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The mkiv Supra Owners Club

Performance in fog


Daston
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Hi guys

 

Just done a 50 odd mile run in this lovly weather and noticed that my car is a bit jerky/jittery at 20-30 mph in 3rd gear, even 2nd was a bit jumpy is due to more water in the air (being fog) and going though the induction???

 

Oh mine is a bog standard N/A (machanicly)

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The power is in cold DRY air. This is denser than warm dry air.

If there are tiny dropplets suspended in the air, the overall result is LESS oxygen molecules, as the water takes up valuable space.

Things get further complicated by the fact that the warmer the air, the more water it can hold before it becomes saturated. Much more.

I'm not sure what the effects would be if the dropplets make it through the airfilter and cover the MAF as well, some ECUs get confused and think that the air mass is much higher than it really is. That's why water injection is always fitted after the MAF.

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The power is in cold DRY air. This is denser than warm dry air.

If there are tiny dropplets suspended in the air, the overall result is LESS oxygen molecules, as the water takes up valuable space.

Things get further complicated by the fact that the warmer the air, the more water it can hold before it becomes saturated. Much more.

I'm not sure what the effects would be if the dropplets make it through the airfilter and cover the MAF as well, some ECUs get confused and think that the air mass is much higher than it really is. That's why water injection is always fitted after the MAF.

 

It is along time since I last sat in a physics lesson, but I thought H2O being a liquid had the molecules closer together than in air. So there is not an actual loss of Oxygen. We use water to put out fires, but in the confines of a cylinder, the H20 uses heat energy to convert back to gas, thus lowering cylinder temperatures. The extra hydrogen is explosive? So is there a significant reduction in the explosive force in the combustion chamber? Or did I skip that lesson?

Serious questions! I just remember our first car was 8bhp( book figure) and we always had to drop into 1st to get up the hill out of the village except on cold often foggy nights when we could do it in second.

I may be talking bollox and therefore assume the position of village idiot.

:looney:

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but in the confines of a cylinder, the H20 uses heat energy to convert back to gas, thus lowering cylinder temperatures. The extra hydrogen is explosive? So is there a significant reduction in the explosive force in the combustion chamber? Or did I skip that lesson..

there are more than one issues here. It's the wrong thread perhaps. But the water does not release the oxygen and hydrogen, not even under the high cylinder pressures. It exits as water vapour.

You were thinking of NOS, weren't you? ;) That one breaks the bonds and releases the oxygen, unlike water.

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correct - the water molecules are very hard to separate into component parts. the 2 H atoms need 1 electron each to complete their "shell", whereas the O atom needs 2 electrons to complete its "shell". what happens is they Covalently Bond (ie share electrons) which is pretty solid.

 

Furthermore - and here's why water behaves funnily in every way, all the bonded water molecules (H2O) now bond with each other through Hydrogen Bonding due to the molecules becoming polarised (i.e. the H2O is more negative on one side and therefore more positive on the other so fellow H2O molecules pull towards one another).

 

So water is very tough to break is what im saying.

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