Whats your best ecomod?

[phh]

Vacuum gauge, $18 from Harbor Freight. MPG increased from 24 to 30+, all short distance city driving.

Car is a 1989 Eagle Summit, 4 dr sedan
3-speed auto transmission (yuk!)
Original EPA rated 27/30


I'm sure an MPGuino will yield similar results. But a vacuum gauge is simple, cheap, and easy to install, so why not!

[MisterMundane]

for me, so far its been removing my intake snorkel. which drew fresh, cold air from my grill and sent it to the intake. and being winter, and -20, it sure made a difference removing it.

[Shawn D.]

Gearing.

When on long trips, I switch my BMW's differential from a 3.46:1 ratio to a 2.93:1 ratio. I swap out the whole center section in an hour. Of course, this means that you need to have two on hand. This gains ~2 MPG. Another benefit is that the car is significantly quieter.

It's not an "eco mod," but I saw my '57 Chevy's around-town MPG go from ~13 to ~15 when I swapped from a TH350 (non-lockup 3-speed auto) to a TKO 600 (5-speed manual with 0.82 5th gear). Since I could get 18 MPG if I held it under 65 MPH on a long trip with the TH350, I'm sure it'd hit 20+ MPG on a long trip with the TKO 600.

[ptjones]

I developed Grill Covers for FORD CMAX and Fusion Hybrid. Improved MPG's 2-4mpg.

[JohnAh]

I drive a 1975 Saab 96 V4 and they can easily consume over 8 litres per 100 km (35 mpg) while following the traffic average on highway mixed with city driving. My consumption made a steady drop to 7 L/100km (40 mpg) when I decided to set 80 km/h as my personal speed limit. Wind resistance is at least a square function, or is it even a cubic relation?

Next big saving was to stop using the brake all the time. Instead I carefully study surrounding traffic and use just the right ammount of throttle combined with a lot of coasting. This got med down to about 6 L/100km (47 mpg) so it's actually even more rewarding than just reducing the top speed.

The old Saab has a Ford V4 carburetted engine and I mix about 25-30% ethanol to the petrol. This LOWERS the consumption sligthly and reduces detonation and "glow-ignition" (guess there's a better word I don't know about in english) This is important for the final change in driving style and the only physical modification I have done.

By installing a kill-switch on the gear lever, next to a start-switch, I often manage to keep fuel consumption around 5 L/100 km. The gear lever is located on the steering column and the gear box also have a freewheel so it's very easy to start and stop the engine frequently. I practise "Burn & Glide" a lot and it's amazing how far a car can travel without the engine running. As a side benefit of this driving technique I'm also superior to planning my driving compared to other drivers. -It's not usual that I sooner or later manage to pass the same cars over and over again despite my slow driving. I guess this driving style has also made me a much safer driver.

5L/100km = 56 mpg and that's a realy good average for a 40 year old "scrapmobile". My best from last summer was a vacation trip overseas to Finland (I live in Sweden) where I got 4.8 L100 with wife, three children and lugguage. (=59 mpg)

The trick is to keep the engine in the BSFC sweetspot while working and if it can't be kept there it should be switched off until next time it's needed. The throttle isn't actually bad, it only converts the expensive fuel to the travel wanted. Using the brakes is wasting all that energy to heat and a proof of poor planning.

Low weight is only beneficial in city traffic where it's more difficult to plan driving without brakes. A higher weight can actually improve fuel efficiency outside city traffic by smoothing out the continous changes in speed while practising Burn & Glide.

[ptjones]

Ethanol has less energy in it which would hurt MPG's normally, but maybe with old carboreted gas engine it makes it run leaner. What your Oil consumption? As a comparison with my FORD CMAX Hybrid I have 4 cross-country gas tanks getting 64 to 68mpg. Also I had a 2007 FORD FOCUS with just adding Steeda air filter Kit and slightly larger Goodyear Fuel Max tires I got my MPG's up to 45mpg on the HWY. 57mpg is impreesive for a 40year old carboreted car.

Paul

[Shawn D.]

Originally Posted by JohnAh

Wind resistance is at least a square function, or is it even a cubic relation?

Drag is a square function, power required is a cubic function.

Originally Posted by JohnAh

I mix about 25-30% ethanol to the petrol. This LOWERS the consumption sligthly and reduces detonation and "glow-ignition" (guess there's a better word I don't know about in english).

The words used to describe that are "pinging" ("pinking" in the UK, Australia, New Zealand) or "detonation" (not the same as "combustion").

[JohnAh]

Originally Posted by Shawn D.

Drag is a square function, power required is a cubic function.

The words used to describe that are "pinging" ("pinking" in the UK, Australia, New Zealand) or "detonation" (not the same as "combustion").

Cubic/square, that sounds clear, thanks!

I'm familiar with both "Pinging" and "detonation" as names for the condition when fuel ignites by preassure/temperature from another location than the spark plug. If I have understood right, the noise comes from two wavefronts/pressure waves meeting with a sharp mechanical chock as a result.

What I tried to describe is a phenomenon that keeps the engine running for some second or even more the moment after the ignition have been switched off. -Same words in english?

Dirty spark plugs, plugs that run to hot or thick deposits of carbon in the cylinder head is probably the reason to this. Compression ratio and shape of the combustion chamber can also affect this. The worst case is when the engine start running backwards on the unburned fumes in the exhaust, since this will make the oil pump suck back some of the oil from the bearings.

Driving with a kill-switch means you are switching off the engine abruptly from medium revs at high load, wich is quite different to how most people drive. I do have old spark plugs, and perhaps they run a bit to hot for my type of driving. I have never noticed the slightest bit of this "hot bulb engine phenomenon" before I started Burn & Glide driving. With B&G I get it most of the times I kill the engine if I don't have at least perhaps 15% ethanol.

With 25-30% ethanol, the fuel/air-ratio is quite lean since the ethanol like ptjones wrote have less energy than petrol. This ratio seems to be close to the point where my carburettor and engine fails to ignite some strokes and beyond this point the fuel consumption will increase again and HC levels will raise abruptly. Perhaps an efficient CDI-system could push the limit a bit more than my old distributor/mechanical breaker can cope with.

[JohnAh]

Originally Posted by ptjones

Ethanol has less energy in it which would hurt MPG's normally, but maybe with old carboreted gas engine it makes it run leaner. What your Oil consumption? ....

I guess that's true with engines that have a closed-loop injection system since they try to keep the fuel/air mixture as close to the leanest possible all the time. A carburettor (or older injection systems without lamda feedback) operates in the blind and therefore must have wider margins to cope with cold weather and poor fuel. Mixing petrol with ethanol can be seen as an easier and more flexible way to adjust the carburettors jets. (with the benefits of better margins to detonation, lower combustion temperature and lower consumption of fossile fuel)

I actually don't know my oil consumption, but after getting rid of some annoying leakage It's amazingly low for such an old lump of cast iron. I pour in a little bit of oil now and then, perhaps slightly more than a new car consumes. I probably got a very healthy engine the last time I replaced it, which seems to happen now and then with 40 year old cars in everyday traffic.

I have never had an engine, or any car before that could start time after time by such a short pulse from the starter that it only gives one or two piston strokes. When my current engine is nice and warm it starts on just a single stroke most of the times, which is a quite bizzarre feeling. -It sound like a missed attempt, the engine almost stops and the suddenly comes to life. Guess I have good piston rings.

Yesterday I summarized two years of statistics. I'm driving about 28000 km per year and I think it's about two years since I installed the present engine. The cast iron cylinder heads are soft so I have to keep an eye on the valves adjustment and I use high quality lead replacement from RedLine. I rarely go for trips shorter than 30 kilometers so I have quite few cold starts.

I have no electric block heater but would definitely use one if I could. Burn & Glide driving is no fun in the swedish winters. Engine temperature can get low and without an electric cirulation pump the windows turn foggy and the feet and fingers turn blue... -That's definitely a backside of improved fuel efficiency.

I have installed LED headlight replacement since we have a law in Sweden that demands us to always have the lights on, even in daytime. I don't think this have more than marginal effect on fuel consumption but the LED lights will make life easier for my battery while I'm silently gliding through the traffic.

[ptjones]

With CDI ignition you could run a bigger gap on the spark plugs. You could fine tune your leanness by changing the ratio of Ethanol. You didn't say how many miles on the ICE.