FPR turbo 1uz - what to get?

[stradlater]

Just that you made reference to 'the ecu controlling the fuel pressure' (perhaps not those words).

I then thought 'what on earth does he mean by the ecu controlling the fuel pressure?'

I didn't think the ECU COULD do that, the only way I could think of doing that would be to turn the pumps on and off, whcih I didn't think happened.

So what I really want is a SARD non-rising rate, but adjustable, fuel pressure regulator? that the go?

[Cuzzo]

I dont see why rising rate is bad?

I guess my dinosaur microtech thinks its a good thing.

[Draven]

rising rate is a term often confused.

Any FI engine needs a "rising rate" reg, because if you add 1psi of boost, you need to add 1psi of fuel pressure just to keep the fuel flowing at the same rate.

What the malpassi unit does is increase more than that. Because an n/a ecu doesn't see boost, and so doesn't add more fuel to compensate for boost, the RRFPR attempts to compensate for this. Usually fairly badly, but it is purely there as the cheap-out option.

[CrUZida]

Rising rates are mainly used to squeeze extra fuel out of injectors when they are either at their limit, or you cannot control what the ecu is doing.

In the event where you can control the base fuel pressure, and the injector pulse width, having a rising rate just adds unneccesary complexity (makes it a prick to tune properly) and another potential point of failure (add extreme load to your fuel pump)

[CrUZida]

rising rate is a term often confused.

Correct

Any FI engine needs a "rising rate" reg, because if you add 1psi of boost, you need to add 1psi of fuel pressure just to keep the fuel flowing at the same rate.

And you have just confused it there.
A 1:1 is NOT a rising rate.
A 1:1 is a LINEAR rate FPR. (almost all stock FPR's are linear rate)

A rising rate (of say 1.7:1) will increase the fuel pessure by 1.7psi for every 1psi of boost.
This means as say 15psi, you'll increase the fuel pressure by 25psi (over the base rate)

[ed]

another brand - aeromotive

and yer, dont get a rising rate, just plain old 1:1 maifold ref

[Draven]

sorry, that was why I put the rising rate in "", but re-reading did not make that obvious

[stradlater]

So how do I adjust base fuel pressure? Is that done by the FPR?

Are they all 'adjustable' for this purpose?

Providing I get a 1:1 SARD thingy, does that by default mean that I can adjust base pressure using this device?

[Cuzzo]

yes you can, when idling you adjust the pressure.

How would you know how much pressure? I normally aim for the stock NA pressure the stock reg will do.

[CrUZida]

Yes, all aftermarket regs have adjustable base pressure.

Stock is around 42psi (at 0psi manifold pressure).
A few people up this a little bit (to high 40's) to increase the atomisation of the injectors.

But remember to do this BEFORE any tuning is done, as adjusting the base pressure will change your whole tune.

[stradlater]

I was reading that Justin was running his at something like 60psi or some such.?

[YLD-16L]

So how do I adjust base fuel pressure? Is that done by the FPR? Yes

Are they all 'adjustable' for this purpose? All adjustable ones are

Providing I get a 1:1 SARD thingy, does that by default mean that I can adjust base pressure using this device? Yes

Don't get a Malpassi, they are rubbish.

[YLD-16L]

I was reading that Justin was running his at something like 60psi or some such.?

Just remember that if 60psi is your base pressure then your pumps will need to be making 80psi at 20psi manifold pressure.

Is your system up to that?

[stradlater]

Good point.

Well it'll be 2 Bosch 044 pumps, so I was hoping it would be.

But maybe not?

[Norbie]

You're replacing your injectors and ECU anyway so all this talk about regulators and pressures is irrelevant. Just get a normal old linear rate regulator (even the stock 1UZ regulator might be OK up to a point), set the base pressure to 42psi or whatever the OEM pressure is, and you're done. Fuelling is adjusted by the ECU, not the regulator.