96S14SE

So what if I put relays in line with 3 of my fuel injectors and three of the coils. Such that I would have on switch which would shut fuel and spark off to half the cylinders that I could use while at highway speeds to improve mileage. It would still reduce pumping losses due to the throttle butterfly being open wider. I do realize that Honda and DC actually deactivate the valves also. Ideas? Experiences?

liqidvenom

iTrader: (6)

aside from being a potential for destroying your motor, i dont see how much more mpg u want. we get like a good 300+ per gallon and thats alot. if u want to save more buy a 4 banger toyota

2k2kev

Considering *most* of the poor mileage comes from stop-and-go acceleration I'd say (again, if you didn't blow the motor) mileage gains would be negligible. You don't use nearly as much gas when traveling at 65mph as you do when going 0-65.

s0ber

iTrader: (7)

......



you're just messing with us right.. :\

sterlingmaxima

iTrader: (16)

just by a gmc truck and be doen with it they got it stock.

mzmtg

iTrader: (11)

Do the math.

How long would it take the MAYBE 5% increase in fuel mileage to pay for the cost of the project?

mtmactom

Chrysler is doing this with the 300 and the Dodge Magnum.

Stephen Max

iTrader: (59)

How do the manufacturers handle pumping losses in the deactivated cylinders? Do they keep the exhaust valve open to prevent pressure buildup during the compression cycle?

Unless you do something about that your fuel economy may suffer rather than improve.

SMX95

iTrader: (8)

Its not the most intelligent idea... Let me fill you in with some info. Your engine will missfire because your not creating combustion in a cylinder(s). Fuel plays an important part, It keeps the piston and combustion camber cool, Im not talking about freezing levels here, its the same concept of antifreeze. Fuel keeps your fuel pump lubricated and also cool. Now no fuel and no spark in a cylinder well... you do the math your going to end up making a quiznos masterpiece.

mzmtg

iTrader: (11)

How does fuel keep the combustion chamber cool?

How will the cylinder become too hot if there is no combustion going on inside it? (Keep in mind air is still being pumped through it and coolant is still circulating around it.)

SMX95

iTrader: (8)

Dont question my knowlegde lol j/k. It's just things ive learned in school. I got to lincoln Tech. A teacher that works for nissans and has a 4th gen maxima was talking to me about engines. He said fuel does keep the cylinder cooler since its away from the engine, in the rear of the car its cooler so It keeps the combustion area cooler. Yes I know the whole process of how engine creates power and the crankshaft turns from the force of each combustion. As for the air part, If air is coming into the cylinder from the oil pan thats usually bad pistion rings. Then you get the air coming in from the intake. I guess your right with it staying cool. I would still say its a bad idea.

96S14SE

Actually the motor will be cooler from the air rushing in and out of three of the cylinders. The old "Northstar" v8's would actually do the same thing I'm purposing if the engine ran out of coolant...the air rushing in and out of 4 of the cylinders would keep the engine cool enough to run 50 miles at 50 miles per hour with out coolant. So the whole fuel cooling the engine thing doesn't hold water.

In terms of cost of the project, wire, 6 relays and a switch can be had for less than $20...I drive 2000+ miles a month mostly highway, plus it's just something to tinker with.

So how exactly would this damage the engine? Honda's doing the same thing with one of their V6's, except they deactivate the valves too. Reading some research on it, claims of 3-5mpg for sedans by simply deactivating half the cylinders. It comes down to pumping losses...making the intake of air most efficient. Since 3 cylinders will be working a little harder the throttle body will be open more parallel to the airflow around the butterfly, thereby the airflow to the cylinders more efficient. This is the actually theory used by Honda, Dodge, etc. And the mileage increase is 10-20% at highway speeds.

mzmtg

iTrader: (11)

It still comes down to the question "Is it worth it?"

I would say it is definitely NOT worth the time, effort and expense to try to design a retro fit system on your existing car.

mzmtg

iTrader: (11)

Also, if you just truned off the injectors and coils to 3 cylinders, the ECU would be confused as hell. The O2 sensor readings would be way off compared to the amount of air being taken in and fuel being metered.

Igobuk

iTrader: (1)

All the cars that turn off cylinder to save on gas were engineered to be able to do this.

You can't just turn off cylinders on your engine that wasn't designed to this. The parts aren't balanced for it, the ECU doesn't know what you're planning, etc. The engine is going to sound terrible, run like crap and probably get ruined.

Good luck.