Diesel
 

I am looking to buy a full size pickup. I would like some advice on wether to go for a regulas gas engine or diesel?
I've been looking at the Chevy 2500 model.


Andy S.
Vero Beach, FL.

I can't speak for Chevy, but my ford diesel has been a huge disappointment, mileage-wise. My 5.0 gas V8 (Chevy) and 4.3 gas V6 (GMC) got better mileage than the 6.0 diesel (Ford). Chevy's 6.6 liter diesel probably gets worse mileage than the Ford 6.0.

Save your money and buy a gas powered truck with a V6 or small V8.

Back in the mid 80's I talked to someone with a Chevy diesel. I think it was a 1500 series. He got 35mpg at 55mph with no load.

Yup, the old diesels were good on fuel economy. Then the horsepower race started. Every production diesel truck is turbocharged and intercooled, AN you can't get a fuel economy axle. The tallest axle offered by the big three is 3.73. Is this progress????

I was considering a ring and pinion swap for my F350 to say, the 3.23, a 3.42, or a 3.55, but you can't buy one, even from the aftermarket.

Do all the new trucks have overdrive? The old trucks didn't? In my opinion the newer ones are detuned. They can still tune them to get better FE and still pass emissions. I've talked to engine tuners, they can tune for better FE but they make the final decision

Yup, all of them have overdrive, usually about .7 ratio. but it's not enough to keep the RPMs down. My engine is still spinning 1900 RPM at 70 mph.

The truck really doesn't need such a short 3.73 ratio. It has a 5 speed automatic that would give plenty of off-the-line power with a 3.23. you have to wonder why they don't even OFFER an economy axle. You can buy a 4.11 for better towing, but no shorter ratio than 3.73.

They make afterket FE chips for truck, but I'm afraid to put one in for fear of voiding my warranty.

1900rpm at 70mph is nothing, are you sure you don't mean 2900rpm?

edit: forgot, diesels rev lower, huh?

Yup, redline on direct injection diesels is usually about 4000 rpm. Turbodiesel make gobs of low end torque, so 1500 rpm at 70 mph would be right in its power band.

I've been looking for a full size truck too, to replace my fuel-swilling 79 F250. I don't use it that much, but enough that it would pay to get a truck with decent mileage. I'm thinking of an early 90's chevy 1500 WT, or maybe a manual Ford inline 6 (less mpg though). I'm still not sure if a 1/2 ton would cut the mustard, but they did improve them a lot in the 90's.

Diesels have a couple advantages: they work well at high altitude, and they get better mpg at high loads (big trailer, lead foot). They also have higher resale than gassers, but routine maintainance is more expensive. The other advantages of long life and generally high mileage don't really apply anymore, due to the horsepower race. The first round of direct-injection turbos were probably the peak: the 12-valve Cummins dodges, the 6.5 chevys, and the 7.3 fords.

BTW, you can try https://www.ringpinion.com/ for gears. I don't know what sort of axle that has, but for example they have a 3.08 for the 10.25" ford.

I just bought a new 2006 chevy 3500 Silverado crew cab 4wd dually last week. It has the Duramax 6.6 deisel linked with the allison 6 speed auto transmission and a 3.73 rear end. The day I pulled off the lot it averaged about 11 mpg. After freakin/wiggin out for a day, I went to a deisel forum and found out that most Duramax's start out with poor mileage and get significantly better mpg after about a 5000 mile break in period. Sometines it takes longer. Most of the guys stated somewhere around 20 mpg (hwy) for the Duramax/Allison 6 speed combo after break in. I am now at 1500 miles and my mpg has increased to 17.5. I expect more after 4,000 more miles of driving. In addition, I just ordered twin hydrogen fuel cells ($675 each)that claim a guaranteed 31%+ mpg increase. I hope to get to 30 mpg with that and a couple of other mods.
That having been said...I love this truck. Way powerful, very quiet, and very smooth. GO WITH THE DURAMAX DEISEL! There really isn't a better deisel out there right now. Do your homework, you'll see for yourself.

I'd like to see a link to these h2 fuel cells!

yes keep us to date on that Hydrogen storage improvement.

Updated F350 mileage: 19.1 mpg over mostly highway miles at ~60 mph. It's TORTURE driving that slowly in MA, you get dirty looks from drivers who were caught behind you.

My F350 has about 35K miles, so it's fully broken in, and the Eprom has been reflashed twice. No excuse for a diesel to have mileage that poor at such low speeds.

Duramax 6.6 mileage is probably worse, because it's bigger and has the same gearing. I should have bought a 5.9 liter Cummins. It's smaller than both Ford and Chevy, and it's a 6 instead of an 8.

I wonder why you can't buy a pickup with the 4.5 liter Powerstroke that Ford puts in its class 5 LCF trucks. I'd swap the 6.0 for the 4.5 if I could find someone to do it.

Yup, I've looked at ring/pinion swaps too, but it doesn't make sense. first is cost. Each axle is going to cost $7-800 installed, and I have a 4x4. Then there are speedo calibration issues. So it's less expensive for me to burn the extra gas, er diesel.

Finally, there's resale vale. With 3.08 gears, I'll never be able to sell the truck to a yahoo who wants to install 44" tires.

Finally, someone is going to DO it! A small, light duty diesel in a pickup truck!

25 mpg in a full size pickup will begin with this engine:

https://www.cummins.com/cmi/content.j...=true&menuId=4

I hate to say it but 19mpg for a 4x4 1 ton sounds pretty good to me. I've yet to drive the 6.0 but I driven every generation of the 7.3. My 95 2wd auto will get 20-22mpg under 62mph. I used a company 99 f250 auto 2wd extended cab and got 23.5 mpg. I used a company 00 f350 6 speed, dually 4x4 and never got over 14mpg(according to the mileage computer). My 91 dodge cummins reg cab, auto, 3.55s got 20mpg with a non lockup convertor. All these numbers are interstate mileage.

To put it simply there is no cheap way to push 4-5 tons around at 70mph. Also remember that most people who claim to get high mileage don't keep a fuel log. They can't tell you a lifetime average. They figure one tank that looks really good and thats what they brag about.

Of all the diesels I've driven/owned the the mechanical injection 12 valve dodge gets my vote. I tuned mine for performance and it only affected mileage when you let it. The first gen cummins was also as simple as dirt to work on. If you can keep the cheap dodge wrapper from rattling apart its a great truck.

On a side note my brother has a 95 gmc 1500 v6 5spd and gets 23+ mpg on the highway which I think is excellent.

Toyota already sells a diesel powered Hilux/Tacoma overseas, and I've read reviews where they get impressive mileage (~45mpg UK). I think this is more of a marketing move for Toyota because by pairing with an american manufacturer (Cummins) they won't incite as much hostility by introducing fuel efficient light pickups, and can also take advantage of Cummins knowledge of smog regs. Apparently, a diesel Hilux/Tacoma from Europe gets o.k. mileage when tested (similar to the difference between EPA diesel/real world diesel here).
Something else thats interesting is the 3.0L turbo diesel supposedly doesn't hurt mileage at all, just adds power/torque.

Aeromods are your friend.

Pickups have so much more room for improvement than cars, that they can have their drag coefficient cut in half with good aeromods. This would allow increases in highway fuel economy between 30-40%, making them not much different on the highway than a normal 27 mpg car.

An aeroshell alone will probably give a full size truck 3-5 extra highway mpg.

Phil Knox has done extensive mods on a smaller truck, and increased highway fuel economy by over 30%. What used to get 25 mpg highway now gets 32 mpg highway, from only aeromods.

Apply the same percentage increase to a 19 mpg highway full size diesel truck if similarly extensive aeromods are performed.

Just from the aeromods alone, you'd get a 5 mpg boost.

Add LRR tires, synthetic transmission oil, machine your brakes to correct any brake drag if it exists, adjust your alignment to 0 degrees camber/0 degrees toe, and you should be set for the upper 20s highway MPG.

Already tried a plywood tonneau cover, which is claimed to improve mileage by ~10%, and it did nothing on a long trip to Maine. A custom aero truck cap might help, but I can't find one on line. Unless I learn how to work with fiberglass and the wife allows me to set up a 'glass shop in the garage, an aero cap isn't in the picture.

The OEM tires are listed by Greenseal as LRR, and the brakes are fine, had them checked before I went.

I think the truck is just too damned big.

I've seen a plywood frame covered with sheets of plastic used as well. It won't look pretty, but it would get the job done.

You could prolly take a heat gun to some coroplast and get it done that way, :)

Bingo! How much does it weigh exactly. 4x4 f350 supercrew checked in at a gravel scale at 9700lbs

According to Edmunds.com it weighs 6162 pounds. I was surprised, I thought it was a shade under 5000 pounds. Three tons! Good Lord!

Sludgy what is your truck exactly. DRW, SRW, x-cab, supercab,etc. I may have my numbers incorrect on the weight of the truck? 6200lbs wet sounds optimistically light to me.

F350 diesel / automatic / 4x4 regular cab SRW.

yep 6200 sounds about right to me. That being the case I would think your mileage could be a bit better. Have you thought about WAI and straight pipe. Also how is your tire pressure.

The problem with bed covers is that they don't really clean up much because the drop from the cab to the bed has already seperated the airflow from the top/side. I'd go for underbody/rear wheel covers, a campershell, and maybe airtabs all around. A WAI will only hurt a diesel, but if you really wanted to, a post intercooler water injection system should help out with FE and power. If you can stand it, and had the cruise control at 60mph, try 55mph. You should see ~21-22mpg.

My '79 F250 crosses the scales at about 4600. That's really light these days... like a stripped half ton. With a few common accessories (like a bed-mounted diesel tank), the newer trucks tare over 8000.

I have a 2002 Chevy 2500 HD Silverado w/ the 6.6 duramax engine w/230k miles and I got 19.6MPG for my last fillup. Not bad for this 3/4 ton truck.
I think I can hit 20mpg if I got a tonneau cover.

Old thread I know but the nice thing about the old International diesels Ford used is you can pour just about anything in the fuel tanks that will burn.

A buddy of mine in Dallas siphons off oil from a waste oil recycling container and adds a gallon or so of E85 to it and pours that straight into the tank and then tops the tank off with a little diesel. He says it's a little harder to start since he is running 50-75% god knows what oil mix and it is winter but once you get going it runs great and is actually getting better mileage than straight diesel does.

Is this allowed in America? I'm sure not in Europe because of the taxes on the fuel.

Nobody has told him anything for it. The security guards where he gets it from don't care and he is actually doing a service since the company that owns that bin don't ever empty it and people keep pouring oil in it which makes it overflow into the storm drains.

We have taxes on fuel here too but if I'm not mistaken making your own fuel here is okay up to a certain amount, after that you have to start paying taxes.

Correct. Details vary from one state to the next but that's how it is pretty much everywhere. It would be almost impossible to enforce for small-time DIYers, far more expensive to enforce than the tax money, and they want to encourage renewable energy/etc.