[quote=Zaner21;10440335] More like complimentary… not integral. The engine could run without a turbo, right?
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Take the spark plugs out, really??? That’s your comparison to driving without a turbo???
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The discussion was about efficiency. My question was how much is the turbo contributing to the efficiency of the diesel engine compared to one without. Could the 7.3, 6.0, 6.7 yadda yadda yadda still get 18+ mpg without the turbo? Who has(had) a non-turbo 7.3 and what mileage did you get? I’m not trying to take sides. I love my V10 but I haven’t ever driven a PSD so I don’t have anything to compare it too. If diesel engines are so grand why are auto manufactures adding turbos to gas engines here in the USA rather than switching over to all diesel powerplants?[/quote]

Because the gas turbo engines are not in a package that has a 26k GCWR.

 

These engines were designed for a turbo.

If you built one from scratch without a turbo, you'd most likely use 20:1 compression and still get good mileage, but you're looking at 30- 50 % less power.

 

The diesel engines came with turbo chargers to add power.

The v10 came with extra cylinders for added power.

Removing the turbocharger would be like hacking off a couple cylinders from the v10.

 

great question. heres the answer:

a turbo on any vehicle harnesses the wasted heat leaving the motor. a turbo is good for increasing any motors thermal efficiency about an average of 2-5%, and a max of of prob 5-7%, by converting wasted heat energy into increased volumetric efficiency of the motors intake tract (by forcing it). i say average, because the % of heat recycled by the turbo is dynamic. at no load, cruising down the highway when the turbo is barely/not making boost, almost no efficiency can be gained. but, as soon as there is a time where load increases to a point that there is enough heat for the turbo to be harnessed, the thermal efficiency starts to increase. this is why its so important to have a properly sized turbo. an oversized turbo will do nothing but decrease mileage, because you'd have to generate heat JUST to get the turbo going (using fuel to light the turbo, not using the turbo to light the fuel).

simple answer: a loss of 1-5% would be likely, 1-2% would be average cruise loss. the 5% loss is assumed that the vehicle in question normally saw loads that would light the turbo and keep it lit for extended periods of driving (i.e. a frequent towing vehicle, or a very heavy vehicle.

no one anywhere has ever built a turbo gasser that is same/more efficient than even a NA diesel. prototype compression ignition gassers with direct injection exist. bmw, gm, im sure ford, mercedes, all have prototype compression ignition gassers on the shelf. with a max compression ratio of approx 14:1, and low injection pressures, theyre still 15-20% behind in their thermal efficiency rating vs a turbo diesel. take the turbo off the diesel, youre still lookin at a 10-15% efficiency gap. and we're talkin the most efficienc gasser on the planet. . . .that cant last very long under those above said conditions.

 

Turbo's can also increase efficiency by the power increase.

They can let and engine make far more power than it could without one, and the frictional losses of the engine have not been increased.

This is why our trucks are getting poor mileage, because they have giant engines.

If we had around 4.0 L engines, with a turbocharger, the mileage would be much higher. This will never happen though, because apparently a diesel without 400 HP is completely useless and even unsafe.

 

you got it backwards. . .maybe youre thinkin right but typin another. . .

the power increase comes from the increase in thermal efficiency resulting from the turbo. the turbo harnesses waste heat and in turn increases volumetric efficiency by ramming air through the intake tract (i.e. head, intake tubes, intercooler, etc) vs relying on the pistons to suck air in. it all stems from the harnessing of waste heat. the higher the volumetric efficiency, the more air is available, the more fuel can be injected, the more power can be made. none of this could be done without harnessing some of the waste heat (increasing the thermal efficiency)

"bad mileage" comes from unnecessarily large displacement emission equipped motors. they had to go bigger to make the power needed to compete in todays truck market, while retaining mileage/power robbing emission equipment. without the emission equipment, they could go back to pre-emission motor sizes like the 6.0 (which was plagued with emissions issues), and the 5.9 cummins.

i know no1 wants to hear it but the 6.0 is just as/more reliable than a 7.3 with about 5-600 bucks in parts and a days labor (studs 'n deletes). in turn it is one of the most mileage friendly motors available. i'd drive one with a 6 spd and big leather seats. . . .

 

Yes I agree, but I guess my point was that you need to use the turbo in order to benefit from it.

 

Yea let's do talk about inefficiencies, ALL of them.
Where I'll start is your declaretion of how a 6.0 WILL leave you stranded. You speak from an experance larger than life. When in fact anybody that does any research on the 6.0 will know different. There is a lot of us on the gas and diesel side that just love the truck itself and chose the drivetrain that suited us. I dont worry about the sky falling. If it falls tomorrow then so be it. I'm not promised the next mile just the one I'm in now. My extended warranty was very cheap. I make money w/ my truck so any repairs is already in the bank. That's all part of busness. You can break the numbers down all you want divide by the sum of whatever your mind can handle and you will answer the question of what's best for me cause your not in my boots. If things go south w/ my 6.0 then about $5k will get it straight. My extended warranty was money in the bank. No expire date and covers bumper to bumper w/ no deduction. I have $8k cash set aside so IF the sky should fall. Wanna make a bet I'm going to have the troubles you claim you have? I'll make it easy for you to decide I've already put 125k miles on it. I bet it get fixed right the 1st time.
The question that Bill asked has been answered several times. Only problem is some gassers wants to challenge it or claim their gasser wither a v10 or smaller will do it better. So no the question will never end. In case you forgot the question was "what's the high points of the psd?"

 

Diesels aren't making it into automobiles in this country for a few reasons. 1) The market for them isn't here because of the bad rep that the fist gen diesel cars got back in the '80s. 2) There's too much green piece propaganda that tells the consumer that diesels are bad. 3) This is the most important reason The EPA has the emission regs so tight on diesels, its difficult if not impossible for a diesel car to pass the EPA. Regardless of efficiency the EPA wants everyone in a gas sipping hybrid, over a diesel.

 

dont forget theres always a cummins swoption. . . .

 

You have got some good posts in this thread


A part of the reason that you haven't seen a turbo gas engine that is more efficient than a NA diesel is the way in which they were built into the engine's architecture. Turbo's have typically been bolted on to gas engines in the pursuit of more power for a given engine/size/weight, and the turbo's have been sized and put on engines to get more power up in the higher rpm range. Turbo's were seen by the general public as a hi-po power adder to gas engines, and were typically fitted only to vehicles that fitted that purpose.

Improvements in technology and the general public crying out for better gas milage on their everyday vehicles has meant that some turbo gas engines are getting damn close to their diesel brethren in gas milage.
Volkswagen's TSI engine (1.4l I4, turbo-charged with a positive displacement blower as well to provide boost at low rpms) gets milage close to their similar powered 2.0l TDI.
I would anticipate the next wave of Ford's ecoBoost engines to perform similarly, their 1.0l 3cyl turbo which will provide similar power to their 1.6 TDCI, and probably provide similar milage.


All in all, in a perfect world, a diesel engine will be more "efficient" per say, but a number of gas engines that have been build with "milage" specifically in mind are closing the gap on real world fuel efficiency.

 

there is an enormous influence by the folks in gov't who think they know whats best, when they dunno anything at all on the matter. . .

we buy up the worlds gasoline that they dont want. meanwhile, there wasnt a single "EPA estimated mpg" rating on any new vehicles on diesels for the past few decades. . .and they get way better mileage both car and truck than their gasoline counterparts. . . .

no way. . .i mean no F in way is a hybrid car better for the environment than a diesel. . .battery cell production/disposal is harmful in and of itself. and it soaks up tons of energy. the transportation of mass produced batteries soaks up tons of energy also. the longevity of the system is nowhere near the longevity of a diesel, and the list goes on.

then again, no one is voting/campaigning on logic/reasoning anyway. so i guess we cant expect them to act in a logical manner.

 

It's the government that ruins everything.

If things wern't so tight, we'd be able to swear AND get good mileage.

 

Ding, ding, ding.

I will add 2 more.
The US has typically had fuel regulations on diesel that are the worst in the developed world - well behind Europe and most parts of Asia - couple this with the strictest Diesel emission standards, and it has made making a diesel for regular vehicles too expensive for manufacturers. The US did some big improvements to fuel quality as of 2008 - although it still lags behind Europe when it comes to having low sulfur/hi-cetane diesel, but at least now you will see that some Euro companies can sell their diesel models (although typically tuned to deal with the stricter emissions/worse fuel)
I will also add that US highway tax regulations make gas artificially cheaper by taxing it lower


On edit: I will add - globally it isn't necessarily a bad thing that diesels haven't been popular, each country needs its energy source of choice, and its best if not every country chooses the same. Europe has big taxation incentives (both road and fuel tax) for diesels, so thats theirs. Lots of South America uses Ethanol blends, North America has typically been gasoline, if there was any dramatic shift to using Diesel, or any other fuel source - there would be dramatic increases in cost of fuel as the infrastructure to support it wouldn't be in place.

 

I agree the batteries are killers on the environment, manufacture, transport, and disposal. The new lemon in the coming years is going to be that hybrid that needs a new battery. I've done work overseeing the charge and discharge of marine batteries onboard ships, and I know all that charge and discharge have gasses associated to them in liquid-cell batteries. I'd like some lab tests to see if the same occurs in these hybrid cells, or not.

The government only ruins things as long as the citizens allow it, we are still a democracy. But this is not the thread for one of my political rants, so I won't climb that soapbox.