The vacuum hose on top of your fuel pressure regulator increases the fuel pressure by up to 1/2 bar, every time you accelerate or start even the slightest incline . If you have a fuel injected pressure gauge try this the slightest vacuum drop, the pressure increases .
By putting a one way valve on your fuel pressure regulator vacuum hose,this will hold the diaphragm to max vacuum.This will keep the pressure to its lowest.
The average fuel pressure on a multi fuel injection is about 2 bar, and increases to 2.5 bar every time the vacuum drops.
This will dramatically improve your fuel economy.
How do i get this valve ?
Just go to your nearest car dismantles/ wreckers and ask for a vacuum one way valve. You should be able to suck through it one way and not the other .
Most 80 /90 model Toyota's have them.

Have you tried this yourself?
It's an interesting idea.
What were your results?

My concern here is that when you step further on the gas and need more power your ECU also adds more fuel to also cool the engine under high power settings. Leaning that out may cause your engine to run too hot. Also the time you accelerate is relatively short so how much fuel would you ssave?

If you could cut back on the fuel pressure a small amount over the whole power band, then that would be a good idea. maybe your idea does this too.

I'd like to hear more about your results such as what your fuel pressure is after this mod.

I can give you my figures but I do not wont another war. All I am saying is , reduce your fuel pressure. Engine vacuum drops dramatically even at the slightest incline try it . Just connect a vacuum gauge and go for a run, you will be shocked and amazed !!!! I am not suggesting this to people that are only putting out 1/2 litre p/min. Don't forget you have to have decent amount of alternative fuel.
If you wont to go to few steps further you can fit a vacuum solenoid to over ride this a 3/4 throttle .
People are spending hundreds of dollars on this project with no success.
$1.00 or less is not a large output to try this.
THINK LESS FUEL PRESSURE = = = = TO LESS FUEL IN THE ENGINE !!!!!!!!!!!
I am not saying that EFIE's are not necessary in some vehicles.
I am not trying to sell you anything or profit from this.
If you are PROFESSIONAL with scan gauge fuel pressure gauges etc go VOLVO WRECKERS and buy an adjustable fuel pressure regulator. But I Honestly suggest the $1 one way valve first !!
Alex from the time you start modifying you EFI system and adding Hydrogen you are truly playing with fire!!!!
If you are not checking your fuel mixtures and temperatures you can damage your motor? YOU ARE PLAYING WITH FIRE. Every model and make of cars are different ,you should record temperatures before any HHO on the SAME run and try and match them with HHO . DO not exceed them and you should be safe.
EXHAUST TEMP's vary so much its a joke!!!
IT works for me. Does it work for you? let us know.

Bambos,

I'm not looking for a war of any kind, I'm only interested in finding the best solution for combustion enhancement.

Any info would be appreciated.

My email - AlexR@cool-flame.com

Thanks,

I wonder if pinching off the hose would do something similar?
Even more interesting idea for the adjustable fuel press. regulator. But again, you'd want an ETG to monitor things, because now you are really playing with heat issues.
Oddly enough, from LACK of fire..