Quote:
Originally Posted by Jordo!
Actually, if they didn't mess with accel enrichment, but added boost, my guess is it's probably skewing very lean on tip in...
Although ideally you want it to quickly arrive at the target AFR for the next map cell, as a general rule of thumb, skewing rich will tend to feel less laggy than skewing lean.
|
You can see on the graph it is rich on tip in (sorry its hard to read, I snapped a photo of the dyno sheet with my iphone)....Around 11.0:1 then quickly leans to around 11.6:1 and hangs there throughout the rev range. At 5,000 rpm this tune is only making 30 hp more than my baseline run. How rich does it really need to be at those low rpms? The supercharger is not making much boost yet.
The stock curve (which makes great power) is at 15:1 at tip in and then quickly goes to 13.5:1, then trends down to 13:1 by 5,000 rpm, then 12.15 at redline. 14:1 is going to make the most power, but runs hot. Most sports cars run around 12.5:1 for power and economy. Tuners go into the 11:1 range for quench and to keep cylinder temps down. They use it for safety, but it hurts power output, fuel economy and emissions. Having an 11:1 A/F ratio at 3,000 rpm when the S/C is making 1-2 pounds boost is counter productive. Having 11:1 A/F ratio at 8,000 rpm and 10 pounds of boost is a really smart idea.