I searched but this is a hard one to search for.

Recently installed a F5 and can't believe that power difference it makes. How exactly does these things do it? If the fuel mileage goes up or stays the same but the HP and TQ are thru the roof... then how does it do it? How can we get something for nothing? Someone please explain.
I'm confused.

 

everything goes through the computer nowadays, so from what I understand the chips fine tunes the PCM to get the desired air-fuel ratio, timing...

 

Where you gain some of your mileage is the shift points, Jody firms up the shift duration so its less time lagging between gears meaning burning less fuel to get up to speed. You won't notice any mileage gains, prolly mileage loss the first month or so playing with your truck. Congrats..

 

About the simplest way I know to explain it is that the power that a diesel engine makes is pretty much directly related to the amount of fuel being injected into the cylinders and the turbo's ability to provide sufficient air to combust that amount of fuel.
Alot of the mpg effects from tuning(again given all else mechanically equal) from my understand, come from the changes in amount of fuel injected, when, and why based on several variable. The "when" and "why" are calculated in a different manner by a tuner, than the ones who program a stock PCM because there are different outcomes desired. IE stock programming thats happy with towing, cruising, emissions etc. vs a tuner looking for mpg, lower egt's etc without having as much to worry about emissions etc as factory programming.

If that makes any sense anyways it might give someone something to add onto

 

I've heard that these engines are capable of higher power, but are "detuned" from the factory. The tuners/chips just tap into what they are capable of, but you have to watch EGT's and turbo boost and maybe transmission issues.

 

I am pretty sure it has to do with the combustion event and efficiency. I have been off the net a bit now, but if memory serves, timing, duration and volume of fuel are manipulated. This is done via tuning as you have seen.

From what I can figure, this begins with timing. Timing in a diesel is pretty much the start of injection or SOI, the duration of the injection event (pulse width) or time the injector is commanded to be open, and what remains is the fuel pressure that is available. This fuel pressure depends on the injector design, available fuel pressure, and the high pressure oil that forces the plunger to inject the fuel.

As you can see there are quite a few parameters to manipulate, not to mention the shifting which will also aid economy and performance as mentioned before. No two engines are alike. Further complicating things are nozzle sizes and the condition of nozzles/injectors not to mention differences in compression and HPOPs right out of the box. Different oil, different ICP conditions etc all contribute to make tuning a challenge but the basic things altered from stock are mentioned.

Aside from the small education on what I think I know about the topic, how you gain power without sacrificing economy via tuning is due to the conservative factory tuning designed primarily to prolong longevity for warranty purposes which leaves a bit of power on the table.

If I have erred on anything here, I am sure someone will correct me and that is what we are about here. Keep in mind I have just covered the basics, not even talking about things like the commanded vs actual SOI and on and on as this topic can go.

 

So basically, it just makes the engine more efficient? That blows my mind. I can't see why FOMOCO wouldn't find a little 'happier place' in the tuning to allow more HP and TQ and still get longetivity out of these engines. Talking about some bragging rights on tv commercials!!! I can understand the result of too much tuning and warranties but my gosh, what a differnece these tuners make! I should have scraped the coins together long ago and done the DPTuner then.

I do have to admit that with the large snowfall we received last night and today that the stock tune was the one to use while plugging around in the snow.

Thanks for the 'science'!

 

Because more power = more emissions, less economy, more stress, less longevity and more importantly higher EGTs. Would Ford have sold more 99-03s if they made the most power, but didn't last long and sucked down the fuel and had transmission issues or melt downs from idiots pulling campers up grades and torching pistons? Doubt it.
Don't kid yourself, adding a tuner will decrease your engine's life span and your mpg. But it is obvious they left a lot on the table power wise.... I'm sure there's no complaints from our popular tuners, lol.

 

I still think its magic...

 

I see what you're saying and agree but the stock setup is a dog. Surely there is a 'happy place' somewhere in the middle????

There are a lot of posts on several of these diesel forums that are saying the MGP is better with a tune. I prefer to see for myself but just haven't had it in long enough to get any data. The MPG increase claims like what got my mind wondering in the first place. "Getting something for nothing"

 

Me too!

 

when the fuel is injected into the cylinder (timing), plays a big part also.

 

im with them......FM

 

this is quoted directly out if my Diesel Technology book for school.

"the injection system timing must inject fuel at the proper point in the combustion cycle regardless of the engines speed and load. if the fuel is injected too early the engine will detonate and loose power, resulting in low exhaust temperatures. if the fuel is injected too late the engine will again loose power, but will have high exhaust gas temperatures and smokey exhaust. in either case fuel consumption is high"

so finding the sweet spot and adjusting it in the matter of milliseconds is the added power!