Fuel Reg

[newboost]

My tuner said i need to get a aftermarket fuel reg.

He forgot to mention if i should get a rising rate or a fixed one.

(malpassi,turbosmart or other)

The car is a r33 gtst.

mods so far

fmic

haltech ecu

turbo back exhaust

bosch fuel pump

splitfire coilpacks

greddy ebc

hyflowed turbo

any thoughts would be great with this one.

thanks

[R31Nismoid]

Do it properly and buy a set of injectors and use the factory regulator (its fine for over 350rwkw).

Obviously depends on the hi-flow as to how viable a FPR is (without injectors).

1. If it'll only make 220rwkw then ok fair enough

2. If the hi-flow will make 250rwkw+, then dont waste time and get a set of injectors

[The Mafia]

Get another tuner.

Doesn't look like he knows enough to be telling you to change components that dont need to be changed.

The injectors need to be changed.

[WMDC35]

As above, and generally all are rising rate? (ie with a 1:1 as the manifold pressure rises so does the fuel pressure)

[Duncan]

yes, it absolutely needs to be rising rate in a turbo car - the rising means that fuel pressure rises as your boost does.

[TiTAN]

get injectors instead.

394kw on the stock fuel pressure regulator here.

[newboost]

what would be a good set of injectors to get.

[GTSBoy]

As above, and generally all are rising rate? (ie with a 1:1 as the manifold pressure rises so does the fuel pressure)

yes, it absolutely needs to be rising rate in a turbo car - the rising means that fuel pressure rises as your boost does.

Um, point of order here. Rising rate regs actually increase the fuel pressure faster than the increase in signal (manifold) pressure. ie, the slope is greater than 1. Rising rate is actually a poor description for them, but that's just how it is. Most things like that are poorly named in the car world where they wouldn't be in the engineering world.

Normal fuel regs are "constant rate".....if you were to use the same poor terminology. But what they really keep constant is the delta P across the injectors.

[Duncan]

Thanks, good clarification

[XKLABA]

there is nothing wrong with changing the FPR, way go to the expense of injectors if a FPR will "fix it" if it doesn't need them, ie if it is getting to 99% duty cycle and the op isn't going higher with power then way not just do the FPR and give himself some headroom and save some coins, other then "it's not the right way to do it" cause the higher ressure will also help atomisation

[XRATED]

If you just need to sneak in a few extra psi to get you accross the line, then just get a nismo fpr that bolts onto your stock rail.... simple and neat.

If your trying to screw 50psi base pressure into it, then get injectors. Nismo, sard etc.

If you just wan't a shiny new toy for your engine bay... buy a well known brand name and make shure it's genuine.

Cheers

Justin

[Steve]

Do you plan on going much further with the power upgrade?

If you plan on going much further, grab some larger injectors. I have run 550s within standard FPR - but consider that most

After market injectors are rated based on a 3kg base fuel pressure, the factory FPR is rated at 2.55 kg

So 'best' option would be to get some larger injectors and a FPR - as mentioned earlier, Nismo bolt on type is a good option, minimal stuffing around and work well with the factory fuel rail.

For a budget upgrade to give a little extra injector headroom - a FPR by itself can do the job well - once again, Nismo type is neat, easy to fit and works well.

Not a fan of rising rate FPR, as you end up with higher pressure than the injectors are rated at

My 0.02c

[Steve]

Oh, and I'm not a fan of sard injectors, personally, too much stuffing around to fit IMO

Nismo, HKS are better

[tazzy]

+1 for HKS..

[chris.33]

does anyone know what psi you should set your fpr at if you do have an adjustable one?

[Piggaz]

does anyone know what psi you should set your fpr at if you do have an adjustable one?

Standard pressure unless your injectors are the wrong size.

[chris.33]

when i bought the car it had a malpasi rising rate and its set at 48-49 psi at the moment

[Duncan]

well that's the thing. any standard (or tuned) ECU is based on a specific base pressure. If you put an adjustable FPR on and are not retuning, you need to set it to the same base pressure as the previous FPR, ie there is no point.

The only real use to an adjustable FPR is to get maybe 10-20% more flow out of injectors without swapping them for something larger. In that case you must retune the car anyway, so set it to the standard base + whatever % you need and tune it from there.

[Steve]

Depends on what the manufacturer rates them at

[chris.33]

ahh ok i see now well ill search for base fpr psi andset it to that till i tune + bigger injector in about mid year