Left field fuel saver.

[Dessertrunner]

I ran a test on the way to work this morning I remove the injector plugs on cylinders 1 & 2 (once the car had warmed up) and drove it about 20k. I was really surprised that it ran as well as it did. Also while down on power it was still drivable. This then got me wondering if I could do a cheat on the engine to save fuel.
I think I have put all the pieces together that mean a standard SVX can coned to save fuel on long trips. This explanation will be rough and dirty so I may miss something. Its in point form:-

- Relay switches cylinder 1 and 2 off this will throw a error code so on the other pole of the relay is a resister to make the ECU think its still there.
- When you click in (stick on steering wheel) the cruise control it trows the relay to shut the injects. If you touch brake to disengage the cruise the shut down cylinders will start.
- the O2 sensor on both banks is only picking up the exhaust of the cylinders that aren't being shut down. The ECU is adjusting on cylinders that are running.

I had just thought the MAF will get screwed by 6 pumping air but it won't bother the set because when you are in cruise the O2 are running the show and what the MAF does doesn't matter.

Okay down side, cylinders that are not running will still pump air but that energy isn't that major prove by the fact that a stater motor car start a engine with 6 cylinder.

Okay so that's todays idea for you all to think about.

Tony

[Wikedjuggalo]

Maybe LAN or someone with a bit more experience could chime in. But if that could be had, that would be awesome, specially for us with a manual?

[Conn SVX]

So what were the # MPG ON 6 ves on 4,,, my Accord has a motor that does that, but with valve timing . Saves a lot of gas 38 MPG with a 6 cyclinder.

[Dessertrunner]

I need to run a proper test to see. If I get time I may drive 100k with one setting and 100 with the other to measure the savings. Untill the exhaust is changed it may not save any fuel due to the o2 not reading correctly.
Tony

[icingdeath88]

The O2 sensors will still see unburned O2 from the fuel-less cylinders, and the ECU will try to richen the mixture.

[Dessertrunner]

Did say the cylinder not running need to bypass O2 sensors. Sensor only see 3, 4, 5, 6 cylinders.

[LetItSnow]

I have to wonder if this will actually be detrimental?

The car requires a certain amount of power in order to maintain a given speed. With mass and rolling and wind resistance remaining the same, gas demand won't change much, being the energy source for that power. My guess would be that you'd be burning 50% more fuel in each of the four cylinders you're still using, meaning that they'd demand 50% more air, as well. With the valves operating as they were, you're compressing 50% more air - a power drain - while the TPS is reading higher than usual, vacuum is different, injector duty cycles extend, and with the imbalance of two missed fires, will the knock sensor start talking, or will there be any long-term effects?

There is the possibility that it would work, even if only under certain engine speeds and loads. It would be fantastic if this flies, but it seems like there's a lot going against it.

[icingdeath88]

Originally Posted by Dessertrunner

Did say the cylinder not running need to bypass O2 sensors. Sensor only see 3, 4, 5, 6 cylinders.

Ok, that works when those two injectors are bypassed, but not when they aren't.

Also, it would be better if a different pair of injectors were turned off each time, so that the engine wears evenly.

Have you read about the way that cylinder deactivation works on the new Corvette (and some other GMs)? It seems like a neat approach to me. http://www.stingrayforums.com/forum/...ctivation.html

[Blacky]

The full size GM trucks use this system. You would think the gains would be significant but the increase in mileage is actually quite small.
Every little bit helps when it comes to the overall fleet mileage of a large auto maker. The gain for a single vehicle considering the time and expense to make it work properly would more than likely offset any real savings in fuel costs.

[edren1]

The only problem with cutting the same 2 cylinders off would be the buildup of oil on the cylinder walls, and depending on how long you drive like that it might fowl out the spark plugs. I found some info on a universal programmer.
http://autoelectronics.com/mag/dynam...recovery-1229/

[oab_au]

Originally Posted by Dessertrunner

Did say the cylinder not running need to bypass O2 sensors. Sensor only see 3, 4, 5, 6 cylinders.

If this was done on the engine with 6 electrical controlled throttle bodies, You could cut the fuel, and close the throttle down, on 1,2, or 3 cylinders, with a controller to move the cylinders that are idling, around the engine, to keep all the cylinders at a uniform temp.

Harvey.