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Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 9:46 am
by mladjan
I have a problem that on revmatch my engine is not enough responsive (log attached, 5:17). I suspect that this is because on hard braking, or just when I left off the throttle, car goes into overrun fuel cut mode, and when I want to blip the throttle to downshit, it stalks.
This is supercharged FN2 with BOV (if this is important), and this bugs me when I drive it hard on the track, exspesially on hard braking before the turn.
My idea is to try to disable overrun fuel cut from 4 to 9k rpms, but not sure if there is a way to easily do that or to play with these two columns related to MAP pressure and rpm:
Image
Any other ideas?

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 11:15 am
by Spunkster
If you are trying to press the throttle and brake at the same time, this will not work as drive by wire will not allow the throttle to open when the brake is pressed.

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 11:19 am
by mladjan
You want to say that if Im doing heel and toe that it will not work? How stock car is doing that?

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 12:13 pm
by R-12914
This in normal on the FN2.
It is for securitiy purposes.

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 12:47 pm
by Spunkster
Are you tuning via AFM or via MAP?

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 3:31 pm
by mladjan
MAF with Map for fuel tables.
Regarding downshift, it doesn't need to be on the brakes, it behaves the same when I leave the gas, and then give him a blip and shift.

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 3:48 pm
by Spunkster
Post your calibration as well as a datalog showing the problem and tell us the timestamp in the datalog where you experience the issue.

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 3:55 pm
by mladjan
Datalog and timestamp are in first post. Calibration attached here:
_LATEST Rotrex-RSP-shaft-drive-1.1.4.fpcal

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 4:33 pm
by Spunkster
Try this: under VTC try unchecking the zero VTC upon decal fuel cut, and then check the box for Use VTC tables upon decal fuel cut.

Re: Overrun fuel cut - How to disable it?

Posted: Thu Aug 31, 2017 11:43 pm
by mladjan
Thx, will try this later today. Which angle should be in the field? 0?

Re: Overrun fuel cut - How to disable it?

Posted: Fri Sep 01, 2017 11:19 am
by Spunkster
Just leave it at zero and see how it runs with it following the VTC tables.

Re: Overrun fuel cut - How to disable it?

Posted: Sat Sep 02, 2017 7:46 am
by mladjan
Thx, that works :)