Will RV275s Help My Towing Mileage?

[jumpjg]

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!)

[RPM]

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.

[Mopar1973Man]

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

[dripley]

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.

[JOHNFAK]

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

[nrfd208]

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??

[Mopar1973Man]

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

[JOHNFAK]

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

[MnTom]

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......

[JOHNFAK]

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

[MnTom]

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.

[Reg02]

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?

[JOHNFAK]

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

[Reg02]

cool thanks!

[JOHNFAK]

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

[drag racer]

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

[2500ctd]

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.

[Mopar1973Man]

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.

[Rogan]

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

[AH64ID]

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.