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Old 05-24-2009, 11:31 PM   #11 (permalink)
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does any one think if you could put the switch on only two cylinders, you could have a button to run on 2 or 4 cylinders?

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Old 05-24-2009, 11:55 PM   #12 (permalink)
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Quote:
Originally Posted by kevinmarathon View Post
does any one think if you could put the switch on only two cylinders, you could have a button to run on 2 or 4 cylinders?
You could do it, and yes it would cut fuel to two of your cylinders but....

It would be a very unsatisfying experience and I recommend against it strongly.
-The engine would run rough.
-The power loss would be substantial, not only are you losing half your power, but your engine will still be working just as hard to pump air into and out of the two dead cylinders.
-The mixing of air from the two dead cylinders into the exhaust stream could drastically affect the readings your cars ECU gets from the sensors, causing the ECU to attempt to adjust the fuel mixture to compensate.

I'm sure some others around here can come up with more reasons why this is a bad idea.
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Old 05-25-2009, 12:05 AM   #13 (permalink)
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you are possibly right about it being a bad idea, just figured it might help while in iddiling.
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Old 05-25-2009, 12:06 AM   #14 (permalink)
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Quote:
Originally Posted by The Fridge View Post
You could do it, and yes it would cut fuel to two of your cylinders but....

It would be a very unsatisfying experience and I recommend against it strongly.
-The engine would run rough.
-The power loss would be substantial, not only are you losing half your power, but your engine will still be working just as hard to pump air into and out of the two dead cylinders.
-The mixing of air from the two dead cylinders into the exhaust stream could drastically affect the readings your cars ECU gets from the sensors, causing the ECU to attempt to adjust the fuel mixture to compensate.

I'm sure some others around here can come up with more reasons why this is a bad idea.
A search will reveal that the running-on-two-cylinders idea has been beaten to death, and that there's pretty much no practical way to do it, unless one was willing to make a custom cam, exhaust manifold, and ECU map to specifically use those dead cylinders as an air pump.

Just switching off the injectors is a sure-fire (no pun intended) way to make your car run awful, and probably get worse mpg.
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Old 06-29-2009, 11:19 AM   #15 (permalink)
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Just a quick update...
My mileage shot up when I learned P&G.
My last 5 tanks: 40.76 US MPG, 39.216 US MPG, 40.937 US MPG, 48.14 US MPG, 44.934 US MPG.
The last 2 tanks are the P&G ones.
CMPG mileage log
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Old 06-29-2009, 11:26 AM   #16 (permalink)
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P&G is great. Congrats on the great mileage.
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Old 06-29-2009, 06:11 PM   #17 (permalink)
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Quote:
Originally Posted by kevinmarathon View Post
does any one think if you could put the switch on only two cylinders, you could have a button to run on 2 or 4 cylinders?
The real problem is that this won't actually save any fuel unless the car is set up to know how to do this. If you turn off 2 cylinders, the car's O2 will see FAR to much oxygen in the exhaust stream. It will assume the car is running super lean, and will richen the mixture. This will dump twice as much fuel into the two running cylinders. All the extra fuel and air will then burn in the cat, and will probable reduce it to a puddle of molten metal under your car.

The GM pickups that do this shut off the valves on the side that isn't running, thereby reducing pumping losses for those cyclinders, and not messing with the O2 sensors.
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Old 06-29-2009, 07:07 PM   #18 (permalink)
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you could always use something like this

i always though these buttons would be cool as an engine kill + push button start

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Old 06-02-2010, 04:16 AM   #19 (permalink)
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Thumbs up Quite good idea actually.. but could be improved on

This is a very interesting idea actually.

Depends on the engine of course as to how big the benefit is
and what the driving conditions are. I just drive around town
up and down hills, so i would expect an increased benefit
from this rather than a decreased benefit.

Vibrations - if the lubrication system in a engine is working
really well then you wouldn't expect to get more vibration.
Actually, you might expect less. No explosion/combustion is
more likely to make the engine run smoother.

At lights and when the vehicle isn't moving, one doesn't
need more power. Being stuck at lights is a total fuel
waste.

This system could be improved by hooking the switch so
that it automatically engages after a certain engine
temperature and when the car is in neutral gear.

so for me it is
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Old 07-01-2010, 12:59 AM   #20 (permalink)
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Good write-up Fridge. This will likely help me complete my own fuel cut-out. Are the ignition coils and injectors all wired separately?

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