I was listening to the radio and heard a guy say that most cars that specify premium fuel don't actually need it. Only turbo- and super-charged cars.
"...People will continue to buy because they like the elitist idea. But even Porsche does not need premium gas. Their engineers admitted in the [USA Today] story that their cars must be able to drive anywhere in the world, so they have to be able to run on regular unleaded gas..."
The statements in that article are only somewhat true. <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">But 30 percent believe their car runs better on it. The latter is simply not true.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
He's right about that.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">In fact, putting premium gas in cars can harm the car if it doesn’t need it.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">That doesn't sound right. Does anyone know how that would work?
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Only cars that have “super charger” or “turbo” engines need premium gas.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Untrue. Likelihood of knock is based on compression, as I understand it. NA cars can have high compression.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Try putting regular gas in your car for a week and see if there is a difference. You won’t notice a thing!<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
That's probably true for many drivers, but I bet if you put regular in a high-compression, high-output engine for a week that included track driving, autocrossing, or street racing, you'd run a high risk of knock.
The bottom line is that if you're a "spirited driver", $2.00 per tank is a small price to pay for what is basically engine insurance.
Our engine has 10.3:1 compression. That plus 100+ degree weather plus full throttle acceleration....
Yes, Porsches can run with regular gas. Probably because they have a good knock sensor that saves the engine by retarding timing and lower performance when knock is detected. This is probably the case with our cars too.
One example of Prem gas causing problems. I had a 1997 FORD F150 (crap) which couldn't adjust to the later detonation which is caused by the higher octane ( I Think ?). All I know for sure is, with 89 or 93 oct, it would ping to death and lose all sort of compression.
Carribean Blue/Auto/ Prem Tire Pack/Willow Leather....ON ORDER *%#*&
Woah, weird...I'd like to know about that, I don't quite get it...how could the gas cause later detonation? I thought detonation couldn't be any later than the spark.
towards the end of my lease on an acura cl type s, i got cheap and started to put 87 octane in the car. it was fine for about 50 miles then the check engine light came on. i noticed a little knocking at low rpms. the think the computer knows when you have low octane gas in the car...so i think it makes a difference.
All cars that require premium gas are also able to run on lower octane grades as well. This is simply because auto engineers know that not everyone will pay for the higher priced gas, especially when the prices soar.
If your car requires the use of high octane gas, and you choose to use low octane gas to save money, then you might lose a bit of power because the knock detectors will retard the timing under certain conditions. However, knock is unlikely to happen, even using low octane gas, unless your engine is old and has a bunch of carbon deposits in the combustion chamber. Also, knock is unlikely to happen during normal driving conditions. Instead, knock usually occurs during high load driving, for example, running wide open throttle uphill.
Struan, I'm not a mechanic but someone told me the higher octane gas detonates later then the 87, whether its related to pressure or temp or ?. Anyway, if that is true, and your piston passes the peak of its compression bfore the spark ignites, then that may explain the noise and problems I had with the F150. If my mechanic is a complete idiot, then please ignore my explaination.
I'm just glad my new G will be under warranty, and Infiniti is the only one that will be doing any major maintainance.
Carribean Blue/Auto/ Prem Tire Pack/Willow Leather....ON ORDER *%#*&
I guess I'd trust your mechanic on this, although it seems weird to me that the gas could detonate any later than the spark. Maybe the computer retards the spark timing for some reason?
Lead electric, for about 15 yrs. I hate to say, but I was caught up in the hair-band era. Nothing like jammin to Bon Jovi for all the neighborhood groupies -- back in the day. Now I try to play a little of John Petrucci, Vinnie Moore, and a few others... you probably never heard of them.
Carribean Blue/Auto/ Prem Tire Pack/Willow Leather....ON ORDER *%#*&
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by G Dream
Struan, I'm not a mechanic but someone told me the higher octane gas detonates later then the 87, whether its related to pressure or temp or ?. Anyway, if that is true, and your piston passes the peak of its compression bfore the spark ignites, then that may explain the noise and problems I had with the F150. If my mechanic is a complete idiot, then please ignore my explaination.
I'm just glad my new G will be under warranty, and Infiniti is the only one that will be doing any major maintainance.
Yes, if you do some research on the web on octane rating, you will see that higher the octane, the higher the temp required for it to ignite. "Knock" occurs when you put lower octane and the fuel ignites before piston hits the highest point (where it is suppose to ignite) causing the piston to travel up faster than it wants! Metal to metal contact = knock!
The problem you are describing seems like a bad/poor/weak ignition system that can't burn the fuel when it's suppose to. Yikes
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Premium Gas???
