Will changing timing tables affect STFT???
12-24-2005, 01:15 PM
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Will changing timing tables affect STFT??? I recently made some changes to my high and low octane timing tables, along with my base spark tables. Before I made changes, my LTFT and STFT were in the 0 to -2 range. Well today I went and put the car in SD mode ie:MAF set to 0, LTFT=off, disabled PE and reset fuel trims. I went for a drive and could not believe my STFT were -12. 
Could this happen from making changes to my timng tables?
If yes...do I have to start all over again with VE tuning? ie:start with LTFT and do the 100 mile re-learn?
Or should I retune my LTFT anyway???
Thanks,
Jason
Could this happen from making changes to my timng tables?
If yes...do I have to start all over again with VE tuning? ie:start with LTFT and do the 100 mile re-learn?
Or should I retune my LTFT anyway???
Thanks,
Jason
Last edited by Blown Interceptor; 12-24-2005 at 01:21 PM.
12-24-2005, 01:43 PM
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Id do your ltft's till they're +/-10 either way and then do stft's. Im not at home otherwise Id send you an excel file Marcin sent me that helps out alot for quickly tuning the ve.
12-24-2005, 02:48 PM
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while we are on this topic, surely you would want timing to be set at the point where the maximum fueling occurs at commanded afr. I would assume that cylinder pressure is maximised with maximum fueling, so to retune and remove fueling will reduce power. maybe that is a bit generalist but as long as timing combusts all the fuel efficiently I can't see why retuning with less fuel is good for power?
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12-24-2005, 06:05 PM
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Yes, I disable it while logging/tuning VE - if you enter PE it will throw the numbers off, depending on how you are tuning VE...
There are different schools of thought on this - some folks set the OLFA table to 1.0 and tune VE exclusively in PE (set PE RPM to 0 and MAP kpa to 0 so it's always in PE). I chose the other route, stay out of PE to tune VE and use PE the way I believe it was intended, as a 'power enrichment' over the base table for high RPM/load/WOT.
Rob (Bad30th)
There are different schools of thought on this - some folks set the OLFA table to 1.0 and tune VE exclusively in PE (set PE RPM to 0 and MAP kpa to 0 so it's always in PE). I chose the other route, stay out of PE to tune VE and use PE the way I believe it was intended, as a 'power enrichment' over the base table for high RPM/load/WOT.
Rob (Bad30th)
