Floppyz Posted November 3, 2021 Report Share Posted November 3, 2021 Hallo everybody, got a new question that I wasn't able to solve: i've set up flat shift on my evo9 rs in this way (DI input on top clucth pedal): The problem is that SOMETIMES as I shift gear (wot) and I release the clutch in next gear, engine start jerking as if mixture was extremely rich or just like a little 'cut percentage' remains, or even negative advance remains. If i suddnely lift throttle and wot again engine runs well (see log "jerk log.llg" shift from 2nd to 3rd gear). See also log attached wot2-3-4. Generally flat shift system work quite good even if the feelig is that durin reintroduction car don't run perfectly smooth but little bit rough... but still can't understand reason why: I've tested even fuel and spark cut mode but is the same. Looking to inj time and ing angle can't see nothing odd, also can't see any percentage of Fcut or Icut after clutch relased... so any suggestions? tks, bye Filippo wot 2-3-4 v2.18 ott21.llg jerk log.llg Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 4, 2021 Report Share Posted November 4, 2021 I dont see anything obvious, although I have never had great success using fuel cut for gear shift, recovery always feels too slow when I have tried. Does dropping the torque introduction time to zero help? I notice you have knock control pulling timing out on the 3/4 shift, but not much on the 2/3 shift. Quote Link to comment Share on other sites More sharing options...
Floppyz Posted November 4, 2021 Author Report Share Posted November 4, 2021 Adam, recently i've set knock target in function of clutch switch and his timer, it is a visrtual hinibition for CLL and Knk feedback, but no difference at least.. I'll make a test with torque introduction set to 0... but I really dont' now what else can be test to find out the issue... the feeling is like sparks plugs became wet of gasoline... but can't understand why if a relase throttle and wot again engine runs perfectly... Quote Link to comment Share on other sites More sharing options...
Floppyz Posted December 12, 2021 Author Report Share Posted December 12, 2021 On 11/4/2021 at 1:15 AM, Adamw said: I dont see anything obvious, although I have never had great success using fuel cut for gear shift, recovery always feels too slow when I have tried. Does dropping the torque introduction time to zero help? I notice you have knock control pulling timing out on the 3/4 shift, but not much on the 2/3 shift. Finally I've tested with 0 ms, and that fix it up!! Also tested several boost presure from 1.5 to 2 bar but result is alway the same. another test fith only 20ms and car runs better, not jeatking, but not smooth as if time is set to 0. Adam, Any other idea or requested test for find out how to fix and use reintroduction torque? it is a pitty can't use that function... by Filippo Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 12, 2021 Report Share Posted December 12, 2021 It is just a function of using fuel cut, with port injection it is not a great method for torque reduction and you will never get a nice seemless gear shift using fuel cut. The reason is fuel is injected ~720deg before the combustion event. So since there is fuel already sitting in all of the ports waiting for the next intake event, even after you cut fuel you still get another full engine cycle at full power. Then to restore power the ecu first needs to wait until the next scheduled injection event, squirt the fuel into the port, then the next combustion event is still 360-720 deg away. At say 6000RPM, 720deg is 20ms so on a 4 cylinder just a single fuel cut event on a single cylinder means you have a 25% torque reduction lasting for at least 40ms. The torque reduction effect from fuel cut is just too granular and too slow for a nice progressive torque reintroduction. Quote Link to comment Share on other sites More sharing options...
Floppyz Posted December 24, 2021 Author Report Share Posted December 24, 2021 Adam, i'm sorry if I bother you with this argument, but I still have issue with this flat shift: Yesterday I've made some test for ALS functions and during flat shift still have jerking behavior (with or without ALS), this time set as 'ign cut'. I'm sure to not have missfire issue (engine runs till 2 bar smooth and fast), but this happen also at low boost (1.4 bar) and always happen during reactivation time after flat shift. What more can I do? There is some method to make a 'low level' parameters log? that because from pc log i can't see nothing odd, no % of fuel neither ing cut but engine jerks and afr is not lean as missfire does, so I'd think could be a timeing issue or failure (random negative adv timening)... As told before, if I don't use flat shift system so releasing throttle as a normal shift, there are no issue at all.. I'm useing a oem gearbox and shift time is about 300ms where clutch remains engaged... Finally: Merry Christmas and best wishes from Italy!! bye Filippo Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 25, 2021 Report Share Posted December 25, 2021 Post a log and the tune. Quote Link to comment Share on other sites More sharing options...
Floppyz Posted January 2, 2022 Author Report Share Posted January 2, 2022 here i am Adam: attached some log where issue happen, some differences in boost and fuel or ing cut, ALS on or off, but issue after clucth release persist even if is reandom,about 1 each 2. Also test with reactivation timeout set to 0. whait for your kind judment bye flat shift jerk fuel cut 1.4 bar log stack.llg flat shift jerk fuel cut 1.4 bar.llg flat shift jerk 1.8 bar.llg evo9RS --nlts issue -v2.21.pclr Quote Link to comment Share on other sites More sharing options...
Floppyz Posted January 8, 2022 Author Report Share Posted January 8, 2022 On 12/25/2021 at 9:40 AM, Adamw said: Post a log and the tune. Adam, do you have some ideas? Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 8, 2022 Report Share Posted January 8, 2022 Sorry it is not really clear what the problem is. I dont see anything too unusual in the logs, the ecu appears to be doing what you ask. I notice there is quite a lot of "ringing" on the RPM trace after a shift which generally means you are bringing the torque back in too fast - although I dont have much experience with clutch/synchro shifted cars, most gear shift tuning I do is clutchless sequential dog engagement. I would try Ign cut with same settings that you have in the map attached above, but set torque introduction to 40ms, to see if that helps with the ringing. It may also help to set up ECU logging to record some related channels at 100Hz which may give better detail. Quote Link to comment Share on other sites More sharing options...
rrob Posted January 9, 2022 Report Share Posted January 9, 2022 Its most likely hanging a valve open after aggressive ign cut events. The valve floats and the lifter follows it and then needs to bleed back. Quote Link to comment Share on other sites More sharing options...
Adamw Posted January 9, 2022 Report Share Posted January 9, 2022 He says it is the same using fuel or ign cut. Originally it was set up as fuel cut. Logs for both are attached. Quote Link to comment Share on other sites More sharing options...
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