My trip to Seattle, bragging on my SL1.
 

I made my first long trip with my '01 SL1. I went to Seattle, specifically Arlington and the Northwest Experimental Aircraft Association convention. I was hoping against reality to make 55 mpg. I did not; but I did pretty well. I had re-installed the alternator belt for this trip.

Home to Seattle 500 mi 9.615 gal 52.0 mpg
Sea-Arl-Yakima 372 mi 7.219 gal 51.5 mpg
Yakima-Home 353 mi 5.996 gal 58.9 mpg

OVERALL 1225 MI 22.830 GAL 53.65 MPG
I averaged 60 mph most of the way with speeds from 55 to 70 mph.

It was quite cool when I left, maybe 55 F. Going over I seemed to climb gentle hills a lot with braking going down steep hills. Coming back I got to climb the steep hills and coast the gentle ones without brakes. It was the leg from Baker City to Meridian on the way home that brought the trip average up. I made 71 mpg at 59 mph average for 125 miles. That leg was in the hot afternoon. I was drafting a bit. My intake air was 190-205 F on most of that leg except for long down grades. I did not draft much at all on the way over and was in more of a hurry to get there. I was carrying about 200 lbs of tent and camping supplies.

Going up 5% grades was not a problem. The car did it easily in 4th gear with IA over 200F. I had to keep pulling grill stuffing as the day warmed up but I was usually behind the the heat a bit. At sea level I had a spot of pinging that lasted less than a second. It only heard it happen once. The scangauge was reporting an incorrect TPS reading. The ECU data may have momentarily been corrupted by an EOC and restart with the throttle slightly open.

Anyway it was a fun trip with no one complaining about the lack of AC or needing to stop every few miles. Don't tell her but you can cover a lot more miles without your wife along. :)

That's pretty damn good! Think I know what's on the menu if and when the Geo wears out...

Nice results -- you should post some pics of the car. I'm curious to see the wheel skirts, etc.

Good numbers for a real world trip

For this reason alone I'm SO jealous of the SL1/SC1 cars... my SL2 auto is impressing me the more I tinker with it, but it'll NEVER hit SOHC numbers.

I know, I know... there is some mysterious SL2 5sp guy getting 60+mpg but I'm not THAT religious about my "hypermiling" just yet, in fact, my tactics are extremely lack-luster ATM but I'm still makin numbers I'm happy with.

That's awesome UsedGEO. There's something to be said about compact cars and their ability to sip gas. Now you get to make a game out of it everytime you head up I5.

Its the final drive ratio in top gear that kills DOHC mpg's, I think. If you ever need new tires, get the tallest, thinnest, high psi LRR tires on the front that will fit.

Op Thats some damn good numbers for the Opel:thumbup:

Very true but, If you don't calibrate you speedo to compensate for the taller tire youll never be able to calculate your savings.

Sc2
 

We recently bought an SC2 for my wife to drive instead of the Bonneville. I was surprised that the engine has less useable torque than the single cam engine. It is sort of gutless on hills. I have Somender Singh grooves in the SL1 but that only made about 7% difference. I have had a scangauge in each car. The '01 SOHC never goes over 34 BTDC. The '99 SOHC goes to a max of 39 BTDC. The '02 DOHC goes to a max of 49 BTDC. It routinely runs up to 45 BTDC while crusing at 70 mph. I had a tail wind to get those numbers. My conclusion is that the DOHC engine has a very stagnant combusion chamber. There must not be much turbulence in it. From pictures on the internet it looks like it has a little squish area.

I am tying to figure out how to get swirl in the combustion chamber without pulling the head. I have thought of regrinding a camshaft for assymetrical intake valve lift like a Honda V-tech but it would be permanent. I have also tried to visualize a means of partially plugging one intake port.

So far I have not concieved of a really elegant way to restrict flow to one intake valve in each cylinder. I don't want to close the valve completely because some fuel will spray on that side and should not be allowed to accumulate.

Any better ideas out there? I know MPGMIke did some port work to get more swirl on damondlarry's. I am looking for something simpler. I thought I could make a baffle plate between 2 intake gaskets until I saw that it just uses a sophisticated o-ring.

I am still brainstorming this one.

Lovmysan did a nicer job than me and posted lots of pics. I just tied the corplast under the car. It slips into the bumpers front and rear. I coverd the exhaust and shielded with valley tin. There is a section in front of the rear wheels that is quite smooth and has no belly pan.

The grill block is just pipe insulation. My mods are just the usual stuff I learned here including rear skirts and outside mirror delete.