Fuel Cut, is it a good or bad thing???

[cnewingham]

I know what it is and have done research but still dont understand if it hurts anything. I am hitting it around 12 psi which is right on target but I am also running upgraded turbo, ic, etc.. and so on. I am going to swap out my injectors and afm next week after I dyno on Sat. to get a baseline.

I guess I just need to know if hitting fuel cut hurts anything. (I always thought it was a safety cushion)

 

[Big Wang Bandit]

Its not good to hit. But if you removed it, it would do a lot more damage.

 

[lagged]

fuel cut is a good thing.

once you hit it, you back off. dont stand on it while its hitting fuel cut.

that bucking cant be good for the driveline.

 

[tookwik4u89]

Fuel cut sucks ass, turn the boost down just enough to avoid f/c.

 

[MK3Brent]

FCO saved my ass a few times... :rofl:

 

[claricae86]

well i guess the simplest way to put it would be, does it feel good when you hit it? i know when i hit fuel cut that it doesnt feel like it could be helping anything, best bet is to do like tookwik4u89 said and lower boost to prevent more fuel cut.

 

[MK3Brent]

I actually had a sore back for a while when I hit FCO in my new turbo setup.

It's violent.

 

[cnewingham]

I cant turn down the boost. I am already only running off my wg spring.

 

[tookwik4u89]

For some reason, when I hit fuel cut , it pisses me off, I just hate it. Definately dont want to eliminate it with that setup, get a wideband before you run it up any more, for now just back the boost down a bit.

 

[jdub]

I cant turn down the boost. I am already only running off my wg spring.

Does that mean you've removed the pressure line from the compressor to the wastegate actuator?

 

[cnewingham]

as stated above I can not turn down the boost. I have a w/b, egt and all other items. I just finished breaking in my built motor and was just wondering if it will hurt anything. I have all the fuel upgrades but wanted to break in the motor on a stock setup and dyno for a baseline before I start moving forward.

 

[cnewingham]

running the hks ss w/g with the hose routed correctly.

 

[Nick M]

If spark was cut like some aftermarket devices, you could fill the crank case with fuel, diluting the oil. And you can put too much fuel in the catalytic converter. Fires in the cat have happened.

Best to just shut the fuel off.

 

[claricae86]

you have all those mods and no boost controller?

 

[hottscennessey]

even if he had one what good would it do? He still cannot turn down the boost. What he needs to do is up his fuel pressure and lower the Hz from his AFM with a SAFC or similar device.

This will keep him away from fuel cut, by reducing the amount of air the ECU "sees", while keeping him from running lean by upping the FP.

 

[jdub]

you have all those mods and no boost controller?

It doesn't matter...he has an external wastegate adjusted all the way out to spring limit. His turbo is gonna make him hit fuel cut.

Fuel cut is a good thing (like stated before), the ECU protects the motor from a perceived over boost. With a big turbo, it gets in the way and due to the ECU cutting off the injectors when the amount of air flow (detected at the AFM) exceeds limit...it's rather violent. This is not good for your motor to happen on a regular basis.

If I were you, take it easy on the throttle to avoid fuel cut until you get the injectors and Lex AFM installed. I def would not take it to the dyno...you're not going to get to the numbers you want anyway.

 

[tookwik4u89]

as stated above I can not turn down the boost. I have a w/b, egt and all other items. I just finished breaking in my built motor and was just wondering if it will hurt anything. I have all the fuel upgrades but wanted to break in the motor on a stock setup and dyno for a baseline before I start moving forward.

Ohhhh, no boost control. I see. Its going to be hard to get a dyno run without one or change spring in w/g. I would forget the AFM and get maft pro with speed density and boost control. You can tweak the stock AFM bypass screw to avoid fuel cut , but with stock inj?, I would be careful, a little at a time if you can watch wideband. Dangerous territory with this fuel system. Where is your a/f ratio at 12 psi before f/c hits?

 

[tookwik4u89]

And scratch what i just said about the afm if you cant up the fuel pressure, I think you should forget the dyno until you do the upgrades or change w/g spring to lower boost.

 

[cnewingham]

my a/f's are reading 10. at wot so I am not hitting a lean condition. I am not going the maft pro route either as I have dealt with the original maft and for reason known to others I refuse to go maft. Lex/550's is tried and true and after that I will be going full standalone.


I do have an afpr set at 28psi hose connected so do you think I could up the pressure a bit to get me past fc?

 

[tookwik4u89]

If you are at 10, you can turn the adj screw out on the afm, that will lean it down, and maybe prevent f/c, it just doesnt have as big of a bypass as the lex.Just take it a little at a time and watch the a/f.