Just got back from a 2-week Southern Tour towing a 28ft Wilderness 5th wheel camper. Truck data in my signature is current. Rig ran great but always in search of better fuel economy. Around town empty it will get ~18 mpg. On two occasions I've taken it on road trips (empty) to Dayton (400 miles flat terrain each way) & gotten a hair over 20 mpg (hand calculations) running 67 mph (2200 rpm). On this trip towing the 5th wheel (trailer wt ~ 8k lbs) on fairly flat interstate roads at ~ 60 mph (slightly under 2000 rpm) I got 13.0 mpg. This was on the first leg of the trip from St Louis to Kentucky - the whole tank was burned with trailer in tow on the interstate. Later fill-ups yielded better mileage but that was due to lots of driving in and around without the trailer. On the flats I'd see around 6-9 psi boost with EGTs running around 675 - 775. But in the hills around Chattanooga boost pressures would often climb to 24 psi and on long grades I'd see EGTs nearing 1000 f. I was controlling the speed manually at first but soon switched to cruise control because my leg got tired. Highest numbers I saw was 27 psi & 1075 f. I had the Juice set on 2x5 on the first leg but later switched to 4x5 to see if it made a difference - not noticeable in fuel econ but better pull in the hills with a slight increase in EGTs.Generally I'm happy with the performance -pulled like a Clydesdale & didn't loose speed except on the very steepest grades. I'm not too disappointed with the towing fuel economy either but 2 or 3 more MPG would have me smiling. Is there anything to be gained while towing from an injector swap?Thanks,Joe in St Louis (Go Cards!)

When I ran the 275's I did see better milage. If I recall it was about 1 to 2 MPG empty, and a bit better than stock under load. Some noticable power difference also. Overall I was happy with them.

My MPG's are good both ways empty (21-22 MPG) or towing (12-14 MPG).

I saw a gain from 18 to almost 20 empty on the highway running 70 to 75. It starts to drop off after that. Towing, I went from 9.8 to 11.4 on my last haul from Nahville tn thru St louis on the way to West Des Moines Ia. I did slow down a little and tried to keep at 65 mph and no faster. I am sure that helped also. I pull a 36' Cardinal that weighs in at 15k. The 275's are a very nice add on, especiallly considering the the cost and ease of instll. Very seldom do I have to down shift as long as the grade is 3% to 4% and I am seeing boost and egt numbers very similar to yours.

13mpg towing a fifth wheel is about as high as you will get on these trucks

Last time I towed my trailer from Idaho to California, I was pulling around 8k and I only lost about 2 MPG. No tuner, no injectors. The only changes from stock was a new VP (it died on vacation) and a FASS 150. I only get 17-18 on the freeway and 15-16 around town. Would the RV's help me out? Or would going bigger??

Slight increase is good but after about 75 HP there isn't much to gain anymore.

Timing box and injectors good for 2-3 mpg increase Personally thought Cpp injectors 75hp were better than rv275 for power and mileage

13mpg towing a fifth wheel is about as high as you will get on these trucks

I have seen 14+ mpg IF and that is a BIG if I keep the speed to less than 60 mph. Now I see 16+ mpg towing my fiver as long as I have propane......

I have seen 14+ mpg IF and that is a BIG if I keep the speed to less than 60 mph. Now I see 16+ mpg towing my fiver as long as I have propane......

Ive seen cummins 2nd gens do under 12 secs on youtube 99% of trucks on these sites wont see over 13 towing a large TT or 5th wheel, or anywhere near 12 secs Just trying to keep it realistic ....... theres always outliers when you generalize ....... I met a guy with a 3rd gen that swears he gets 18mpg towing his 12000 lb 5th wheel ........ do I believe him - no .... does he believe him ...... I think so I'd love to run propane ....... didn't like h20 ........but seems anything apart from large engine changes like Porting/Cam/Compression change or gearing isnt going to net anything over where I am now ....... that makes it worth it

Ive seen cummins 2nd gens do under 12 secs on youtube 99% of trucks on these sites wont see over 13 towing a large TT or 5th wheel, or anywhere near 12 secs Just trying to keep it realistic ....... theres always outliers when you generalize ....... I met a guy with a 3rd gen that swears he gets 18mpg towing his 12000 lb 5th wheel ........ do I believe him - no .... does he believe him ...... I think so I'd love to run propane ....... didn't like h20 ........but seems anything apart from large engine changes like Porting/Cam/Compression change or gearing isnt going to net anything over where I am now ....... that makes it worth it

I am keeping it realistic. I have not ported, polished, or anything else on my truck. Just injecting some propane into the intake I netted a 5 MPG gain across the board. I get 25.5 MPG at 65 mph running empty. Ask Stodg73 what he gets out of his.

seams like everyone gains a little mpg and quit happy with these rv275! what would I be looking at for price on a set and where is the best place to purchase?

seams like everyone gains a little mpg and quit happy with these rv275! what would I be looking at for price on a set and where is the best place to purchase?

Any of the vendors here are good ..... go to the vendor/wanted section and request a price - or PM them direct

cool thanks!

Some used ones for sale in the classifieds as well ;)

When I ran the 275's I did see better milage. If I recall it was about 1 to 2 MPG empty, and a bit better than stock under load. Some noticable power difference also. Overall I was happy with them.

x2. 275s with an Edge EZ are a sweet combination without getting too crazy

With the stock HY, smarty and the Rv's I had a great towing setup. As normal I wanted more, Swapped in my current turbo and a noticable difference in turbo spool. Not enough fuel for it, but still ran great. If you are going to upgrade the turbo go a bit bigger, maybe 100's.Worse mpg's I got with the RV's was 11mpg. Towing around 15K cargo trailer. 33' bumper pull, heading north on I-5 Had a head wind strong enough I couldn't pull in overdrive on flat land. Overall I recommend them.Best was just over 21 at 70mpg on flat land. It was 20mpg the tank before. I got about .5 from just adjusting my valves. Was at 160K ish.

Lowest ever recorded was 14.1 MPG (hand math) with the Rv275's and towing my RV which is roughly 7,500# and 31' foot long. But rarely driving over 60 MPH. Note: My ST tires are rated for only 65 MPH. I really don't want to have a blow out.

My highest ever records on this 3500 is 13.3. Lol. Empty and 60mph. Sent from my SPH-L710 using Tapatalk 2

There are 2 sides to consider on the injectors and mileage. If you run the same weight and speed as pre-injector it stands to reason you will see a mileage increase; however, if you use the added power of the injectors your mileage will probably decrease as you are now injecting more fuel.

I remember when I 1st started on this site Michael, you used to post about the order of mods we should do to our trucks that you recommend.

Would you please state those again, or any of the knowledge that you've gleaned along the way.

Thanks,

Dave

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Also do you have any of the pix that you are using now for the wall paper of your site. I want to check it out better, Truck & camp setup look Sweet!

Dave