Radical changes in fuel pressure with malpassi.

[2JZR31]

So I set my malpassi to 50psi base (referenced to atmospheric) Then had a look a week later and its at 30psi. My car was going VERY hard at that fuel pressure with wheelspin through first and second with 0.7bar. So I put it back to 50psi as I think it was at 50 when we tuned it. (I say THINK because I set it a few days before we tuned it and it may well have went down before we tuned it).

After I put it back to 50 I went for a drive and the car ran like crap and was misfiring. So I checked it again and it was at 75psi base! I put it back to 50 again and it seems to be staying there now.

WTF is going on?

[Robbos_Toyotas]

faulty regulator perhaps?

[2JZR31]

Maybe. I have been checking it all the time now and it seems OK. Some people have told me that malpassi regs a SHIT.

[Robbos_Toyotas]

would a foreign work in conjunction with the malpassi pump? In the way of a bosch or walbro?

[MS-75]

I helped a mate set up a turbo 308 VK recently and in the end we ditched the Malpassi as it was totally unreliable-wildly fluctuating pressure, horrifically affected by heat soak etc. I've also spoken to more than a couple of others with the same problems.

Solution-bin it yesterday dude. (sorry)

Get a sard one off ebay. Cheap, reliable and good quality.

[2JZR31]

I have heard that Sard isn't much better? Can anyone deny confirm? I have been suggested a SX minimum?

I'm going to see how the malpassi goes and if it does it again I will piss it off. I would run my stock FPR but I'm not sure how it can deal with twice the normal flow rate from a 044.

[oldcorollas]

run two stock FPR's? one at each end of rail and centre feed it?

[2JZR31]

It would be pretty hard to fit another stock FPR as it has special seat in the fuel rail.

[oldcorollas]

T another into somewhere between pump and rail?

[TA22-3SGTE]

I'v had trouble with near every malpassi I'v come across , Yes they are shit , Also had trouble with sard , I am now fitting Aeromotive regs and they seem a lot better .

Trevor

[2JZR31]

oldcorollas, it would be a total bitch to try and use 2 stock ones. You can't really fit a fuel line onto in the intake of a stock one as it is designed to slide into the fuel rail with an O ring.

TA22, How much does an Aeromotive cost? What problems did you have with the Sard, and would you say they are a lot better than a Malpassi?

[thechuckster]

i've replaced my malpassi RRFPR as at idle and higher stable throttle positions, fuel pressures seemed to wildy fluctuate (enought to make a cold idle stall).

My data logs were showing a slow wave in th AFRs despite no throttle activity or changes in air or coolant temps.

With a 2nd-hand sard, my cruise down the freeway tonight was stable AFRs reacting to commanded changes only.

I think the malpassi are more suited to a carbi-turbo setup where your base (static) pressure are much lower. The reg did run a lot quieter when i foolishly set the static pressure to 20psi.

[2JZR31]

I finally figured the Sard FPR's out.

http://www.upgrademotoring.com/performance/sard_reg.htm

The Ebay ones appear to be the 450hp ones. The bigger one costs a lot more. So what would happen with a 450 one? My guess is that if you use more than 450hp worth of fuel the pressure starts to drop since it can't handle such a large variation in flow.

My mate with the Aristo with the Sard changed from a stock fuel pump to a 044 and base pressure shot up by like 20psi. Some people might say, well DUH there is more fuel flow. But to me that is a sign of poor regulation with varying fuel flow. What happens when the engine is using most of the fuel from the pump? My guess is the pressure will drop. If pressure goes up by 20psi with more X amount fuel flow, its going to go down by like 20psi when the engine uses X amount of fuel flow up. Does that make sense?

His sard does seem to be stable though. Its always the same when you check it unlike the malshitty.

[thechuckster]

mine came out of 747-1JZ's car - from memory, the sticker on the body of the unit said '200-800kpa'.

[2JZR31]

I think both are rated to 200-800kpa. I might ask Shane what he had.