WOW-Newly tuned Smarty 6.7L

[CUMMINZ]

With all the talk about TQ control and upping the TQ on the HO 6. 7L I decided to try something on my Smarty to run on a short trip this weekend down thru Charlotte to the KOA. U used the following tune:



Catcher #3, TM #4, ITiming #2, RPressure #2,& VGT #4



We hooked to the DayDreamer and drove 50 miles down I-85 which is mild country. The overhead averaged 14. 5 - 16 mpg. That is a full 2 mpg better than we have gotten before. While driving down I-85 unloaded the overhead ran in the mid 20s.



DO Not attemp this tune towing unless you have guages and are willing to manual shift the 68rfe. The low end even thru the upper gears was terrific. . And I assure you without careful management of the throttle you will do damage to your drivetrain but the power and mileage was great. It was a different engine.



Also the 68rfe would do toward lockup much faster so I had to watch the throttle closely. If you like a foot on the floor this is not for you.



At the request of AH64 I am adding this addition:"DO NOT attempt this tune towing unless you have a fully built auto" Gauges won't tell you crap as far as the beating the trans is taking. You could be putting as much as 50% more tq thru the trans in low gears than stock!



DON'T BE AN IDIOT LIKE CUMMINZ AND USE THIS TUNE WHICH USES NO TORQUE MANAGEMENT. ALTHOUGH IT MAY GIVE YOU 2-3 MPG MORE ON MILEAGE IT IS NOT WORTH IT. JUST DON'T DO IT... . :-{}:-{}:-{}

 

[AH64ID]

I assume you mean Timing 4, and TQ 2?



What kind of boost do you see on VGT4?



A side note for folks new to Smarty, the more timing you add the lower your max EGT becomes. Like stock can take 1450*ish, TM2 1350*, TM4 1300, TM3 1400* are the numbers I use as a MAX "transient" if you will, I drop 50* off that for continous.



But it sure is nice towing with tq isn't it!

 

[CUMMINZ]

I assume you mean Timing 4, and TQ 2?

What kind of boost do you see on VGT4?



A side note for folks new to Smarty, the more timing you add the lower your max EGT becomes. Like stock can take 1450*ish, TM2 1350*, TM4 1300, TM3 1400* are the numbers I use as a MAX "transient" if you will, I drop 50* off that for continous.



But it sure is nice towing with tq isn't it!

No, like I said Timing was 2 and TM was 4. I don't measure pressure only EGTs and transmission temp.

 

[AH64ID]

By TM do you mean Torque Management? Most refer to torque management at TQ, and timing as TM.



TQ4 is really aggressive, # 4 - Wild ( after market clutch / AT Transmission NEEDED! )



If your towing with the tq set on 4 plan on a new trans very very soon.



For towing you want to stick to TQ2 or TQ1.

 

[CUMMINZ]

Yes, TManagement is on #4.

 

[AH64ID]

I think that's crazy on a stock trans when empty, let alone towing! I doub't you find many that disagree.



Even with the new 800 ft/lb tune there will still be plenty of tq management down low to keep the driveline in tact, TQ4 removes that safety factor. . but hey its your truck/trans.

 

[CUMMINZ]

I appreciate your opinion. The point I was trying to make is that I saw a 2-3 mpg increase on the trip.

 

[MChrist]

But did you hand calculate? Smarty doesn't seem to accurately read how much fuel is really going into the motor. With my smarty off, I may read 21 on overhead, and 28 with it on, although I may really only be getting 1-2 mpg better.

 

[AH64ID]

Which is a good increase, if the hand calc works out to be the same. I know on my truck the individual setting, TQ and TM, effect the overhead readout separatly.



Just don't want you to think your getting 2 mpg better, but you have to buy a new trans next week. I have read about guys destroying a trans in one day with TQ on 4.



I would add to your original post: "DO NOT attempt this tune towing unless you have a fully built auto" Gauges won't tell you crap as far as the beating the trans is taking. You could be putting as much as 50% more tq thru the trans in low gears than stock!

 

[morbius]

I appreciate your opinion. The point I was trying to make is that I saw a 2-3 mpg increase on the trip.

Cumminz, do you still have all your smog stuff intact and dpf in ? If so, how are your regen doing ? Tossing around the idea of trying out a smarty ...

 

[CUMMINZ]

My wife and I just got back from a round trip to Winston-Salem at 60-65mph. The overhead was steady between 18. 5-20. 5. . Historically my overhead has been 3/4mpg fast and I will not be able to get hand calculated figures for a while.



I will say that I am a very anal connected driver to my seat driver. I use the paddle shifter all the time and feel that as long as I drive with an egg under my foot which I usually do the transmission will be OK and I appreciate all you guys concern.



I do have my big cat & DPF connected. I installed a straight downpipe from Diesel Power and an Aero 5050 muffler.

 

[HBarlow]

Cumminz's reports and the discussion in this thread makes me cringe with concern for broken parts and a very expensive repair bill.

Good luck. I hope you get away with it. I lack the courage to do that.

 

[CUMMINZ]

If my results after a trip with hand calculations is true it will shatter the idea that adding HP & TQ will always result in less fuel mileage. I have been toying with my Smarty constantly and thought I had reached a conclusion that preset tunes were the best but I now know that is not true.

 

[AH64ID]

I don't know that I have ever heard that adding hp and tq will decrease mileage, in fact the opposite has been the accepted truth for as long as I have been around the modern diesel world, not long albeit. . but long enough that is the trend.



Its well known that higher tunes always get the best mileage, if you keep your right foot out of it. . Towing is where that is generally not true as your using the newly made power and aside from the power gained from timing, hp takes fuel. But if you can keep your hp requirement the same as it was stock and run a decent tune you will get better mileage. . On the Smarty Jr Bob Wagner has always said the auto trucks get the best mileage on SW3.



Do not confuse that with tq management. Tq management is factory enabled to save the drive train from itself essentially. The trans that is built to take the full 650 ft/lbs, stock, of the Cummins in lower gears is very expensive and NOT factory equipped. Let alone the 725 or more you are putting to the ground with SW3 (probably close to 775 at the crank). If you were to run your truck on the dyno at TQ1 (stock) and TQ4 (WILD) you would not get any more power to the wheels because TQ management only occurs in gears 1-3 in the 68RFE. So what you are doing by decrease the tq management is putting a lot more tq thru the trans, and it doesn't matter if you roll into it with an egg under your foot or not, you are quite simply putting more tq thru the trans than it can handle. An egg under your foot will help you for a while, but not long. . I hope you have 7K laying around to rebuild your trans.



You also cannot assume that because the OH is off with one tune its the same with another tune. The other thing is OH's are generally off by a percentage, not a hard number. So it may be 3/4 mpg at 12 mpg, but at 16 mpg that will be a full mpg. . And if you track it tank to tank you will see that it varies. Mine averages 17% off, but varies from 13% to 24%. Thats with the same setting in the Smarty over a year or more.

 

[CUMMINZ]

I filled my tank up today and will make 100 mile trip this weekend and will hand calculate. Driving it today I love these settings.

 

[DieselLady]

We call the overhead readout the "Lie O Meter" when you add a program, especially one that gives you fuel, You don't have to push as far down on the throttle to get the same fueling as when you had no program. And since the computer looks primarily at throttle position to determine fuel economy, the higher the program is set, the more fuel economy the overhead will tell you you are getting. Sorry to tell you, but when you do the math yourself, I am sure you will find that you are a lot lower on the economy than you thought.

 

[CUMMINZ]

We will find out today. :-laf

 

[MChrist]

My prediction: Same to . 5 mpg better

 

[CUMMINZ]

Drove to Charlotte from home last night. 103 miles round trip. Going to Charlotte we were in stop and go traffic for 30 miles. One the way home we drove the interstate at 65 mph. Engine went thru re-gen one time. Overhead read anywhere from 19. 5 to as low as 13. 5 while in re-gen. Got home and filled up and it took 6. 87 gallons. That is 14. 99 mpg. That is for a 9500 pound dually with 19. 5" wheels and tires.



What I like about this tune is the way it locks up much earlier in 4th gear. :-laf

 

[Jim W]

That sounds great, but I do not like to use just one fill up to calculate my mileage. There are too many variables that will effect your mileage to make a concrete decision on just one fill up. I normally use a minimum of 5 fill ups to report mileage, this will help in eliminating some of the variables that occur with filling up a tank with fuel. I would like to see what your average is after 5 or 6 fill ups using both Highway and City driving combined. This will then tell us what your improvement really is.

I am tracking a years data to compare between the SW 14ME and the SW 23ME, update on the Smarty, to see if there is a real improvement. So far so good but I will not know until Nov. to be real sure.

Jim W.