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Sedans Luxury Performance Sedans
10006 messages, Last post on Nov 26, 2009 at 6:59 AM
You are in the Sedans Forum. Your Hosts are pat & karens
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Replying to: pearl (Jul 17, 2006 2:57 pm)
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Replying to: david83 (Jul 23, 2006 8:41 am) Like it or don't, the brakes on your A8L are WAY stronger than the engine. Best Reagards, Shipo
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I find the network early morning (7AM) "news programs" almost always entertaining and sometimes informative. I confess, I'm the ONE. So, when this morning on the Today Show, when I saw the teaser about a segment something like "does your car really benefit from Premium Gasoline?" I thought "finally, we can stop addressing the seemingly endless queries pertaining to 'Do I Really Need Premium Gasoline' here on Edmund's and other Internet discussion groups." The segment goes about its words and pictures and it did seem to accurately lay out the case for when and when not to use Premium Gasoline. The story correctly stated that if your car is designed to run on Regular (87 octane) there is no need and no benefit to use Plus or Premium -- only added expense. But then the story discussed two types of circumstances where two words were used -- and initially used correctly -- but, due to a slip of the tongue, were used interchangeably later in the story. Correctly, the narrator indicated if you car REQUIRES Premium (according to the sticker on the filler door and/or in the owner's manual), that you will do at least two things if you use less than Premium: degrade your performance and mileage and ultimately damage your engine. A cut away to an "expert" said you will "ruin your engine" if you use less than Premium if the car's manufacturer says your car REQUIRES Premium. Cut to the BMW propeller badger on the trunk lid of a Bimmer. Fine, fine, and finally, I said to myself -- but then outta the blue the discussion with the "expert" from Consumer's Reports said there are cars that REQUIRE Premium, DON'T require Premium and those that RECOMMEND Premium. Here is where it seemed to me to get "fuzzy." Now what they did say was that a car that recommends Premium doesn't HAVE to use Premium and if you use Mid-grade or Regular-grade there will be "no harm" to the engine and then somewhere in there slipped in, "but it will perform better with Premium." Well, not so fine, since no time whatsoever was spent to truly explain this and then, the announcer "inadvertently," I assume interchanged the words REQUIRE and RECOMMEND as he attempted to sum up this segments salient points. The viewer, I assume, could be left with the sense that there is no merit to using Premium except paying a higher price per gallon -- almost period. Rather than simply report this to this group here on Edmund's and go no further, I have some questions: 1. What are the models of vehicles that RECOMMEND but DO NOT require Premium? Are there really specific cars that say "Regular is OK, but we'd rather you used Premium?" 2. With respect to the cars above do they perform better (better power better efficiency) with higher octane, and if the answer is yes, does it equal or better the performance to justify the extra cost per gallon AND does using a higher grade in any way add "life" to the engine (thwart ruination, that is?) One -- that I know of -- Audi automobile I had in the 90's claimed it REQUIRED 91 Octane but it also claimed slightly better acceleration AND mileage if 93 Octane fuel were used instead. This Audi, however, did NOT even hint at allowing Regular usage. 3. Are there cars that REQUIRE mid grade? I have never seen a car that required mid-grade -- "but that don't make it so!" At least they tried. 
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Replying to: markcincinnati (Jul 24, 2006 6:45 am)  Are there cars that REQUIRE mid grade? I'm not sure whether the language says "Recommended" or "Required", however, I believe the 5.7 liter Hemi in the DC cars specifies 89 octane mid-grade fuel. Best Regards, Shipo |
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Replying to: markcincinnati (Jul 24, 2006 6:45 am) |
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Gas filler door on my M35 reads "Premium fuel is recommended for maximum performance".
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Replying to: sfcharlie (Jul 24, 2006 10:04 am) |
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Replying to: shipo (Jul 23, 2006 11:31 am) The current car, an Infiniti M35x feels free reving and nearly effortless if using premium, but loses maybe as much as 40-50 HP if you use regular. It will run, won't ping, but it won't accellerate with the abandon that it does running premium. So, depending on how much flexibility the engine management system has, how much power you started with, and your driving habits, you may not notice a difference. if you are perceptive and don't drive like a little old lady, you will probably notice. If the engine management system cannot compensate for the diverse octane levels, and you dont' put at least the minimum it was required to run with, you will experience pre-combustion and damage the valves and or pistons. This is more prevalent at higher speeds and under higher loads (well, basically the same thing, as you load it with the higher speed, but a hill or mountain pass could make it worse). You don't have to hear it to have it make damage. As an engine ages, if it is not treated well, it can accumulate carbon deposits. These can increase the compression ratio and turn a car that would run fine on regular into one that requires mid or premium to prevent pinging. Normally, though, the check engine lamp would have come on way before that was a symptom. |
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Replying to: james27 (Jul 24, 2006 10:38 am) The fact that the computer attempted to save the engine from internal damage via retardging the spark may well have been the case -- but even my 1982 Audi 100S with the 2.8 V6 REQUIRED 91 octane. The 1999 A6 w the 200HP 2.8L V6 also required Premium. The compensation offered by the EMC was INTENDED to allow the temporary use of regular when no premium was available. I called my Infiniti dealer (I say mine as if), and they told me I could USE less than premium in the M35 -- but that the engine did indeed REQUIRE premium and that the mere retarding of the spark was to allow you to get to the next station where Premium was available. I assume these are true statements. My wife's BMW, too, REQUIRES premium -- I just need to see if the words imprinted are recommended or the stronger requires. The truth of the matter is that these cars will run on less than premium but with some long term risks should you run them on regular or plus over the long term. Thanks to those who commented about mid grade -- I have, to this day, never seen a car that said MID GRADE was the design point of the engine. I always wondered. My 3.2 MUST have 91 (as did my 2.8 and 2.7T and 4.2) and it achieves maximum performance with 93 (I wonder if any higher, were it to be available at the retail level, would be of any benefit?) Most cars that require regular will run just fine on mid and premium but it is a waste of money to do so. I would NOT use premium if I didn't have to -- but on a twenty gallon tank the difference is, at most $4. Seems, in the overall scheme of things a small price to pay. |
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Replying to: markcincinnati (Jul 24, 2006 12:42 pm) The engine in the M35 is almost identical to that found in the G35 and FX35. Both can run on regular. I agree, however, that the V8 should be fed premium (335 hp) and to realize optimum fuel economy premium should be used. The V6 can run quite well on regular. Infiniti only "recommends" premium in the V6. As with any grade of gasoline, if you hear the slightest knocking noise from the engine, first try another brand of gas, and if that doesn't work, move up one grade to mid-grade. Hope this helps Apparently, not true? If "Premium is recommended for maximum performance" is intended to mean "Premium is recommended if you want you car to go faster than a bicycle and if you don't want to wreck the engine" it's quite a euphemistic, if not intentionally misleading, statement from Infiniti. |
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