I have a 2015 Mustang, twin turbo on E85.
I had the car dialed in on 12lbs of boost on E85 with no knock and about 19 degrees of timing. It did 806/786 on this setup. I changed exhaust to the Magnaflow street setup and had a custom H-Pipe built. Ever since then I have been getting knock like crazy. I assumed its a loose clamp or the exhaust hitting the body. I have searched and searched and re-checked every clamp and fitting. All is good.
I assume it has to be false knock, even on about 8 lbs of boost and 16 degrees of timing it will pull full knock retard at 4k. The E85 tests great, almost a little high near E90 and AFR is mid 11's on the gauge or .77/.78 lambda. The upstream widebands read .72/.73.
I assume its false knock, I tried de-sensitizing the knock sensors in the gain table. I dont want to turn them off, just reduce them by 25%-50% to test.
Are the numbers on the table backwards? If I divide that number in half it gets WAY worse knock. But for testing purposes I doubled those numbers in the table and get 0 knock. Thoughts?