|
Yes on the original date; but, I posted because it got resurrected the day before on Aug 17 and I got referenced.
I do struggle with smooth idling down to 500 RPM with a D cam. I have a B20E with the D cam and my warm idle is typically 850 RPM. At that engine speed my MAP is pretty high, around 50 - 55 kPa and the raw MAP value is quite bouncy. If you try to drop your idle RPM your idle MAP value is going to increase and likely have greater fluctuations making fuel control at idle more of a challenge. I use the idle spark advance control function in MSExtra which helps to smooth out the idle; but, it is definitely not modern car smooth.
In 1972 Volvo replaced the D cam with the K cam which is just about the same cam except slightly less overlap. The objective was to comply with air quality standards (in 1972 mainly tested at idle) with a side benefit that the 1972 B20F engines idle better than the 1971 B20E engines.
|