2001 acura MDX - Premium vs Regular GAS
#2
Going to regular gas will reduce power output under high engine stress applications (rapid acceleration, up hill, etc.)
Octane in your fuel raises the temperature at which the fuel detonates, or explodes. When the explosion occurs, it is before top-dead-center (TDC) and is called knocking or pinging. In ideal combustion, the fuel air mixture burns at a controlled (all be it VERY fast) rate with a subsonic flame front when ignited by the spark plug on or about top dead center (depending on the design of the engine). In detonation, the high compression of the engine causes the fuel-air mixture to explode with a supersonic wave front well before TDC, driving the piston in the wrong direction.
If you recall way back to high school or college chemistry, as you pressurize a gas, or in this case a fuel air mixture, the temperature rises proprtionally to the pressure (anyone remember p1v1/t1=p2v2/t2 ?). In a high compression engine, you need the higher detonation temperature of higher octane fuel.
The MDX, as with all modern high compression Honda engines, has a knock sensor to determine if detonation is taking place. If the sensor detects this condition, it reduces the amount of fuel / air mixture delivered to the cylinder. Knock is very bad for the engine, and will shorten the life of the engine.
Octane in your fuel raises the temperature at which the fuel detonates, or explodes. When the explosion occurs, it is before top-dead-center (TDC) and is called knocking or pinging. In ideal combustion, the fuel air mixture burns at a controlled (all be it VERY fast) rate with a subsonic flame front when ignited by the spark plug on or about top dead center (depending on the design of the engine). In detonation, the high compression of the engine causes the fuel-air mixture to explode with a supersonic wave front well before TDC, driving the piston in the wrong direction.
If you recall way back to high school or college chemistry, as you pressurize a gas, or in this case a fuel air mixture, the temperature rises proprtionally to the pressure (anyone remember p1v1/t1=p2v2/t2 ?). In a high compression engine, you need the higher detonation temperature of higher octane fuel.
The MDX, as with all modern high compression Honda engines, has a knock sensor to determine if detonation is taking place. If the sensor detects this condition, it reduces the amount of fuel / air mixture delivered to the cylinder. Knock is very bad for the engine, and will shorten the life of the engine.
#4
Originally Posted by NorCalAcura
Every Acura on our lot runs 87 octane and I've never noticed any problems.
I would hoope you haven't seen any problems. You'd be running the car at the high end of the engine output - not a nice thing to do to a car you're trying to sell, especially since it's not broken in yet.
I've detected the occurance on my 2000 TL when my wife put 87 octane in the tank and I was accelerating (had it floored) going up a steep hill on I-71.
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As I've said... never experienced it. New and pre-owned Acuras including NSX.
Like I'm not going to drive a used NSX hard to make sure it's working 'right.' It's a tough job sometimes.
Like I'm not going to drive a used NSX hard to make sure it's working 'right.' It's a tough job sometimes.
#6
If you are worried about gas prices, put 87, then an octane booster...might be cheaper...
also, i've always wondered the reason why Acura says premium fuel and Honda says regular unleaded...aren't they basically the same engine?
also, i've always wondered the reason why Acura says premium fuel and Honda says regular unleaded...aren't they basically the same engine?
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If you read the fine print on octane boosters you'll see that, when added to a 10-12 gallon gas tank, your octaine goes up perhaps 1 overall. At this rate you'd spend more on octane booster than you would just putting in the higher octane gas to begin with.
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Originally Posted by NorCalAcura
Every Acura on our lot runs 87 octane and I've never noticed any problems.
That's because you guys never keep each Acura for long.....
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And how many miles go on these cars while they are on your lot? I'm pretty sure it's no where near what the average or evan a fraction of what a average person drives. You won't feel the long term affect of putting 87 octane from cars on a sale, which are what, driven like 10 miles on a test drive compare to one used for a daily driving.