Weird Ignition Compensation - negative timing on full throttle. - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Gt86Force · 10-02-2023, 09:42 AM

Hi to all,
I have a weird issue and i cannot understand why.

https://datazap.me/u/gt86forcenew/we...mark=4944-4980

During a low rpm/high load acceleration, for no apparent reason the timing goes negative. I immagine is some kind of compensation, but i cannot understand what kind so I cannot fix it.

- Transient ignition is not available during that range, or at least i think. (oem tables, my2015, eu calid).
- IAT comp. is 0 at that temp.
- Clutch is NOT down.
- No knock events

Car is a my15, eu calid "xxx01G, ecutek RR 12.1, supercharged with a custom rotrex kit but not important since this happened barely when in boost (abs. 1.1).

During the log you can see the event, the driver got scared so backed off the throttle for a second and after that started accelerating again without any issues. I will get the car this evening so I can try to replicate it myself.
This happended multiple times but this is the first time that he logged the problem.
The calibration is not finished, we are fixing the CL and "daily driving" area, no wot pulls yet, probably happens also in OL but I cannot say for sure.

Thanks for the help!

tomm.brz · 10-02-2023, 03:18 PM

i think 99% it s the transient retard table, and on second flooring he just did a bit slower and didn't trigger it as much, and @ 2800 rpm oem table has less retard than @ 2400

it is available in that range, in stock form basically the only requirement is coolant over 70C
just reduce retard in that table and it will go away

Gt86Force · 10-02-2023, 05:53 PM

First of all thanks! It seems like that, I was thrown off by the engine load...

I was thinking at a different approach, on the my17 model, the transient table is completly different, maybe i can integrate that and see how it goes.
Also the minimum CFP delta for the activation seems better looking. Have you tested it yet or is a dumb idea?

tomm.brz · 10-02-2023, 06:20 PM

cfp delta yes copy from my17
transient table is ok and very safe but it will exacerbate your problem
as it is even more retarded
you just have to mod yourself
keep high retard over 5000rpm
the more you retard also at low and mid rpm, the safer it gets so it is a compromise
Be sure not to have knocks
do sth like this with the smoothing function of proecu:

AussieBRZ · 10-05-2023, 01:07 AM

Generally with boost you run way less ignition timing than on an NA car so the NA transient regards can be way to aggressive especially at low rpm . Just reduce the trans retard amount where your getting negitive timing

Gt86Force · 10-09-2023, 05:30 AM

Yep.
Thanks to all for the suggestions. At the moment I'm running like this, with the my17 CFP delta.

It seems ok, at least for now. We will see once we start working on the higher rpms zone, but at least I'm working in the right direction!

10-02-2023, 09:42 AM	#1
Gt86Force Member Join Date: Aug 2018 Drives: GT86 Supercharged Location: All over the place Posts: 31 Thanks: 5 Thanked 13 Times in 8 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Weird Ignition Compensation - negative timing on full throttle. Hi to all, I have a weird issue and i cannot understand why. https://datazap.me/u/gt86forcenew/we...mark=4944-4980 During a low rpm/high load acceleration, for no apparent reason the timing goes negative. I immagine is some kind of compensation, but i cannot understand what kind so I cannot fix it. - Transient ignition is not available during that range, or at least i think. (oem tables, my2015, eu calid). - IAT comp. is 0 at that temp. - Clutch is NOT down. - No knock events Car is a my15, eu calid "xxx01G, ecutek RR 12.1, supercharged with a custom rotrex kit but not important since this happened barely when in boost (abs. 1.1). During the log you can see the event, the driver got scared so backed off the throttle for a second and after that started accelerating again without any issues. I will get the car this evening so I can try to replicate it myself. This happended multiple times but this is the first time that he logged the problem. The calibration is not finished, we are fixing the CL and "daily driving" area, no wot pulls yet, probably happens also in OL but I cannot say for sure. Thanks for the help!

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10-02-2023, 03:18 PM	#2
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	i think 99% it s the transient retard table, and on second flooring he just did a bit slower and didn't trigger it as much, and @ 2800 rpm oem table has less retard than @ 2400 it is available in that range, in stock form basically the only requirement is coolant over 70C just reduce retard in that table and it will go away

10-02-2023, 05:53 PM	#3
Gt86Force Member Join Date: Aug 2018 Drives: GT86 Supercharged Location: All over the place Posts: 31 Thanks: 5 Thanked 13 Times in 8 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	First of all thanks! It seems like that, I was thrown off by the engine load... I was thinking at a different approach, on the my17 model, the transient table is completly different, maybe i can integrate that and see how it goes. Also the minimum CFP delta for the activation seems better looking. Have you tested it yet or is a dumb idea?

10-02-2023, 06:20 PM	#4
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	cfp delta yes copy from my17 transient table is ok and very safe but it will exacerbate your problem as it is even more retarded you just have to mod yourself keep high retard over 5000rpm the more you retard also at low and mid rpm, the safer it gets so it is a compromise Be sure not to have knocks do sth like this with the smoothing function of proecu:

10-05-2023, 01:07 AM	#5
AussieBRZ Senior Member Join Date: Aug 2022 Drives: WRB BRZ Location: Australia Posts: 112 Thanks: 14 Thanked 51 Times in 36 Posts Mentioned: 10 Post(s) Tagged: 0 Thread(s)	Generally with boost you run way less ignition timing than on an NA car so the NA transient regards can be way to aggressive especially at low rpm . Just reduce the trans retard amount where your getting negitive timing

10-09-2023, 05:30 AM	#6
Gt86Force Member Join Date: Aug 2018 Drives: GT86 Supercharged Location: All over the place Posts: 31 Thanks: 5 Thanked 13 Times in 8 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Yep. Thanks to all for the suggestions. At the moment I'm running like this, with the my17 CFP delta. It seems ok, at least for now. We will see once we start working on the higher rpms zone, but at least I'm working in the right direction!

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