[diesel_john]

Ernie, Good to hear from you. Did you notice much difference in wheel slip going from concrete to asphalt? There is the ground effect. But maybe rolling resistance is the biggest. I noticed the roads that are very noisey to require more fuel. A rise in shock or tire temperature could indicate more fuel. Hot asphalt deflects more so your driving up hill both ways.

Do diesels run better on foggy days despite the heavier air?

I am getting that leaning out most diesels don't help much cause they are already leaned out. Am slowly advancing the static timing. I am assuming that advances the dynamic timing also on the mechanical rabbit. I suppose the head gasket will blow if I stretch the head bolts too much. Piston slap noise definitely is louder, so I am carrying more pressure over TDC. Guessing the max. VW spec. is close to the max. MPG.

roflwaffle, correct me if i'm wrong, you obviously know a lot more about pumps. how much timing advance is too much? when EGT's drop? On the mechanical system should i raise the internal bypass pressure?