Quote:
Originally Posted by hassmaschine
Quote:
Originally Posted by Michaellcoates
I was reading another forum that some turners tune out LTFT because ST is more responsive with aftermarket SC kits. They basically default LTFT to 0.00. Why does the car drive great with only STFT, but wack out when LTFTs are finally registering? I guess I'm still not understanding what conditions cause this.
My understanding that LTFT are adjustments made from ST feedback after that cars DME has adapted to conditions. Both LT and ST are based on feedback from the wideband O2 sensor. So my question is, if the O2 sensor is getting wacky numbers (even if it's faulty O2 or real numbers calculated by faulty conditions) why would the car act ok under ST and not under LT?
Pardon my ignorance I'm honestly just trying to understand and get that "ah-ha" moment.
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If they're turning off LTFT then I think they probably don't know what they're doing. It definitely can be done on these DMEs without disabling LTFT.
No, the car wouldn't act OK - because on the N52, the O2 feedback loop has a lot of control over fueling. With no MAF, it's like 80% of the algorithm.
The point of a LTFT adjustment is the STFT will never be very large, because it's only meant for minor transient changes - it needs to be able to respond quickly. If you need a 10% LTFT to have a 1% STFT, and then you disable the LTFT, you'll just end up with an 11% STFT (which it's not really meant to do). |
Thanks again. If you'd ever be open to taking a look at some logs let me know. I guess I might not do any good since you don't know how the tune is set up.