I fueled up today. 492 miles, 7.8 gallons, 63 mpg. Scangauge had me at about 61.6. I forgot to write down average speed for the tank. There were 300 miles since the Somender Singh grooves.
Yesterday, I drove back to where I grew up, 75 miles one way, 500 ft elevation change, maintained 61 mph on the freeway. Outbound I had a heck of a time getting better than 52 mpg. I had a slight upgrade and 15 mph headwind. I was thinking of all the ways I would have to eat crow on those grooves. The 90+ temperature was making me sweat too. I had started out with a cold car and that did not help. The trip was a spur of the moment thing. I had been avoiding the freeway for several months. I did have a several mile downgrade that almost saved me. I ended up at about 56 mpg outbond. Of course I had to get back up the hill coming home. There were intersections, stop signs and slow curves for a short distance. The trip back with the hill and tailwind worked out to about 64 mpg. I did not shut off the engine but I did neutral coast on hills where I could. The Today numbers were 59.8 mpg, 55 mph ave, 155 miles. Given the 1.5% error of the scangauge I am still calling that 60 mpg at 60 mph. There is not much margin though. I was running 210 WT and 185 IAT. It came back up the hill, which had coasted down at 75 mph, at 61 mph in 5th gear at temps of 220 WT and 200 IAT. The grooves do help slightly with the torque thing.
Often times on the way back with the taliwind the load on the engine would get so low that the timing would fall back to no load timing, 18 BTDC with the gph just about .2 or .3 gph above driveway gph for that rpm. I could have used taller gearing for sure. Maybe I should have just bumped it up to 65 mph or better to keep a little load on the engine. I can see why those running like this are installing hand throttles. It would be good to keep enough load on the engine to keep the timing up there at 33-34 degrees. That would be DWL though I guess. It is hard to do with your foot.
After I filled up this morning I did a run out to work and back home. Up to work was 70 mpg and home was 110 mpg. These are personal records by about 10% above anything previous. The TANK currently sits at 85 mpg, 29 mi, 35 mph ave. I know I cannot maintain that but it is still a nice way to start the tank.
Gee, this is almost as good as those guys on the TOP ten list
. I still feel like an imposter there. This site made it very easy for me to achieve what I have in what seems like a pretty short time.
I have convinced my self of the groove effect. Even though it took me two days to get the grooves in if I could find some hypereutectic flat top pistons I would pull the engine apart again. I think it could use about 10.5:1 compression ratio and about 1 tooth retard on the cam.
Incidently After 2.7 hour without alternator I still had 12 volts while loaded. I have a large deep cycle battery in the trunk. If I do this again I am going to unplug the running lights though.
This is the most fun I have had in quite a while.
I noticed CO had trouble opening the Somender Sing Grooves thread in the experiments section. I replaced all the pictures with links. That should help out.
Sorry, I wrote so much but I like talking about it.
) 
! As it sits my avg speed was at an even 40 mph .
.
Linear Mode
