What is WOT?

I just read two sites about cats and it was interesting but not very tech.

If one were to remove the cats would you be able to run leaner and get the fuel mileage up.

Would it cause and issue in the PCM not having the cats in?

When I ran carbs before computer cars I could always set my carb jets with the plug color and plug heat range and reset the advance curve and timing on my distributor to make it honk.

Now it seems with the 'puter controlling everything you can't do much unless you can change the program. I suppose the PCM programmers will make it so I can control the mix, timing, curve and plug heat range like in the past.

 

WOT = wide open throttle

Running a factory cal without cats will cause a check engine light and won't buy you much, if anything in part throttle fuel economy.

An ordinary flash tuner like an SCT XCal2 gives you minimal end user control over spark advance and mixture (small positive and negative adders). There are fancier systems out there that give you more but they are a lot more expensive.

A dealer like Rogue Perforance can tweak your calibration in any direction you like. However, you can only do so much with mixture because you're still pushing the same brick down the road.

The story is still the same one we don't want to hear, at least I don't - slowing down is the easiest, cheapest way to save fuel. And that's what this thread is about.

 

Yeah, I guess my days of running a 3/4 race engine with 3-2's on mech. progressive and dialing in my perameters by hand are over. It was fun while it lasted but the '50's and 60's won't come around again. Nor any of the other pleasant experiences between then and now.

I guess since I'm past ripping the engine out and building a bear to wipe the streets with I had best keep it between 65-75mph and enjoy my lil' trk. Maybe a tuner to tweek it with and be happy. She is the best trk I've owned.

I sure would like to get the high speed limiter and acceleration limiter off it and I think the tuner will do it. I sure ain't a timid driver and never will be even though I am a little more mild mannered now.

On the other hand, considering some of the foolish things I've done maybe I shouldn't get the tuner. I need to think about this some.

One thing for sure I have learned some of the things I was seeking about basic can and can'ts of tweeking the PCM and I think I'll contact Rogue. Is that Fred?

 

Yes, his screen name is Fredness on R-F and his site is http://rogueperformance.com/RogueCustomTuning.html

Fred's a good guy and he'll take good care of your truck.

 

This post is turning out pretty good. Bob thanks for the input!

My observations of instant MPG can't be considered "scientific". But I can tell you this... I only take readings when on a dead flat area and give the truck at least a solid 1/8th mile to stabilize readings. Usually when I'm recording it it's only moving +/- 0.1 It's not purely scientific.. but it is "real world" for the environment I live in.

I'm thinking I need to make a 0-85mph mileage graph. Maybe one during the winter on "winter gas" and one during the summer on "summer gas" If nothing else I'll find it interesting.

Regards, Rich


btw, this morning driving a steady 30mph (in 4th) it was only getting 7.8mpg!?!? I then dropped it into 3rd and the mileage went down to 5.6mpg.

 

I've been meaning to do the same since I installed the trip computer. Not necessarily to check my FE but to get a curve of how steady state speed affects fuel economy.

There is plenty of BS put forth on Ranger boards about how traveling at 70~75 MPH freeway speeds yields better economy than at 55~60. Another popular myth is that max FE occurs at the advertised torque peak.

Casual observation shows that my truck gets mediocre fuel economy in the lower gears and hits a sweet spot around 40~45 after it has shifted to 4th locked, RPMs are low and aerodynamic drag is not yet a big problem. I'm seeing about 20~21 MPG on the level at a steady 55 MPH but, as expected, that drops to about 17~18 at 70 per. I find that to be very consistent with the trend shown in your graph.

 

Whats driving me to do all this is to make my cartest software as accurate as is possible. To help me determine 1/4mile effects of weight/traction/power. (I'll be in the high 14s this summer )


Bob do you know of any relationships between load / rpm / speed?

For instance if your towing a 3500 boat. At what point is 4th or 5th gear a better choice for milage? (assuming TQ C. is locked in both cases)
(Maybe this summer I'll do a road test to find out)

Rich

 

Those relationships are complex. so transmission calibration engineers use special graphs to represent and interpret them.

Personally, I use OD gear in any situation where the transmission does not continually hunt and where engine braking is not needed. That's not scientific at all but it should get you close. The ScanGauge would be an excellent tool for picking the true "break even" point for any given set of conditions. Obviously, that point would vary with trailer weight and frontal area, road gradient, wind direction, etc.

 

+1 on that

 

Rich, if your planning to use the Scangauge to produce a graph of fuel mileage by driving at each, say 5 mph increments, I don't think it will be accurate. The figure in the display is a projected or estimated fuel mileage to expect. The only way it may even be exact is if there is no head, tail or side wind and you are on perfectly flat level ground. It's going to be hard to find a road like that.

The only way you can do what you want is to put in a day on a chassis dyno. I'm not sure if that is a perfect indicator.

When I used to do dyno tests on Cummins engines we used a flow rate gauge to compute fuel consumption. The problem is the engine don't use all the fuel that goes to it and some is returned to the tank just as our fuel injected engines do. We had to get the flow to and the return flow and compute the fuel consumed. Most the time we used a 5 gal. bucket on a spring scale. We pulled the fuel out of it and the return fuel went into it. After a period of time with a stop watch and watching the scale reading we would then compute pounds per hour of consumption. Not perfect but close enough.

Does the Scangauge do that?? I doubt it as that would require a flow gauge in the supply and return line and I doubt our truck engines are equiped with those sensors for the Scangauge to read.

You have to many variables to deal with. At best all you'll get is an average.

Another thing I don't understand is the relationship of road mileage to 1/4 mile times on the drag strip that you are looking for. When your racing you want all the fuel the engine can use. When you want mileage you want the least fuel needed to maintain the speed you select to drive at.

It seems you are chasing an elusive goal as there are to many variables and the two things are on opposing sides. That is why when someone says anything about fuel mileage it's always an average not an absolute.

The same with your times at the track, there are to many variables to get an absolute time, it'll always be an average of several runs and each run will be different just as fuel mileage on the road will be.

 

Like I said.. it's not scientific Just real world observations **for my environment**


The fuel pressure along with how long/degree the injectors are open (pulse width modulation) will give an accurate measurement of fuel used. Yes the scan guage will tell you fuel used per mile. (GPM is the reading callout)



I agree and that's why I stated it's just my observations.



Carl I don't think your familiar with the car test software. Or.. even other more modern ways of calulating performance.

When you don't have a purely scientific way of testing a single parameter.. you cross reference as many different items as you can. For instance, I have timeslips, autotap datalogs, SCT X-Cal data logs, car test software, virtual engine calculator, this new scanguage, and over 20years of being a gear head w/over 500 passes at the dragstrip. It's true this is not a truely scientific method that I'm using. But then again it's all just for fun... and I'm not too far off in my readings either.

Addressing specifically what you say.. that's not true. When you have all your input correct. A software (like cartest) will indeed give a theoritical "absolute". Or otherwise to say it'll give you a *potential best*

So far I've used this software on 6 different cars and it'll pretty much nail my ET and speed within 0.05 seconds and 0.2mph. But like I said.. the inputs have to be proper. DA, wind, traction, power, ect...

The two areas I've found that are very hard to predict are inconsistant shift points, and wind gusts. Otherwise once I've made several passes and then plug in the info. It's usually very accurate.

As of right now.. the software says my milage is lower than I'm actually seeing. Calculated old school style (miles/gal & avgeraged over 3-5 tanks)

So.. I'm still trying to figure out why. I think in part the TQ curve is flatter/higher down low than the software says. That means I need to adjust the inputs until the outputs match reality to a fairly accurate degree.

But like said.. this is all just for fun. I'm a gear head and a automotive engineer. To me gathing info and comparing it is just plain old fun. Give me some boiled peanuts, BBQ ribs, and a calculator.. and I'm a happy camper.

Regards, Rich

 

Hey Rich, that was an interesting post. Yes, I am not up on the electronic gear that is used now. Nor am I an engineer, just a diesel and gas mechanic that quit that in about 1988 and went back to machine work untill I retired.

It seems there is a lot of tracking of sensors by the Scangauge. I understand a little more about the Scangauge and what you are using it for now.

As to the fuel mileage differences wouldn't you trust the miles traveled and the gals. used before trusting the Scangauge? It looks to me to be a real world mpg compaired to an electronically determined mpg. If the Scanguage were giving an accurate gph fuel consumption the mpg should be the same using odometer and gals purchased and the Scangauge reading. The only variable I see is the way it reads fuel consumption. The miles traveled should be the same on the Scangauge and the trk. If the mileages don't agree then which is wrong?

 

I'd definately trust mileage divided by gallons over the scan guage. Although that in itself has it's own problem of one fill being the same as the other. So.. you have to average them to get a good running result. Same gues for the scangauge IMO. With it you need to make sure you plug in the proper amount of tank capacity and such.

Here is a link to all that the scanguage does as far as trip and MPG info.
http://www.scangauge.com/features/tripcomputer.shtml

Note it can show the following:
» Fuel Used
» Trip Fuel Economy
» Distance to Empty
» Time to Empty
» Fuel to Empty


Rich

 

Rich, glad you posted back that fast. I like the Scangauge and may get one but I want to get the programmer first and since I am retired money is the issue, not the desire to get one or both.

The very first thing I did when I got this Ranger was take my stop watch and head for the interstate. Did 10 miles at as close to 60 using cruise c. I was surprised when it came up within 5 seconds of 10 minutes. Assuming the mile markers were accurate and I was fast on the button as I passed the first and last marker it is remarkable because I have never had a vehicle that accurate. Then I put 9,000 miles on it in 4 months and kept records of total miles and total fillups. I figured the mileage for each fillup and the total trip because I wanted a breakdown of everything. On the trips I did notice the odometer and the milemarkers ticked off at the same time over about 30+/- miles.

I just put a new set of tires on it but the old ones had 40% tread left. My son gave me a gift cert. for tires so what the heck. Hit the road with the trk and stop watch. 9 miles in 9 minutes and 5 seconds so the new tires didn't change anything, that's good. BTW, I run 40 psi in the tires.

The next long trip will be with stop watch and I'll do a longer test run but I think this trk has an unusually accurate speedo and odometer. That's why I think the mileages I have posted in some threads are accurate.

Having read every post I can find about fuel mileage I believe I am getting better than almost anyone, maybe better than anyone. I know my driving method helps a lot but it's not a guarantee because of weather, road and traffic, etc..

I was kind of disappointed when I didn't get as good gas mileage as my old trk. and that's why I did all the testing.

I'm a tinkerer and very curious about things so all this discussion catches my attention.

 

My 07 FX4 has 23k on it now. I've recorded every penny spent and mile traveled so far.

Lately, up here on winter gas, 50/50 driving, and 20s temps I'm getting about 18.5mpg. (miles/gal method) In the summer I was up in the 21s. But that's 50/50 commuter driving during motown rush hour. Out on the freeway and uninterupted driving I'd think it'll do 23-24.

As for the tuner vs scanguage. Put your money towards a tuner. The ability to change things and data log are far beyond the scanguage. It costs and arm and a leg, but the truck acts like it found two long lost cylinders! Man it comes alive with a good tune. Especially when you get the timing bumped up.

Have you checked out my WEB PAGE?
On there I have all the mods listed so far. I keep updating it as info rolls in. Although I tend to not post hard data. Pics mostly.

Rich

 

I looked at your web page. It's not on your site or profile but I finally remembered yours is a 4.0L. That's some fine gas mileage. Was that with a non factory program?

Mine is a 2003 Ranger Edge 4 door 3.0L flex fuel auto 4.10 L/S. Mileage is 65mph=approx. 25mpg, 70mph=approx. 20mpg, 75mph=approx. 18mpg, all on 87 octane.

When I can get the money and talk to Fred I plan on the best mileage program and the best performance program and what ever he suggests for the third program included with the programmer.

I used to be a very aggresive driver and sometimes I still am. I hate slow traffic but try to be patient now. Getting good fuel mileage requires me to control myself and the throttle.

I don't like driving 65 on the interstate and want to get at least 22mpg @ 75mph. I hope a mew program can get me there.

 

Yes my mileage reported is with all mods in place. IMO the crank underdrive and the tune gave the best mileage improvements.

Rich