serx7 Posted December 18, 2015 Share Posted December 18, 2015 Thanks, took a quick log on the way home from work. Not sure what af learning a,b,c,d are but maybe you can give me some pointers? I don't understand what a/b/c/d mass airflow ranges indicate. I'm running 93oct on a 91oct map. was informed this would ensure i'd run on the rich side... I pulled up the Cobb OTS Stage 2 91 oct map to see what the AF Learning airflow ranges are. They appear to be A (0-5.60 g/sec), B (5.6-10 g/sec), C (10-40 g/sec) w/ D implied to be > 40 g/sec. Your most recent log shows AF Learning C is 7.1 and D is higher at 10.6. Maybe a slight boost leak (?) My understanding is that unless the D trim is disabled in the tune (it's not disabled in the Cobb OTS from what I'm seeing), the D trim is also applied to open loop (which incl WOT). Assuming that's true, at WOT the ECU will be adding 10% fuel on top of the supposedly already rich OTS mapping. Perhaps it's rich knock, I don't really know. If you had a WBO2 installed you could see what your true AFR is under boost. The Cobb Primary Open Loop fueling table calls for AFR in the mid-high 10.x range in the regions where you're seeing high load knock. That doesn't mean that's what your actual AFR is, but assuming actual AFR fairly close to what the table calls for, w/ a 10% trim active on top of that, you could potentially be in the low 10.x to high 9.x AFR which I believe most would consider very rich. Link to comment Share on other sites More sharing options...
artard Posted December 19, 2015 Share Posted December 19, 2015 I pulled up the Cobb OTS Stage 2 91 oct map to see what the AF Learning airflow ranges are. They appear to be A (0-5.60 g/sec), B (5.6-10 g/sec), C (10-40 g/sec) w/ D implied to be > 40 g/sec. Your most recent log shows AF Learning C is 7.1 and D is higher at 10.6. Maybe a slight boost leak (?) My understanding is that unless the D trim is disabled in the tune (it's not disabled in the Cobb OTS from what I'm seeing), the D trim is also applied to open loop (which incl WOT). Assuming that's true, at WOT the ECU will be adding 10% fuel on top of the supposedly already rich OTS mapping. Perhaps it's rich knock, I don't really know. If you had a WBO2 installed you could see what your true AFR is under boost. The Cobb Primary Open Loop fueling table calls for AFR in the mid-high 10.x range in the regions where you're seeing high load knock. That doesn't mean that's what your actual AFR is, but assuming actual AFR fairly close to what the table calls for, w/ a 10% trim active on top of that, you could potentially be in the low 10.x to high 9.x AFR which I believe most would consider very rich. I had just recently installed the uppipe and downpipe and flashed to the new map. I'll go in today and tighten down the exh bolts and clean the maf. then, try running on the 93oct map. hopefully that may help curb whatever is going on. btw, where do you find the trim ranges? Is it via the accessport manager? thanks again! Link to comment Share on other sites More sharing options...
joeleodee Posted December 19, 2015 Author Share Posted December 19, 2015 You can find the trim ranges via Accesstuner Race software provided free through Cobb. Link to comment Share on other sites More sharing options...
joeleodee Posted December 20, 2015 Author Share Posted December 20, 2015 I didn't actually post a log. 2005 Legacy GT 5 MT sedan AVO450 turbo with all supporting mods E85 self tuned 3rd gear pull. I have a new higher volume fuel pump on its way so that should take care of running a little lean and the 100+ injector duty cycles. I'll also be able to scale the MAF down a little since I'm trying to overcompensate so as not to run too lean. https://docs.google.com/spreadsheets/d/101U4MflfdXbGp1o_Wwi3liUf2NvvdBhlocNfhHi9uMU/edit?usp=sharing Link to comment Share on other sites More sharing options...
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