Quote:
Originally Posted by Ajrothm
Have you logged timing to verify this?
Engines are more efficient with more timing advance, to a degree...(no pun intended)  |
No logging but if you have tuning software you can pull up the tables that show spark timing maps vs. coolant temp and you will see that on cold start timing is retarded and more fuel is added, which to our delight makes for a louder exhaust note when combined with the open valves of the NPP exhaust. The engine runs in Open Loop and use some predefined tables and MAP sensor for their calculations until the coolant temp reaches about 140 degrees and the O2 sensors warm up. Then it switches to closed loop and uses the feedback from the O2 sensors to calculate the air/fuel ratio. From an emissions standpoint the manufacturer is also trying to heat up the catalytic converters as fast as possible.
So, I agree with you on the timing and efficiency but we are talking about a cold start, which is harder for the engine to do hence less timing and more fuel initially. Once the engine is warm, you will notice when you fire it back up it won't sound nearly as aggresive as cold start since it is not running the fuel rich cold start routine.