Cutting fuel to cylinders

[Joenavy85]

Originally Posted by abently

Why not relocate the 02 Sensor to the header runner that won't be connected to a deactivating cylinder?

but then if something is amiss with that cylinder during normal operation it tries to make corrections for the entire engine; if that 1 cylinder starts running rich for some reason the ECU will see the entire engine (or bank of cylinders) running rich and will lean out and you risk burning pistons

[stovie]

i plan on taking my I6 and having 3 cylinders run off of compressed air so then you cut the fuel consumption down right there, then have a kill switch on the injectors that run off of the throttle body so that the injectors shut off completely at idle so you only use compressed air at idle and fuel when accelerating or cruising. (but only at operating temp) there's a 400 psi compressor for $1500 that i want for framing cause i'm in construction, i could use that for the compressed air to run my 3 cylinders. Then basicly make the throttle body into a 2 inch ball valve that closes all the way, killing air flow to the fueled cylinders at idle.

[brucepick]

I think you'll have success if you address other areas.

MPGuino to see fuel consumption. And an aftermarket digital temp gauge so you can see that it warms up properly, and so you can build a grill block and observe that it doesn't run too warm. Needle gauges are nice but I like digital for engine temp.

Face it, the Prelude is made for sporty performance, especially the Si version. Probably is geared low for higher engine rpms and has wide tires, both of which will cost you mpg. When it's time for tires, get LRR ones, and get the narrowest that will fit your rims. Consider one size larger diameter tire than stock. Very likely it will clear OK, especially if you go narrower than stock. Compare with similar weight Accord of the same year to see how much tire is needed to support the car.

When you really get into it, consider a belly pan.

[Joenavy85]

Originally Posted by brucepick

Probably is geared low for higher engine rpms and has wide tires, both of which will cost you mpg.

the Si has a pretty good torque curve, and the Manual trans (6 Speed?) is geared low for the low gear but usually has a pretty good top end gearing. one of my friends has an '07 Civic Si that has a 6 speed that works great for hypermiling, i've driven it quite a few times and after a little practice perfected shifting 1-3-5-6 which it had no problem with due to the torque the engine produced. Wider tires aren't always bad (as long as they aren't 275's like Porsche put's on their carrera's) as the wider contact patch lowers rolling resistance, but you have to find the "sweet spot" that works the best, if there is a minimal amount of tire exposure as far as frontal area goes than there isn't a significant problem (but on my Jeep wider tires would destroy mileage because a good portion of the tire is exposed as frontal area)

[Heihetech]

Originally Posted by SlideWRX

The bigger issue to me would be the emissions equipment and fuel control. Without shutting off the non-firing cylinder completely, it is pumping air into the exhaust. That will throw the O2 sensor for a loop and the computer will dump fuel in to try to burn the extra Oxygen it is detecting.

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[Heihetech]

Originally Posted by Shinjitsu

I've read about people putting kill switches on to cut the signal to the injectors momentarily to kill the engine for coasting. I got to thinking, what if you cut one or two of the cylinders (more for larger engines like a v8 or v6) and run the car at highway speeds - just a steady pace. My car uses about 20hp at 70 mph. I'm sure 3 cylinders would carry it easily and I would hardly notice that 1 cylinder is missing - and 2 cylinders would probably still carry the car just fine.

Has anyone tried anything like this? It would be more convenient than pulse & glide and could have comparable results. I've gotten the wiring figured out I believe so my only question is this: Is there going to be any damage caused from cutting the signal to the fuel injectors for extended periods of time? I would assume that if one cylinder never had combustion take place, it would be in better shape than the other cylinders which had the extra stress of the combustion heat and pressure. So I would think there would NOT be any long term damage caused by doing this but please, correct me if I could be wrong - I cannot afford to blow my engine right now.

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