Now up to 57.3 mpg at 60 mph in my 97 Saturn SC1
 

Gettin up there! Maybe I'll make it to 60 mpg when I finish aero mods and get my preheated fuel gizmo I built working. I wish I had lighter rims and tires, and a 98+ trans, but just too much money to change those things. Once the mods are stable, I'll make one try with gas additives just to see if they help or not.

This is a 97 SC1 5 spd 1.9L with AC and PS on normal 87 octane Mobil gas, no additives, driving at about 60 mph on the same 22 mi test loop I've been using with small hills and turnaround cloverleaf, etc, avg speed 57 mph, max speed 62 mph, outside temp about 60f, no wind, slight drizzle, no drafting trucks, no coasting, had to hit brakes 1 extra time due to traffic. All readings from my Scangage with error max about 1%. I also have a constant Air/Fuel LED readout and its not running lean. I had about 35 lbs of groceries in the car, but have the spare removed to reduce weight

Aero mods
- no antenna (I have a CD changer, who cares)
- no wipers (using RainX like my race car)
- Taped front end for lower drag with holes sized for optimal cooling (like my race car)

Engine/Trans
-hotter thermostat Napa 268
-105 ohm resistor on a switch instead of IAT sensor for 242-247f signal
-all synthetic fluids + Valvoline Synthetic Oil Treatment
-insulated hot air intake (actual temp about 150f) look in my pics at Saturnfans.com
-Champion copper plugs gapped .040
-Bosch plug wires

Other
-45 psi tire pressures

that's amazing - nice
 

that's amazing - nice work. you should really use the gaslog feature. i'm sure folks would like to see your tank-by-tank results too.

my firefly only gets that mileage around 53/54 mph.

What determined your gap on
 

What determined your gap on the spizzark plugs?

wow nice, i hvae a hard time
 

wow nice, i hvae a hard time keeping it above 50 mpg/55mph with tire pressure 55 psi + those areo mods sure rock!

And its a domestic! Nice job man.

Re: that's amazing - nice
 

My only problem is that I don't get to do much highway driving anymore. I did have the trip out east a couple weeks ago (50+ mpg thru Ohio at 65), and I'm still on that same tank of gas from filling it on cheap Indiana gas because I'm unemployed (or retired with no pension) anymore, and don't drive much except to the library, racquetball, grocery, or to visit friends, barely warming it up. Around town I'm only getting 38 or 39, but out on the highway I am getting it pretty tweaked. Last I looked this tank was at 43 mpg avg, and I should need gas by around the end of the month when I go on a trip to the races.

I been using my same test loop because its almost exactly the same driving each time because there are no stops and its steady speed except for the turnaround cloverleaf and getting back onto the expressway into traffic. It would be hopeless trying to test mods with my normal driving because you'd never know if the mod worked or not, because mpgs would end up being determined by destination and traffic conditions.

Re: What determined your gap on
 

One site I found (same guy that was advocating Acetone) said to reduce stock gap by 10 thousandths, so I reduced it by 5, figuring that 10 was 25%, and that was a huge change. 5 was only a 12% change. Diamondlarry has the same motor, and is also running a reduced gap.

Anyway, it seems to run fine. I didn't do a separate test with them at 40, then down to 35, so I really can't say there is any measurable difference in MPG due to spark plug gap. Larry did do a test with different brands of plugs, but I don't think he tried stock style copper Champions, just the fancy/expensive stuff.

Maybe someone else has done a heads up test on gaps and could tell me?

Re: What determined your gap on
 

Actually, I did use a set of standard NGK plugs in my test. If I'm not mistaken, I ran them at .030" Right now I'm running Halo Brisk plugs and the gaps can't be changed.
Congratulations on the mpg numbers! My numbers since the head swap have been 60-65 mpg at 55 mph and are at 63 mpg most of the time. I can't wait to see how things look when the cam timing gets set to where we want it. We were looking for a centerline of 102 degrees but it ended up at 96 because we ran out of time for getting it dialed in closer. Memorial day weekend will be when we get things dialed in correctly.

Re: What determined your gap on
 

I would guess my copper Champions are similar to the stock NGK's. My question was related to a test of lets say NGK's at stock .040 vs the same plugs regapped to .030 on the same cars, etc., with no other changes. I cheated and didn't do a test, so don't really know if the smaller gap helped.

If by chance you did try it with different gaps, could you tell us what was the results?

No, I didn't do a test of
 

No, I didn't do a test of different gaps. Since I did 5, 2 mile runs for each of 5 different plugs back to back, I was too tired to do anymore testing that day. The temp was in the mid to upper 80's and since I was doing testing, I had the windows rolled up and no A/C. Fran at hydrogen-boost.com suggested several times that I do a test of different gaps and I never got it done.
I think I mis-understood your statement about your mpg. I automatically [bold]***[/bold]umed you were talking about a steady cruise situation. :oops: The numbers I gave earlier were for steady cruising and not over a course like you did. A trip to Chicago sounds like fun. I won't be able to make the trip until after Memorial Day when I go to get the cam timing dialed in on my car. PM me with your location and we could start to make some plans.

57 mpg is impressive. If you
 

57 mpg is impressive. If you have that already, completing your aeromods would do a bit more than 60 mpg.

As for top speed, assuming you can't reach redline in the highest gear, the increase should be considerable.