Quote:
Originally Posted by nelsmar
So here is an idea.... How about you un-screw the MAF at idle. Lift it up while logging and see if the load value changes... If you lift the MAF out of the intake pipe your IAT temp may change which would possibly alter a speed density volumetric efficiency value slightly... but not crazy significantly... However removing the MAF from the intake pipe on a MAF tuned car will make a significant change and the car will struggle quite a bit.
Upping the fuel pressure is going to be a massive waste. There is a very high likeliness that less than 20% of your fueling after 3,200RPM is from the port injectors. So if you are running 13.5AFR and trying to get to 12.5 which is 8% more fueling and you are running 20% fueling from port with 4 bar fuel pressure you are going to need something closer to 7-8 bar of fueling to hit that target. And thats if it is actually 20% fueling... The factory tune in the low end actually uses pure DI until iirc 5000RPM or 1.5 load value.
If the motec tune has anything similar to the OEM setup it will be the same. And I'm going to guess that since they were caring more about performance than economy they were not going to use the port injection very much. As you don't have enough engine load to justify a port injection to shorten the direct injection time to improve quality of fuel mixture. You are realistically probably 5-10% port injection after 4,500RPM or so. And since the DI system has its own pressure sensor it can compensate. The DI pump is simply going to stop increasing the fuel pressure once it hits a certain point and nothing will happen.
More importantly where is the o2 sensor that you used to determine 13.5:1? If it was in the tail pipe and you had an exhaust leak and a large exhaust tip it is easily acceptable to consider the 13.5:1 being an inaccurate reading. You should place the o2 closer to the engine to verify you have a good reading. Or maybe try reading with the motec unit.
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Its purely di, the pi is not used at all. never.
they didnt care so much about performance as opposed to longevity (toyota didnt want any cars blowing up on tv.. bad press)
you are right in assuming it was in the tailpipe, I will be doing it from the o2 sensor next session. though i do not think it was far off the mark as many others have tested with similar results.