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Malpassi rising rate?

matixx

By matixx,
in Engines & Forced Induction

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matixx Enthusiast

matixx

Posted
Posted

Hi everyone, my r33 gtst is currently receiving some modifications and i have been recommended to use a malpassi rising rate fuel regulator/pump? any ideas on these gizmos? current mods are hks dump pipe/exhaust, gt2530, apexi hybrid front mount, powerfc (to be installed). I am hoping to run some decent boost, perhaps 15-18 psi and have been told the injectors will struggle to keep up with this sort of airflow... any tips?

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4door_Sleeper Veteran

4door_Sleeper

Posted
Posted

I too am interested in responces to this question. I have simmilar mods and my injectors are at about 90+% duty cycle.

I question running 15-19 PSI with a factory turbo (though I have heard on this forum of those who do) but I think Ill stick with the safer 11-13psi pange.

PS - what prices can people get these for, as i dont see many come up on the for sale forums.

GTS-t VSPEC Grand Master

GTS-t VSPEC

Posted
Posted

I'm currently using a Malpassi and have managed to get over 400rwhp from the standard injectors with it. It is preferable to increase the size of you injectors rather than simply increase the fuel pressure, but so far it's worked for me with no side effects.

I wouldn't run a rising rate regulator without upgrading the pump though, as the standard pump will struggle against the higher pressure.

Steve Grand Master

Steve

Posted
Posted

GTR pumps will support 250rwkw, but are a bit pricey when you consider that for the cost of a second hand unit you can buy a new bosch pump.

044 will cost about $400 or less, but require a bit of messing around to fit, not too bad but would be expensive to pay someone else to fit and make sure you have all the parts because some of the connectors can be a bit hard to source.

Bosch also do intank pumps that would flow as much as a gtr pump for alot cheaper, ie 250-300 mark, but I think it would be better for someone who has fitted one of these to explain it like Rob77. Apparently alot easier than the 044 to fit.

For under $200 you can get an adjustable ruel pressure reg from japan that will fit in the stock position and look stock, such as Nismo. They have an adjustment bolt on the top. They will also do the job.

Some food for thought, BOOSTD has over 260rwkw with a bigger fuel pump and stock injectors but stock fuel pressure reg, so it may not be necessary to upgrade both, depending on what power you are chasing. But definately do the pump at least.

MRK25T Experienced

MRK25T

Posted
Posted

I too have a 2530 like matrixx + all the other stuff including pump and malpassi.

A few minutes ago I replaced my stock s2 AFM with a Z32AFM and set the powerfc air intake to 80mm VG30 (is this the correct setting?).

On low boost I have no problems with injector duty, but on high boost the powerfc reads 100% before I hit redline.

When I get the car tuned this week, will they just increase the fuel so duty at high boost < 100% or do I need injectors?

Mark

Steve Grand Master

Steve

Posted
Posted

MRK25T, you may not need to change the fuel pressure (but sounds like you will).

When you change the setting to VG30, the power fc automatically seems to add abit of fuel (well mine definately did anyways) - probably a safety thing until you get it tuned.

My injector duty dropped by 10% (at peak) when I got it tuned.

I doubt it will be anything to worry about, and will be sorted when the car goes back on the dyno. It will become more apparent what you need to do then. Until that time, Iwould suggest low boost:)

Guys on this forum have made up to 300rwkw with stock injectors and a RR fuel reg, although its not ideal, it shows how far people can stretch injectors.

  • 1 month later...
PHaT MR30 Grand Master

PHaT MR30

Posted
Posted

My car runs a malpassi rising rate std injectors and a 400hp bosch pump, i was told that the malpassi is set pretty much to std pressure, what am i going to benefit by winding it up? i have not yet lit the wick with the boost side of things, only about 9-10psi (car tuned on 12psi)

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