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!

[JeffBowlsby]

The concern about constant operation at maximum pressure is that you would not want to use any critical part that was to be dependably reliable at its peak output, for very long. Unless you are racing and that's an extreme condition. I had understood this topic was an about everyday application which assumes reliability over extreme conditions - i.e a safety factor.

it would not be reasonable to run 100 PSI pressure rated fuel hose routinely at 100 PSI. Motor oil rated for 300F @ 300F. Your engine constantly at redline. Etc.

Why the heartburn?

[JamesM]

The concern about constant operation at maximum pressure is that you would not want to use any critical part that was to be dependably reliable at its peak output, for very long. Unless you are racing and that's an extreme condition. I had understood this topic was an about everyday application which assumes reliability over extreme conditions - i.e a safety factor.

it would not be reasonable to run 100 PSI pressure rated fuel hose routinely at 100 PSI. Motor oil rated for 300F @ 300F. Your engine constantly at redline. Etc.

Why the heartburn?

Which leaves the question, what is the peak output of these parts?

Fuel Hose - I would hope anyone swapping out their injection has installed at least 30r9, all of which I have seen has at least a 100psi working pressure (newer gates hose is rated 225PSI working pressure) with a burst pressure usually 5-10 times that, so 43psi shouldn't be a concern.

Fuel pump - Stock pump may be an unknown, especially with age, however if we are swapping parts its just a matter of right sizing the pump.

Pressure regulator - I wouldn't anticipate this being an issue provided the pump is sized properly, but even it it was its a simple swap.

So that pretty much just leaves the injectors, the actual limits of which are currently unknown. But... given injectors are flow rated at 43 psi I wouldnt have concerns about any immediate failure. As to long term use, without actual data (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)
but, i think it should be pointed out these are not 50 year old injectors and modern injectors/cars run at higher pressures, heck even later vanagons push close to 40 psi if i recall.
Something else to consider is that if you take an injector designed to run at 43psi and then run it at a lower pressure you potentially run into issues as well, generally more issue than you would have vs increasing pressure as you have the possibility of inconsistent spray pattern and atomization issues. But without the data, who is to say?

Personal opinion, I think ~43 is the safest place to start (if possible) with the injectors, and having seen the difference in atomization between 2 bar and 3 bar pressures first hand, if proven to be reliable either via long term testing or additional data from FiveO, I see no reason to go lower.

When working with something like megasquirt a lot of the time you are in undiscovered country, if you are not comfortable testing things yourself then it might not be for you. Thankfully now there is a LOT more information on available than there was 15 years ago as a few of us have been out there trailblazing and testing this stuff out.