I love threads like this. I get to use the best features of the Forum!!

 

I agree with this statement for the most part.

However, generally speaking....you will usually gain mileage if you aren't hotrodding it all the time.

 

Thank you! =o)


Mobey,

I'm really trying to be fair here...

Do you understand how load affects fuel consumption?

If so, you'll understand load affects fueling more than RPM.
If you can tune a turbodiesel truck to make power at reduced load (by carefully tuning fuel, injection timing and bost mapping), you can get more power AND more mileage.

Open up your mind a little here...
You haven't spent a day of your life tuning vehicles.

At least have enough passion to research a subject before you jump on a soapbox.

You've previously stated your interest/expertise in guns.
I'm not going to tell you a Para P12-45 is superior to a weapon you say is much better, because you probably know a hell of a lot more about the subject than I do.
It just goes right back to "talk what you know".
Speaking of which...I'm thinking about buying a para Ordinance P-12 .45
What do you think? I get mixed answers from the guys at shoot straight...

Anyways...
Diesel tuning was my passion for nearly 4 years.

Did you know that you can increase boost, alter injection timing (increase in some areas, decrease in others), and alter your fuel tables to make more power and consume less fuel in normal driving?

Even with gasoline tuning.....
Did you know that most gas engines make more power making two basic changes (among other things):
1. Increase ignition timing (improves engine efficiency, same deal...more power under less load)

2. Lean the air fuel ratio. This one is a no-brainer. Less fuel.


It's actually pretty basic, and most dynotuners can pull it off, albeit some better than others. It also depends on how bad the stock files were...

If you can increase power and are able to decrease calc engine load under most driving conditions (other than WOT, of course), you can gain power at all throttle positions and gain MPG pretty much anywhere in the curve other than WOT or near WOT.

Some trucks are different, and some stock programs don't offer much room for improvement.
Also, you get the occasional dynotuner who just "pours the fuel on" too much, too soon and it can adversely affect mileage (of course).

Anyways......it ain't no thang =o)


Should I buy a para, or something else?

 

Which features are those?

 

My previous truck was a 2000 F-250 7.3L 4x4. I installed a Hotchips(?) 80hp/150#/ft chip and a 4" Turbo back Exhaust. Before the chip, I got around 16.5-17mpg . After the chip the mpg jumped to 19-20. i even got to 21.7 on a trip "trying" to be easy on it. I noticed that I didn't have to use as much accelerator to get the truck to move most all the time. The truck was much more drivable, and smoother with the chip. Unless I really abused the snot out it, the mileage was better.

No scientific testing, just honest everyday results.......

P.S. I like my Kimber .45 ALOT

 

Vic.

This all seems interesting to me. Why don't our trucks already come stock with the better tunning that you say is possible? Are they just taking shortcuts or are there specific reasons such as increased emmisions and decreased engine/turbo/transmission longevity. It would **** me off if Ford was screwing us on engine preformance and fuel consumption just because their engineers couldn't figure out what all of these tunning companies already have.

I am familiar with with tuning of gas engines and I know that just by changing ignition timing and leaning out the fuel ratio that you can never ever see the same kinds of horsepower gains that you see from tuning of diesel engines. Why is this? Most gas engines have a limit as to how much you can advance and retard the timing and usualy your stock settings are going to be close. The same goes for leaning out the fuel ratio, leading to burning up valves from the high EGTs. I must be missing something here with diesel engines. Thanks

 

Your questions are all valid, and could seriously cause a 50 page response, lol.

The short, short short version.

Fair warning: Statements here are going to be at random =o)

Gasoline engines have plenty of power potential in them, especially when they benefit from forced induction.

Buick Grand Nationals, Typhoons, 300zx Twin Turbos all can gain an easy 60 HP with some simple tuning and an increase in boost.

Even on the now famous 03-04 Cobra (which has a stock wheel HP of around 360), can make 400 wheel HP with a simple tune and air filter.....and that's without making any boost changes.
Add a pulley and retune...and you've quickly got 470+ RWHP.
I've tuned many of them.

Now to get really, really, really random and extremely general:

Diesels are entirely different animals than gas engines:
1. Diesels do not have an ignition, so they do not have ignition timing.
2. Diesels ignite fuel with compression (heat), so when we adjust timing on a diesel, we are adjusting INJECTOR timing, that is, at what point the fuel shoots into the cylinders. Generally, this is way, way, way retarted from the factory. So much it actually hinders efficiency and can hurt fuel mileage.
There are many different strategies when it comes to putting together an effective injection timing curve, and it all depends on where you want to make the most power. It need to be lowered in some placed and raised in others. Sometimes, lowering injection timing, then ramping it back up quickly can induce more engine load (which creates quicker spoolup and a higher peak torque rating). Also, you can run less of an uphill curve if you want mroe bottom end throttle response, but usually at the loss of some peak power.
This is really an endless subject. The injection timing curve is literally the personality of a diesel engine, and even having complete control of it will have some sacrifices since load and boost works on a 'what goes up, must come down" philosophy.


3. Gas engines consistently jump in/out of open loop. For closed loop operation, 14:1 is an acceptable air fuel ratio, in open loop 13.2:1 is acceptable for most normally aspirated gas engines and 11.5:1 to 12:1 is acceptable for most supercharged or turbocharged (or nitrous) gas engines.
Most Turbo Diesel engines run in closed loop all the time (unless something is wrong) and are able to run at MUCH leaner air fuel ratios, particularly at cruise.
This is part of the reason why a couple more lbs of boost at part throttle can go a long way in giving you fuel mileage. It causes greater efficiency and greater power with less LOAD, which saves fuel.
Kind of funny....a guy I worked with at SC was sitting next to me and we were reading a Ford press release/article on the 6.0 which stated "Ford is considering raising boost levels at cruise in the powerstroke, because it has been discovered that it causes gaines in fuel mileage.
He and I looked at each other and said: "Duh". hehehhe.


Ok, I'm rambling a little and being really, really general, I know =o)


Something important to know about tuning a turbocharged vehicle, gas or diesel.

When you can electronically control boost, you can raise it and immediately create a situation where you can add more fuel to maintain the correct air/fuel ratio to make maximum safe power.

The brutal power gains you see in diesels isn't so much because they are diesel, but they are turbocharged, conservatively tuned from the factory, and boost, fueling and injection timing can be controlled electronically (through the tune)....not to mention a plethora of other power creating variables.


Back to gas:
My daily driver is a 2006 Audi A4S Quattro Turbo.
It's a 2.0L FSI 4 cylinder gas engine.
It has no modifications other than an APR Tune.
The car makes 50 more HP and 90 ft lbs more than stock, AND gets 2 more MPG!

This is on a 4 cylinder gas engine! it's making nearly 300 ft lbs of torque from 1800-4000 RPM!

That's forced induction for ya......

Even some non forced induction gas engines make some big gains with tuning.
2003 Ford Explorer 4.6:
The stock AFR is so ridiculous and timing is so retarted, even a novice tuner can make an easy 30 HP and over 60 ft lbs at the tire with only a tune.

Ignition timing is far different from injection timing.
Gas engine will ping or "detonate" if the ignition timing is too advanced, causing engine damage (it can literally 'hammer' the main bearings).

Diesel engines are DESIGNED to detonate, lol.
Of course, too much injection timing can cause a diesel engine to die an early sudden death, too.

Picture this:
You are riding a bicycle, focus on one leg for now.
When pedaling, your right leg comes up and it goes down.
When it's all the way UP, we can call that TOP DEAD CENTER.
Hold that thought for a minute....

Of course, combustion takes time to occur, so the spark induced (gas) or fuel is introduced (diesel) lets say....10 degrees before top dead center, so the "explosion' occurs at the most efficient moment to make the most force sending the piston back down, making more power.
Someone discovers that advancing it from 10 degrees to 15 makes more power, and 20 makes even more power.

How much timing is too much?

Imagine you are back on the bike and you try to push the pedal back downbefore it reaches top dead center......
Ouch.

With gas engines, the car will (usually audibly) ping or "detonate" , letting you know the timing is too far advanced.

In a diesel, it will usually start smoking more and more,and eventually start making a really LOUD hammering sound on each combustion stroke.
At this point you are literally trying to send the piston back down before it's done coming up!
VERY VERY BAD!!! =o)

Of course, optimal timing changes with engine load and RPM, which is why timing is tuned in a map, with each cell representing a specific load/RPM scenario.

Now you know why it takes to long to tune engines correctly!

I've been so general here, it's silly really.....but it will give you an idea.


Ok, enough 2 AM randomness.

 

My lie-o-meter with Hypertech on performance reads 20.6 mpg but when I filled up last night it was only 13.9mpg by hand. Does anyone know why this happens? I also have Superchips 1805 and it reads very close to the same as the dash meter.

 

Making the lie-o-meter work correctly with a tune is difficult.

There are some torque maps and many other maps that help the PCM calculate engine load and if the tune does not include the careful tuning of these maps (among many other necessary changes), the lie-o-meter will have NO IDEA what mileage you are getting, lol.

Don't trust the meter any farther than you can throw it, other than for comparison.
It's good at telling you which driving habits generally yield better mileage, but that's about it.

As a matter of fact, the NGS+ scan tool has an "instant fuel mileage" tool which helps you find fuel mileage sweet spots.
The lie-o-meter is great for this if you don't have an NGS, but you'll have to keep resetting it to see the "real time" data.

In other words, you can reset the meter and for a second or so, see your "real time" fuel economy.
Again, don't focus so much on the actual MPG reading, simply note which scenarios show the highest MPG number.

It's great for finding the RPM/GEAR/MPH in a given load situation that will *probably* give you the best mileage.


Don't you love all of my disclaimers:
-probably
-maybe
-possibly
-I've heard, but not confirmed
-testing has shown, but not proven completely

Lets see...how many more of these have I used over the last few years?

LOL.