Learned a bunch. From Chicago to Indiana all was well, but as time went by the MPG dropped. At first I thought it was headwinds. Any way, I noticed the spark advance had dropped to low 20's instead of high 30's and my water temp was up to 211. Somewhere in Ohio I stopped and cut holes in the front cover I had made, and kept stopping and increasing the size of the holes as the spark advance and MPG were improving as water temp dropped. I got it now where on the road it stays under 197f, but still goes up in city driving (the last couple mi was city type driving), so I'll need to open it up just a bit more.
I also got an error P0112 in eastern ohio because the intake was getting way too hot. The air in the airbox was hitting 252 when I got the code. As with the water temp, I stopped a few times adjusting a the manifold shape and distance from the headers to get the temp to come down.
Eventually by the time I got to Pa, I had the temps reasonable. It seems that I need to keep the intake and coolant under 200f to get the spark advance to high 30's at 60 mph on level ground.
Net bottom line was 43.8 mpg going east at 65 mph with about 10 stops for adjustments.
The trip back was much better. Made a couple more stops in Pa to adjust the intake, and then reset the scangage at the ohio line when I had the teps stable under 200f. I got 50.3 mpg going thru ohio at 65 mph with a couple stops for food and coffee. I also checked my odometer against mile markers and its within 1%. In indiana the speed limit goes up to 70, so I reset the scangage at the line. The 1st 1/2 hr or so in indiana I got 46.8 mpg doing 70. After that it started raining and I had a headwind strong enough to hold flags straight out, so mpg went into the dumper down to 40. I had taken the wipers off, and the rainx worked pretty well for a couple hours, but seemed less effective by the time I hit chicago. Water temp went up to 206f again in the suburban driving on the last couple miles. I've learned I can feel/hear the sluggishness when it gets too hot if the radio is off. So I need to open up the front a little more.
Hmm, damn saturns and temperature based ignition retard. I'll have to test when I get my superMID for the coolant temperature stuff and wai stuff, but we shall see.
diamondlarry had similar issues with the intake temperatures above 252 degrees, I guess it's just a failsafe type thing to check for sensor malfunction or holy-****-the-car-is-on-fire type stuff.
There are 2 different issues there. Its only a problem if the ACTUAL air temp gets over 200f or the ACTUAL water temp gets over 200f. It starts running sluggishly, sparks gets retarded, and MPG's drop drastically. I can have the sensor telling the computer that its 247f just fine as long as the actual air temp stays under 200f.