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Hi everyone

I have a malpassi regulator in my zed(on rb20det)and i dont know alot about these. So i am hoping that someone can shed some light on how they work, what they do etc. Id also like to know what things can go wrong with them etc as im not sure mine is working. the guage sits on the lowest point, how do i know if its working??

thanks in advance

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well Malpassi regulator if it is on your turbo Zed it is most likely a Rising Rate type regulator. that means that as the revs go up the pressure into the injectors increases at a greater rate than 1:1. im not sure if its 1:5 or 1:7? gone blank atm, but yeh as revs go up the regulator increases the pressure into the fuel rail hence pushing a bit more out of the injectors throughout the rev range. im not too sure of the technicalities of how it works but thats basically what it does! helps squeeze more out of your injectors across the entire rev range.

nothing can really go wrong with them as such? they just regulate the fuel so if your car is running fairly well then chances are that your injectors are getting at least the amount of fuel they require. sometimes a rising rate Malpassi can cause a car to run rich as it pushes a bit more fuel in than is required. however, this is more safe than sorry really so its not too much of an issue.

what does the gauge say? the gauge will be a fuel pressure gauge, allowing you to set up your fuel pressure at idle, bearing in mind as the revs increase the regulator will increase the pressure at the 1:5/1:7 rate, whichever it is :cheers:

so yeh wat rate is yours at now on the gauge? you really need to ask someone else with an RB20 and similar mods to yours what pressure they recommend. however, if the pressure is too low at idle, the car will not idle very smoothly as its not getting enough fuel. on the other hand, too high at idle and it may idle rich, and thus become richer and richer as the revs go up. this may cause misfiring or fouling up plugs quicker than usual.

malpassi arent bad as long as it still is working which i assume it is if your car is running alright, its worth keeping it but just asking or workshop or someone what they recommend as the idle pressure on it.

to adjust to idle pressure, you take the nut off the top of the regulator, and you will see a flathead screwhead. you undo the nut below that screwhead and this will allow you to turn the screw left and right to adjust the idle pressure up and down. u can monitor this with your gauge.

hope this helps! just installed one on my own car the other week haha

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