D-Jet Fuel Pressure Regulator, How high should it go? Options

[GregAmy]

What should be the maximum capability of the stock D-Jet pressure regulator? Mine only goes to 36.

If that's normal, is there another similar-format regulator that can go up to around 45psi?

Background: Microsquirt project. Was hoping to use the stock regulator, but now need something that I can easily mount in the same location, if possible. Injectors I'm using are rated at 43.5psi.

Discuss!

[914_teener]

I know some folds have done MS systems so maybe they'd chime in.

I have done quite a few of them (IMG:style_emoticons/default/piratenanner.gif)

I know... (IMG:style_emoticons/default/shades.gif)

[GregAmy]

The OP didn't say if he was going to retain the stock pump

It's a Bosch 2-port replacement. Probably Bosch 69133?

I'd assumed he was going to use the linked high impedance injector...

A correct ASSumption.

The OP didn't mention displacement.

Dead stock 1974 2L engine, as far as I know. Zero knowledge of its history, though evidence of having been out before. Leaks a little bit at the case bolts.

Whole lotta dick-swinging around here and yet...no one answered the OP's original question.

[914_teener]

The OP didn't say if he was going to retain the stock pump

It's a Bosch 2-port replacement. Probably Bosch 69133?

I'd assumed he was going to use the linked high impedance injector...

A correct ASSumption.

The OP didn't mention displacement.

Dead stock 1974 2L engine, as far as I know. Zero knowledge of its history, though evidence of having been out before. Leaks a little bit at the case bolts.

Whole lotta dick-swinging around here and yet...no one answered the OP's original question.

You can use the stock preasure regulator


Swing your own dick at the rest.

[JamesM]

Whole lotta dick-swinging around here and yet...no one answered the OP's original question.

Who is swinging dick? I thought we were just having a discussion.

Not sure there is hard data on the pressure regulators range to give a definitive answer, at least i have never seen it. Like I said though, I have seen one that was cranked out to near 50PSI so I suspect the limiting factor here may be an old pump, but TBH I cant say for sure, may have been a fluke.

I really want to go test this out myself now but my test bed car currently has the fuel rails pulled off. Had to steal some lightly used NOS 2.0 injectors off of it so I could keep my Bumble Bee project totally stock (I have my limits, the LE has to stay stock)


Thats a real clean install you have going so far, I dig it! I like your coil location choice. Working on something similar for my next refresh but using a newer VW 4 coil pack. Great minds....

[JamesM]

Was poking around a bit and and found these injectors from FiveO which look to just be the low impedance version of their A280H

https://www.fiveomotorsport.com/hose-type-e...-sport-compact/

Interestingly enough, they publish the pressure ranges for this injector on their site (along with the latency info which is a huge bonus for MS)

Notice they list a MINIMUM pressure of 36psi.
Im NOT saying these specs are going to be the same as the A280H (i have no idea), but seeing this would give me doubts about running them at 28-30PSI, at least not without getting confirmation from the manufacture.

Voltage: 8-15 Volts, Nominal 13.5 Volts
Amperage: 4.5 Amps
Latency (dead time): 0.700 ms at 14 volts - Complete latency table sent with each set of injectors.
Excellent atomization for medium compression, single- and multi-valve engines.
Injector Dimensions:
Overall length: 3 in./77 mm
O-ring to o-ring: 2.6 in./66 mm
Body Diameter: .95 in./24 mm

Will not require more than 1% trim
Pressure: Min. 36 PSI (2.5 bar), Max. 101 PSI (7 bar)

[JamesM]

Just remembered I still have the paperwork for mine...

No minimum pressure listed, but looks like they should be good for way over 43.
Highly suspecting that they have the same pressure range based on this.

Original recommendation stands... I would find a way to get the rest of your fuel system up to run them at 43psi (realizing that was your original intention here).

[JamesM]

What should be the maximum capability of the stock D-Jet pressure regulator? Mine only goes to 36.

@GregAmy

What fuel pump are you running?

Literally just now learned this, but it looks like the factory pumps have an over pressure relief system built in (that is apparently what that annoying 3rd port on the 3 port pumps is for) designed to not allow pressure over 3 bar, and guessing on an older pump that number might even be slightly lower due to wear. Just guessing here, but if you are running a stock pump this could explain the max pressure you are seeing.

Per https://oldtimer.tips/index.php/en/d-jetronic/81-fuelpump
It looks like the bosch universal replacement (0 580 464 999)is rated to 4 bar

https://www.amazon.com/MERCEDES-Admiral-Bos...5/dp/B00BHGUKQU

Though amazon is great and showed me this much cheaper ($35) replacement that looks physically identical and rated at 35 gal/hr @ 45 psi Max pressure - 8.5bar (125 psi) - provided you are not afraid of cheap parts.

https://www.amazon.com/Universal-Replacemen...EWG9SKBVNB4MCXX





I personally have been running this pump on one of mine with the stock regulator for 10+ years

https://www.summitracing.com/parts/msd-2225

Its probably a little overkill (good to ~500hp) as well as being on the loud side, but it gets the job done. only mentioning it as i dont have personal experience with either of the other 2 to vouch for them yet.



Im curious to know what you find out here.

[JamesM]

Hey, looky what I found....


https://www.injector.com/cart/pc/Adjustable...No-0610-p48.htm

I would deal with/verify your pump situation first but if for some reason you still cant get your stock regulator to 43 psi this looks like it might be a fit providing the picture is an actual representation.

Edit:
Looks to be the same as an MSD 2222 (and if you look real close at the picture it says made in germany and had a bosch part number, not sure what that is about)

https://www.summitracing.com/parts/msd-2222

Also the MSD-2220 (same thing without the boost port)
https://www.summitracing.com/parts/msd-2220

Both are listed as 36-45 PSI


anyways, you have options. Thinking that should be enough info to take care of all the issues (IMG:style_emoticons/default/biggrin.gif)

[JamesM]

Found another picture of the MSD 2222 where you can see the full bosch part number...

you will never guess what it is...

(IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/lol2.gif) (IMG:style_emoticons/default/lol3.gif)

[GregAmy]

Since we're going deeper into the design...

And, by the way, before we get too deep into this I wanted to recognize the assistance I've received from EricP, @Montreal914 . He has his own build going on but we've been swapping info back and forth. Thanks, Eric!

My design basis an over-riding "prime directive": use as many stock components as reasonably possible, and try to design it such that anyone can install it. I also have a design cost of <$1500 in parts. Unless someone wants to take this design and sell it as a kit for the community (and if you do, please contact me), I plan to do a full write-up of parts build lists, sources, design, and instructions.

Toward this, my goal is to use the "stock" fuel pump and pressure regulator, if at all possible.

I got the pump I'm using from Chris Foley at Tangerine; it is a 2-port replacement for the factory 3-port. He thinks it's the Bosch 69133. I've yet to find any specs on that pump but I havne't looked hard; I was working under the impression that the limiting factor here was the regulator. Maybe that was a flawed ASSumption.

More later; time to go to work to pay for all this. - GA


EDIT: Current plan is to tune the engine to 35psi, with "255" as the flow number for the injectors.

[barefoot]

Many years ago I had a project to design automotive fuel injectors working with then the Bendix company who did the initial patents on the D jet type system before Bosch got into the game.

Solenoid operated injectors take about 1.7 milliseconds to open before any fuel is delivered and an engine operating at 6000 RPM goes one full revolution in 10 milliseconds. the 10 ms is typically the 100% duty cycle for these injectiors.

Looking at the entire flow range of this system or "turn down ratio" you have about 2 to 10 ms flow range for the injector itself plus the trigger points range from idle speed of say 800 RPM to 6000 RPM max yields 8 to one for the injector and 7.5 to one for triggering interval for a total of 60 to 1 flow ratio for the system, that's pretty good.

Modern direct injection engines cannot use anything like 10 ms time as all injection has to occur in the compression cycle. new piezo injectors do not have any initial lag, so are a must for direct injection

As previously mentioned, flow rate is not linear with pressure, but varies with the square root of pressure. So if you've got to larger bore cylinders and want to match with more fuel flow, that can be done by adjusting pressure:
For a 10% larger displacement, in theory you want 10% more fuel flow. to achieve this you need 1.1 squared pressure increase ar 1.21 pressure increase.
So if standard pressure is 28, you'll need 33.9 psi. Hopefully the pressure regulator can be adjusted by this much.

Barefoot

[Montreal914]

Though amazon is great and showed me this much cheaper ($35) replacement that looks physically identical and rated at 35 gal/hr @ 45 psi Max pressure - 8.5bar (125 psi) - provided you are not afraid of cheap parts.

https://www.amazon.com/Universal-Replacemen...EWG9SKBVNB4MCXX

Thank you @JamesM for the find! Exactly what I need for my build as I am taking this opportunity to relocate my fuel pump to the front with a '75 pump panel. (IMG:style_emoticons/default/beerchug.gif)

Looking forward reading the results @GregAmy . Still digesting your electrical discoveries... (IMG:style_emoticons/default/blink.gif)

[JamesM]

Since we're going deeper into the design...


My design basis an over-riding "prime directive": use as many stock components as reasonably possible, and try to design it such that anyone can install it. I also have a design cost of <$1500 in parts. Unless someone wants to take this design and sell it as a kit for the community (and if you do, please contact me), I plan to do a full write-up of parts build lists, sources, design, and instructions.

Toward this, my goal is to use the "stock" fuel pump and pressure regulator, if at all possible.

Totally possible but you may be better off just running d-jet, l-jet, or possibly vanagon injectors, with load resistors at the stock pressures in that case. Pretty much every d-jet component except for the throttle position sensor can be re-used in a Megasquirt build (including the stock wiring harness if you are crafty enough) but having run one like that for ~15 years I can tell you it has its short comings. My first d-jet to MS conversion i think my total parts cost including the MS ECU components (I soldered it myself) was roughly around $150 bucks, but the necessary labor was beyond what i would recommend to anyone.

I got the pump I'm using from Chris Foley at Tangerine; it is a 2-port replacement for the factory 3-port. He thinks it's the Bosch 69133. I've yet to find any specs on that pump but I havne't looked hard; I was working under the impression that the limiting factor here was the regulator. Maybe that was a flawed ASSumption.

More later; time to go to work to pay for all this. - GA

Not sure about the Bosch 69133 but the factory 2 ports are also supposed to have a built in over-pressure circuit. Hard to say what might be limiting your total pressure but that MSD FPR that is rated 36-42 PSI has the Bosch d-jet part number on it. So I would think that if everything were healthy you should at least be getting close to 40 if not more. I have first hand seen one that was set ~50psi.

That being said if all you can get is 36 you could just leave it there, those injectors may be fine running at that and while it is helpful to know the exact response and flow numbers at a given pressure it isnt mandatory as you build your own fuel map anyways. Given thats the top end of your fuel system output and the bottom end of acceptable pressure on the injectors though I think Jeffs point as to a safety margin may be something to be considered.

Compromises like this are why i have moved more and more away from using a lot of the d-jet bits over the years. I can elaborate on the details a lot more if you like but that only matters if you are interested in changing your goals slightly. I get your current goals, I used to share them, and they are totally doable, just realize they involve compromises and one of those being running as optimally and reliably as it could, though no more so than running a d-jet system. You just wind up inheriting its short comings.

[GregAmy]

Eric, I'm actually starting to "write all this shit up" like I promised I would; I got into a writing spree yesterday and drafts are going up on my Blogger site now.

I'm looking for some time with a local DynaPack buddy, maybe get it in either this or next Saturday for a general baseline auto-tune and fiddling. Mostly depends on the weather (the 914 does not see the roads until all the salt crap is rained off.)

Anyone know what AFRs these engines like to run at?

Totally possible but you may be better off just running d-jet, l-jet, or possibly vanagon injectors, with load resistors at the stock pressures in that case.

Eric and I discussed injectors. Eric took the "go with DJet" direction; I'm interested to see where he ends up. I, on the other hand, compared the cost of cleaning/testing my injectors ($125 incl shipping round-trip), the risk of one failing (a good used one $75-150), and the availability of replacements in the future (low, and getting worse). Coupled to the need for a resistor pack, I chose to replace all four injectors with FiveO's for ~$300 shipped (they offer 15% off coupons all the time).

Same goes for a lot of the other D-Jet components. There's a strong argument for using parts readily available from FLAPS.

All of my design decisions and results will be part of the Blogger writeup.

Not sure about the Bosch 69133 but the factory 2 ports are also supposed to have a built in over-pressure circuit. Hard to say what might be limiting your total pressure but that MSD FPR that is rated 36-42 PSI has the Bosch d-jet part number on it.

ASSuming this is a consistent result - in other words, I have nothing "failing" - then I'm planning on tuning the car at 35psi. I can always re-tune to a higher pressure later.

[JeffBowlsby]

Check this.

"35 gal/hr"

Seems a bit ridiculous for 1 injector, no?

[JamesM]

Though amazon is great and showed me this much cheaper ($35) replacement that looks physically identical and rated at 35 gal/hr @ 45 psi Max pressure - 8.5bar (125 psi) - provided you are not afraid of cheap parts.

https://www.amazon.com/Universal-Replacemen...EWG9SKBVNB4MCXX

Thank you @JamesM for the find! Exactly what I need for my build as I am taking this opportunity to relocate my fuel pump to the front with a '75 pump panel. (IMG:style_emoticons/default/beerchug.gif)

Looking forward reading the results @GregAmy . Still digesting your electrical discoveries... (IMG:style_emoticons/default/blink.gif)

To be clear, I cant vouch for that pump, never ran one, it just popped up in amazon when i was looking at other pumps. It could be complete cheap garbage like a lot of the other knock off crap on amazon these days. But for 35 bucks with a prime guarantee, not a lot of harm in trying.

This one is even cheaper... how low do you want to go?


https://www.amazon.com/Electric-Universal-P...14B2ZEZG3SWM9F7

[JamesM]

Check this.

"35 gal/hr"

Seems a bit ridiculous for 1 injector, no?

What is the flow rate on the factory pump?


The pump I have on my car is 43/gal/hr, and yes, it is overkill.

[GregAmy]

Found another picture of the MSD 2222 where you can see the full bosch part number...

you will never guess what it is...

(IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/lol2.gif) (IMG:style_emoticons/default/lol3.gif)

Wait, missed this...D-Jet part? Not the one with the boost port...?

[JeffBowlsby]

Check this.

"35 gal/hr"

Seems a bit ridiculous for 1 injector, no?

My mistake, apologies. I had mistakenly thought this was an injector...it’s a pump.

[JamesM]

Found another picture of the MSD 2222 where you can see the full bosch part number...

you will never guess what it is...

(IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/lol2.gif) (IMG:style_emoticons/default/lol3.gif)

Wait, missed this...D-Jet part? Not the one with the boost port...?

Both the one with the boost port and the one without have the same Bosch part number on the body, at least in the pictures I was seeing. Only difference between the two appears to be the adjuster screw. The part number in question though shows it to be a VW/914 d-jet pressure regulator, so if the MSD published specs are believed it leads me to believe that the stock d-jet regular should go to 42PSI, and given I have seen one go higher than that in the past I have to think its accurate. Still has me curious why you are only seeing ~35.

Also, given it looks like the only thing needed to add boost reference to these things is to port the adjustment screw to add pressure to the back of the diaphram, im wondering if its not also possible to affect the max pressure by shimming the adjustment screw??? Ill have to take one apart and examine it a little closer.