av8 Posted June 2, 2023 Report Share Posted June 2, 2023 Hi, Just running through some logs and I'm seeing something a bit weird. On light throttle, the AFR immediately runs lean, and then when I lift off, it goes rich (see graph below)....seems to do the opposite of what I would expect? [G4X on RB25DET with Link CanLambda, Bosch 1000 injectors] running CLL where AFR line is straight Any thoughts? if you need more info just shout. Quote Link to comment Share on other sites More sharing options...
koracing Posted June 2, 2023 Report Share Posted June 2, 2023 Please post a copy of your tune and your log file. There are a lot of parameters that can affect this behavior and you're not providing enough information to make any specific recommendations. Adamw 1 Quote Link to comment Share on other sites More sharing options...
av8 Posted June 3, 2023 Author Report Share Posted June 3, 2023 Here's the map. The log file is too big, i will see if i can truncate it RB25DET.pclx Quote Link to comment Share on other sites More sharing options...
av8 Posted June 3, 2023 Author Report Share Posted June 3, 2023 I couldn't find a way to truncate or trim the log file so I've tried to compress it, but can't get the file below 3.8MB, so I'm going to have to do another run and create a smaller log filer Quote Link to comment Share on other sites More sharing options...
remski2 Posted June 3, 2023 Report Share Posted June 3, 2023 Just use a file sharing service .. like google drive, dropbox.. etc.. av8 1 Quote Link to comment Share on other sites More sharing options...
av8 Posted June 3, 2023 Author Report Share Posted June 3, 2023 https://www.dropbox.com/s/d3jjbdxo5q7f6v0/RB25DET_log.llgx?dl=0 The log file is on my dropbox on the link above Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 3, 2023 Report Share Posted June 3, 2023 Mostly I would say it related to your VTC kicking on and off due to the "MAP > 65kpa" condition that someone has set. Contributing to the "lean tip in"; I suspect there is also not quite enough accel enrichment and the fuel table has a bit of an unrealistic shape to it like it hasn't actually been tuned. It looks like there is a patch around -20kpa, 1500-2000 RPM where it is a little lean. As for "rich on lift off"; this is pretty normal - when you lift off and the vacuum suddenly increases this evaporates some fuel off the port walls. Your VTC kicking off at the same time is exaggerating this. Quote Link to comment Share on other sites More sharing options...
av8 Posted June 4, 2023 Author Report Share Posted June 4, 2023 Hi, Thanks for the info, I'll take a look at the accel enrichment settings and the fuel map. Regarding the VTC, it's set similar to the base map. Mine is 'RPM>1200 and RPM<4400 and MAP>65kPa' .... (Base map is >1200 <5400 >65kPa) ... should i change it to a higher kPa? and maybe a longer 'Off delay'? Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 4, 2023 Report Share Posted June 4, 2023 If your engine runs then the base map has done its job, you now need to tune it. Typically to find the best switch points for a switched cam you do a run on the dyno with VTC off and another with VTC on full time, then overlay them, where the lines cross is your optimum switch point. Im pretty sure the last VTC RB i done was on around 2000 & off at 5300 but it was quite a few years back and im going from memory. Im not sure if I even used a load condition. av8 1 Quote Link to comment Share on other sites More sharing options...
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