent you has that washer. If you need any measurements off it or anything lemme know.

I'm gonna go start the car and see if it blows up. IMO a cold start is the ultimate test, cause it starts out in OL with high fuel pressure and minimal injection amount, so that's the point the rail experiences the most stress. I'll update later tonight about the start, and tomorrow about the drive if i drive it

[SilverDemon]

I think the only measurement I would need is the thickness of the sealing washer, but I can wait until I receive the parts in the mail.

[superskaterxes]

does anyone know if the other DI platforms have this same rail return line? can we get some more design info from them?

[djuosnteisn]

Meh, had to drive it.

Doesn't work, lol


Instead it makes kind of a "whistle tip" beep sound hahaha. Not sure if it's from flow going through the hole or if the pill is possible rattling.

I had to grind down the threads to get it to fit in there past the point that wasn't tapped, so this is fail on 2 fronts really. 1) Rattle is bad, cause won't be long till metal is knocked off into the pump or worse into the injectors. 2) Fuel prob just goes right around the pill since it's not a perfect fit in the un threaded bore.

Fuck this shit is silly.

I think i just need to cap the fucker off. Not sure what the best way to do it is. I really don't want to pull my fuel rail just to tap the remainder of the bore, esp if we end up capping it in the anyways. I think i'm just gonna brave one and cap it.

I have extra parts, so i think i'll cut down one of the brass nipples so that i can keep the threads on the pill and it'll still clear. Then i'll weld the hole shut on the pill and thread it in. Then thread brass nipple, and connect my hpfp line to it.


As always ideas are very welcome.

[mkriebs]

Good luck, you brave... brave soul.

[FreeFlyFreak]

Originally Posted by djuosnteisn I think i'm just gonna brave one and cap it. I have extra parts, so i think i'll cut down one of the brass nipples so that i can keep the threads on the pill and it'll still clear. Then i'll weld the hole shut on the pill and thread it in. Then thread brass nipple, and connect my hpfp line to it. As always ideas are very welcome.

Talk to John PTP before you do that....... I know I read he had a fuel rail burst during his experimentation.

I would hate to see you burn your car up due to a burst fuel rail, when a quick phone call may prevent it.

[Smoke_31]

Just keep in mind, you are now counting on that brass to structurally hold back what ever pressures may occur with that orifice plugged off. With the hole in the middle, it would bypass pressure to a certain extent (or all the way with this first attempt). Will the threads hold 2000+ psi with massive differential pressure (2000+ psi obviously) across the pill?

Another thought is that you have no idea what pressure that pump is capable of putting out or how quickly it will ramp up to dangerous (fuel rail splitting/pill fracturing/injector destroying) pressure. Keep a fire extinguisher handy please. Best of luck! I will be watching with anticipation.

[cld12pk2go]

Not to put a damper on the ongoing innovation but...

As a chemical engineer, I would also offer caution about removing the RV completely from a positive displacement pump fed system involving an incompressible fluid.

The pressure can spike damn fast in this type of system with catastrophic results.

We really need a relief valve with a higher set pressure. Any other option is rather crude IMHO (and this is being rather generous).

[SilverDemon]

As soon as I have the RV in my hands I should (fingers crossed) be able to source a higher RV through some of the vendors I deal with. Or at least something we can adapt over to our application. I will know more in the first few weeks of January.

[djuosnteisn]

I think a few of you are missing some critical details.

There are 2 valves used to regulate pressure.
1) The internal, solenoid controlled spill valves. This are the primary source for pressure regulation.
2) The emergency over-pressure relief valve, whom i'm butting heads with right now.

Before i ever put my ckt on, with the hpfp, the system NEVER relied on the relief valve. You can hear it when it opens, just ask skater. And the internal spill valves work so well that they can regulate down to ~400-500psi even at higher rpms (cam driven pump) with light throttle.

So if anything, by "upping the pressure", these spill valves will have to work even less to regulate pressure.


I really think the relief valve is like an airbag, not a seat belt. It's not intended to be a critical part of the regulation process, but more so a fail safe to keep the rail from reaching damaging pressures (3k+).

When john blew up a rail, he was mucking with the internal spill valves, and had fully blocked this relief valve. I'm not gonna touch anything internal, cause i believe the ecu controls it fine.


So i think my logic stands. I've never heard the relief open w/out my ckt, and that means the spill valves are flowing much more fuel upstream than it would be when running the rail at a higher pressure.

...double post merge...


Think of it like this, imagine that silver had already sourced a new valve that doesn't open until 2500psi... How is that any different that just blocking it off.

It isn't unless a high pressure event occurred, which from my experience, doesn't.

[superskaterxes]

you tell them naysayers dustin!!!!

[SilverDemon]

I totally agree with you DJ. When I did a few of tests with the SB, I saw total saturation of the sensor. Meaning, when I scaled the sensor with an outrageous number I saw a full 2100 psi until I let off the throttle (this log was on the stand back itself, not the dash hawk). I think 2100 is max reading on the sensor, correct me if I am wrong. So what does this mean? Was I actually throwing more fuel than the RV could handle? Or was this a sensor phenomenon? I did see the AFR's go to the low 8's while the fuel pressure at 2100psi.

[djuosnteisn]

Man i'm not sure honestly.

Been thinking about this too, cause i've heard of zero mention of relief valve blocking with SB fuel pressure stuff.

I don't know how the SB works well enough to tell you if it was a legit 2100psi, or if thats just what it was trying to target, but not really seeing. I also don't know what calibration they use to calculate pressure from sensor voltage. It could be you were just at 1895 (relief valve pressure) and their calcs were off or something.

The afr's do drop quick when upping the pressure too. Soon enough we'll see how much they drop at 2100, lol.

[SilverDemon]

The SB was reading sensor voltage before the ECU. I was watching (on the SB in real time) both pressure and voltage, I saw about 2.5 volt offset from voltage in and out while the pressure climbed to 2100 and stayed. Damn it, i wish I had better weather up here in Ohio to go out and play with this a little more...LOL!!