False knock?
05-10-2012, 07:23 AM
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False knock? To the guys that dabble with tuning here. I'm having a hard time finishing off my TVS road tune. This is for a stroked 402 with a TVS 2300 in a gen 1 caddy. E67 pcm. Using efi live v2.
I'm running a 2bar SD OS, VVE tables are spot on, IATs are good, MAF is off, AFRs under boost are a nice 11-11.3 at max, so just working on finalizing the high octane tables. I'm doing pulls in 5th gear from 2-5k rpm. At around 4k (apcyl .98-1.00) I'm seeing 6 degrees KR. Pulled 6 degrees in the affected cells, did another run and I see 6 degrees KR again. Boost I'm pegging at 13 boost on the TVS. Running 91 ethanol free gas.
Was running 18 degrees in those cells, pulled it back to 12. Same result.
Car runs strong, don't hear pinging or anything out of the ordinary. Everything else seems ok i.e. idle, part throttle etc. Only happens at max boost.
Kind of baffled now and thinking this is false knock. My knock sensors are fresh. From what I read few things to check are torque on knock sensors and if anything may be making contact with the frame/engine. I know my driveline is a bit shot (diff on its way out, DS is not 100% balanced). Only other odd thing is my bank 2 precat o2 is sometimes reading 10% leaner than bank 1 but I see this in many other cars I've logged also so not sure.
Kind of curious if anyone has any outlandish ideas here.
I'm running a 2bar SD OS, VVE tables are spot on, IATs are good, MAF is off, AFRs under boost are a nice 11-11.3 at max, so just working on finalizing the high octane tables. I'm doing pulls in 5th gear from 2-5k rpm. At around 4k (apcyl .98-1.00) I'm seeing 6 degrees KR. Pulled 6 degrees in the affected cells, did another run and I see 6 degrees KR again. Boost I'm pegging at 13 boost on the TVS. Running 91 ethanol free gas.
Was running 18 degrees in those cells, pulled it back to 12. Same result.
Car runs strong, don't hear pinging or anything out of the ordinary. Everything else seems ok i.e. idle, part throttle etc. Only happens at max boost.
Kind of baffled now and thinking this is false knock. My knock sensors are fresh. From what I read few things to check are torque on knock sensors and if anything may be making contact with the frame/engine. I know my driveline is a bit shot (diff on its way out, DS is not 100% balanced). Only other odd thing is my bank 2 precat o2 is sometimes reading 10% leaner than bank 1 but I see this in many other cars I've logged also so not sure.
Kind of curious if anyone has any outlandish ideas here.
