Well? If the Check Engine light comes on, and the engine starts knocking/pinging, better not ignore that Check Engine light.
Right?
Tester
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[quote=âkescott1910, post:1, topic:135251, full:trueâ]
I am looking for my wife a newer car and have considered some that clearly say only use Premium gas. Will the low grade gas damage anything in the car? I have just always considered the higher grade gas a waste of money. Is there any proof that the car runs better on the premium or will get damaged on the lower grade gas? I always wondered if the gas companies
There is a difference between must and recommeded Iâve been told by the dealer. I bought a 2009 Murano in 2009 and the dealer said that they all used regular in them. I had the car for 7 years and it ran fine before I traded it in for another one. Great cars too1
Didnât you look at those pictures . . . ?!
You can design a car with a compression ratio that would require 91 octane gas but then put on a knock sensor to retard timing enough to let it live with 87 octane or you can design one with still higher compression ratio that the sensor canât fully compensate for because of diminishing return for retarding timing. Also, different cars with identical engines may need different octanes because of vehicle weight or gear ratios. The heavier the car and/or/the taller the gear ie lower numerically, the more load on the engine.
Like the Volkswagens sold in Russia in 2009-2010 (see post # 64), that engine wasnât available in the US until 2016, I hope that they got the software right by then. Has this become a problem in the United States?
I wonder what the sweet spot is for octane and compression ratios? I know back in 1926 Hudson got very good performance with F head engines, better than the would have had with full OHV engines just as Mercer did with T head engines. The F and T head engines could have much larger valves because they did not have to fit both valves into a cylinder diameter and the regular gasoline would only support a 5 to one compression ratio so they didnât need a small combustion chamber.
It is like the question of whether or not all engines should have overhead cams. If the question is how to get the most hp out of a certain displacement, then yes. But GM has said no in some cases saying the ohv engine is lighter and takes up less room and is cheaper to build and we can get just as many mpg with the lighter engine and advanced fuel management systems. They made it work for years with the 3.8 L V6s and still make it work with their V8s, esp the Corvette.
Your 2012 Camry has a compression ratio of 10.4 to 1.
50 years ago that would require premium gasoline. The 2019 Camry has a compression ratio of 13.0 to 1 and uses 87 octane fuel.
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I wouldnât ignore it, but as multitudes of posts from irresponsible people have shown us, there are a whole lot of people who are content to drive around for monthsâor even yearsâwith the CEL glowing.
No, I am certainly not defending irresponsible people. However, I do think that anyone is isnât willing to own up to some basic responsibilities of car ownership probably shouldnât be buying vehicles that require premium gas, and I also recommend that people seek rapid solutions when that CEL first lights up.
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Increasing compression ratio improves the efficiency but it isnât linear. Going from 10:1 to 11:1 gives a greater improvement than going from 11:1 to 12:1. Even less going from 12:1 to 13:1. When you get beyond about 14:1 you start becoming a diesel - or compression ignition, and a thatâs a can of worms!
A Model T engine had a compression ratio of 4.25 :1 so it would run on the low octane (about 60) fuel of the day. Once tetra-ethyl lead (Ethyl fuel) was added as an octane booster (87 or so), compression ratios could be raised - a lot! War-time fuel improvements developed for airplanes boosted it again to 100.
The flathead, or side valve engine designs in budget cars couldnât build a lot of compression without strangling the airflow. Car makers, knowing full well about double overhead cams and 4 valves per cylinder since Dueseneberg and other high end road cars had adopted this layout to build powerful engines. Those were too expensive to build in volume so the went the OHV route from about 1949 onwards. Compression went up and up until you could buy road cars, such as the rare '63 Z-11 427 Impala, with 13.5:1 compression.
Modern engines, with all the electronics to retard timing, adjust camshaft angle to bleed off compression pressure and the cooling effect of direct fuel injection are now growing CR again. My premium fueled Honda S2000 with 11:1 to my regular gas Mustang with 11:1.
CRâs are growing towards compression ignition. There are a bunch of manufacturers working on compression ignition gasoline engines right now. Mazda introduced its CI-gas concept in 2017 for sale in 2020.
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I have heard stories that the old timers with their Model T Fords could boost the octane of the gasoline by putting mothballs in the gas tank. They could then advance the timing with the spark advance lever on the steering column. Maybe this is a poor manâs way to get premium fuel performance at a regular gasoline price.
Mothballs never increased octane, but the ones made with napthalene would burn, and in a Model T, I suppose anything that burns helps. 
In seriousness, a common phrase amongst car tuners is âyour butt-dyno is full of @#$@,â and that holds just as true to old-timers throwing mothballs in their tanks as it does to kids with Civics putting a K&N filter on there and thinking they added 20hp.
Any time you modify a car, you tend to unconsciously assume that you made it faster, and so it feels faster when you drive it.
The real trouble with mothballs comes when you donât read the package label for your mothballs, because some of them are made with dichlorobenzene, which produces hydrochloric acid when itâs heated, and that can do bad things to your engine.
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Yes. Premium is recommendedâŠnot required. My 14 Highlander with the same engine says to use Regular. I have exclusively since I bought it.
Mine has been on since circa 2003. 
Iâm sure youâre not the Lone Ranger and sometimes thatâs the best recourse.
With all the crap theyâre putting on new cars now it will be a vast majority of people driving with CELs or other warning lights illuminated. Iâll bet lots of cars have warnings because of TPMS in-the-tire transmitter batteries going belly-up. Lane change, auto braking, sensors in the windshield⊠Many folks only see a â$â when those puppies start lighting up because of all that crap that some politicians thought were needed on cars.
Add to that car manufacturers having to reprogram these systems because of glitches, the huge expense of repair, and many of the gadgets wonât be able to be put right by many, many technicians.
CSA
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POLITICIANS? REALLY?
How about INSURANCE COMPANIES. TPMS, Lane departure warming, auto brakingâŠare all lobbied for and backed with MILLIONS of dollars by the insurance industry. Every auto safety device dating back to the seatbelt became law because of the INSURANCE INDUSTRYâŠ
weâve had TPMS in our vehicles since 2005âŠafter several hundred thousand miles later- weâve had to replace only ONE sensor battery.
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Yeah, and when TPMS has a problem, the TPMS light illuminates. Not the CEL.
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It should say in your owners manual which one to use . Higher octane burns slower than lower octane. Higher octane is used in high performance engines because they have high compression ratios which make greater power output. Another thing is gasoline with low octane ratings burn faster and may explode rather then burn when introduced to high compression ratios which can cause prrignition the higher the octane the less likely to explode. So when compression ratio increase the octane rating of the gasoline should be increased to prevent abnormal combustion.
CorrectâŠThe CEL light is for engine. The CE in CEL stands for Check Engine. First vehicle with OBD-II we owned was my wifes 1996 Accord. Since then I think weâve had a total of 2 times the CEL illuminated. Both were simple fixesâŠOne was a gas-cap. And the other was a cam-sensor. Less then $100 for both fixes. I donât know why anyone would complain about OBD-II.
Thatâs funny, I was just over there the other week! I wonder if that particular Amish family uses Premium feed or Regular feed? 
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