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

[GregAmy]

Still has me curious why you are only seeing ~35.

- Pump can't go that high (capability or internal bypass);
- Regulator can't actually do it;
- Bad regulator.

I've got some dyno time scheduled for the 14th. I think I'll drop the coin with Summit and buy one. Edit: Items appear to be no longer available.

...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.

Yeah, that would have to happen inside; I ran out of threads then I screwed it all the way in.

[GregAmy]

It's not the pump. I went out there, jumped the FP relay, and used pliers to squeeze off the return line. It hit 90psi before I lost my nerve and released it.

Edit: Looks like these are all similar. No info on max-avaialble pressure, though.

Bosch 0280160001
Delphi FP10545

[ChrisFoley]

I have a few FPRs here. You're welcome to try one of mine to see if it gets closer to your desired operating pressure.

[GregAmy]

Thank you sir!We're already overdue for a beer visit. I may pass by tomorrow if you're in.

Here's some docs I found when I was going through paperwork. The injectors should be OK at higher pressures. Just not clear where I *should* run them. I clearly do not need the flow rate at higher pressure, but I wonder if reducing the duty cycle improved efficiency. I wonder if I'll even notice a difference at all by bothering to go over 35psi.

[JamesM]

Thank you sir!We're already overdue for a beer visit. I may pass by tomorrow if you're in.

Here's some docs I found when I was going through paperwork. The injectors should be OK at higher pressures. Just not clear where I *should* run them. I clearly do not need the flow rate at higher pressure, but I wonder if reducing the duty cycle improved efficiency. I wonder if I'll even notice a difference at all by bothering to go over 35psi.

I would run them at 43 If possible as that is the lowest pressure you have all the datapoints for. Increasing the pressure may improve the atomization but if your pulsewidths get to small mixture control at idle can become a problem.

But... if those injectors can make a decent spray pattern at 35psi I doubt you would notice much if any difference by going to 43, the only question is how well do they fire at 35?

[Montreal914]

Just catching up on the thread this morning.
Greg, 90 psi on the pump, that is impressive! Regulator... (IMG:style_emoticons/default/beerchug.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

Thanks James, obviously, I am fully aware that these are what they are (IMG:style_emoticons/default/rolleyes.gif) . but WOW, $20!!!!
I really wonder if there is actually a quality difference between a $35 and $20 one. Both are low quality for sure. I might just buy two $20 ones... (IMG:style_emoticons/default/laugh.gif)

[GregAmy]

Quick update... per Summit Racing, MSD has discontinued the MSD-2220.

Rock Auto has the Delphi version, says it's 29psi.

I tried two used ones from Chris; one only got to 34psi, the other had the locking nut stuck so I didn't force it.

NAPA can get me a "FPR for the Porsche 914" but it's special-order only, and they don't know how adjustable it is.

Rock Auto looks like the Delphi version as well, 29psi listed.

I can't find a FPR for the car on Pelican's web site.

I'm guessing that if I'm running more than 35-36 psi I'll have to go aftermarket on the FPR...

[ChrisFoley]

Bosch Fuel Pressure Regulator at Pelican

[GregAmy]

And...they're out of stock. Refers me to "Genuine Porsche" version for $145 which "in some case...must be imported from Porsche's German warehouse -- which requires longer shipping times and an additional "Germany shipping" surcharge."

I'll call my local dealer, see what their tithe is.

[ChrisFoley]

You might want to start soaking the three used ones from my shop, and yours for that matter too.

[JamesM]

Didn't have time to tear into one this weekend but from the looks of the diagram im wondering if MSD didnt get to higher pressure via a longer adjustment screw. Would need to measure how much more could be added before the coils bind. From the drawing though I would think you should be able to dead head the pump with a long enough adjustment screw

Not sure when the last production run would have been, but guessing at 50 years old the OE springs may be getting a bit tired.

[JamesM]

Just did a bit more searching... this is an interesting read on the pressure regulator

https://www.thesamba.com/vw/forum/viewtopic...s+inside++fails

Cant tell for sure but it looks like the adjustment screw may be a custom part, so swapping may be out of the question. Also looks like new ones from anywhere may have gone NLA sometime over the last couple years and if that post is to be believed these have a high potential for wear that will affect every used one out there.

May be time to look at other options

[JamesM]

Knowing that 914 l-jet regulators are a direct swap (fitment wise) I started exploring what might be out there the the realm of cars that used similar systems.

914 L-jet regulators are non-adjustable, vacuum referenced and is supposed to give ~37-38 with zero vacuum. Those can still be had available new but isnt quite where we want to be...

Vanagon regulators are similar pressure wise


and then by some random luck i stumbled on this...

Bosch 0 280 160 256

vacuum referenced, 3 bar non adjustable. Would need an adapter on the inlet but other than that appears to be externally similar to a stock regulator.

https://www.amazon.com/gp/product/B00C818WG...45-cd78f07a84d8





This has some interesting candidates as well though i am not sure where they can be purchased. FPR 05-40 B (adjustable from 0.5 to 4 bar) and FPR 15-50 are of particular interest.

https://www.bosch-motorsport.com/media/down...minikatalog.pdf

[JamesM]

This is interesting. In the latest bosch catalog it looks like they only offer rail pressure regulators now, but they have an adapter to convert a rail regulator into an inline regulator...

https://www.bosch-motorsport.com/media/down...atalog_2020.pdf

http://www.bosch-motorsport.de/content/dow...abs=50227595-4/

May be more bad news for d-jet

[JamesM]

https://shopbhp.com/products/kit-car-fuel-p...ant=28302418369




Looks like adapters for the modern bosch regulators may be the way of the future for older cars. Perhaps one of our vendors could machine one thats a perfect fit for a 914


Edit:
I should have checked the dub shop first... Mario always has awesome stuff
http://thedubshop.com/universal-fuel-pressure-regulator/

that looks like it would fit in place of a stock regulator. Other vendors look to have a adjustable regulators that will fit that adapter that can be turned down to lower pressures, so may be a solution for d-jet as well

[GregAmy]

May be more bad news for d-jet

Well crap.

I have not had a chance to digest all this in detail, but your bottom line appears to meet my experience over the last few days: the OE fuel pressure regulator is becoming scarce. One of my core reasons for developing a Microsquirt for myself was as a low-cost alternative to declining D-Jet parts (and tunability for mods); one of my design parameters was to do that with as few parts as possible. I was working under the ASSumption that the FPR was readily available new; that appears to be flawed.

Aftermarket adjustable "return/bypass" FPRs are common, but they won't fit into the stock bracket. I may have to rethink this paradigm and come up with something around an aftermarket part.

[GregAmy]

Here's a 3-bar one. eBay ad claims (I think) it can be set higher:

https://www.ebay.com/itm/Fuel-Pressure-Regu...28/401379447531

Can't really tell what the hose fitting size is.

Searching for "107001001303 regulator" results in other sources for the same part, implying it's used on AMG Mercedes (if I am translating properly).

[JamesM]

May be more bad news for d-jet

Well crap.

I have not had a chance to digest all this in detail, but your bottom line appears to meet my experience over the last few days: the OE fuel pressure regulator is becoming scarce. One of my core reasons for developing a Microsquirt for myself was as a low-cost alternative to declining D-Jet parts (and tunability for mods); one of my design parameters was to do that with as few parts as possible. I was working under the ASSumption that the FPR was readily available new; that appears to be flawed.

Aftermarket adjustable "return/bypass" FPRs are common, but they won't fit into the stock bracket. I may have to rethink this paradigm and come up with something around an aftermarket part.

Your goals are the same that I had when I did my first install, only back then it was only the start of OEM d-jet parts supply drying up. Fuel pressure regulators going NLA is a fairly recent development though, from what I can tell sometime in the last couple of years. Its a bit of a surprise.

Take a good look at that part from the dub shop, i really think that may be the best bet. Using that 6AN to 5/16 barb bulkhead fitting it looks like it would mount in exactly the same way as a stock regulator, and the actual pressure regulator component is replaceable with modern Bosch of any pressure rating (or fully adjustable)

I think i may order one today just to play around with it.

[GregAmy]

Am I correct in inferring his non-regulator one is 3 bar?

[ChrisFoley]

That's probably what Mario was thinking you would use when he gave you an initial tune for the system.