TUNING FOR POWER OR ECONOMY?
This may seem contradictory at first, but tuning for power and tuning for economy are the same thing. If this doesn’t make sense, hopefully you like analogies.
Imagine that you are moving and have all your stuff packed in boxes. All of your stuff is packed in either small boxes that are light, or big boxes that are heavy. You have two people that are helping you move these boxes, one is strong and one is weak. It is a hot summer day and you have Gatorade because your two helpers will be working up a sweat. The weaker person will be thirstier because he is working and sweating more, right?
When the weak person lifts a small box, he needs 2 Gatorades.
When the weak person lifts a large box he needs 4 Gatorades.
When the strong person lifts a small box he needs 1 Gatorade.
When the strong person lifts a large box he needs 2 Gatorades.
You can do a bunch of math and figure out how many Gatorades each weak or strong person needs to move different size boxes, but it should be plain to see that you get more work per Gatorade out of the strong person.
The strong person has more physical strength, which you can think about as having more power. The strong person is able to perform more work easier, which means he will drink less Gatorade instead of sweating all over your boxes of stuff. If you hate this analogy, read the paragraph at the * at the end to see why I explained it this way.
Imagine that you are moving and have all your stuff packed in boxes. All of your stuff is packed in either small boxes that are light, or big boxes that are heavy. You have two people that are helping you move these boxes, one is strong and one is weak. It is a hot summer day and you have Gatorade because your two helpers will be working up a sweat. The weaker person will be thirstier because he is working and sweating more, right?
When the weak person lifts a small box, he needs 2 Gatorades.
When the weak person lifts a large box he needs 4 Gatorades.
When the strong person lifts a small box he needs 1 Gatorade.
When the strong person lifts a large box he needs 2 Gatorades.
You can do a bunch of math and figure out how many Gatorades each weak or strong person needs to move different size boxes, but it should be plain to see that you get more work per Gatorade out of the strong person.
The strong person has more physical strength, which you can think about as having more power. The strong person is able to perform more work easier, which means he will drink less Gatorade instead of sweating all over your boxes of stuff. If you hate this analogy, read the paragraph at the * at the end to see why I explained it this way.
wasted FUEL = WASTED energy = wasted money
When you burn fuel in your engine, you are extracting energy from that fuel by burning it to produce power. When more energy is being used to accomplish the same task, that is a waste of energy. That waste energy in an engine is mostly heat.
Think about the reason why people install cold-air intakes. It's not because added heat is a good thing.
When an engine runs lean, it is producing less power and creating more heat. Remember that heat is wasted energy. Instead of producing heat, doesn't it make more sense to produce more power with the same fuel?
Think about the reason why people install cold-air intakes. It's not because added heat is a good thing.
When an engine runs lean, it is producing less power and creating more heat. Remember that heat is wasted energy. Instead of producing heat, doesn't it make more sense to produce more power with the same fuel?
RUNNING LEAN
Less Fuel Provided to the Engine
Less Power
More Heat Generated = Hotter Engine Temperatures
Less Power
More Heat Generated = Hotter Engine Temperatures
RUNNING EXCESSIVELY LEAN
Excessive engine Heat
Melted piston rings - etc
Decreased Lubrication - Engine oil will break down faster due to higher engine temperatures
Decreased Mileage Per Gallon
Melted piston rings - etc
Decreased Lubrication - Engine oil will break down faster due to higher engine temperatures
Decreased Mileage Per Gallon
RUNNING RICH
More Fuel Provided to the Engine
More Power
Less Heat Generated = Cooler Engine Temperatures
More Power
Less Heat Generated = Cooler Engine Temperatures
RUNNING EXCESSIVELY RICH
Black Exhaust Smoke - Rollin' Coal
Decreased Lubrication - Excess fuel “washes” engine oil off cylinder walls and remains in the engine oil
Decreased Mileage Per Gallon
Decreased Lubrication - Excess fuel “washes” engine oil off cylinder walls and remains in the engine oil
Decreased Mileage Per Gallon
The advantages of running rich far outweigh the mechanical and economical advantages of running lean. Lots of people ask me, “I want to get better miles per gallon, what calibration should I use to go leaner?” Most of the time, they are already running too lean and mileage per gallon is suffering BECAUSE OF BEING LEAN, so they think they are running too rich. Going leaner will make it worse or could cause engine damage. Long-term overheating of an engine and an engine rebuild is not worth saving a few pennies at the gas station.
Still many other people think that they have a problem with carburetor heat soak when they are actually just running too lean and heating up their engine! Instead of using the energy in the fuel to create power, running lean is causing excess heat and wasting that energy!
The good thing is that your engine will tell you when it is making the most power, and you can measure this!
The best way to tell if your engine is happy is with a vacuum gauge. When the vacuum reading is as high as possible, that is when your engine is performing the best and is effectively utilizing all of the fuel that you are feeding to it.
You can also use an oxygen sensor to read your air-to-fuel ratio, but do you really know where your engine will perform the best? Hint: it’s not A/F Ratio of 14.7. Oxygen sensors are a good baseline test for telling you if you are stoichiometric rich or lean, but you need to take other things into account if you want to really fine tune a carburetor.
Still many other people think that they have a problem with carburetor heat soak when they are actually just running too lean and heating up their engine! Instead of using the energy in the fuel to create power, running lean is causing excess heat and wasting that energy!
The good thing is that your engine will tell you when it is making the most power, and you can measure this!
The best way to tell if your engine is happy is with a vacuum gauge. When the vacuum reading is as high as possible, that is when your engine is performing the best and is effectively utilizing all of the fuel that you are feeding to it.
You can also use an oxygen sensor to read your air-to-fuel ratio, but do you really know where your engine will perform the best? Hint: it’s not A/F Ratio of 14.7. Oxygen sensors are a good baseline test for telling you if you are stoichiometric rich or lean, but you need to take other things into account if you want to really fine tune a carburetor.
*I tried to explain this in the easiest possible way that didn't involve chemistry, fractions, or engines. It isn’t perfect, and doesn’t have to be to explain the common misconceptions about leaning a carburetor. There are plenty of sites on the web that get a lot more in depth – this is just for people that just want the basic idea to get their carb tuned. People have been tuning carbs for a long time because they understand the underlying concepts, not because they have a PHD in chemistry.