Home Forums Gear Hunting Trucks and Four-Wheel Drives What kind of MPG will a 3/4 ton 4 x 4 diesel get

Post deleted by Stetson

LOL, Geee I feel so inadequite. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> Aren't you right back where we started? Run a chip sink more money in your truck. hmmmm. Your a modest one aren't ya. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> Here's one of your posts helping another guy out.


"Let's see, my truck makes more power than yours, is quicker than yours, faster than yours, gets better gas mileage then yours, has more ground clearance than yours, handles better than yours, rides better than yours, and and won't wear out its shocks in 11,000 miles." <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />

Thats the "better" guys huh? I'm glad I'm not one. Were all diesel fanatics but we all dont have to agree or get from A to B the same way. If we did you wouldn't be able to shout how great you are because you have a faster truck. Now wouldn't that be boring for you?


Badger, Thanks for the reply but you really didn't answer my question. Why is peak HP on a diesel at the lower end of the power curve if others claim peak HP can only be achieved with the richest fuel mixture or the pedal all the way to the floor? I thought you are advertising as a tech or a garage so I was hopping you might explain this for me. I would really like to understand this concept better.

While we are at it can someone explain why a considerable number if not the majority of guys at the DP feel there is no MPG gain with a chip?
If the chip causes no harm why do you have to take it off before you go in for factory service?

Stetson,

The post to Steve you are taking out of context was made as a "teasing" defense to Steve's comment about about aftermarket mods being "weird mumbo-jumbo." You failed to add the part of my post that put the humor and explanation into it.

Here is the missing part:

[quote]Somehow, I just cannot see that type of "weird mumbo-jumbo" as not being practical. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />[quote]


There are three of us here--with experience with aftermarket performance enhancements on modern diesels--that have found things are different than what you are saying. To that end I suggest you take your own excellent advice: "we all don't have to agree or get from A to B the same way". That sir, was well said!

However, just becasue I am happy to let you do what you want, and just because I have ZERO ill-will toward you, don't think I am going to stop arguing this stuff with you. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

LOL, If you did that really wouldn't be much fun. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> There is no ill will here towards anyone here. If we weren't talking about chips it would be Chevy Vs Ford. That's part of the fun. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
In the end it seems to boil down to common sense on the users part. For those of us really not concearned in any way about speed but who tow then my understanding is that a mild chip can be beneficial. Since we began the conversation with fuel economy I will go back and simply say it seems to me that the majority on the Diesel place feel there is no fuel economy gain with a chip.

OK,

I'll give it a shot <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />

As stated in my earlier post, the burn rate of diesel is much slower than gasoline, which limits the efficient rpm range of a diesel engine. Note that this is not the same as maximum attainable rpm. There are many variables to consider such as drive pressure from the turbo (the effective volume of compressed intake air at acceptable temps. As boost increases, so does air temperature which decreases efficiency, which is why the performance guys will use bigger, more efficient dual turbo setups and bigger intercoolers to flow more air at lower temps).
Your assumption that diesel engines don't make max hp at max rpm is not always the case, however. My Cummins , not Cummings <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> develops max hp (stock) at 2900 RPM, with a redline of 3200 rpm. Peak torque occurs at 1400 rpm & remains constant to almost 3000 rpm. Most gas engines make peak horsepower short of their redlines too. Camshaft design, fueling curves, forced or natural aspiration, and cylinder displacement, as well as type of fuel used all have a huge impact on an engine's horsepower and torque curves.
My command of the English language is not the greatest so I hope this has been of some value.............
badger

Yes thank you. Its easy to form an opinion and then later find out you were only partially correct. I'm more interested in discussion and learning than being right. Its easy for a lot of us to all the the same thing a different way. I'm no writer and as you noticed I mispwell often. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> This conversation reminds me of one of our wives saying lets paint the garage blue. If all of us were standing in the garage we would likely all think of some different shade of blue and yet all of those colors would indeed still be blue.
Am I incorrect in thinking that the air fuel ratio at 2900 on your truck is leaner then at 3200 rpms? If not would someone please explain that for me. Is it just that past 2900 rpms your engine is no longer running as efficient and even though the mixture is richer at 3200 your engine does not utilize all of the potential energy and the exhaust contains more unburned fuel?

Unlike gas engines that need to run fairly close to the ideal stoichometric (sp?) ratio, diesel air/fuel ratio varies wildly depending on boost pressure, engine load and rpms. I honestly don't think there is a "set in stone" answer to that question, neither is it as critical to a diesel. Gas engines will detonate & self destruct if too lean (especially forced induction engines), & lose power & destroy cat. convertors if too rich. Diesels will slow down if "too lean". Bad things can happen, however, if you give a diesel too much fuel. Melted pistons, blown head gaskets, rod failures etc. It is possible to kill the combustion flame with too much fuel too <img src="/ubbthreads/images/graemlins/blush.gif" alt="" /> <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />. I've seen photos of blocks broken in half lengthwise using too much boost & fuel.

Photos here
http://www.ls1tech.com/forums/showthread.php?t=420925

badger

That dude in the third photo down don't look too hapy. Thats what he gets for running a corn binder and not a JD. <img src="/ubbthreads/images/graemlins/smirk.gif" alt="" />
I went to a tractor pull for the first time last year. Very cool but if you think Daytona is loud you better take ear plugs when you go. <img src="/ubbthreads/images/graemlins/shocked.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

What difference does fuel mileage make these days, just fill her up, it will only cost more tomorrow. If you can't afford it buy a bike.

I think people are surprised to find a modern 4x4 diesel gets at least as good of mileage as a 1/2 ton gasser, but has substantially more hauling/towing capacity and is much more durable. Add the power chips and then the diesels out run the 1/2 tons as well.

At least I was surprised to learn that, as well as surprised as to how much more these new diesels cost vs a gasser.......................

I was suprised. I never would have thought that I could get a bigger truck and get better fuel economy. I think the best I have ever done with a half ton gasser is 16 average. My wifes 1/2 ton hemi gets 14 pretty much all the time.

The fact I can get a 3/4 ton 4X4 that will get the same mileage as my 3 liter toytat 4X4 is a big deal, especially when it comes to pulling my boat, and getting better mileage under load!

Now if I can just find the right early 2000's 2500 crew cab ram w/ cummins and manually tranny for ~$20k w/ ~50k miles, I'll be a happy camper indeed <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

My 4 cyl Nissan PU only gets about 19-21 on the Hwy.

I wasnt, but I grew up with a diesel pu in the family. When Dad bought his first one in '87 everybody told him it was a mistake. Now most of those guys drive a diesel.

I think one other important thing with milage is that a diesel may get the same milage as a half ton gasser, but the milage when towing a load is way way better. I just went on a fishing trip with a guide that tows a boat every day with a new f150 gasser. 8mpg towing. I know I get at least 11 towing a MUCH heavier trailer and thats with an older non-turbo indirect injection diesel. Gas doesnt even compare for load hauling.

The one thing I hear a lot about is diesels are too expensive to work on. Mines got 180k, dads old one had 280k, nothing was ever needed on either except an injection pump, glow plugs and glowplug relay/controller. Thats pretty cheap cost per mile.

I just wish diesel was still cheaper than gas like when I bought mine. Price gougeing pisses me off. Some stations dont know what to charge, locally there is a 25cents per gallon difference in price depending on what station you go to when gas is all pretty much the same price. bastards.

lat month over a 400 miles trip from Prescott AZ to So Cal we averaged 26.2 MPG In a 2005 Dodge CTD.

Michael

My 01 F350 crew 7.3 PS A/T probably gets around 15-ish with short trips/town driving. I've got 20-21 with no load & minimal stopping at decent speeds (sweet spot seems to be around 62 mpg which is just slow enough to keep me out of trouble in the 55mph areas) <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Pulling a 2 horse trailer out to Colorado last fall loaded for elk hunting I got 14-15 mph running pretty fast on interstate. Dad started out pulling the trailer with his new cummins A/T 3/4 ton but he was getting horrible mileage when pulling the trailer so we tied the trailer to my truck. I dropped from an average of around 18mph on that trip to my 14-15 & when he unhooked he jumped from about 8 pmg up to 18 rolling free.

and yes I have a tuner & a little oversized tires. superchips micro tuner & 285's (no real big mods as far as the tuner & tires are just slightly larger than stock)