Delay Volume and Transition Volume settings (FF)

[sgod1100]

Hey guys,

Out of curiosity, what do these two settings affect if they have incorrect values put in? Will my fuel trims be off for a certain period of time right after a large ethanol content change? I currently have both of them set to .02L with no real justification behind it other than stealing those values from another ctsv ff tune. I haven't tried different settings on these to see what the effect will be either. My car is a 2014 cts-v and the FF sensor is right on the rail so would the "delay volume" be essentially the volume of my fuel rail? Any insight would be helpful, Thanks

ff delay and trans volume.JPG

[GHuggins]

Those are how much theoretical fuel has to pass through the sensor - I'm pretty sure calculated off of injector flow - before the ethanol sensor will change it's reading. I use .1's. Haven't seen any negatives from doing so and if anything it seems to keep fueling more in line or rather trims from shifting around.

[07GTS]

yea i just go little higher or lower depending if the sensor is at the tank or close to the rails, or if its dead head or return after rails changes how quick the ethanol get to the injectors

[sgod1100]

Those are how much theoretical fuel has to pass through the sensor - I'm pretty sure calculated off of injector flow - before the ethanol sensor will change it's reading. I use .1's. Haven't seen any negatives from doing so and if anything it seems to keep fueling more in line or rather trims from shifting around.

Sounds good Thanks Greg. I'll try that out.

[sgod1100]

As always, thanks for the info!

[Alvin]

I like smaller delays and volume transitions than the factory settings. It helps greatly when you dump in a full tank of E85 when it's been running straight gas. I haven't seen any negatives yet. The Alc content will change much much faster.

[sgod1100]

I like smaller delays and volume transitions than the factory settings. It helps greatly when you dump in a full tank of E85 when it's been running straight gas. I haven't seen any negatives yet. The Alc content will change much much faster.

So, like .01L for both?

[Alvin]

I haven't had any problem so far doing that.