fuel cut ?

[zentac]

How does the fuel cut work? does then ECU cut the fuel when the injectors get say 80% used, or is it done on boost?

Reason Im asking is that Ive got some larger injectors ready to go in INSERT INTO post VALUES (450cc rather than 390cc) so its its done on %age of injector utilisation then I should be able to run higher boost before I hit the fuel cut.

[BraindG]

one of the guys was saying that hes never heard of any of the guys in Japan needing to change the injectors.. think it was -legnumvr4- might want to ask him..

try a search

[haydar]

Originally posted by zentac
How does the fuel cut work? does then ECU cut the fuel when the injectors get say 80% used, or is it done on boost?

Reason Im asking is that Ive got some larger injectors ready to go in INSERT INTO post VALUES (450cc rather than 390cc) so its its done on %age of injector utilisation then I should be able to run higher boost before I hit the fuel cut.

To stop the fuel being cut due to higher boost you need a Fuel Cut-off Defensor! The ECU cuts the fuel if it thinks you are running a higher boost because it assumes you are sending it the wrong speed information INSERT INTO post VALUES (which is done to remove the 180kph limit of Japanese cars).

HKS do a FCD for £95.00.

[zentac]

Brain, the new guy who was asking about con rods/pistons, is currently running 420bhp with a single turbo conversion and getting 99% through put from his injectors, hes thinking about dropping 6 x 770cc in INSERT INTO post VALUES (and its in an FTO

[BraindG]

/puts hands up

fair enough

[Brind]

Originally posted by zentac
Brain, the new guy who was asking about con rods/pistons, is currently running 420bhp with a single turbo conversion and getting 99% through put from his injectors, hes thinking about dropping 6 x 770cc in INSERT INTO post VALUES (and its in an FTO

All that through the front wheels, good luck to him!:eek:

[EdmundVR4]

Zentac, I can't say if the fuel cut is activated by boost pressure or injector duty cycle %, but in my car when I hit 14 psi according to my Autometer Pro Lite boost gauge for about one second I get the dreaded fuel cut. So, I just keep my Turbo XS dual stage boost controller on low boost, which creeps up to 12 psi in the higher gears when the weather is cool or 11psi when it's hot. My tuner seems to think that if you lean out the A/F ratio with a Fuel Controller you will achieve higher boost without fuel cut.
Are you sure the stock injectors on the 6A13T are 390cc ?
Ed

[zentac]

Ive been told by a couple of people that they are 390cc

[calum]

Fuel cut is pressure activated.

EdmundVR4 - your tuner's wrong. Air/fuel ratio is nothing to do with it.

Manifold absolute pressure is manifold absolute pressure and that's that. It is manifold absolute pressure that the ECU monitors to determine whether or not to stop you being a naughty boy by applying fuel cut/ going into limp home mode.

It is not affected by air/ fuel ratio.

If your tuner thinks it is I would suggest you find a new tuner. If you do intend letting him lean out ratios then I hope you have either an exhaust gas temperature gauge, a detonation microphone and headphones or both.

Zentac - what do you intend using to control your additional fuel? Are you using a programmable ECU, or a std ecu with unichip or similar?

If the guy mentioned IS running 99% duty cycle then he's going to melt his injector solenoids soon. 80% as a max safe top limit, 85% is on the edge.

Cheers,

Calum

[zentac]

Ive got an SAFC sat here waiting to go on. Long term it will be a progrgamable ECU.