I know we are all loking for mpg's out of these beasts.... but it just occured to me that the engines automatically shuts down half the cylinders when overheating.

Wouldn't that increase mpgs on highway if it didnt send fuel to respective cylinders??? All cylinders would still get oil and cooled, right?


"A fail-safe cooling system is designed to help protect the engine from potential damage due to a loss of coolant. If the engine overheats, it will automatically switch from 8-cylinder operation to alternating 4-cylinder operation. The vehicle will continue to operate, but with limited engine power. This system allows the driver to travel a short distance to obtain service or to reach a service facility if the engine overheats. The distance that can be traveled depends upon vehicle load, outside temperature and road conditions"

If that is the case:

a) How do I shut off a heat sensor to test this? I would think all i would need is switch on a thermal sensor to fake an overheating condition on open road.

b) If it works. how hard would it be to program a chip that way?

I have an Eddie Bauer with an MPG display so I would know if it works right away

Has anyone had experience with Fail safe mode???

Please advise

 

Now I'm definately no expert on this but wouldn't that decrease the MPG? The reason I say so is if you were only using 4 cylinders it would have to work a hell of a lot harder to pull that beast of a truck. A 5.4L/4.6L 4 cylinder pulling 6000lbs would probably not be a good thing for the engine to do on a regular basis and you'd probably have to floor it just to get anywhere which would increase the revs thus decreasing MPG.
Maybe someone else can confirm or deny this but it just seems logical to me

 

...pay attention.

1: All 2006 Hemi's will have cylinder displacement deactivation, Rams,Durangos, Grand Cherokees,Magnums,etc. No it does not affect towing or acceleartion.Cylinders are deactivated under a light load only.

2: GM is offering it on the 5.3l for cars for sure (Impala SS,Grand Prix).
Don't know when the trucks get it.

No, you cannot flash your Triton engine to operate as the above engines.
To operate properly you have to disable the valves on the cylinders that are shut down.

If you could do what you propose ,every engine with more than one cylinder and electronic fuel injection could have cylinder deactivation.
Not possible, there is mechanical hardware involved also.

 

Who would want to drive a Hemi. Goodness. Too bad they put a nifty system on such a worthless engine and chasis package.

HAHA. Good luck Dodge people. HAHA

 

That's almost what I was trying to say. He was trying to say just not send gas or spark to those cylinders but still have the same displacement, different then the "cylinder displacement deactivation" you were referring to.

 

Just shutting off the spark and fuel is not enough. You are still pumping air into the cylinder, compressing the air and pumping it out of the dead cylinders This robs power and defeats the purpose.

By the by I work at a Ford, Chrysler, Dodge ,Jeep dealership. I neither love nor hate the Hemi.

The reason you see cylinder deactivation on the Hemi and GM engines is it's easier to shut off the oil flow to the lifters in a pushrod engine.

You can do it in a overhead cam engine, Honda does it on their 3.5 V6.

Mercedes did it on the V12, they just shut one bank off making it an inlne six.

Rumor is Ford is working on it but nothing yet on how it operates.

 

2000 Expedition,

No, this cannot be done -simple as that. There is no way thru tuning to simply go in an invoke the overheat mode at a whim - nor would you ever want to, that causes all sort of other issues.

If you want better MPG, you need to do all the things that everyone else does - maintain top alignment, run the tire pressure as high as possible without causing increased wear & harsh ride, use only the very best quality fuel (steer clear of "cheap" gas), and then on the modification side, you can do things like custom tuning, opening up the intake & exhaust, electric fan conversion, underdrive pulleys, etc. - there are plenty of posts here from those who have done those mods and who have gotten nice MPG gains - it all works together, a little bit of gain here, and little bit there, from something different etc., until you've got it to about the best it's going to do.

Good luck!

 

Thanks SuperChips...

When I was a kid in the 70's, I used to get the old JC Whitney catalogs....

I used to see all the gadgets from headers that saved gas, electronic ignition, fuel atomizers, wheel balancers etc.


I always though, if 1 item is advertised to increase mpg 5 %, another gadget that would increase it mpg by 10%..etc...

My childhood logic told me that if i bought a bunch of them I could increase gas milage by 70 % by using all of them!! LOL

Now that I am an adult, reality has set in

 

HI 2000 Expy,

Hey, I grew up on those old JC Whitney catalogs, too! Absolutely loved them, as you could get all kinds of neat (cheap) oddball gadgets that you wouldn't get anywhere else - and they actually shipped them most of the time.

Now even as a kid, I never took seriously all the various mileage gain claims, but that was where I first learned of exhaust cutouts (to the absolute hatred of the rest of my family once they arrived!), and so many other things.

J.C. Whitney brings back many memories - too bad when they folded about 10 years ago, they kept everyone's money they had taken orders for, and then re-opened a little while later under different management or ownership, I don't remember which - but J.C. Whitney catalogs from those days will always bring a smile to my face and a warm feeling to my heart - thanks for the blast down memory lane!