proxlamus© Posted February 20, 2008 Share Posted February 20, 2008 Hey guys.. ive been going crazy trying to tune my car for a perfect 12.5 AFR over 100kpa... I am having issues with 4th and 5th gear pulls being about 10.8-12.3 AFR depending on the temperature... and in 2nd and 3rd gear pulls the AFR's are 12.8-13.8 AFR and it's driving me INSANE! I can only assume 2nd and 3rd gear have the greatest load so it leans out a bit.. If i adjust the values so 2nd and 3rd gear are around 12.5 AFR then 4th and 5th gear are in the 10:1's.. really really rich. any ideas?! This is only under BOOST by the way I am presently running 16psi Quote Link to comment Share on other sites More sharing options...
TimZ Posted February 20, 2008 Share Posted February 20, 2008 Hey guys.. ive been going crazy trying to tune my car for a perfect 12.5 AFR over 100kpa... I am having issues with 4th and 5th gear pulls being about 10.8-12.3 AFR depending on the temperature... and in 2nd and 3rd gear pulls the AFR's are 12.8-13.8 AFR and it's driving me INSANE! I can only assume 2nd and 3rd gear have the greatest load so it leans out a bit.. If i adjust the values so 2nd and 3rd gear are around 12.5 AFR then 4th and 5th gear are in the 10:1's.. really really rich. any ideas?! This is only under BOOST by the way I am presently running 16psi I have a pretty strong suspicion... In 2nd and 3rd you still run through the gears pretty quickly, so there isn't time for the manifold air temps to rise significantly. You spend much more time in 4th and 5th under boost and the manifold air temps will almost certainly climb. The hotter air temps will result in a richer mix. Any ideas on your air temps? Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 20, 2008 Share Posted February 20, 2008 Yepo as TimZ said its your air temps. You might need to move the air temp sender out from behind the radiator. Or if you can adjust the air temp % table that would be even better. Can you do this in megasquirt? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 20, 2008 Author Share Posted February 20, 2008 I went through all the menu options in Megasquirt and the only thing I can find relating to Intake Air temp and Coolant temp is adjusting the ignition =( I can only think of warmup enrichment, but I am at normal operating temp... so regarding the temperature adjustments.. I dont even think Megasquirt can control this?! Ted where would you recommend moving the IAT sensor?! Mine is on the charge pipe right before the throttle body (behind the radiator as you mentioned) Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 20, 2008 Share Posted February 20, 2008 You need it after the intercooler so I would say the first bend on the passenger side. I have same problem right now with my car being n/a I will be lean if I sit at a light for awhile then drive it but once I move alittle bit and my IAT's come down then the a/f are perfect. I believe you can adjust it. Its in the code though. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 20, 2008 Author Share Posted February 20, 2008 Ted I did a search in the MegaManual and havent had alot of luck finding anything with temperature tuning other then "Speed density alpha N tuning" which uses throttle and temp and rpm based tuning. Maybe you can point me in the right direction?! Quote Link to comment Share on other sites More sharing options...
Silent Posted February 21, 2008 Share Posted February 21, 2008 spinning perhaps. not reaching full boost in 2nd and 3rd. iat's affect ignition timing, not afr. i take it the fuel side is set the same afr regardless of boost levels in the fuel side? had a similar problem in a twin turbo lincoln i was tuning with megasquirt. small bumps in the fuel map under boost would create not so pleasent results Quote Link to comment Share on other sites More sharing options...
TimZ Posted February 21, 2008 Share Posted February 21, 2008 iat's affect ignition timing, not afr. I assume you are referring to what is tunable in the MS software, right? If you don't compensate for IAT, it will have a measurable effect on your AFR. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 22, 2008 Share Posted February 22, 2008 iat's affect ignition timing, not afr. Nope afr's adjust fuel as well as timing. If you look at your injector opening time and then warm up your iat it will decrease. And vice versa getting it cold. Prox, I did a quick search about a month or so ago and didn't find anything as well. So can't be much help there. Sorry. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted November 11, 2008 Share Posted November 11, 2008 Any progress on this prox? I'm curious how MS handles IAT changes as well. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted November 12, 2008 Share Posted November 12, 2008 In Tuner Studio, under the "Other Tuning" menu there is IAT based fuel correction, MS has all the same features, so its got to be there. Quote Link to comment Share on other sites More sharing options...
Noddle Posted November 12, 2008 Share Posted November 12, 2008 Megatune 2.25 p3 using MSII Rev 2.88500, Other Tuning / IAT-Based Fuel Correction Nigel Quote Link to comment Share on other sites More sharing options...
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