Matt68
April 2nd, 2011, 03:50 PM
I am working on a 01 Vette on a chassis dyno. Car has Patriot Heads, Cam, shorty headers, 42lb/hr injectors.
I did the autoVE and MAF tuning and everything was coming in good. When going into the higher RPM's (>4000) on the MAF tuning we were getting KR above 4000. It wasn't the normal saw tooth, it just shot up to 9.9deg. The actual timing in that range after the KR reduction was in the 12*. I went though and removed 2* across the board and still had it. We pulled plugs and everything looked fine, AFR was sufficiently rich. The valve train is a little noisy, so we were wondering if it was setting off the knock sensor. I logged several of the EST_XXX_DMA.pids and it looked as though the Brake Torque Management was removing timing during that same time in the logs. We tried changing settings in the tune to eliminate this. You can see it in log 006_1 and we removed it in 0016_1 but the KR is still removing timing.
After several hours of trouble shooting we decided to try and increase the timing and see what happened. Added 2* of timing in the loads above 4000RPM and we picked up torque. Added another 2* and continued to pick up torque. Went though this until we have about 30* of timing at the upper RPM's and continued to make power. The car went from about 330ft-lbs to 377ft-lbs and power went from 319 to 395.
Are there any ideas as to what could be causing this? Also, we have been searching for ways to adjust the impace the KR has or eliminating the knock sensor, and can't find a good setting that makes an impact. My concern is that we are just "tricking" the computer right now, and if whatever is making the KR appear gets repaired then there will be problems.
Thanks,
Matt
10273
10275
10274
I did the autoVE and MAF tuning and everything was coming in good. When going into the higher RPM's (>4000) on the MAF tuning we were getting KR above 4000. It wasn't the normal saw tooth, it just shot up to 9.9deg. The actual timing in that range after the KR reduction was in the 12*. I went though and removed 2* across the board and still had it. We pulled plugs and everything looked fine, AFR was sufficiently rich. The valve train is a little noisy, so we were wondering if it was setting off the knock sensor. I logged several of the EST_XXX_DMA.pids and it looked as though the Brake Torque Management was removing timing during that same time in the logs. We tried changing settings in the tune to eliminate this. You can see it in log 006_1 and we removed it in 0016_1 but the KR is still removing timing.
After several hours of trouble shooting we decided to try and increase the timing and see what happened. Added 2* of timing in the loads above 4000RPM and we picked up torque. Added another 2* and continued to pick up torque. Went though this until we have about 30* of timing at the upper RPM's and continued to make power. The car went from about 330ft-lbs to 377ft-lbs and power went from 319 to 395.
Are there any ideas as to what could be causing this? Also, we have been searching for ways to adjust the impace the KR has or eliminating the knock sensor, and can't find a good setting that makes an impact. My concern is that we are just "tricking" the computer right now, and if whatever is making the KR appear gets repaired then there will be problems.
Thanks,
Matt
10273
10275
10274