My have things changed

We recently bought a newer truck and retired our 16-year-old truck. The old truck had 310 HP and 425 lbs. of torque. The new truck has 440 HP and 925 lbs of torque. I love every single HP and every single pound of torque. What a tremendous difference in ease of towing. I feel much more relaxed while driving down the road. Towing now is pure pleasure and easy in comparison. I liked the old truck, but now I'm in love.

E&J push'n wind wrote:

Turtle n Peeps wrote:

jaycocamprs wrote:

Turtle n Peeps wrote:

BenK wrote:
Gasoline has fewer BTU's per unit measure than diesel, so diesel will most always produce more power per gallon

Nope. Not the way it works Ben. Nitomethane is the most commonly used powerful motor fuel ever. Look up how many BTU's it has.

Yea but the nitro cars are burning close to 5 gallons of it, in a 1000 feet

Nope. Try 13 to 15 gallons/ run.

And that's my point. It has so little BTU's/gallon it take a lot of fuel to make a run.

Wow, everybody bit on that one! The subject was about gasoline and diesel right? Not methane, butane, propane, nitromethane, JP5, solid oxide (since we went down that road) or any other fuel. Nitromethane is just a bit off topic and not germane to the subject. It wasn't hard to understand what BenK stated, "Gasoline has fewer BTU's per unit measure than diesel (any dispute?), so diesel will most always produce more power per gallon." It can be added (than gasoline) for anyone that may have missed it or didn't understand that point. Forgive me if this comes across as "mean spirited" but this definitely took a left turn down the rabbit hole.

It's interesting that although diesel has a little ore BTUs per gallon it has about the same BTUs per pound as gasoline.

Turtle n Peeps wrote:

jaycocamprs wrote:

Turtle n Peeps wrote:

BenK wrote:
Gasoline has fewer BTU's per unit measure than diesel, so diesel will most always produce more power per gallon

Nope. Not the way it works Ben. Nitomethane is the most commonly used powerful motor fuel ever. Look up how many BTU's it has.

Yea but the nitro cars are burning close to 5 gallons of it, in a 1000 feet

Nope. Try 13 to 15 gallons/ run.

And that's my point. It has so little BTU's/gallon it take a lot of fuel to make a run.

Wow, everybody bit on that one! The subject was about gasoline and diesel right? Not methane, butane, propane, nitromethane, JP5, solid oxide (since we went down that road) or any other fuel. Nitromethane is just a bit off topic and not germane to the subject. It wasn't hard to understand what BenK stated, "Gasoline has fewer BTU's per unit measure than diesel (any dispute?), so diesel will most always produce more power per gallon." It can be added (than gasoline) for anyone that may have missed it or didn't understand that point. Forgive me if this comes across as "mean spirited" but this definitely took a left turn down the rabbit hole.

ShinerBock wrote:
Yep, must be a magic unicorn. Everyone one else including the engine manufacturers, must be wrong when they say that adding a turbo to a diesel increases it's efficiency 20% along with added power and a significant reduction in black smoke.

I agree that any reduction in black smoke means that more fuel was burned properly and converted to useful power. We have probably lost some efficiency over the years due to pollution control requirements so the gains from the turbo may not be as visible as the 20% that you mention though.

Do you have any information on the back pressure increase due to running a turbo, how much power that robs from the engine and how it balances with the power generated by feeding pressurized air into the engine? I would expect that feeding air into 6.7l engine at 32psi and 2700rpm would generate several horsepower compared with the slight vacuum encountered by a natural aspirated engine.

Yep, must be a magic unicorn. Everyone one else including the engine manufacturers, must be wrong when they say that adding a turbo to a diesel increases it's efficiency 20% along with added power and a significant reduction in black smoke.

ShinerBock wrote:

No it does not. Black smoke from a diesel is uburnt fuel(i.e. not enough air for the amount of fuel being added).

How to reduce black smoke in diesel engines

Older N/A diesels used to blow black smoke all the time because they did not have enough air to burn the amount of fuel being added. That changed with the introduction of turbochargers and they mainly only blow black smoke when the turbo is not spooled up or there is a fuel issue.

A leaner air fuel ratio with the same amount of fuel will create more power therefore less fuel is needed to create the same amount of power meaning it needs less fuel to do the same amount of work.

Must had a magic diesel then...unless accelerating hard or climbing a steep grade, no black smoke and we were towing at right around the trucks limits. Hard acceleration and grade climbing were a tiny percentage of miles, so really doesn't move the needle in terms of efficiency.

Or we simply were staying within the engines ratings and not pushing it outside it's design parameters.

Turtle n Peeps wrote:

jaycocamprs wrote:


Yea but the nitro cars are burning close to 5 gallons of it, in a 1000 feet

Nope. Try 13 to 15 gallons/ run.

And that's my point. It has so little BTU's/gallon it take a lot of fuel to make a run.

I'm not a racer, so I really don't know. I had assumed that the 13-15 gallon number was from the time they started the car. That would include the burn out and staging, and that 4/5 gallon number was the just the timed run.
One thing is sure. It's a lot of fuel, and there is lot going out the pipes.

valhalla360 wrote:

ShinerBock wrote:

Nope. You still seem to be confusing gas with diesels. What do you think the black smoke coming from diesels is? Un-burned fuel. Why? Because it does not have enough air to burn said fuel. This is why old N/A diesel blew puffs of black smoke just about all the time and turbo diesels blew a puff off the line until the turbo was pushing enough air to burn all the fuel being added which only took a second. Adding more air does improve efficiency in a diesel because it is able to use the fuel to more efficiently use the same amount of fuel to make more power instead of blowing it out as black smoke..


And I still don't believe your story. Not only, that, but none of the guys in this(LINK) 7.3L forum even say that 16 mpg is normal and if you look at fuelly.com here(LINK) it is even less than that.

Black smoke means you are pushing the engine outside of it's limits. For a couple seconds under hard acceleration, it's not harmful but if it's continuous as you are cruising down a level freeway, you are overloaded and that will kill efficiency in any engine type. Only difference with gas engines is the unburnt fuel isn't visible under similar conditions.

Believe what you like, it was pretty consistent over a long period of time.

No it does not. Black smoke from a diesel is uburnt fuel(i.e. not enough air for the amount of fuel being added).

How to reduce black smoke in diesel engines

Older N/A diesels used to blow black smoke all the time because they did not have enough air to burn the amount of fuel being added. That changed with the introduction of turbochargers and they mainly only blow black smoke when the turbo is not spooled up or there is a fuel issue.

A leaner air fuel ratio with the same amount of fuel will create more power therefore less fuel is needed to create the same amount of power meaning it needs less fuel to do the same amount of work.

ShinerBock wrote:

Nope. You still seem to be confusing gas with diesels. What do you think the black smoke coming from diesels is? Un-burned fuel. Why? Because it does not have enough air to burn said fuel. This is why old N/A diesel blew puffs of black smoke just about all the time and turbo diesels blew a puff off the line until the turbo was pushing enough air to burn all the fuel being added which only took a second. Adding more air does improve efficiency in a diesel because it is able to use the fuel to more efficiently use the same amount of fuel to make more power instead of blowing it out as black smoke..


And I still don't believe your story. Not only, that, but none of the guys in this(LINK) 7.3L forum even say that 16 mpg is normal and if you look at fuelly.com here(LINK) it is even less than that.

Black smoke means you are pushing the engine outside of it's limits. For a couple seconds under hard acceleration, it's not harmful but if it's continuous as you are cruising down a level freeway, you are overloaded and that will kill efficiency in any engine type. Only difference with gas engines is the unburnt fuel isn't visible under similar conditions.

Believe what you like, it was pretty consistent over a long period of time.

valhalla360 wrote:

ShinerBock wrote:

And you are confusing how a gas engine operates with a diesel. Two different things. Gas engines have to stay within a certain air/fuel ratio(roughly 14.7:1 +/-3 parts air) meaning the more air you add, the more fuel you must add. Turbos do slightly improve a gas engine's thermal efficiency

Diesels can operate at a much wider air/fuel ratio from as low as 14.5:1 all the way up to 80:1 or even 100:1 depending on the engine. An N/A diesel does not have the ability to run that lean because it cannot suck enough air for the fuel being added as with any engine that operating at low rpms. Adding a turbo allows the engine to increase the amount of air to the same parts fuel making more power with the same amount of fuel. Turbos also increase a diesels thermal efficiency even more than a gas engine.

All three half ton 3.0L diesels don't just produce the same power as an old N/A HD diesel it exceeds it by at least 50 or hp and over 100 lb-ft all while using less fuel. Hell, even my 2.0 liter turbo diesel in my car makes more power and torque than the old Ford 6.9L and 7.3L N/A diesels.

I am not believing you on your brother in law story. So you are telling me that you two filled up and followed each other for a whole tank and refilled up again just to record each others mileage? And that a 2008(with emissions) truck weigh's within a couple hundred pounds of an old N/A engine truck? I am more surprised that you were actually were able to keep up with him in an old N/A diesel. I remember driving my grandfather's 185hp/338lb-ft 7.3L IDI, and it could even get out of its own way let alone keep up with a 350+hp/600+lb-ft 2008 turbo-diesel.

Unless you are pushing the engine outside it's normal operating ranges...they both are burning all the fuel that goes in. Once all the fuel is burnt, adding more air does not improve the efficiency.

You still seem to be confusing HP production with efficiency.

...and, no problem running at around 70mph on the freeway with the old 7.3. We weren't drag racing. Michigan to Arizona...And he owned the old truck before I bought it off him and he said he got similar MPG, so it's not the driver.

Nope. You still seem to be confusing gas with diesels. What do you think the black smoke coming from diesels is? Un-burned fuel. Why? Because it does not have enough air to burn said fuel. This is why old N/A diesel blew puffs of black smoke just about all the time and turbo diesels blew a puff off the line until the turbo was pushing enough air to burn all the fuel being added which only took a second. Adding more air does improve efficiency in a diesel because it is able to use the fuel to more efficiently use the same amount of fuel to make more power instead of blowing it out as black smoke..


And I still don't believe your story. Not only, that, but none of the guys in this(LINK) 7.3L forum even say that 16 mpg is normal and if you look at fuelly.com here(LINK) it is even less than that.