Creating a Switch to Shut Off Cylinders on the Fly
 

I saw someone talking about how on their old volvo they had made a switch to shut off two of their four cylinders while at cruising speed. From what I understand it is just installing a switch to shut of the fuel injectors going to each cylinder, but the spark and all that keep going...so, if I do this will it harm my engine or make it wear oddly? Does this seem like a safe thing to try out in terms of engine health and all that? Hmm, thanks.

Old school cylinder deactivation
 

Do you have a link to the guy talking about it? I'd like to read more about this.

SuperMID revisited
 

I got it in an email it was just like, I did that, and nothing about it. I will look for some though eh. And something about doing it with dpfi. ^_^

How much does weight have to do with fuel economy???
 

I'm not sure if this is what he's talking about but here is a link to something similar.
https://autos.groups.yahoo.com/group/BetterMPG/message/2595

Driving Mountain
 

That's what I was talking about, haha.

How "normal" people view FE driving techniques?
 

The new Chrysler 300 V8 does something like that. It automaticly shuts off 4 cyl's when the power is not needed. So it is a doable project.
If you worry about uneven wear set up all 4 injectors and every month switch from 1 and 3 to 2 and 4.

some things you can do as moderators
 

Yeah, a lot of the US autos are moving that way from what I understand, but really only the gas guzzlers, so, makes people feel good about themselves for gettin 10mpg instead of 8, sigh. I dunno why they won't do it for resonable stuff like I dunno, are there any US cars that get over 30 avg...? In any case, I have a 4 cylinder, but it only has two injectors, so you think I can still do this by shutting off one injector?

PBS tonight: Who Killed the Electric Car? (Sony pictures)
 

It would be the front 2 or the back 2 cyl. It would depend on the firing order. It could make the engine run to ruff. It may just work better the more cyl there is. That is why car makers only use it in V8's. Wont know till you try it.

Exhaust Experiment Prep Questions
 

This would be a VERY EASY modifcation to use. I'm curious though as to what happens with the two other cylinders? So the injectors don't shoot gas, but they still get air. The spark still shoots. I guess the momentum of the previous cylinder's explosion will still propel the piston downward, so i guess it won't lock up or anything. I dunno. For some reason I just get the feeling that it can't be good to do this to an engine. Will it cause emission problems?

Someone with a better understanding of engines has to be able to answer these questions.

The good thing about this is that it would be a VERY easy modifcation. It would be all in-cabin wiring. You could even hook up four switches, one for each cylinder.

Maybe a device could even be created that would switch between cylinders every minute. Minute 1 injectors 1,2,3 and on, and then minute two 2,3,4 are on... etc. etc.

Someone convince me this isn't bad the the engine.

Drag Coefficient wrt speed
 

Hopefully he can give us a straight answer about this, and with dpfi would be good for me too...^_^ Worthless dpfi that it is.

06 Civic Engine Belly Pan
 

well here's the deal. you have 4 pistons (obviously) and so two of them go down, two of them come up. however it is the middle pistons that go down and the outer pistons that come up. by doing this, the motor is balanced at all times. the combustion is being put on the middle two pistons pushing them away from the head to the bottom (BDC bottom dead center) and pushing the outer two pistons to the head to the top of the combustion chamber (TDC top dead center)

if you were to disable any of the pistons, you would want to disable one of the inner two pistons and one of the outer pistons. pistons are numbered 1,2,3,4 you could either disable pistons 1 and 3 and have pistons 2 and 4 firing. Or have pistons 4 and 2 disabled and have pistons 1 and 3 firing.

now, i am not sure, however, my hypothesis is this. even if you were going to get those pistons disabled while cruising. you would have to push harder on the gas and make these two pistons work harder than they normally would.

as far as disabling a injector. the spark plug would be doing the same thing as strikign the flint on a lighter without pushing the button that releases the butane. It would spark, and that's it.

i am not necesarily sure if running on two cylinders would be advantageous or not. it makes me wonder though.

new forum ideas
 

I was thinking the same thing actually. Wouldn't RPM go up at this point? Wouldn't the ECU detect a very lean mixture coming out of the exhaust and start running the two remaining injectors REALLY rich? Wouldn't this lead to wasted fuel?

Hmm
 

Might as well post up this, but I recently learned this is impossible on dpfi engines because it is usually running on only one injector and then the second injector kicks in under heavy load. So I'd end up killing the only injector.

Re: Hmm
 

How odd. I guess this is the reason why people call DPFI a "glorified carb."

That's all it really is... just a glorified carb with fuel injectors.

MPFI seems to be the way to go. :)

I would be able to do this
 

I would be able to do this on my car fairly easily. But it seems like it would be bad on the engine. With 2 cyl getting no fuel, wouldn't it put wear on the cylanders not getting any fuel.

Hmm
 

It should only put as much wear on them as they would get normally, mehbe less because things are blowing up in there.

what about the spark plugs?
 

Do you disable the spark plugs as well? Wouldn't a sparkplug not burning any fuel on the compression stroke burn a hole in the top of the cylinder after say 10K miles or so? Any ideas?

~ryan

Re: what about the spark plugs?
 

I'm not sure how a spark without fuel would be more damaging than a spark WITH fuel. It seems to me that the violent explosion would be more damaging than a tiny little spark.

Re: what about the spark plugs?
 

I agree, though it's easy enough just to hook the switch up along the spark plug wires if you so wish.

Re: what about the spark plugs?
 

Agreed. It would be best to do the switch to turn off both the injectors and the spark plugs. This would also increase the life of your plugs.

Remember there are several
 

Remember there are several thousands of volts across the spark plug wire. If you used a switch to directly cut off current to the plug, the high voltage would surely jump the contacts of the switch and short it out.

Hmph
 

Surely there is someplace to control power to the plugs besides the actual wires? I would think so, but snuggling into the ecu might not be the best idea for something meant to be simple, or mehbe this is actually a hard thing to do. I figure someone just needs to do it and leave the plugs firing to see if it helps mpgs before we get all complicated with it.

That's a good point.
 

That's a good point. There's no reason to get complicated if the principle just won't work. I really don't see why you would need to worry about the sprak plug still firing. Even if they did wear out slightly faster, they are only $1.50.

I'm not an expert on ignition systems, but I would think most of the control is being done by the distributor. I know the ECU can affect timing but I'm not sure how. Maybe the ECU can only shift the timing but not cut it off completely? The entire system might be high voltage.

Come to think of it, you could effectively turn off the spark plugs by shorting them out. You'd put a switch in parallel with the plug and when it's closed, there would be no gap. You'd also need a resistive load in series with the switch, but this would probably be the simplest way of doing it.

Any person who mods
 

Any person who mods turbochargers will tell you that if you go too lean it will destroy the engine.

I assume it would be ok if the spark plugs were shut off along with the fuel injectors. But i'm not doing that, don't turst my wiring ability with spark plug wires.

Hmm
 

That's true about being to lean, of course, but I don't think this would really lean it out, you'd still be taking in 14.7:1, just only blowing it up in two cylinders instead of four.

we could devise a method
 

we could devise a method where, at highway speed, the injectors (mpfi) shut off for 1 & ,3 a pice of cardbord gets wedged between the contacts in the dizzy to keep the plug from firing, and a metal plumimg valve would open or vent between the spark plug and the head.
this would elimate all drag from the 2 unused cylenders. we could get advanced and evrey other fring order the 2 would switch. so 1-3-4-2 would die then next 1-3-4-2 would die. :P

in thearoy this is posible all within the ecu, except the vent valves but it could work :)

my car has I-VTEC & I-CCSY (cylender canceling system) :P

Wow
 

Wow, when you say in theory that this would work, I understand a bit from the ecu point of view, but not the mechanical point. So I'm wondering would you be able to chip for that and then not vent and see an improvement or would you have to do the whole damn thing?

On a related note, is chipping the pm5 possible? I want to lean out idle and some cruising speeds. ^_^

yes it is possable but your
 

yes it is possable but your onn your own whin it comes to reprograming it. i spent 2.5 years looking and i couldent find ****.

Haha
 

Yes, I looked on pgmfi and the thing was just like: dpfi, the bastard that is like no others. I figure I should at least be able to find a base map to work from right?

Remember that when the
 

Remember that when the engine is being overdriven (coasting but still in gear) the ECU detects this condition and usually cuts off the injectors itself. There is obviously no short term effects of turning off injectors and leaving the plugs firing. I doubt there would be any significant long term damage also.

i've decided. You need
 

i've decided. You need MPFI.

I have a whole setup (minus the dizzy) for manual. I can get the auto ECU though at the junkyard cheap.

Accurate injection unit
 

Years ago I worked with a device called the Accurate Injection Unit. Invented by Dr.(honorary) Sonne Ward, and works on implosion !!! (He had originally called it antigravity and they wouldn't let him get by with that)... ANYWAY.... this device was a very simple pendulum that would swing foward while going down hill or stopping. This in turn, would progressively turn off two injectors. So...sitting idle and level all injectors fired. Accelerating the pendulum would swing/stay back and all injectors would fire. But... when you'd let off gas it would swing forward and cut two injectors. It also would cut them going down steep hills. Using this and a few other mods, like aero devices he got over 88 mpg driving 75 mph with his old honda civic. At any rate, it shouldn't be difficult to make something to turn off injectors. As for emissions.. I would think they'd go down. You'd just be pumping air and diluting the exhaust from the cylinders that are firing.

Does this Sonne Ward fellow
 

Does this Sonne Ward fellow have some sort of website/information on this product that can be looked at, or mehbe just a write up of how exactly is it put together? Very interesting idea indeed.

nrgrebel, this device sounds
 

nrgrebel, this device sounds fascinating. It will shut off your injectors based on the conditions of the road. totally brilliant.

I would love to get my hands on one of these, or find someone smart enough to manufacture one.

Re: nrgrebel, this device sounds
 

*raises hand* oh oh oh i am oh oh pick me pick me :P

i could do that w/ a cam and leaf switches. :) i live up on a hill too sothat would aid in testing :D

this is what i will contribute. to see if i can make this. i'll make it my goal :) and no mateo no chiping :P even thoughi just got a new burner that dosent work.

Haha, I can't wait to see
 

Haha, I can't wait to see what you come up with, I wonder who will finish their project first: you with the pendulum or me with the pm5 tuning. :-)

The Accurate injection unit
 

The Accurate injection unit was very simple and did shut off injectors. As pointed out elsewhere some later model computer do this from the factors, BUT many don't. Another simpler and IMHO better way to do it is to use a hobbs switch to shut off injectors any time manifold vacuum is say 2" over idle vacuum, and only after engine is warmed up. A good friend of mine combined the latter with Wiseman's Efie to work more progressively allowing one to lean cylinders for cruise economy, cut cylinders for decel and still have stock power/performance. All automatic.

https://forum.mpgresearch.com/index.php

Hey there- I'm a newbie
 

Hey there-

I'm a newbie here, but I'm thinking about those mercury thermostat switches on the old-school furnaces instead of a pendulum.

Also, I've been thinking of this cylinder deactivation idea on highway cruising for a long time and didn't think to cut the power to the injectors. Any concerns on OBDII? (1998 Integra LS Auto). So I can run a switch to cut 1-3 or 2-4??? I'd love to try this. It's the latest rage in Detroit for V-8s, so why not for the DIY'r?

RH77

Hey there- I'm a newbie
 

Hey there-

I'm a newbie here, but I'm thinking about those mercury thermostat switches on the old-school furnaces instead of a pendulum.

Also, I've been thinking of this cylinder deactivation idea on highway cruising for a long time and didn't think to cut the power to the injectors. Any concerns on OBDII? (1998 Integra LS Auto). So I can run a switch to cut 1-3 or 2-4??? I'd love to try this. It's the latest rage in Detroit for V-8s, so why not for the DIY'r?

RH77

Re: The Accurate injection unit
 

Hey there-

I'm a newbie here, but I'm thinking about those mercury thermostat switches on the old-school furnaces instead of a pendulum.

Also, I've been thinking of this cylinder deactivation idea on highway cruising for a long time and didn't think to cut the power to the injectors. Any concerns on OBDII? (1998 Integra LS Auto). So I can run a switch to cut 1-3 or 2-4??? I'd love to try this. It's the latest rage in Detroit for V-8s, so why not for the DIY'r?

RH77