Clutch Fuel Cutoff (CFCO) Question

[hawk02]

I'm not a big fan of the popping and burping from the CFCO when I shift gears on my ZL1. I don't mind it on deceleration just not when I shift gears.

What are the drawbacks other than no longer having the ability to do "no lift shifting" to having the CFCO disabled?

Thanks!

[DSteck]

You might notice a slight uprev when you go to shift gears at part throttle.

[hawk02]

You might notice a slight uprev when you go to shift gears at part throttle.

Ok. That's good to know.

Sounds like I should leave it enabled and learn to live with the popping and burbling.

[DSteck]

Try it and see. You definitely won't hurt anything. The only way to learn is to just experiment! I've disabled it on some cars. A few rev up slightly when you go to shift, some just seem to hang a bit, and others barely have a difference. I have yet to find a rhyme or reason.

[hawk02]

Try it and see. You definitely won't hurt anything. The only way to learn is to just experiment! I've disabled it on some cars. A few rev up slightly when you go to shift, some just seem to hang a bit, and others barely have a difference. I have yet to find a rhyme or reason.

I just disabled it and didn't notice any difference except the lack of popping and burping when I shift. Car didn't appear to up rev with it disabled. Think I'll keep it disabled for now.

[MikeOD]

I find CFCO extremely annoying...I disable it in everything I drive/tune.

[wetcoast]

Is there any way to modify CFCO to retain no-lift shift and reduce or eliminate the popping during shift?

[MikeOD]

Just do no-lift shifting with the rev limiter. Set the control method to spark or fuel (whichever you prefer) but disable ETC. Set the switchover delay to 20 (the entire table), then set the cutoff RPM vs gear wherever you want it. The numbers you put in Park and Neutral should be the same, and the computer will hold them when you have your foot on the clutch pedal, when you're off the clutch pedal, it'll rev to the numbers in the rest of the table.

The way I do it, I set my in gear numbers to 7200 RPM, and my park neutral to 6000...when I shift, the PCM cuts spark (to the numbers in the minimum final spark table I believe) but the throttle plate stays open. This seems to help abuse the transmission less, and it returns to life instantly when my foot comes off the clutch pedal. You can set the same RPM too...but I found if shift at 7K, I want the tach right around 6K anyways.

[wetcoast]

Just do no-lift shifting with the rev limiter. Set the control method to spark or fuel (whichever you prefer) but disable ETC. Set the switchover delay to 20 (the entire table), then set the cutoff RPM vs gear wherever you want it. The numbers you put in Park and Neutral should be the same, and the computer will hold them when you have your foot on the clutch pedal, when you're off the clutch pedal, it'll rev to the numbers in the rest of the table.

The way I do it, I set my in gear numbers to 7200 RPM, and my park neutral to 6000...when I shift, the PCM cuts spark (to the numbers in the minimum final spark table I believe) but the throttle plate stays open. This seems to help abuse the transmission less, and it returns to life instantly when my foot comes off the clutch pedal. You can set the same RPM too...but I found if shift at 7K, I want the tach right around 6K anyways.

Awesome!!! Thanks so much!