R34 Decel Timing and Idle Target RPM
Posted: Tue Sep 20, 2016 11:33 am
I am trying to solve an issue with my RB25DET NEO tune where there is a significant amount of 'popping' out the exhaust during decel.
I'm trying to increase the closed throttle decel timing, but the tables "Idle/Decel Neutral Timing (RPM)" and "Idle/Decel Gear Timing (RPM)" don't seem to be being used.
No matter how much I increased the timing at the top of these tables, it didn't seem to make any difference. So I did a logging run to see what was happening.
The first log "NIStune_2016-09-19_1659_49.csv" is using "tune1.bin", which has modified Decel Timing tables to increase timing up to 25deg at 1500rpm (DecelTiming_Modified.png). I modified both the IDLE and GEAR tables to match.
What I can see in the log however, is the closed throttle timing is 10deg over about 2000rpm, then 5deg between about 1800-1600rpm, then 0deg below about 1400rpm. It then jumps up to about 15-20 before returning to 5 at idle. As best I can figure, this table would look something like the image in DecelTiming_Actual.png.
The decel events in this log are at:
00:10 to 00:20 - neutral decel from ~5700rpm down to idle.
00:40 to 00:48 - 1st gear decel from ~5200rpm to ~1300rpm.
00:57 to 01:12 - 2nd gear decel from ~4700rpm to ~1500rpm.
01:24 to 01:45 - 3rd gear decel from ~4400rpm to ~2200rpm.
I then tried returning the Decel timing tables to OEM (tune2.bin - DecelTiming_OEM.png) and did another quick log with a neutral decel and idle. This log is in "NIStune_2016-09-19_1710_36.csv". It seems to do exactly the same thing with regards to timing on decel.
Am I looking at the wrong tables here? Is there a different table used for this decel timing?
Also, I've noticed the Idle target RPM doesn't seem to work quite as expected. In both of these logs it's idling at ~925rpm, which is a couple of hundred rpm higher than the expected target rpm of 688rpm (IdleTargetRPM.png). Is there something else that affects idle rpm?
Idle can be seen from about 14s in the second log, and the following places in the first log:
00:00 to 00:07
00:13 to 00:19
03:06 to 03:18 (end)
ECU is 23710-AA50F.
Thanks in advance,
Martin
P.S. I had to zip the attachments as it seems like it would only let me attach 3.
I'm trying to increase the closed throttle decel timing, but the tables "Idle/Decel Neutral Timing (RPM)" and "Idle/Decel Gear Timing (RPM)" don't seem to be being used.
No matter how much I increased the timing at the top of these tables, it didn't seem to make any difference. So I did a logging run to see what was happening.
The first log "NIStune_2016-09-19_1659_49.csv" is using "tune1.bin", which has modified Decel Timing tables to increase timing up to 25deg at 1500rpm (DecelTiming_Modified.png). I modified both the IDLE and GEAR tables to match.
What I can see in the log however, is the closed throttle timing is 10deg over about 2000rpm, then 5deg between about 1800-1600rpm, then 0deg below about 1400rpm. It then jumps up to about 15-20 before returning to 5 at idle. As best I can figure, this table would look something like the image in DecelTiming_Actual.png.
The decel events in this log are at:
00:10 to 00:20 - neutral decel from ~5700rpm down to idle.
00:40 to 00:48 - 1st gear decel from ~5200rpm to ~1300rpm.
00:57 to 01:12 - 2nd gear decel from ~4700rpm to ~1500rpm.
01:24 to 01:45 - 3rd gear decel from ~4400rpm to ~2200rpm.
I then tried returning the Decel timing tables to OEM (tune2.bin - DecelTiming_OEM.png) and did another quick log with a neutral decel and idle. This log is in "NIStune_2016-09-19_1710_36.csv". It seems to do exactly the same thing with regards to timing on decel.
Am I looking at the wrong tables here? Is there a different table used for this decel timing?
Also, I've noticed the Idle target RPM doesn't seem to work quite as expected. In both of these logs it's idling at ~925rpm, which is a couple of hundred rpm higher than the expected target rpm of 688rpm (IdleTargetRPM.png). Is there something else that affects idle rpm?
Idle can be seen from about 14s in the second log, and the following places in the first log:
00:00 to 00:07
00:13 to 00:19
03:06 to 03:18 (end)
ECU is 23710-AA50F.
Thanks in advance,
Martin
P.S. I had to zip the attachments as it seems like it would only let me attach 3.