renxun

what does the above mean..? issit the pressure when our key clicks to on but havent start the car ..?

OR

does it mean pressure when the car was started...?

basically what is the fuel pressure of a car during idling...? im using a 1jz... just bought a sard regulator... duno what pressure should i set.. now i just put it at 2.1bar during idle and drive for the time being.... can anyone enlighten me?

     

speedchaser

Base fuel pressure is set when your car is idling. Unplug the vacuum hose from your fuel pressure reg and then you set you base pressure from there. For a 1JZ-GTE, the stock base pressure should be set at 45psi (3 bar).

     

renxun

thanks alot bro....very much appreciate.

     

markii

what is the suitable pressure to set to for 1jz?

     

renxun

was mentioned above.... 3bar base pressure.... in my case i up it a little bit pass 3 bar.... around 46psi

     

Joeker

Yes, base presure is set during idling.

But when the vacumn hose is unpluged from the regulator, the regulator is reading WOT.

So my query is, how is it possible to set iddling base pressure when the regulator is reading WOT?

     

renxun

but then my car is turbo ... how could it be wide throttle if unplug the vacuum?
do enlight me... so what you mean is i should set 3 bar when my car is idling wid vacuum plug on?

     

Joeker

Fuel pressure regulator controls how much fuel goes back to the fuel tank.

When engine is iddle, vacumn is strongest ie. negative manifold pressure.

When the vacumn hose is disconnected, there will be no vacumn, thus simulating a situation similar to WOT.

Therefore I'm surpsie how could base fuel pressure (iddling fuel presssure) can be dial-in under WOT? Hope speedchaser would enlighten us.

     

ART///SPEED

all engine is 3bar

     

renxun

3 bar in what condition? during idling with vacuum hose plugged in ?
3 bar when the key is click to on before starting the car?
3 bar during idling WITHOUT vacuum hose plugged in?

lets discuss this

     

speedchaser

On a "stock" regulator with vac unplug, that's the WOT (base) pressure for an NA. "Idle pressure" is what you should be getting when you plug in the vac. It determines not only how much fuel goes back to the fuel tank, it also determines how much and how fine the fuel goes into the cylinders.

On an adjustable FPR, we need to set it with the vac unplug cos we need to get the same WOT pressure or more (modded cars) for safety or performance issues, and sometimes the "idle" pressure could be affected with different FPR even if you set the base pressure correctly. Most of the time it's negligible. Some aftermarket FPRs might have different rising and ramp rates and we might have to compensate it by tuning it out on the ECUs if it cannot be compensated with the engine's stock close loop operation on idle.

On a turbo, the FPR is control not only by vac but also by the rising rate of the pressure in the manifold and it will go beyond what is set on atmospheric. That is why setting the FPR on idle without the vac (atmo) is the middle point.

Fuel pump is another issue that must to be factor in for it is the heart of the fuel operations.

Hope this helps.

     

speedchaser

Sorry, I beg to differ on this! Not all cars are the same. This is completely wrong info.

     

Joeker

DO you mean, at positive pressure (pressurized manifold condition) the AFPR will supply more fuel?

Please do not take any aftermarket engine management or fuel pump into consideration.

     

jinkl

if its a sard regulator or aftermarket fuel regulator it will bro
1:1 for sard small , means, 1psi of boost will increase 1psi fuel pressure

if FSE 1.7:1 is diffrent, 1psi boost will increase 1.7psi fuel pressure

     

kruger

Agree with speedchaser... You must tune your FPR based on your Air Fuel Ratio. Basically you must use wideband.