Purple Tractor Posted August 27, 2018 Report Share Posted August 27, 2018 My 2008 D13 is set at 435 HP, for $500 the dealer will raise it to 485..... will this hurt or help fuel economy? I know my Dodge Cummins gets better mileage when I turn it up to 420 HP than it does at 320 HP. A little harder on back tires maybe but more fun to drive. 2008 Volvo 670,D13, 13 speed,2018 Montana 3210MS Link to comment Share on other sites More sharing options...
Moresmoke Posted August 27, 2018 Report Share Posted August 27, 2018 Your right foot controls the fuel economy. Extra HP only uses more fuel if you use it. Link to comment Share on other sites More sharing options...
GlennWest Posted August 27, 2018 Report Share Posted August 27, 2018 500 is a lot to hook up a computer. I was going to turn mine up but his software didn't work on my 06. Was going to charge less than 100 but on Saturday in the lot. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
GlennWest Posted August 27, 2018 Report Share Posted August 27, 2018 1 minute ago, Moresmoke said: Your right foot controls the fuel economy. Extra HP only uses more fuel if you use it. True but diesels usually improve mpg with hp increase. We don't have hot rods so should increase. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
noteven Posted August 27, 2018 Report Share Posted August 27, 2018 I’m going to install a 2000HP Cummins K50 in my truck. I expect I will have to deal with stale fuel in the tanks because my mileage will be so good. "Are we there yet?" asked no motorcycle rider, ever. Link to comment Share on other sites More sharing options...
jcussen Posted August 27, 2018 Report Share Posted August 27, 2018 Took my ISM from 450 to 500 hp. Mileage went from 7.0 to 7.01 mpg . With my savings, I will be able to get a McDonald's senior coffee by the end of the year. Foretravel 40ft tag 500hp Cummins ISM 1455 watts on the roof, 600 a/h's lithium in the basement. Link to comment Share on other sites More sharing options...
HERO Maker Posted August 27, 2018 Report Share Posted August 27, 2018 58 minutes ago, jcussen said: Took my ISM from 450 to 500 hp. Mileage went from 7.0 to 7.01 mpg . With my savings, I will be able to get a McDonald's senior coffee by the end of the year. Now that is funny, and probably true! Rocky & Sheri Rhoades '01 Volvo 770 2016 DRV Mobile Suites, HoustonHERO Makers Ministry Link to comment Share on other sites More sharing options...
Hewhoknowslittle Posted August 27, 2018 Report Share Posted August 27, 2018 I took my DD15 from 425hp to 560hp. Torque to 1850 Cost me 1600.00 dollars. Haven’t pulled yet but have a over flow tank to catch the fuel savings so I can put them back in the tank I know my mollies will go to about 28.6 miles to the gallon at least that maybe more! Link to comment Share on other sites More sharing options...
Purple Tractor Posted August 28, 2018 Author Report Share Posted August 28, 2018 Well sounds like I need to get to work on the needlenose,6nz project a little harder, that thing should refine it's own fuel..... but if I could get just a little more MPG's out of the Volvo, my DW would be all over it..... she's a frugal accountant. And I agree $500 to hook up a computer is robbery....... I'll get it done cheaper. 2008 Volvo 670,D13, 13 speed,2018 Montana 3210MS Link to comment Share on other sites More sharing options...
beemergary Posted August 29, 2018 Report Share Posted August 29, 2018 Old mechanical diesels are turned up (more fuel). More hp/tq is only good for mileage if you really need it. Just keep an eye on boost gauge and right foot. Link to comment Share on other sites More sharing options...
GlennWest Posted August 29, 2018 Report Share Posted August 29, 2018 I get the chance again, will have to find out. Want the 65 speed limit off also. I get less than 7 towing. Get 7 bobtailing. Actually closer to 6 towing. That's going by the truck readout. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Jack Mayer Posted August 29, 2018 Report Share Posted August 29, 2018 47 minutes ago, GlennWest said: I get the chance again, will have to find out. Want the 65 speed limit off also. I get less than 7 towing. Get 7 bobtailing. Actually closer to 6 towing. That's going by the truck readout. Glenn, the truck readout is often inaccurate. Do a measured test if you can..... For others....MY opinion: if you are super concerned about fuel mileage and are in recreational service, it is likely you do not want an HDT. Because the expense of owning an HDT and keeping it properly maintained makes any fuel savings that you achieve seem like peanuts. Don't worry about fuel economy. Get the truck you want, set it up the way you want, drive it, and most importantly MAINTAIN it. Jack & Danielle Mayer #60376 Lifetime Member Living on the road since 2000PLEASE no PM's. Email me. jackdanmayer AT gmail 2016 DRV Houston 44' 5er (we still have it) 2022 New Horizons 43' 5er 2016 Itasca 27N 28' motorhome 2019 Volvo 860, D13 455/1850, 236" wb, I-Shift, battery-based APU No truck at the moment - we use one of our demo units 2016 smart Passion, piggyback on the truck -------------------------------------------------------------------------See our website for info on New Horizons 5th wheels, HDTs as tow vehicles, communications on the road, and use of solar powerwww.jackdanmayer.com Principal in RVH Lifestyles. RVH-Lifestyles.com Link to comment Share on other sites More sharing options...
Pete Kildow Posted August 29, 2018 Report Share Posted August 29, 2018 Driving by the Boost gauge will do more for MPG's then anything. Boost = HP and HP = Burned fuel. As long as the Boost is allowed to stay low for what your pulling. MPG will improve. But get up above 20+ lb of boost, well fuel is being burned. MPG is going down. With your Gross weight 435HP should be plenty. I ran a couple of million miles with less then 350 HP and lots of times grossing way north of 80,000 lbs. Shoot pulling logs (Grossing 100,000+) with a 315 Big Cam cummins. And while I did not fly up hills. It did a great job. Back in 1988 ran a Detroit 11.1 set at 365HP. And even grossing 79800 that truck did the job well. And have a 11.1 now in the Kenworth. Its set at 400hp and 1350 Torque. And will take Torque over hp any day. Link to comment Share on other sites More sharing options...
GlennWest Posted August 29, 2018 Report Share Posted August 29, 2018 All trucks don't have a boost guage. Mine don't. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
NoDirectionHome Posted August 29, 2018 Report Share Posted August 29, 2018 I think Jack hit all the points... except ENJOY IT! "There are No Experts, Do the Math!" 2014 Freightliner Cascadia DD16 600hp 1850ft-lb 18spd 3.31 260"wb SpaceCraft S-470 SKP #131740 Link to comment Share on other sites More sharing options...
GlennWest Posted August 30, 2018 Report Share Posted August 30, 2018 oh, I do enjoy it. So much better than the dually. Oh wait, mime a dually also. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
DJohns Posted August 30, 2018 Report Share Posted August 30, 2018 A dually on steroids. I told a guy the other day to go pull a larger trailer with a 3500 or 4500 then pull it with a HDT. Fuel economy is pretty much the same BUT the ride and braking is WAY better. Test drive before making judgement on HDT. 2002 Beaver Marquis Emerald C-12 Cat 505 HP 2014 Volvo 630 D-13 I Shift SOLD 2017 New Horizons SOLD Link to comment Share on other sites More sharing options...
Pete Kildow Posted August 31, 2018 Report Share Posted August 31, 2018 On 8/29/2018 at 12:17 PM, GlennWest said: All trucks don't have a boost guage. Mine don't. Not hard to install. And for most OTR guys. There will be a EGT gauge and boost gauge. But for most they will never learn how to use them. Link to comment Share on other sites More sharing options...
CDR Posted September 3, 2018 Report Share Posted September 3, 2018 On 8/29/2018 at 4:04 AM, Jack Mayer said: Glenn, the truck readout is often inaccurate. Do a measured test if you can..... For others....MY opinion: if you are super concerned about fuel mileage and are in recreational service, it is likely you do not want an HDT. Because the expense of owning an HDT and keeping it properly maintained makes any fuel savings that you achieve seem like peanuts. Don't worry about fuel economy. Get the truck you want, set it up the way you want, drive it, and most importantly MAINTAIN it. Glenn is spot on! I have seen post for mpg from 6 to 15, but "no" one ever gets rid of their HDT's due to MPG. But if you can't afford to fix it, you just have a lump of unusable metal!!! 2001 Freightliner Century, 500hp Series 60, Gen 2 autoshift, 3.42 singled rear locker. 2004 Keystone Sprinter 299RLS (TT) 2 & 4 Wheelers! 2013 Polaris Ranger 800 midsize LE Our motto "4 wheels move the body, 2 wheels move the soul!" Link to comment Share on other sites More sharing options...
GlennWest Posted September 3, 2018 Report Share Posted September 3, 2018 My truck still gets better mpg than the Duramax did. Not a lot though. But so much more truck. My truck burns a little oil. Amagine that where my mpg gone. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Pat & Pete Posted September 3, 2018 Report Share Posted September 3, 2018 1 hour ago, GlennWest said: My truck still gets better mpg than the Duramax did. Not a lot though. But so much more truck. My truck burns a little oil. Amagine that where my mpg gone. More likely because of that lead in your right boot . LOL Goes around , comes around . Link to comment Share on other sites More sharing options...
GlennWest Posted September 3, 2018 Report Share Posted September 3, 2018 Actually drive fairly easy with Freightshaker. Governed to 65. Mostly run 60. My Ultrashift shifts better if not rushed. 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
KWT660HDT Posted September 4, 2018 Report Share Posted September 4, 2018 I’ve had the paccar mx-13 derated by 25% for an electrical problem with my DEF level gauge and my fuel economy was noticeably better Mine is 485hp so I was derated near 365 hp and it didn’t make a huge difference pulling a 20k fiver on level ground. Hill climbs were a whole other story It got me thinking it would be pretty sweet to have control over the max power output like you can on diesel pickup tuners but there’s no such doohickey for big rigs as far as I can tell I would set mine to 100% power for the hills and about 400hp for everything else 2013 KW T660 485HP, 18 speed & locking tandems 2015 XLR 45' Toy-hauler Link to comment Share on other sites More sharing options...
noteven Posted September 5, 2018 Report Share Posted September 5, 2018 KWT660 - are you sure?! I mean we had many people make the statement “ upped my ISX to 875hp uses waaay less fuel...” Offered to buy lunch if they would stop by with before and after detailed fuel records... I, ahem, have no detailed fuel records to share yet... Your mileage may vary .... "Are we there yet?" asked no motorcycle rider, ever. Link to comment Share on other sites More sharing options...
KWT660HDT Posted September 6, 2018 Report Share Posted September 6, 2018 lol yeah I'm sure man after nearly 40,000 miles at 7 mpg it's hard to miss the 10-15% improvement I got when I was derated in my case at full power it's nearly impossible to keep the torque gauge under 100% when I'm climbing hills or starting from a stop...could be an issue with foot weight or patience but I didn't get an HDT to save on fuel it still amazes me that I can get roughly the same fuel economy towing with the KW as I can with a ram cummins dually even though I drive the KW pretty HARD 2013 KW T660 485HP, 18 speed & locking tandems 2015 XLR 45' Toy-hauler Link to comment Share on other sites More sharing options...
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