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Double your gas mileage almost or close to it.

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Do you have any photos? This is something I would have to try but my car is increadably hard to work in. The engine is cramed in really tight so it is hard to fix or modify anything. I am lead to belive that if you are going down to a 1k resistor an the engine is thinking that it's driving through hell, then you would get considerably less power out of the engine. You could add a multi throw switch to modify the resistor value without having to pull over and replace the resistor.

Throw a temperature sensor of your own in there so it starts out on the 1k resistor in the summer at a certain temperature, and on the 10k in the winter below another temp.

The first photo is the air intake a few inches past the air filter is the temperature sensor. The second photo shows the plug removed from the temperature sensor and a 1K resistor is inserted into the plug. 1K = Brown Black Red. I have a twist tie holding the plug to the temperature sensor so it won't go flopping around all over the place.

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???????????? A "typical" 750 bullet bike weighs about 450 to 500 pounds, and puts out maybe 100 - 125 HP. With rider, the weight/power ratio is around 6 pounds/HP. Name a me a typical sedan in that ballpark. And the gas mileage would be in the 35 - 40mpg city range and about 50 - 60 highway depending on speed (air drag is dominant). The "liter" bikes (1000 cc) can have power up to maybe 160 HP. Gas mileage drops slightly, but is still far better than any car with comparable performance.

If you know somebody with a bike that gets comparable mpg numbers to a typical sedan, that bike either needs work or got worked on by a moron.

That sounds about right. My CBR600F4 with an inline 4cyl outputs 110HP @ 12500 RPM, curb weight is 434 Lbs. Never really checked my mileage but 30-40 mpg seems about right.
 
That sounds about right. My CBR600F4 with an inline 4cyl outputs 110HP @ 12500 RPM, curb weight is 434 Lbs. Never really checked my mileage but 30-40 mpg seems about right.

So doesn't that seem odd or suspicious to you or anyone else that your bike weighs 1/5 of that of a small car that gets equal or even better MPG numbers? :confused:
 
What's odd is an engine of less than 100 cu in can produce 110HP without any special bolt on gear. That alone should be enough to understand why it is getting 30-40 MPG. Detuned for economy, it would probably be closer to 60-70MPG. My old CB750 was faster then greesed lightning, and it got between 55-60 MPG.
 
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What's odd is an engine of less than 100 cu in can produce 110HP without any special bolt on gear. That alone should be enough to understand why it is getting 30-40 MPG. Detuned for economy, it would probably be closer to 60-70MPG. My old CB750 was faster then greesed lightning, and it got between 55-60 MPG.
I think it's a myth that detuning an engine automatically makes it more fuel efficient. In reality, the opposite is true since the designs which "peak" power output are doing it by maximizing efficient use of the fuel. In bikes, it means fine tuning the intake/exhaust flow characteristics and also the flow within the combustion chamber as well. Also, cam timing is critical.

However, I think the most important difference in economy between a bike and car is weight. It takes a lot less power to pull a lighter vehicle. back in the 70's when car makers were first forced to "improve efficiency", they responded by shrinking all the cars in size and weight. The cover of TIME magazine called it the "Big Scale Down". However they gradually got better at making more efficient engines and transmissions. They are really good now. You get 4000 pound cars with a 300 HP engine that can get 25 mpg highway mileage. Back in the 70's or 80's, that was a pipe dream.
 
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So doesn't that seem odd or suspicious to you or anyone else that your bike weighs 1/5 of that of a small car that gets equal or even better MPG numbers? :confused:
NO, not when you consider the fact that bike can do 0 - 60 in three seconds and turn a quarter mile around 11 seconds. Consider a 500 HP Shelby Mustang which has comparable (but still less) power-to-weight and it probably gets 12 mpg city mileage if that. Compare apples-to-apples and it is obvious.

And small cars do not get "equal or better" MPG numbers. Even some of the faster bullet bikes can do 45 - 50 on the highway and 30 or better city. There are no "gas only" cars in that range with any kind of performance at all.

And if somebody really designed a bike for mileage only (small/efficient engine, same power to weight ratio as car) it probably could get easily over 100 mpg.
 
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Going back to the 70's, my Suzuki 350cc two stroke twin only did about 30mpg, but up to 70-80mph you could beat Ferrari's :D

Mind you, when you stripped the carbs you could tell why - one carb per cylinder, and each had a main jet the size of that in a 1600cc car.
 
I think it's a myth that detuning an engine automatically makes it more fuel efficient. In reality, the opposite is true since the designs which "peak" power output are doing it by maximizing efficient use of the fuel.

I disagree. Much of the tuning for power performance works against economy, and visa-versa. Higher performance isn't really about getting the most from the fuel, it's about getting the most from the engine's displacement. That doesn't mean the fuel is used effeciently. Economy is about getting the most from the fuel, and not necessarily using engine displacement effeciently.
 
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I disagree. Much of the tuning for power performance works against economy, and visa-versa. Higher performance isn't really about getting the most from the fuel, it's about getting the most from the engine's displacement. That doesn't mean the fuel is used effeciently. Economy is about getting the most from the fuel, and not necessarily using engine displacement effeciently.

It's not difficult to understand, to get more performance you chuck more fuel in the engine, to get more efficiency you chuck less fuel in :D

The two are pretty well direct opposites - most engines will be designed and tuned in the middle somewhere - giving decent performance, and decent economy. Not to forget of course, in this day and age, emissions to meet the required regulations - which this supposed 'improvement' will completely destroy, along with probably ruining engine life.
 
It's not difficult to understand, to get more performance you chuck more fuel in the engine, to get more efficiency you chuck less fuel in :D

The two are pretty well direct opposites -
This is one of the most pernicious urban myths:

1) increasing power has to hurt fuel economy

2) disconnecting the emission controls will increase power and mileage

As for "power and efficiency" being opposites:

open your eyes folks. Look at the engines from the 60's and 70's compared to now. The 220 HP 318 CID engine in my 67 Dodge got 12 mpg in the city. My buddy just bought a new 5 Liter Mustang with 300 HP that gets about 20 mpg city and 30 mpg highway.

It is true that an idiot trying to "soup up" a well designed engine will likely cause a drop in fuel mileage since:
a) he has no clue what he's doing
b) he's following the "stuffing in more fuel will make it go faster" approach

but that certainly does not prove that power and mileage have to be at odds. In reality, a lot of the power gains made were done by reducing wasted fuel usage and improving efficiency of combustion.

My point is to warn people that screwing with their engines does not automatically increase power or mileage. Chances are it will increase emissions, shorten engine life, and damage components like the cat converter if it is fed an overly rich mixture for long.
 
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open your eyes folks. Look at the engines from the 60's and 70's compared to now. The 220 HP 318 CID engine in my 67 Dodge got 12 mpg in the city. My buddy just bought a new 5 Liter Mustang with 300 HP that gets about 20 mpg city and 30 mpg highway.

You can't compare engines almost 50 years apart :p

Modern engines are better designed, and have the advantage of 50 years extra development - but most importantly they have the advantage of masses of hi-tech electronics - both improving power, and improving efficiency.

Which is why blindly repacing important engine sensors with a fixed resistor isn't a good idea.
 
What it all comes down to is what are you going for.

Power?
Fuel economy?
Longest emissions component life?
https://en.wikipedia.org/wiki/Air–fuel_ratio_meter

Right now typical vehicle engines are built for longest emissions component and engine life not peak mechanical efficiency or peak fuel efficiency which is what I think this thread is all about, how to gain fuel mileage by some method of DIY sensor tweaking.

I personally am above average mechanical and electrical skills and have little to no concern about what politicians and tree huggers want.
I like big powerful engines and I don't like paying for fuel any more than I have to. So for me its all about how efficiently can my engine convert that fuel energy ,regardless of source, into mechanical motion while still providing the power I need to do what I want. :D

I run propane on my vehicle because its cheap and with the design of todays emissions compliant engines I have found that it now has on average an equal power and MPG average as that of gasoline but I can get it for half the cost! Plus with an engine built specifically for efficient propane use it can even show slightly higher power and fuel economy numbers that what the origional gasoline version of the engine had. :p
 
My old 1967 chevy truck gets 18 mph with the stock 350 engine with 600 CFM carburetor. My 1999 Chevy Tahoe gets 12 mph with the stock 350 engine with EFI. My 1965 Chevy Malibu got 18 mph with a V8 engine too it had a smog pump that pumped air into the exhaust and a carburetor. The old engines got better gas mileage than the new engines. According to the information I read about polution you have to burn too much fuel to get a clearer burn. Ok so we waste fuel to produce less polution. If I could put my 1967 chevy carburator on my 1999 chevy tahoe I should be able to get 18 mph.

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My old 1967 chevy truck gets 18 mph with the stock 350 engine with 600 CFM carburetor. My 1999 Chevy Tahoe gets 12 mph with the stock 350 engine with EFI. My 1965 Chevy Malibu got 18 mph with a V8 engine too it had a smog pump that pumped air into the exhaust and a carburetor. The old engines got better gas mileage than the new engines. According to the information I read about polution you have to burn too much fuel to get a clearer burn. Ok so we waste fuel to produce less polution. If I could put my 1967 chevy carburator on my 1999 chevy tahoe I should be able to get 18 mph.

Yep I have seen the same things here as well far too and many times myself but explaining it to non engine people is basicaly letting that info fall on blind eyes and deaf ears.

I had a 1985 F150 extended cab with the stock 5.8 l v8 that was lucky to see 7 - 8 MPG on the highway. I swapped the engine with a 460 I custom built myself leaning heavily on the mechanical efficiency aspect in component choices and went from a dismal 200 Hp at 8 MPG to a solid 400 Hp at 14+ MPG on gas!

That 5.8l is now in one of my dads pickups and it still is lucky to get 7 - 8 MPG to this day but unfortunately now my 460 powered pickup is sitting behind the shop since the day that a little old lady took the front end off if it but I am still looking for a newer pickup to drop it into someday though.

Many many emissions compliant engines are dismally inefficient in comparison to an efficient old school carb setup that is done up right.
 
In 1985 a Chevrolet half-ton 350 V-8 got around 14MPG city and 18 MPG highway. It produced between 170-210 HP. A 2011 Chevrolet silverado 1500 gets between 12-15 City and 18-22 Highway. The 5.3L V-8 produces 326 HP. So newer enginers, at least for this example, get about the same fuel economy, but much better performance. That's the result of better engine design and manufacturing, better fuel delivery, better engine controls, better drive train, etc. The new engines also run cleaner and are able to use different fuel formulations, start easier, need fewer tuneups, etc.
 
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