Ford Rethinks Big Block V8s

[Lead Head]

Originally Posted by dkf Turbos don't produce power from heat. They produce power from moving air/gases from the exhaust. Heat is the enemy of making power with any forced induction. Thats why intercoolers and water/meth injection can up the power significantly by reducing temps. All the turbo problems Ford has had in diesels makes me very warry of the turbos in the ecoboost. I guess we'll see how it turns out. Those moving gases are the result of expansion from the heat of combustion. So yes, turbos in a sense do work on heat. Heat on the turbine side has little do with heat on the compressor side. Compressor side heat is caused by the compression of the air charge. The 6.0 turbo problems were the result of diesel soot causing the variable vanes of the turbo to respond slow or completely stop moving. Gassers don't really have a problem with soot. Not to mention ford doesn't even make turbos.

[Krewat]

Uh, not to get further into a useless debate, but ... the "expanding exhaust gases" actually hit the cooler exhaust piping and CONTRACT. The engine is pumping the already expanded gases out the exhaust port - the "expanding gases" gives the engine it's power by pushing on the pistons.

But anyway ...

[wendell borror]

The boss engine will be used, ford has too much money invested in it. They just like playing head games with the competion and us. My dad is a ford retiree, and he gets a magazine every month called ford world. According to ford world, the boss engine is still on track, however, release dates keep changing. High gas prices or not, there's still people out there that need and will buy trucks. In the same token, the competion still has ford out muscled in truck engines. To get people to buy your truck instead of someone else's, you need an edge, the boss would be that edge. It's not like the boss would be the only engine choice, but it should be an option for those who need brute power in thier trucks. I'm sure they will sell a lot of them, cause people buying trucks need them for one reason or another and it isn't to save gas.

[97squarebody]

Originally Posted by wendell borror

The boss engine will be used, ford has too much money invested in it. They just like playing head games with the competion and us. My dad is a ford retiree, and he gets a magazine every month called ford world. According to ford world, the boss engine is still on track, however, release dates keep changing. High gas prices or not, there's still people out there that need and will buy trucks. In the same token, the competion still has ford out muscled in truck engines. To get people to buy your truck instead of someone else's, you need an edge, the boss would be that edge. It's not like the boss would be the only engine choice, but it should be an option for those who need brute power in thier trucks. I'm sure they will sell a lot of them, cause people buying trucks need them for one reason or another and it isn't to save gas.

Come on now, you are actually applying logic to the situation? I thought we were supposed to be running around like chicken little screaming "the sky is falling". After all that is what many of the more vocal people here are doing.....

[phelios27]

Originally Posted by dkf

All the turbo problems Ford has had in diesels makes me very warry of the turbos in the ecoboost. I guess we'll see how it turns out.

The 7.3 powerstroke was and still is very reliable. I think turbos are the way to go as well. Some nice Turbonetics T4's or even just one big 60 trim would probably do the trick...the only catch would be making sure the power is useful down low and throughout the power band...quad turbos perhaps?

[tjthegreat]

Originally Posted by phelios27

The 7.3 powerstroke was and still is very reliable. I think turbos are the way to go as well. Some nice Turbonetics T4's or even just one big 60 trim would probably do the trick...the only catch would be making sure the power is useful down low and throughout the power band...quad turbos perhaps?

the 7.3 was a good engine imo much more reliable than any other diesel ford has built

[Krewat]

I believe the EcoBoost thing requires a variable-vane turbo - which haven't turned out to be so reliable.

[Lead Head]

Originally Posted by tjthegreat

the 7.3 was a good engine imo much more reliable than any other diesel ford has built

Ford didn't built the 7.3, or any of the powerstroke family.

The main problem is that most of us have only seen the VGT turbos on the 6.0, which get sooted up.

Gas engines have far less carbon/soot output. Most gas engines I've seen with VGT turbos are just fine

[tjthegreat]

Originally Posted by Lead Head

Ford didn't built the 7.3, or any of the powerstroke family.

The main problem is that most of us have only seen the VGT turbos on the 6.0, which get sooted up.

Gas engines have far less carbon/soot output. Most gas engines I've seen with VGT turbos are just fine

i kno none of the big 3 make their own diesels,i was reffering to the truck,but mis worded it

[DanielC]

The exhaust side of a turbo does use the heat in the exhaust. The turbine wheel controls the expansion of the hot gases moving through it, and the net loss of heat in the exhaust gasses is converted to rotational enegry. That rotational energy is used to spin the compressor wheel, and that increases the pressure on the intake side of the engine. Part of that enegry also heats the intake charge. You cannot compress a gas without creating more heat in that gas you just compressed.
The economy gain comes from waste heat enegry in the exhaust is being used to do some of the compression of the intake air, and the piston does not have to do as much work to compress the air before the power stroke.
About a third of the total chemical energy in the gas you burn is comverted to mechanical motion. About a third is converted to heat, the cooling system has to get rid of, and about a third just goes out the exhaust pipe.

[Krewat]

Originally Posted by DanielC

The exhaust side of a turbo does use the heat in the exhaust. The turbine wheel controls the expansion of the hot gases moving through it, and the net loss of heat in the exhaust gasses is converted to rotational enegry.

If the turbine wheel is using energy to create work, the exhaust gas BEFORE the turbine is going to compress. There is no reason for the exhaust gases to expand AFTER they are burned, there is no extra heat being put into the exhaust gases. Heat is being LOST.

It's really just the backpressure pushing the turbo. Which also means, a small amount of energy is lost from the engine in pushing the turbo.

Turbos are NOT free power.

[DanielC]

If a turbine does not use the heat, and works on backpressure only, can you explain how every gas turbine and jet engine in the world works?
.

[Krewat]

Originally Posted by DanielC

If a turbine does not use the heat, and works on backpressure only, can you explain how every gas turbine and jet engine in the world works?
.

Uh, much different use of the word "turbine" ?

Jet engines take incoming air, mix it with fuel and burn it. The energy applied to the output turbine makes the intake turbine compress air, for a better burn, which in turn drives the output turbine, adding energy to the intake turbine. The resulting gases go out the back making thrust. Some applications, take a jet-powered helicopter as an example, use a transmission to take rotational energy from the turbines and drive the rotor. The higher the pitch of the rotor (more resistance), the HIGHER the pressure inside the jet engine. In other words, impede the turbine, pressure increases in the combustion chamber.

A turbo charger is more like a steam turbine, except the rotational energy is then used to compress air into the engine intake. The higher the compression on the intake side, the higher the pressure on the exhaust side before the turbine.

Which is backpressure.

I'm not explaining it correctly, most likely, I'm doing three things at once

[DanielC]

Just so we understand each other. The turbine side of a turbocharger is the exhaust side, to be more specific, it is a "radial inflow gas turbine". Most modern jet engines, and gas turbines use an axial flow gas turbine. The compressor side of the turbo is the intake side. It is just a centrifugal compressor.
If you increase the pressure on a gas, either the temperature goes up, or the volume goes up. Sometimes both.
If you increase the temperarture of a gas the pressure goes up, or the volume increases.
If you decrease the volume of a gas, the pressure goes up or temperature goes up.
If you allow a gas to expand, the temperature drops, and the pressure drops. This is why your air tools get cold when you use them. On a gas driven turbine, the pressure drops across the turbine, and so does the temperature. That is where the enegry comes from to drive the turbine wheel. The temperature loss repersents an enegry that is transferred to the turbine wheel. My understanding is that on many engines running a turbocharger, actually have a higher pressure in the intake manifold than there is in the exhaust manifold between the exhaust valves and the inlet to the turbine of the turbocharger, under some conditions. This seems impossible, until you remember that not all the heat enegry from burning the fuel in the first place is used in moving the piston. The turbocharger turbine is able to capture some of the formerly wasted energy, and use it to compress the intake charge.
If you design the engine with this in mind, it is possible to use the wasted exhaust heat to do part of the work of compressing the intake air, and free up a part of that power to drive the crankshaft.
On your helicoptor engine example, the increased rotor load on the engine does increase the pressure. It also increases the temperature of the gas, allows for a greater temperature drop, and the greater temperature yields more power to drive the rotor. The temperature also goes way up on the the engine parts.

[Krewat]

We're arguing the same point.

The temp drop across the exhaust side of the turbo is a by-product of the expansion of the exhaust gas. You're not harnessing the heat to produce energy. Quite the contrary.

Conservation of energy. No Such Thing As A Free Lunch.

Anyway...