MPG run, part deux

[eurotiva]

I also waxed my whole car between runs at the dragstrip and picked up 1.6 mph.

[batstiva]

Never would have thought a good coat of wax would have made a noticeable difference. Interesting.

[TominMO]

Thats soap......I mean put a real coat of wax on it. I got 2 mpgs more on my trip home with some waxing.

Interesting, I'll try it.

[eurotiva]

Thats soap......I mean put a real coat of wax on it. I got 2 mpgs more on my trip home with some waxing.

[TominMO]

Wax the windshield too.

Shirley you are joking! Actually the whole car will be waxed; I just use the kind of car-wash solution that has the little wax beads in it.

[batstiva]

As for keeping less air flowing through the engine bay, wouldn't this have a negative effect on your engine's breathing and cooling ability as it's designed for? Wouldn't it be better to let the air pass through and perhaps be forced up over the windshield for a more aerodynamic exit?

That was kind of my thinking. Not so much on the aerodynamics, but on the engine breathing. If you think about it, a lot of folks block off part/most of their grills in the winter to improve their inside heat, and reduce the cold air flow into the engine, so why wouldn't it cause the same thing in warm weather. When you really don't want you engine running any hotter than it has to. Anyway, nice results Tom. :thumbleft:

[eurotiva]

Wax the windshield too.

[TominMO]

Yeah, i wonder if having a slightly more powerful motor would get you more mpg's in windy or hilly conditions as you're not having to floor it to keep to speed.

That's my thought too. I'll keep you posted when I do this, probably in the next couple of weeks.

[thered56]

As for keeping less air flowing through the engine bay, wouldn't this have a negative effect on your engine's breathing and cooling ability as it's designed for? Wouldn't it be better to let the air pass through and perhaps be forced up over the windshield for a more aerodynamic exit?

[MJD]

Result: for 75 miles, I used 1.2 gallons of gas. This comes to 62.5 MPG. I was very careful to fill the tank completely both times; if anything, I might have put in a couple thimblefuls more the second time.

The moral of this story: low RPMs and less wind resistance really matter. I doubt that the seat removal was much of a factor, if any.



Tom in Mo. -- Great story ! I live in pretty much rural countryside. I drive to work 4 days a week, 10 miles one way. I work a night shift, and I drive to work on a 2 laner, the other guys always passing me up..zoom. I go about 50, and I think we get 45 mpg. with our 5-speed 1990 L Plus. I really believe in the lower RPM thing.
The slower pace and careful driving thru town, I hit the stop lights all green and keep on driving steady. Good results for fuel use. I just do not like high balling it down the road, and there are critters out there at times. I have hit dog, cats, racoons, rabbits, skunk, snakes ! Dodged deer more than once. But ....I just do not want to hit the bigger animals because of the hard damage to Festiva, so I take it easy. All weeks we drive these a lot, and get the high mileage, but have to smile at the light, when stopped next to the huge Suburban or 4 wheel pickups we have so many of here. I have Dodge Ram too, but she sits unless I am carrying a parts car Festiva on a trailer........ ha !

When we were in Europe a few years ago, there was mostly little cars...driving fast...even pulling tiny camper trailers. I did not see any big American trucks, etc. They do think we Americans are very wasteful. I see that point now with our fuel appetite. One of the biggest shocks to me returning home via Denver, was the freeways loaded with big American models after a 2 week stay in Germany, France area. Shock !
Got to admit, I liked the Autobahn and the cars there...just a note about mileage. I think it is important, and I hope our cars can become better. That is why we really love our little 2 Festivas to drive.

:happy7:


mjd

[Arnie]

Yeah, i wonder if having a slightly more powerful motor would get you more mpg's in windy or hilly conditions as you're not having to floor it to keep to speed.

[batstiva]

Lol, I was doing 75MPH with what must've been a 50 or 60 MPH head-wind...

I got 110 miles to a tank, it was brutal.

So, roughly 10 mpgs?? :shock: That is brutal.

[blkfordsedan]

I'm trying to keep this real-world, and not use special tricks. No one's gonna want to take duct tape off their car every time they want to get into it or raise the hood! And covering the grill opening would just move the resistance from the firewall to the grill.

I understand what your trying to do. In all seriousness, I think covering the grill would make a noticeable difference. I guarantee there would be less resistance with the air flowing smoothly over the nose of the car and onto the hood. It would help maintain the smooth flow and boundary layer over the car. The air flowing through the grill and being trapped under the hood creates a lot of turbulence and probably also effects the smooth flow of air under the car, which is as important as the air flowing over the car. I have thought about adapting an Escort GT grill (the solid ones with little diagonal slits on the radiator side) to the front of my Festiva. Then install a belly pan under the engine/transaxle, just like my old '95 Protege' had, to improve the bottom-side aerodynamics. Then, lower the car or install a small spoiler under the front bumper to keep as little air as possible from flowing under the car. There is a reason many new cars are designed this way and BMW has even used underside aerodynamics as a selling point. I realize these are all mods that most people won't do, but most people won't drive 45 MPH on the freeway either. With all the effort and testing your doing, why not find out what is possible and offers the best "bang-for-the-buck"?

As for the ignition, a multi-spark discharge will help provide complete combustion of the fuel mixture which is the main goal. Jacobs Electronics sells a system called the Economaster that has been proven to work. I don't know for sure if it's compatible with our ignitions or not. Keep up the good work!

[TominMO]

I get much better mileage when the temp is 95+ degrees. As you said, less dense air requires less fuel to achieve proper mixture. Might I suggest the old Duct tape trick, just like the old Salt Flats racers? Cover all body seams and cover as much of the grill opening as you can. That will improve aerodynamics and keep the air out from under the hood, which creates resistance against the firewall.

I'm trying to keep this real-world, and not use special tricks. No one's gonna want to take duct tape off their car every time they want to get into it or raise the hood! And covering the grill opening would just move the resistance from the firewall to the grill.

[blkfordsedan]

Higher elevation will give you noticably better results, due to (1) lower air resistance and (2) less fuel used, since the computer mixes the available (less) air with less gas, so you maintain a mixture not too lean or rich.

There's little practical opportunity to do a full tank without going on the highway, where you are almost forced to be doing something like the prevailing speed to make it safer for everyone. You would need some type of closed course, or a long little-used back road, to try this at lower speeds. I want to try one run at 35 MPH/4th gear, early Sunday morning on a farm road, then stick with runs at 55 with different variables: ignition timing, high-volt coil/increased plug gap, any other suggestions you all might have. Naturally I will use the same car for every test.

I get much better mileage when the temp is 95+ degrees. As you said, less dense air requires less fuel to achieve proper mixture. Might I suggest the old Duct tape trick, just like the old Salt Flats racers? Cover all body seams and cover as much of the grill opening as you can. That will improve aerodynamics and keep the air out from under the hood, which creates resistance against the firewall.