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!

[JamesM]

Higher pressure provides better fuel atomization, one reason newer cars dont run at 29psi.


Not understanding what the concern with running higher pressure/having a "safety" margin is about. Those are completely custom injections so nothing d-jet applies here (except for maybe the pump and pressure regulator if you retain those). Injector flow rates can potentially get sketchy when run above 80% duty cycle, that is where I would have concern with a safety margin and running lower pressure means higher duty cycle needed to deliver the same amount of fuel, so in that respect you are potentially safer running the HIGHER pressure depending on your fuel needs.

If there are concerns about the injectors though I would say contact FiveOMotorsports about them.

I would run them at the pressure with the known flow rating.

As for the stock pressure regulator, not sure what its maximum pressure spec is but I have seen a d-jet car sitting at ~50psi at the rail before (DAPO, dont ask), so not sure if that is something attainable with most stock regulators and pumps but i have seen it.

[914_teener]

Higher pressure provides better fuel atomization, one reason newer cars dont run at 29psi.


Not understanding what the concern with running higher pressure/having a "safety" margin is about. Those are completely custom injections so nothing d-jet applies here (except for maybe the pump and pressure regulator if you retain those). Injector flow rates can potentially get sketchy when run above 80% duty cycle, that is where I would have concern with a safety margin and running lower pressure means higher duty cycle needed to deliver the same amount of fuel, so in that respect you are potentially safer running the HIGHER pressure depending on your fuel needs.

If there are concerns about the injectors though I would say contact FiveOMotorsports about them.

I would run them at the pressure with the known flow rating.

As for the stock pressure regulator, not sure what its maximum pressure spec is but I have seen a d-jet car sitting at ~50psi at the rail before (DAPO, dont ask), so not sure if that is something attainable with most stock regulators and pumps but i have seen it.

I think that is what Foley is saying. The OP didn't say if he was going to retain the stock pump and I'd assumed he was going to use the linked high impedance injector which is rated at 280 cc/ min at 300Kpa. The OP didn't mention displacement.


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

[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.

[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....