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Car Stolen - Need To Sell


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#11
darreltian

Posted 15 June 2010 - 04:19 PM

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QUOTE (gregy @ Jun 14 2010, 05:24 AM) <{POST_SNAPBACK}>
... I'm sure stock ECUs have already been programmed for our specific climate and base sea level.

Hi Gregy,
can you explain how does sea level plays a role in ECU programming?...thanks

#12
gregy

Posted 16 June 2010 - 01:40 AM

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QUOTE (darreltian @ Jun 15 2010, 04:19 PM) <{POST_SNAPBACK}>
Hi Gregy,
can you explain how does sea level plays a role in ECU programming?...thanks


More specifically, the air pressure at the location you are in. If you live at higher altitudes, the higher the pressure, the thinner the air. The ECU must be able to compensate for air pressure (which I believe most would) to achieve stoichiometric ratio of 14.7 parts of oxygen to 1 part of fuel.
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#13
tpl

Posted 16 June 2010 - 07:53 AM

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confusing man...
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#14
gregy

Posted 16 June 2010 - 03:29 PM

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QUOTE (tpl @ Jun 16 2010, 07:53 AM) <{POST_SNAPBACK}>
confusing man...


It's not confusing really. To achieve perfect combustion, an engine needs 14.7 parts of oxygen for every 1 part of fuel. If you have less oxygen, your car will run rich, if too much then it will be lean. The ECU does a balancing act, going back and forth between slightly rich and slightly lean all the time, transparent to the user. That's why sometimes you'll find that for one tank of gas you get more mileage, then suddenly the next you get a bit less, everything else being equal.

When you travel up to Genting, although the ambient temp is cooler the air is thinner, that means less oxygen particles in the atmosphere. This is why some cars struggle when climbing, and overheat due to prolonged lean burn. The added stress of using a low gear and high rpm exacerbates the problem. For those cars, the cool air in Genting isn't able to counter the added heat generated from the lean burn, so having an efficient and fully working cooling system is paramount for Genting runs. This is very apparent with carburetted cars with fixed air-fuel ratios, less so with EFI.

On ground level, if you drive at night, do you feel your car being slightly more responsive than driving in the mid day sun? That's because cooler air is more oxygen-rich, allowing more work to be done given the same volume of air entering the engine. When the ECU detects more oxygen particles in the air that's coming in, it allows more fuel to pass through to be burnt, resulting in more power.
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#15
tpl

Posted 16 June 2010 - 04:13 PM

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QUOTE (gregy @ Jun 16 2010, 03:29 PM) <{POST_SNAPBACK}>
It's not confusing really. To achieve perfect combustion, an engine needs 14.7 parts of oxygen for every 1 part of fuel. If you have less oxygen, your car will run rich, if too much then it will be lean. The ECU does a balancing act, going back and forth between slightly rich and slightly lean all the time, transparent to the user. That's why sometimes you'll find that for one tank of gas you get more mileage, then suddenly the next you get a bit less, everything else being equal.

When you travel up to Genting, although the ambient temp is cooler the air is thinner, that means less oxygen particles in the atmosphere. This is why some cars struggle when climbing, and overheat due to prolonged lean burn. The added stress of using a low gear and high rpm exacerbates the problem. For those cars, the cool air in Genting isn't able to counter the added heat generated from the lean burn, so having an efficient and fully working cooling system is paramount for Genting runs. This is very apparent with carburetted cars with fixed air-fuel ratios, less so with EFI.

On ground level, if you drive at night, do you feel your car being slightly more responsive than driving in the mid day sun? That's because cooler air is more oxygen-rich, allowing more work to be done given the same volume of air entering the engine. When the ECU detects more oxygen particles in the air that's coming in, it allows more fuel to pass through to be burnt, resulting in more power.

hmmm... very thank you for your explaination.. and yes i do noticed nite driving always the best.. or rainy days.
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#16
darreltian

Posted 18 June 2010 - 10:31 AM

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QUOTE (gregy @ Jun 16 2010, 01:40 AM) <{POST_SNAPBACK}>
More specifically, the air pressure at the location you are in. If you live at higher altitudes, the higher the pressure, the thinner the air. The ECU must be able to compensate for air pressure (which I believe most would) to achieve stoichiometric ratio of 14.7 parts of oxygen to 1 part of fuel.

Thanks for the explanation.... no wonder i easily feel out of breath when jogging in cameron highland smile_tongue.gif

#17
vr2turbo

Posted 19 June 2010 - 04:41 PM

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QUOTE (gregy @ Jun 16 2010, 03:29 PM) <{POST_SNAPBACK}>
an engine needs 14.7 parts of oxygen for every 1 part of fuel.

That should be 14.7 parts of air, right? as we always talk in terms of air/fuel ratio.
It would be difficult to get 14.7 parts of oxygen as our atmosphere is 78% nitrogen..... smile_blackeye.gif

#18
gregy

Posted 19 June 2010 - 07:32 PM

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QUOTE (vr2turbo @ Jun 19 2010, 04:41 PM) <{POST_SNAPBACK}>
That should be 14.7 parts of air, right? as we always talk in terms of air/fuel ratio.
It would be difficult to get 14.7 parts of oxygen as our atmosphere is 78% nitrogen..... smile_blackeye.gif


Haha you're right, thanks for correcting me, I meant air smile.gif
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#19
LanGanu007

Posted 21 June 2010 - 02:12 AM

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I think Bro Subash meant his friend want to sell the car he had just stolen smile_blackeye.gif

I suggest Bro Subash search the Black Market...I'm sure there are many buyers out there very interested to buy stolen cars, goods, etc trink39.gif
--007--

#20
SplitFire

Posted 23 June 2010 - 11:37 PM

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QUOTE (LanGanu007 @ Jun 21 2010, 02:12 AM) <{POST_SNAPBACK}>
I think Bro Subash meant his friend want to sell the car he had just stolen smile_blackeye.gif

I suggest Bro Subash search the Black Market...I'm sure there are many buyers out there very interested to buy stolen cars, goods, etc trink39.gif



Wahahahaha.....good suggestion. smile_big.gif
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