VALVE TIMING OPEN CLOSE @ .006 INT: 23 BTDC 66 ABDC EXH 73 BBDC 20 ATDC THESE SPECS ARE FOR CAM INSTALLED @ 112.0 INTAKE CENTER LINE INTAKE EXHAUST DURATION @ .50 216 220 LOBE LIFT .3090 .3130 LOBE SEPARATION 114.0
LS1 1.75 Rocker Kit W / 5/16 guide plates 5/16 magnum pushrod 7.400 CS O-E "R" Series lifters LS6 intake Vararam cold air intake X pipe Header - no AIR and no rear 02 sensors Borla exhaust from my X pipe to tips Custom Dyno tune
End result of that shops tune and the morons ruined the front O2 sensors by unscrewing them while wiring was still connnected to main wiring harness and then again when installing them back when headers were installed which chokes off the air reference path in the wires
We then did a custom tune to clean the mess ( such as tuner had set WOT timing to 32 degrees, turned off torque management and stress control of the A4) up and from the OBD-2 Ease scanner data we were able to remotely find that there was this O2 issue and had owner replace them and rerun the car to see the end results.
2 common issues seen, with all the mods No ONE had considered that the stock injectors were too small which is seen with the test results below where fuel injector duty cycle was at 108% with 20 mSec pulse widths and this was in only 53 degree weather so in the heat of summer or on the drag strip engine would be even leaner then the 7% lean in todays weather
Second issue is the common BS that the Vararam is some hot cold air cleaner design when as we see in every case of this product as seen below that in 53 degree weather the average part throttle IAT was 14 deg hotter then weather and as high as 100 deg at low engine loads.
Add that even at 128 MPH the maximun airflow was only 38 lbs when best would have been about 42-44 lbs and that the maximum CFM was only 558 which is nowhere close to a stock 1998 MAF that can flow to 750 CFM
Overall the poor functioning of that Vararam restricts airflow and caused much hotter air into the engine which causes poor burns in the cylinders and only have larger injectors could overcome this but a better aircleaner CAI would reduce fuel needs.
Team ZR-1 True Custom Performance Tuning Teamzr1.com
