Before I get started, this thread isn't intended to start any kind of "mine is better than yours" tiff between tuner owners. Im only posting this data because I see lots of posts that say something along of the lines of "with xxxxx setup, what kind of fuel mileage can i expect?" Im not here to light my own fires, just to give an example (which may or may not represent the majority of similarly-equipped trucks) of how my particular setup has performed thus far.
Ok. So i've just recently rolled over 10K miles since the Smarty was installed on the truck. In those 10K miles, i've driven around town, on the highway, bobtail, and pulling my little flatbed trailer with weights ranging from the 3000lbs. the trailer weighs empty up to 9000lbs. including trailer weight. Certainly not the heaviest of loads, but a good indicator of how the Smarty helps the truck pull I think.
Here are the vitals on the truck during the timespan:
*Early '08 model (Nov 07 build date) (means full sized intercooler)
*Truck weighs 7800lbs. with full tank of diesel (no driver or passengers)
*45000-55000 miles during timespan
*Quad Cab, Short Bed, 4x4
*G56 Manual Transmission
*2" level lift, 35" tires
*Speedometer calibrated for tire size and GPS-verified
Performance modifications along with the Smarty are as follows:
*5" TBE with AeroTurbine 5050xl muffler and 330ohm sims
*EGR Delete (EGR cooler still in place)
*Shibby Grid Heater Delete
*Amsoil 100,000 mile nanofiber airfilter in OEM airbox
*Intake baffle removed
Data gathered was observed primarily from the use of ISSPRO EV2 boost and pyrometers along with an Edge Insight for rail pressure, IAT, and load %. All fuel economy figures are hand calculated. All highway miles had a cruise control set speed of 63mph (which is right at 1600rpm on my rig).
Another thing to note is that, contrary to most others, I have never once seen a single bit of fuel economy gain by running any kind of electronic performance enhancer on this truck. At one point or another i've tried a Bully Dog Power Pup, an Edge Juice w/Attitude, a Bully Dog PMT, and a DiabloSport Extreme PowerPuck before I finally settled on the Smarty. I have gotten the same or better fuel economy on stock settings than running performance tunes with all of those.
Fuel Economy Data:
50/50 City/Highway mix, bobtail: 18-18.5mpg (20.4-20.7mpg OHC)
Highway, 3000lbs. unloaded flatbed bumper pull trailer: 18.5-19mpg (21.0-21.3mpg OHC)
Highway, 8000lbs. loaded flatbed bumper pull trailer: 16mpg (18.2-18.4mpg OHC)
Highway, 9000lbs. loaded flatbed bumper pull trailer: 15.7-16mpg (17.5-18.1mpg OHC)
Highway, bobtail: 20.5-20.8mpg (24.3-24.5mpg OHC)
My normal weekly route back and forth to Kingsville used to yield right at 17mpg hand calculated and after the Smarty I have yet to see it fall below 18mpg. So, i have gained a solid 1mpg gain in the city/highway department.
Pulling the trailer is hard to gauge before/after mileage results off of because every load has a different shape, weight, and feel to it. 2 loads may have the same dimensions but 2000lbs. difference in weight. Another 2 loads may weigh the same yet one is tall and broad gathering a ton of wind resistance while another is low and flat and sleek. That being said, the truck just feels better pulling with the Smarty installed. It seems the EGTs are 75-100 degrees cooler, and the truck just doesn't seem to be working at all with a small load behind it.
My all-highway fuel economy hasn't changed with the Smarty. On stock programming I can average 20.5-21mpg all day long so the Smarty hasn't gotten me anything in the highway fuel economy department. It's a shame too, i truly thought the Smarty was going to be the one that got me over my set goal of 22mpg with this truck. I guess it just shows that the truck has reached it's most efficient point on the highway and isn't going to get any better no matter what i do (unless i put smaller tires on or something obvious like that which is not an option i will consider). While cruising bobtail i show sub-4psi boost readings, my EGTs hover right at 600 degrees, my rail pressure is 10-12K psi, my IAT is 10 degrees above ambient, and my load % hovers around 15-18%. I don't see how the truck can run much better than it is right now.
With the Smarty, I've run primarily the DR07 and DR08 firmware with brief jaunts on DR09 and DR10. I didn't like the way the truck ran with 09 and 10 and I also noted the fuel needle moving faster when compared to miles driven than it did with 07/08 so I reverted back and plan to stay there until there is the One Update To Rule Them All. I've also played with the SW settings a bit, running each one for a minimum of 1000 miles (typically 2 fillups, since i usually fill up with 1/4 tank left which is typically around 500 miles on the tank). I've tried the following setups:
*SW1, TQ-default, TM-default, RP-default
*SW1, TQ-default, TM-3, RP-default
*SW3, TQ-default, TM-default, RP-default
*SW3, TQ-default, TM-3, RP-default
*SW7, TQ-default, TM-default, RP-default
The truck likes SW7 the best with all the REVO settings at default. However, with any kind of weight on the trailer, the clutch threatens to turn in it's 2 weeks notice if SW7 is still loaded up, so I had to back down to SW1 to be safe when the trailer was loaded. Any kind of grade with SW7 and the clutch would slip like madness. However, there is no doubt that even with the clutch slipping, the truck was getting better fuel economy with SW7 than with SW1. I haven't tried upping the timing on SW7 yet but I might try it and see if i can milk any more fuel economy out of my bobtail cruising. Since I am the anti-hotrodder I don't have any need to mess with the torque management settings and I have my reservations messing with rail pressure so I tend to leave it alone.
Initially, I had 2 codes that would continue to show up, though they wouldn't always trigger the CEL. Sometimes there would be no CEL yet when I would check for codes, there they would be. The 2 codes are p2080 and p2084 which both are EGT sensor codes that trigger when the temperature in the exhaust does not change once the engine reaches optimal operating temperature. This stands to reason because I am running 330ohm resistors in the exhaust so the ECM think the EGT is right at 1200 degrees always. I would get these with DR07 but haven't seen them in the past 6000 miles while running DR08. Perhaps DR08 incorporated a fix for this, perhaps the ECM has learned and adjusted it's parameters; I frankly don't know. Aside from that I have been code and problem free with every single mile I've logged on the Smarty.
Overall I like the Smarty. Im a little disappointed in not having gained anything on the bobtail highway fuel economy department, but with the parameters I have monitored I can't really see the truck running much more efficiently so I suppose it's about as good as it is going to get and nothing (not even the Smarty) is going to compound upon it. Nothing, that is, that has a cost/benefit ratio that makes it feasible to invest in. I have plans to add a Shibby Stage II air intake and boost tube to the truck once Shibby has the intake available and hope that will show a bit better mileage.
Power-wise, I love the Smarty. It has a smooth, effortless onset that makes driving the truck fun. I don't have a problem in the world with the timing rattle and enjoy that, while the truck sounds more like a TRUCK now, it is still relatively quiet and refined in the cab while cruising down the road. I can't comment on HP numbers or 1/4 mile times with the truck because I am the anti-hotrodder (with this truck, that is).
Hope this helps anyone who is curious. Anyone else feel free to post your own impressions with your setup so that a variety of different setups can be compared.
Cliffnotes: Smarty gave me 1mpg cruising around, but no change on the highway. Towing the mileage is respectable and is fun to drive. The OEM clutch hates SW7 with every fiber in it's being. I am long-winded.