Acceleration enrichment and spark knock
#1
Acceleration enrichment and spark knock
Hi all,
After 8 auto tune sessions I managed to get my VE correction within 1-2%, set cruise and idle AFR to 13.0-13.2 running full open loop (I ride in 100F+ and gridlock traffic a lot), added 4* globally to spark advance table, then run log tuner to spot the knock events and retard where necessary, after 4 log tuner sessions I cannot ping the bike even when I want to ping it and still having very aggressive advance table. When CHT gets really hot at 280F plus, I still get very very slight ping with datalog indicating 1-1.5* knock retard, never more..I was very very happy and content, my engine was super responsive and powerful, except that off course my milleage suck at 30MPG in the gridlock city traffic to 32-33MPG out of town and still get really hot sometimes reaching 320F on the worst day....
Then I DIY'ed a cooling fan from 5.2" Spal Fan, the thing does wonder at dropping my CHT, now I get max CHT @ 265F on the hottest day and worst jam, averaging 235-250F normally with fan on. After succesfully dropping my CHT, I wanted to get better fuel economy by re arranging my AFR table by setting idle and cruise between 13.4-13.6, off course still running full open loop for the entire table, happy with the result MPG jumped to 33-34MPG in the gridlock city traffic and 35-38MPG out of town with little to no traffic, engine still responding very very nice with CHT maxing out at 265F on the worst day. THE PROBLEM is, now I do get ping when accelerating suddenly on low gear/cracking throttle at low rpm/speed with 1.5-4* max being pulled out by the anti knock system. Nothing major, just very very slight very short audible ping.
I know on 103" engine that no matter how well tuned your engine is, you cannot get rid of ping completely without ending up with very weak spark advance table and leaving a lot of power and efficiency on the table. Even Jamie Fuel Moto stated the same thing...I can live with minor ping for good advance table but I would like to get my auto knock retard at 2* max, no more than that....
The BIG question is....Should I re tune my advance table by doing another log tuner and adjust advance slightly where it retarding more than 2* OR play arround with my acceleration enrichment???
I only get more than 2* retard when accelerating from low speed/standstill or under high load (accelerating on high gear low speed), other than that no ping at all or 0.5-1* max retard. Does adding a bit more fuel when accelerating by playing around with acceleration enrichment would help with my ping without weakening the advance table???
Advice needed and thank you very much in advance folks!!
After 8 auto tune sessions I managed to get my VE correction within 1-2%, set cruise and idle AFR to 13.0-13.2 running full open loop (I ride in 100F+ and gridlock traffic a lot), added 4* globally to spark advance table, then run log tuner to spot the knock events and retard where necessary, after 4 log tuner sessions I cannot ping the bike even when I want to ping it and still having very aggressive advance table. When CHT gets really hot at 280F plus, I still get very very slight ping with datalog indicating 1-1.5* knock retard, never more..I was very very happy and content, my engine was super responsive and powerful, except that off course my milleage suck at 30MPG in the gridlock city traffic to 32-33MPG out of town and still get really hot sometimes reaching 320F on the worst day....
Then I DIY'ed a cooling fan from 5.2" Spal Fan, the thing does wonder at dropping my CHT, now I get max CHT @ 265F on the hottest day and worst jam, averaging 235-250F normally with fan on. After succesfully dropping my CHT, I wanted to get better fuel economy by re arranging my AFR table by setting idle and cruise between 13.4-13.6, off course still running full open loop for the entire table, happy with the result MPG jumped to 33-34MPG in the gridlock city traffic and 35-38MPG out of town with little to no traffic, engine still responding very very nice with CHT maxing out at 265F on the worst day. THE PROBLEM is, now I do get ping when accelerating suddenly on low gear/cracking throttle at low rpm/speed with 1.5-4* max being pulled out by the anti knock system. Nothing major, just very very slight very short audible ping.
I know on 103" engine that no matter how well tuned your engine is, you cannot get rid of ping completely without ending up with very weak spark advance table and leaving a lot of power and efficiency on the table. Even Jamie Fuel Moto stated the same thing...I can live with minor ping for good advance table but I would like to get my auto knock retard at 2* max, no more than that....
The BIG question is....Should I re tune my advance table by doing another log tuner and adjust advance slightly where it retarding more than 2* OR play arround with my acceleration enrichment???
I only get more than 2* retard when accelerating from low speed/standstill or under high load (accelerating on high gear low speed), other than that no ping at all or 0.5-1* max retard. Does adding a bit more fuel when accelerating by playing around with acceleration enrichment would help with my ping without weakening the advance table???
Advice needed and thank you very much in advance folks!!
#2
I haven't had much luck with the accelerator enrichment. Seems to stumble if you add any and not much change if reducing. I have had better luck with tuning the ping out using the Data Logging and adding 2 to 3% to the VE table in the right place seems to work better than reducing the timing. There may be a slight glitch in the Data logging as you frequently get 2 degrees retard reading and really nothing showing up. the conditions you described is the same times I see a problem.
#3
I haven't had much luck with the accelerator enrichment. Seems to stumble if you add any and not much change if reducing. I have had better luck with tuning the ping out using the Data Logging and adding 2 to 3% to the VE table in the right place seems to work better than reducing the timing. There may be a slight glitch in the Data logging as you frequently get 2 degrees retard reading and really nothing showing up. the conditions you described is the same times I see a problem.
You are spot on correct about this possible glitch on power vision, today I did another datalog run to spot my knock retard activity, I tried my best to ping the bike, saw up to 5* retard when reading on the fly datalog, but when I run log tuner I only saw maximum 1.2* retard....this is confusing. I ended up pulling timing as advised by log tuner, wasn't much averaging by 0.3 to 1.2 retard and will give it another try tomorrow. I created three maps to test, one with timing pulled out by datalog, one no timing change but added 0.04 of acceleration enrichment from 197F up and another one both timing pulled and enrichment added...
Oh yeah, out of curiosity I tried re tuning to closed loop on idle and cruise range today...WOW BOY!!! Didn't know what I was missing.....I always assumed closed loop is bad for my riding environment, apparently with combination of properly tuned bike and cooling fan, closed loop is the way to go....my CHT never reached above 255 and today's day temp was 102F, bike feels snappier than ever, MPG reading slowly creep up steadily....Nice....
Last edited by uwiik; 10-14-2013 at 05:03 AM.
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