jpeto4755 Report post Posted September 26, 2020 I have a 2008 Fleetwood Bounder 38V (gvw 31k) with a 6.7 ISB motor that has the particulate filter but doesn't use DEF. What I want is more torque for the mountains here in Arizona as I have a 4100 lb toad. Have been considering a Bully Dog RV & Medium Duty Gauge Tuner (MDGT) for Cummins 2008-2018 6.7L ISB 46502 and would like to know if anyone has experience with this unit. If you have another brand please write on that. Thanks. Share this post Link to post Share on other sites
wildebill308 Report post Posted September 26, 2020 Welcome to the forum. I have done nearly all the up grades when I had a 5.9 Cummins in my 2003 38N towing a Honda CR-V. Do not do any modes without first installing a good Exhaust Gas Temperature monitoring system. I generally ran Banks products. I had the diesel tuner and the water methanol systems installed. I had the Bankes IQ to monitor what was happening. I think you can spend a bunch of money and be quite disappointed in the results. I ended up leaving it on the economy setting that may have helped a little. All that and some more can be taken away with a light head wind. What you do need is the EGT gauge and learn to drive a big rig without lugging it and having high EGT temperatures. I have been over every major pass in the lower 48 and never had a problem getting over them. Well ok the traffic has slowed me to a slow speed more times than the hill. Bill Share this post Link to post Share on other sites
f442485 Report post Posted September 27, 2020 I have installed a few Diablo's on a few customers rigs. My suggestion is don't waste your money. Your hp and torque gain is minimal at best. If you do decide to try a programmer, DON'T put it on the performance setting unless you have deep pockets. Make sure you install a EGT gauge before you do anything. Just my opinion. Share this post Link to post Share on other sites
rsbilledwards Report post Posted September 27, 2020 Buy a coach with a bigger power plant than a 6 liter engine and agree with the foregoing two. There is no substitute for cubic inches especially in a diesel! Share this post Link to post Share on other sites
rayin Report post Posted September 28, 2020 X 4 for the exhaust temperature gauge pre-turbo; melted valves are expensive. When you are pushing a 12' x 8' wall at speed there is no substitute for CI. As a buddy put it, "you can't soup-up a boxcar." Share this post Link to post Share on other sites
jpeto4755 Report post Posted September 28, 2020 In doing more inquiries on this ECM programming I have contacted a Freightliner franchises which has a location one in Tucson and another in Phoenix area. Tucson said they would reflash for about one hour labor ($155) and the service manager in Phoenix said he would not do it because of problems they had. Contacted Cummins Rocky Mountain in Tucson and was told that if I bring it in they will check to see and if not already done will charge $299 which is about double what Freightliner would charge.(No charge if already done) Seems like a safer alternative to Bullydog but I don't know how much of a change this would make unless someone has configuration similar to my coach and has done this. With Bullydog you get a monitor which makes it easier to see readouts versus little scrolling menu in dash which is hard to operate while your driving. Of course I can get separate gauges but I don't know how to hook them up. Life is chock full of mysteries, eh? Share this post Link to post Share on other sites
jleamont Report post Posted September 28, 2020 What is your current horsepower and torque ratings now and what transmission do you have? Share this post Link to post Share on other sites
rsbilledwards Report post Posted September 29, 2020 Hate to discourage you but the real mystery will be what it does to your wallet down the road. Fun for a while till you over do it and it will happen...it is intoxicating for sure... Share this post Link to post Share on other sites
jpeto4755 Report post Posted September 29, 2020 Not sure about the horsepower and torque. The engine was built in July 2007 and I don't have any more info The transmission is Allison 3000. Share this post Link to post Share on other sites
jleamont Report post Posted September 29, 2020 7 hours ago, jpeto4755 said: Not sure about the horsepower and torque The reason I ask, there is a very good chance its already maxed out for what Cummins can do. In the RV industry they have a tendency to take the smallest of engines and set the HP and torque to its limits in the medium duty world, often times you will see they cross over into the next engine's class in the truck world. Said another way, I have ISB's at work rated to 325 hp, I also have ISL's rated to 325 HP. The ISB will only have another 5 hp of wiggle room while the ISL has 125 HP of wiggle room on a factory reprogram. If you knew what it is now we might be able to save you a few dollars and time going to the Cummins dealer for them to charge you $200 and tell you its maxed out already. At least the transmission should be able to sustain more power. I am surprised it has the Allison 3000 series, most ISB's run the 2500, with that being said I suspect its maxed out in HP and Torque thus the reason for the larger transmission. Share this post Link to post Share on other sites
fagnaml Report post Posted September 29, 2020 jpeto -- Welcome to the forum! There are many good forum members willing to provide help anytime! What is the current HP rating for your 6.7L ISB? Reason for asking, is I have a 6.7L ISB (2017 version) coupled to an Allison 3000 transmission in my Ventana LE that is rated at 360 HP which per Cummins is the the high end of the ISB engine --> https://www.cummins.com/engines/b67-2017 The Cummins website shows that 400 HP can be obtained from the ISB engine but different, higher rating parts and pieces are needed --> https://www.cummins.com/engines/cummins-67l-turbo-diesel-2019 Thus far I've been pleased with the performance of my engine while towing a Jeep Wrangler in the Texas Hill Country which has some reasonably steep hills in the lakes area of the Hill Country. Those hills however are not the long climbs in your part of the country. Share this post Link to post Share on other sites
jpeto4755 Report post Posted September 29, 2020 This has the ISB for sure but in order to determine more info I would need to get the engine serial # and then look it up with Cummins. Unfortunately I won't be able to get that for at least a week as I am 200 miles away and won't be back for at least a week. Thank you for following up on this and I will post again as soon as I have the info. If anyone has used the Bullydog medium duty programmer please feel free to comment. Share this post Link to post Share on other sites
jpeto4755 Report post Posted September 29, 2020 Thanks for the link. It seems that the newest 400 hp version is meant for pickup. Heavier vehicles seem to have lower hp ratings on a particular engine probably because of heat, etc issues. Famous quote: People buy horsepower and then drive torque\ on heavy vehicles. Share this post Link to post Share on other sites
wildebill308 Report post Posted September 30, 2020 (edited) Something to be aware of the Cummins engine in RVs is not the same as used in Dodge trucks. Things like oil filters don't cross fit. Bill Edited September 30, 2020 by WILDEBILL308 Share this post Link to post Share on other sites
jpeto4755 Report post Posted October 28, 2020 Update on my quest for more power. Took RV to Cummins and they said after computer hookup that they could increase the horsepower by 25 hp but that there would not be any gain in torque. If they would have done this the charge would be $285 however they said that it in conclusion they would be glad to do it but I probably wouldn't make a difference that I would notice. So I thanked them for their time and wheeled away. Should I have done this anyways? EGT probe & gauge seems like something I might want to do. Share this post Link to post Share on other sites
manholt Report post Posted October 28, 2020 You can upgrade the Torque on a Allison 3000 to 1750 ft. lbs, but it won't do any good, unless you have the ISM engine. Share this post Link to post Share on other sites
rayin Report post Posted October 28, 2020 (edited) Actully there is very little that can be done to increase torque and HP without severely shortening the original lifespan of the engine. The Cummins reply said it all. Allison RV transmission specs. Edited October 28, 2020 by rayin Share this post Link to post Share on other sites
aob Report post Posted January 7, 2021 (edited) I did the banks ecominder w/Data monster for a claimed +55hp +110LBFt on my 340hp (stock) Cummins isb 6.7 powered 08 Winnebago Destination and I couldn't be happier. Made a huge improvement in drivability, performance, and fuel economy. Hills like the grapevine that would drop me to ~48mph lightly loaded I now do at 60+. My worst observed EGT now is 1248F, after flogging it max power up a hill continuously it peaked there then settled down. Returning from a cross country trip now I've picked up about 1.5 mpg average post tune and I'm not light on the throttle. I usually do 5-10 over. As for reliability it remains to be seen, no observed increase in trans temps so I'm not terribly worried there. I usually set the trans in eco, the tuner at 2-3(out of 6), and leave it in cruise until there's traffic. Imho the biggest reliability threat isn't the tuner or the trans, it's the turbo and the lack of a lift pump. I plan on addressing both. The EGR puking grime and sludge onto the compressor wheel is bad design. That VGT Holset turbo just won't last, stock or not in the factory configuration. I'm looking into options for that. I plan on adding a FASS lift pump and filtration to help out the CP3. If anyone knows of an EGR solution for the medium duty 6.7 I'd love to know more. I know the SA engine tune has a lower EGR duty cycle, that probably helps some. There are tons of performance and reliability upgrades available for the 6.7 isb unfortunately for us a lot of them are built around the FCA ecm. That said the cummins ecu is tunable; TS Performance does modify them.. Everytime pulling away from a stop now I just smile with the tuner set to 6 she really gets up and goes at city traffic speeds, at least for a big bus she has some moves now. Edited January 7, 2021 by aob Share this post Link to post Share on other sites
