The 351W Long-Rod Thread of Doom.

[CheeseSteakJim]

I should've added, in a car weighing as much as a Panther.

[1987cp]

This isn't an ideal situation. It most definitely is not adiabatic, even given the elevated cycle speed.

True, but the faster a gas is compressed, the less heat escapes during the compression process, and the closer it approximates actual adiabatic compression. In my Physics II lab we did an approximation of adiabatic expansion by using an acrylic cylinder and slamming the piston upward as quickly as possible. Obviously, the groups who moved the piston the fastest got the best results.

[Pirate]

What kind of fuel economy could you possibly see with this kind of motor, say with 3.55's?

I've heard claims of 19-21 in a 5.0 Mustang, and with the iron-headed motor I built, he was getting around 18 freeway with a C4 and a 3.50 gearset/Ford 9" rear, with 245/60R 15's on the rear (1969 Ranchero, if I recall correctly). I never got to hear about what mileage the AFR-headed engine I built, as it got sold off to someone else after I built it.

[Pirate]

True, but the faster a gas is compressed, the less heat escapes during the compression process, and the closer it approximates actual adiabatic compression. In my Physics II lab we did an approximation of adiabatic expansion by using an acrylic cylinder and slamming the piston upward as quickly as possible. Obviously, the groups who moved the piston the fastest got the best results.

Engineers, sheesh.

[1987cp]

Hey! I don't know jack about engineering, I don't.

[P72Ford]

Actually, I've been doing some thinking.

Technically, I believe you could assume adiabatic conditions. The reason I say this, is because I do not believe there is a significant change in component temperature for every cycle.

Once the engine reaches operating temperature, the temperature of the piston and cyliner walls probably stays fairly constant. Yes, evertime combustion occurs, more heat is added, but the components have more than likely reached thermal equilibrium. Temperature does not continue to climb, just because you are adding heat (ie, boiling water). So, in theory, it isn't adiabatic, because heat is being added each time combustion occurs. But in reality, I think we can say it is adiabatic, as once operating temperature is reached, the effects of the added heat from combustion, is negligible.

I'd like to see a plot of cylinder wall/ piston temperature, as a function of engine cycle to say for sure.

I would say the internal combustion engine is less of a control volume, and more of a closed system, processing units of air and fuel at a time.

[1987cp]

I'd like to see a plot of cylinder wall/ piston temperature, as a function of engine cycle to say for sure.

I think I see what you mean. Just out of curiosity, do you know of a link to such a plot for a representative typical IC piston engine?

[P72Ford]

Unfortunately not... Larry is going to be pissed that we are messing up his thread...

[Pirate]

Unfortunately not... Larry is going to be pissed that we are messing up his thread...

'
No I'm not. It's intelligent discourse, isn't it?

[CheeseSteakJim]

I've heard claims of 19-21 in a 5.0 Mustang, and with the iron-headed motor I built, he was getting around 18 freeway with a C4 and a 3.50 gearset/Ford 9" rear, with 245/60R 15's on the rear (1969 Ranchero, if I recall correctly). I never got to hear about what mileage the AFR-headed engine I built, as it got sold off to someone else after I built it.

I saw the 19-21 in a Fox-body also, but he didn't mention what gears he was running. If 4.10s were being used, that highway economy is fan-freaking-tastic - but if he's running 2.73's then I'd say that's terrible.


Did your client's C4 have OD?

[Pirate]

I saw the 19-21 in a Fox-body also, but he didn't mention what gears he was running. If 4.10s were being used, that highway economy is fan-freaking-tastic - but if he's running 2.73's then I'd say that's terrible.


Did your client's C4 have OD?

No O/D behind the C4.

[1987cp]

Overdrive behind the C4?

[Pirate]

Overdrive behind the C4?

$2500 in Aluminum Form.

[Pirate]

http://waynesengines.com/index.htm

The site is back up....these are the guys that sell modded 5.565 Chevy 400 rods for 302's, and modded 400 Ford rods for 351W's....prices are around $275-$300 for a set of rods.

[CheeseSteakJim]

That's not too bad. I'm going to keep these dudes in mind.