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Reader's Letters June 2014 - Letters To The Editor

Postal Route: Our Readers Write Back

Diesel Power Staff
May 29, 2014
Reader Injections
I just read Sean Holman’s editorial in the March 2014 issue. His plan of a diesel in a late-’60s Ford is great. I’ve wanted to do that with my 1966 F-100. I’m thinking of a 6.0L like I have in my 2004 F-250 4x4. That would be fun.
Nicholas J. McCausland
via email
I just wanted to let you know your article “Car Guy Stuff” was spot on. I found myself laughing because everything you wrote was true. On an unrelated note, what if you put VM Motori’s 3.0L into a CJ or something similar? I know a lot of people are waiting for a Wrangler diesel.
Matt Petersen
via email

Photo 2/5   |   2014 Ram 1500 Ecodiesel And Ram 2500
I just read your article on the new Ram 1500 and 2500 diesels. I have a 2012 2500, and the mileage I see isn’t anywhere near what you saw in the 2014. Was something changed to affect it? What can I do to get better mileage?? My truck is completely stock, and I see approximately 15 mpg on the highway and 11 mpg towing.
Steven Keedy
via email
There have been many minor changes to improve efficiency of the 6.7L over the past couple of years, probably the most effective being the introduction of SCR/DEF for 2013, which certainly improves fuel economy.

Manual Toughness
I love stick shifts and am sad to see them fall by the wayside. However, the increased power of diesel engines backed by automatics over the manual transmission makes the autos very attractive, and that’s where I am confused. In your October 2013 article, “Don’t Do This: Top 10 Competitive Mistakes of DPC,” you stated “...the manual transmissions that come behind modern diesel engines are extremely stout and can handle absurd amounts of power compared to their automatic counterparts…”. So why does Ram (the only manufacturer still offering a manual transmission) de-tune the Cummins paired with the manual by 150 to 200 lb-ft of torque compared to the Cummins paired with the 68RFE or A69RC? The answer won’t change a thing, but the question has eaten at me for a long time. Who wouldn’t love an 850-lb-ft Cummins with a six-speed manual?
Chris K
Suisun City, California
According to Ram, the manual transmissions are limited by the manufacturer’s torque rating of the transmission, although we have seen that tranny survive at higher power levels with the proper clutch and driving techniques.
Ram Air
I have a question on this month’s article on the Ram 1500. When you scaled it towing the trailer, were you over the vehicle GVWR or gross axle rating? The reason I ask, is I want to know what happens with the air suspension if you are over GVW or axle rating.
Matthew Mello
via email
When towing a trailer, it is the gross combined weight rating (GCWR) that is relevant. This number is the total allowable weight of the truck, occupants, cargo, and trailer combined. For our test, we exceeded the truck’s GCWR by only 5 percent, a negligible margin. The truck’s air suspension had no issue compensating for the trailer’s tongue weight, and while the air suspension will attempt to level the truck no matter the load, it is never advisable to exceed the manufacturer’s GVW or gross axle weight rating (GAWR).
Photo 3/5   |   Diesel Power March 2014 Cover
Letter of the Month
I am a Diesel Power subscriber, and I’m currently in the market for a new Ram 3500 Crew Cab longbed dualie with the available H.O. Cummins and Aisin transmission. My differential gear ratio options are 3.42, 3.73, or 4.10. While I know the amount of weight each gear ratio allows me to safely tow (the range is from 21,000 to 29,000 pounds), I can’t find any reliable information about the mpg differences between the ratios while cruising down the highway empty, meaning no trailer and nothing in the bed. I only tow a few weekends a month, so the truck is not always loaded. While it would be nice to know, I am not looking for the actual mpg ratings. I just want to know if there is almost no difference, only a 1 mpg difference, or perhaps as much as 5 mpg difference between 3.42s and 4.10s while cruising down the highway at 65 to 70 mpg on cruise control. I’d also like to know if 3.73 splits the difference evenly or not. Do you know the real-world answer?
Some people say the 3.42s provide much better mileage, while others say that with modern computer-controlled fuel management, 4.10s can give you close to the same mpg since the engine is not working hard in the higher rpm range to pull you down the road. They can’t both be right. Also, some people say that in-town driving with 4.10s provides better mileage than 3.42s because you are not pushing on the throttle as much as you accelerate from light to light. Is that true?
Has your magazine staff ever tested identical trucks except for the differential ratios? If not, I would love to see this test performed. I am willing to give up 1 or 2 mpg driving empty to be able to tow a lot more than the 21,000 pounds the 3.42 gears are rated for, but I am not willing to give up say 5 or 7 mpg while empty to be able to tow 29,000 pounds a few times in my life.
Tim Vickrey
via email
A lot of it depends on how fast you drive, as 4.10s at 70 mph is going to turn more engine rpm than 3.42s at the same speed. If you’re on the highway a lot, it is more justifiable to do the lower gearset. However, there are so many configurations of the Heavy Duty, there isn’t a clear-cut answer to the fuel economy spread between the lower and higher gearsets. We contacted our friends at Ram Trucks to get an official response and were told that Ram recommends all of the company’s customers choose a gear ratio based on the max loads the customer intends to tow. As our Letter of the Month, Tim will receive a $100 gift certificate from aftermarket parts specialist Auto Anything (www.autoanything.com).
Photo 4/5   |   Jeep Liberty Engine
Belt Time
I love your magazine and really enjoyed your pursuit of 200,000 miles CRD timing belt article. That article was timely, as I just purchased a Liberty with 113,000 miles with the assumption that the belt was not replaced at 100,000 miles. The parts list helped immensely, and now I have the tools and parts ordered. I only somewhat enjoy the large horsepower articles, but really enjoy the articles on the smaller diesels that most of us use in our everyday lives. I’m always in search of tips on improved mpg and longer life for our vehicles, such as my 1980 IH Scout 2 with the Nissan diesel, 1984 Ford truck with a 8.2L Detroit Diesel, 2006 Jeep Liberty with the 2.8L CRD, and early 2007 Dodge 2500HD with 24-valve 5.9L diesel. Keep up the good work!
Ray Russell
Bottineau, North Dakota

VP44 Love
I have been reading Diesel Power and most of the diesel magazines out there since I bought my 1999 Dodge Ram 2500 4x4 shortbed extended cab five-speed three years ago. Other than the fifth-gear nut backing off (which I fixed with this sweet, locking-splines nut) and my pilot bearing going out and locking my clutch up, I have had no problems and love the truck.
I like your mag and know you got a letter three or four months ago from someone who feels the same as I do about the lack of respect from all the mags and manufacturers showcasing parts for our trucks. I don’t get it, most of us have paid off our trucks and have long ago passed the warranty period (I just passed 200,000 miles) and have money to spend. It would be nice to see some more builds on VP44 trucks.
I for one have been saving for the dreaded fuel pump replacement and would like to see some ink on pump and injectors, head studs, tuners, turbos, the dowel pin fix, and tweaks to make dyno pulls. It would also be nice if Titan would make a tank for us in the spare tire spot. I have my 150-gph AirDog on order and am looking for an exhaust system right now, as mine is rusting off the hangers. I plan on installing a Gear Vendors overdrive, as I drive my truck every day. I work and put a lot of miles on it, and every little bit of extra mpg helps these days. So come on guys, we love our trucks and want good parts and write-ups on our trucks, too.
Mike Allison
Renton, Washington

7.3L Injector Info
I just read that on the 7.3L Power Strokes you have to replace the injectors every 100,000 to 150,000 miles no matter the year. Is that true? My husband loves the 7.3L and is looking into buying one, but I don’t want to spend the money on a truck that is going to need parts replaced constantly. Thanks for any information you can share. It’ll definitely help me out.
Lauren Mauriello
via email
While some injectors may need to be overhauled or replaced at 100,000 to 150,000 miles, not all do. In fact, we would say most don’t. Since you bring up the 7.3L, we’ll start there. These injectors are known to last 200,000 miles before poppet valve wear (the poppet valve is what allows high-pressure oil to enter the injector) decreases performance and starting ability so much that it can no longer be ignored. This is pretty good considering how many components go into an HEUI system fuel injector (what the 7.3L Power Stroke uses). Although many 7.3L injectors last much longer than that, 200,000 is a good general rule of thumb to live by. A good maintenance regimen consisting of oil changes every 3,000 miles will keep the injectors in tiptop shape for a long, long time. Reliability and the 7.3L go hand in hand, so we wouldn’t worry for a second about picking one up and relying on it for years to come.
Damn Dirty Liars
I’m a longtime subscriber and love the mag with one exception... While I realize you can’t investigate every claim regarding the trucks featured in your Readers’ Diesels column, maybe you could dispense with the outlandish fuel economy claims of some readers. Are we really supposed to believe that a GMC 2500 4x4 lifted with big tires is getting better than 25 mpg?!? Did that happen to be while rolling down a hill in neutral? With the engine off?
Brian Higgins
Long Island, New York

Photo 5/5   |   Caterpillar D11T
I enjoy getting your magazine in the mail and have been a subscriber for a few years now. I work on heavy equipment for the local dealer out here in Arizona, and I received your March 2014 edition and noticed the Cat D11T and was excited -- only to be dumbfounded when I heard your description of the fuel system and turbo on the C32 that is used in that application.
First off, it is an MEUI injector with two solenoids internally; one controls the spill port and one controls the pilot pressure behind the poppet at the tip of the injector. This enables the injector to have three different injection types: a square wave, a ramp-up, and a pre-injection. There are no external high-pressure lines of any sort, meaning it is not a common-rail.
Cat uses common-rails on the Tier 4 engines from 9.0L and down, and on the behemoth C175 4,000-plus-hp V-20. Secondly, the coolest part about the engine is the turbos. You stated it uses a single, fixed-geometry unit. That is horribly inaccurate, as it is a twin-turbo setup. One bank of the V uses one turbo, and the other bank uses the other turbo. Yes, it is fixed-geometry, and yes it’s not variable nozzle like a Holset, but it is a Cat-branded next-generation turbo, which is so simple it’s beautiful. The turbine housing has two scrolls, one is big and one is small. The turbine has a unique shape where the small scroll lines up with a portion of the fins on the turbine, transmitting the exhaust pressure most efficiently to the turbine. This has a huge impact on the shaft speed and boost level, as the scroll is larger and exhaust is directed to the outside (farther out on the turbine), and therefore has less effect on the turbine. A simple bypass valve that looks like a wastegate controls how much of the exhaust goes through the small scroll, making the turbo able to replicate what a VNT or VGT turbo does with only one moving part, which is genius.
Although it looks like a single exhaust manifold, there are actually two (for cylinders 1, 2, and 3, and 4, 5, and 6 on the inline-six). The front manifold feeds the EGR cooler and is directed into the small scroll of the turbo. The rear feeds the large scroll, and when boost is achieved, EGR can be ingested. The ECM controls a little PWM solenoid, which diverts some of the flow from cylinders 1, 2, and 3 to the large scroll when boost pressure is met.
Keep up the good work, and hopefully someday soon the EPA will quit trying to destroy the force that moves the world, Diesel Power.
Nathan Smith
Maricopa, Arizona
We goofed on this one. Caterpillar’s literature regarding its C32 ACERT’s injection system steered us into mistakenly calling it a common-rail. The C32 ACERT uses its new MEUI-C system, which is capable of 30,000 psi of injection pressure and multiple injection events per cycle but still retains the unit injector architecture.



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