Spartan Install and Real MPG

[Str8Strokin']

I figured I would make a thread on my install and actual MPG numbers. We finished the install on 1/10/13. I have pics of the install and wil talk about that later but right now I'm on a road trip and wanted to throw in my actual hand calculated numbers.

I had some hard shifting at first but I have gotten used to driving the truck and everything has smoothed out for sure.

EL vs LL (Early Lock/ Late Lock)
For those who don't know what this is, it's basically when your last gear kicks in, early is 45 MPH and late is 55. Early is better for MPG. I didn't know any of this before the install so I figured I would throw that in here since spartan will ask you when installing the tune.

I have a crew cab short bed FX4 black on black. Sinister EGR cooler delete (no elbow), DPF/CAT delete, 5" flo pro DP back...Running the 275 EL tune.

I did a little city driving and ran out to my shop a couple times which is 55 MPH...I was around 18 MPG with that...took a 200 mile trip running about 79 MPH and was excited to see what I would get...unfortunately I only got 16.3?...dash said 24 exactly, for what its worth...was surprised and disappointed

[superduty6.4]

I would say that at almost 80mph 16.3mpg is pretty good.

[Str8Strokin']

You know, that's why I threw the 80 MPH in there, I'm not real sure what's good and what isn't for the speed...I just figured I would be more around 20

[superduty6.4]

There's not alot of people that consistently get 20mpg. I guess if a person drove all highway and no faster than 100kph it may be possible.

[drewactual]

Wind resistance is exponential, so the truck is working harder maintaining 80mph than it is at 60mph (relatively speaking).. so... If it took 6 units of load to hold 60mph, it would NOT take 8 units at 80mph, but more like 10..

I've found that my truck, w/o hauling or towing, gets its best economy right around 65mph.. if you have a tuner you can monitor egt's... Setting speed based on that is a dang good way to drive economically.. keep them under 550*, let the engine dictate speed and not a sign, and you can get 18~20mpgs all day long, unloaded.. load her up with cargo or a trailer, though, and you're going to cut into that pretty good, but should still stay in the double digits..

While towing a load, ease into highway speeds.. use your foot to maintain speed (no cruise control) hold it steady over a decent stretch of road while monitoring your egt's... Aim for that temp for the rest of the trip.. you'll be slower than traffic often, but sometimes you won't be.. again, this is allowing the truck/load dictate speed and not some sign..

I'd love to find a cruise control device that sets speed at engine rpm or pyrometer.. it would pay for Itself pretty quickly I'd guess..

[Str8Strokin']

i got 15.71 MPG on the way back...

[Doss]

80 MPH is pretty fuel hungry on this barn.

I get best around 60-65 but usually drive at 72-75... err... I mean 70.

You can't really do an honest MPG calculation on one tank or even 5 or 6 tanks of fuel. Too many things come into play. I'd guess that after 10 tanks on the same sort of trip, you're beginning to zero in on a better average.

Not that it's not nice to have your numbers though. It's a great starting point.

[drewactual]

Couldn't agree more, Doss...

But, its nice to have those figures when you're budgeting a haul.. and, if you monitor them closely, if something goes awry you can spot it pretty quick (if there isn't an obvious reason)..

I like using fuely, an app for droid.. it logs on an online db and gives some good info over whatever period you're working with.. currently, I have a stack of receipts with miles written on them I gotta enter, but if I'm right, I'm averaging about 18.5 or so overall.. not too bad by my reckoning.. its being eaten alive right now though, because all I'm pretty much doing is using the truck like a floggin minivan..

[Str8Strokin']

oh most definitely...i did 12,000 miles worth of pre spartan to get as accurate as i could so i could post my post spartan improvements...i believe my average was 11.6 MPG mostly city with 13.63 being my highest which was mostly highway...pulling a trailer was the lowest with 7.19

we have two cummins that plow for 8 hours straight and only eat 1/4 of a tank, given they are both 24v, '98 and '99, all stock...haven't done the calculations on those yet since they are work trucks, hard to know who is going to fill it up next and keeping track of everything

so far with spartan i only have a few calculations so only time will tell...

[Doss]

Yeah, definitely keep us updated. I have a full fuel log of over a year of runs and everything that was done to my truck in that time. I'm waiting until I build up more deleted runs before I give the verdict, but so far it looks considerably better.

I did notice that on a round trip a couple of weeks ago that the mileage was considerably off on the return trip. Don't know what happened. The lie-o-meter showed 23 MPG going down and around 18 coming back.