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How do I install a Malpassi Rising Rate Reg?

4door_Sleeper

By 4door_Sleeper,
in Engines & Forced Induction

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4door_Sleeper Veteran

4door_Sleeper

Posted
Posted

I went to pick up a hi flow malpassi rising rate regulator today :) but got a shock when I saw it. :alien:

I thought it could fit at the front of the fuel rail, and replace the factory one but I noticed the following problems.

1 - the malpassi has 2 inlets (I think) and one outlet on the bottom, as well as the vacume line whilst the little factory unit has one inlet, and one outlet. (What do I do with the 2nd inlet?)

2. how do you mount it to the end of the fuel rail? the fitting for the original is a screw on item, and the fittings provided look VERY incompatable.

Any instructions, photos or information would be greatly appreciated.

rbs13 Community Regular

rbs13

Posted
Posted

dude i got one of these. fuel goes in at the bottom and out of the the outlets on the side. vac on top and plug the other one up. on my rb20 it has the hose going from regulator to the side of the plenum and then another hose connected to the std regulator.. the std one has no vac.. this is how i bought the car.. seems to work fine.. but latley my car is chuggin and shit when idleing at anything belove 1000rpm.. lights fade, car nearly stalls, ONLY on idle.. i belive this is cause of the fuel regs pressure is to high.. so make sure you get it set up on a dyno or something.. my car blows a fair amount of flames/pops n stuff so i guess its too much fuel being unused.. but yea..there you go.. hope this helps.

muffas 180 Enthusiast

muffas 180

Posted
Posted

Hi,

Its very simple.

1, Lets say the top of the reg is the section that has the vacuum nipple and adjustment

2, The holes in the sides are fuel in and fuel pressure gauge. If your not using a gauge then you must block one of the side holes off.

3, The hole in the bottom is fuel back to the tank.

4, Your original reg is bolted to the rail with a vacuum line and fuel hose attatched to it which if you follow it goes to the tank.

5, The hose coming off your original reg you need to cut some where, where you can mount the Malpassi reg. This hose has to join the original reg to the side of the Malpassi.

6, The other end of the hose that goes back to the tank pushes on to the bottom of the Malpassi.

7, The vacuum line for your standard reg is where you get vacuum for the Malpassi so just get a t piece and t into it leaving the standard one connected. This is so you still have a fairly smooth idle as just using the Malpassi can create idle problems due to too much pressure.

8, You will need to set the pressure on the malpassi while the car is idling and the vacuum line is disconnected on both the malpassi and standard reg. Set it to about 40psi. Then hook both vacuum lines back on.

9, A mounting bracket bolted to the rhf strut bolt is generally the easiest to put it for a skyline. Enjoy!

Michael...

muffas 180 Enthusiast

muffas 180

Posted
Posted

Yes you can have vac to both regs. Doing this will give you standard pressure at idle meaning smooth idle. If you are running high pressures on the malpassi and dont have the vacuum line connected to the standard reg you might have idle problems such as stalling and very low idle.

Michael...

Craved Grand Master

Craved

Posted
Posted

Not too sure if this point is valid but would likie some confirmation on one thing, if your installing the malpassi to increase fuel pressure on the rail shouldn't it replace the standard one? if the standard is there wouldn't it override the efforts of the malpassi?

some ideas would be good!

Cheers

4door_Sleeper Veteran

4door_Sleeper

Posted
  • Author
Posted

H'Day EnricoPalazzo

I was hoping for some pics aswell, maybe over the weekend.

Last Friday I was just dropping in to say G'Day - couldnt realy go on the cruise as my wife and kids were all at home sick with the gastro bug.

Once I get the fuel pump, regulator and a dyno tune though I'm looking forward to some good cruzes. Hoping for in excess of 200 RWKW :)

BHDave Grand Master

BHDave

Posted
Posted

If you put a malpassi with a higher base pressure after the stock regulator then you will have higher base pressure through out the whole system. The stock regulator will open at say 40psi but the malpassi is behind it is maintaining say 50psi. That means that the stock regulator is just sitting there causing a restriction in the fuel system.

Anyone got rich idle problems when running a bigger fuel pump? This is because the stock reg cant flow enough fuel to maintain the 40psi (this is just an arbitary number) base pressure and hence the pressure behind the injectors increases and they squirt in more fuel for given opening time. When you are driving, there is more fuel being used by the engine and so the regulator doen't need to flow as much to maintain a set pressure so it's ok.

By fitting a rising rate malpassi you can eliminate this problem by setting the standard base pressure, and hence get good idle mixtures, and as it has a 2:1 rising rate (from memory) you get additional fuel into the engine when you are on boost which is where you really need it.

If you are running a higher base pressure then you will require tuning to get the idle right but due to the higher pressure atomisation of the fuel mixtures will be affected so you may never achieve a factory idle.

Just my 2 cents.

Dave

Mase Mentor

Mase

Posted
Posted

I have tried to find a fitting to replace the stock regulator all day but had no luck. Could you just drill the internals of the orignal fuel reg out at all and just keep it on to save getting a fitting made????

Please let me know asap as im having a lot of fuel dramas.

thanks

Jayson

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