I live by Gurnee, IL. 40 minutes north of Chicago, and I just paid $3.19 gallon for BP(Amoco) 93 octane.

 

Um I was just wondering, I AM NOT SURE ABOUT THIS, but dont most of the cars in the TLs class also take premium?? and come on does $0.20 a gallon make a difference when people pay $5 for a regular $1 bottle of water at clubs? (or am i the only 18 year old here that cant drink lol)

 

Why buy a nice ride and put weak shit in it? You gonna mod the difference anyway so wtf??? Buy the right stuff, and not pay in the long run for early engine troubles - which are sure to be hella more pricey than your gas savings accumulated to!

Maybe you should buy a 4 cyl if it is a bother. Not rushing you to the concrete...just saying...

 

HAH!

 

Go buy an Accord... they use regular...

 

1st off, I do put premium in our TL and will continue to do so as long as it's available... That's my personal choice.

2nd, I asked the service manager at our Acura dealership and he told me using regular would not have an adverse effect on the engine as long as there is no knock. He went on to say that if there was a knock to move up to mid-grade to see if that would eleminate the knocking. So, if there were to be a warranty issue, it would come right back at him!

3rd, I thought this was a reasonable question, and don't understand why some people have to be such snobs about it!

The decision is an individual one, and asking questions of other users is a good way to recieve feedback and evaluate what is best for each individual. Factual answers (sans condecending sarcasm) would have been acceptable...

 

Youre right..Its a great question. This means that the individual posing the questioning is acutally THINKING and questioning - thinking outside the box. Yea, he/she may not have the knowledge, but they came here for some answers, and a lot of people did give factual answers...about your second point thou....you can pre-detonate without knock. Knock is an indication that you have basically reached an extreme. Any detonation before the flame front in the chamber will cause long-term engine damage. You want to maintain uniformity and control in your explosion, and with our high compression ratios, high octane fuel is the only way to maintain that.

 

Thanks for the explanation, the service manager didn't go into that much detail, he probably should have! Anyway, as I mentioned previously, I intend to continue to fill up with premium. Paid way to much for this vehicle to let .20 per gallon ruin it! My son-in-law, who is an ASE Certified Mechanic also recommended sticking with what the owner's manual recommended. He works in a family owned shop, so he mostly sees older vehicles that are out of warranty and has told me some pretty scary stories about things he's seen when people don't maintain their vehicles IAW the manufacturer's recommendations! It's kind of like, pay now or pay later, but one way or another you're going to pay!

 

It looks like my little comment opened a can of worms. Sorry you had to dig through the mess to find your answers but hey, at least solid answers were there.

 

Hahahahaha..but sarcasm is funny as hell!!!!!

 

WOW - I posted this question yesterday afternoon and got 49 responses already! Even though some were a bit cynical, I appreciate all of them. After posting I did the math last night and realized that it probably is no more than $100 - $150 a year based on the mileage I drive. Sort of like making a mountain out of a molehill. Anyway, thanks for all the feedback and what a great forum - if I buy the TL I'll be hanging around Acurazine for a while!

 

Don't mean to hijack this thread, or open another can of worms, but what are your thoughts on the use of acetone mixed with fuel to obtain better MPG? See the article at the link below:

http://www.pureenergysystems.com/new...00069_Acetone/

 

Indy, i've wondered about that too.

 

If it makes any of you feel better, just realize that premium is almost always ~20 cents / gallon more than regular. Even when prices go up, the price difference between regular and premium stays the same.

So, by making the switch to premium, you're just ahead of the curve. You're in the future, you've got now what other people won't have for months. Isn't that supposed to be cool?

Also, what ankur914 said about detonation is completely correct. Detonation, in the derogatory sense, is the air/fuel mixture exploding before the spark-plug ignites it. Lower octane fuel's will ignite upon compression (the piston rising in the cylinder). Detonation could occur right before the spark-plug was about to fire, an issue which would not present itself, or it could happen so long before the spark plug was about to fire that the explosion would exert a downward force on the piston as it is rising, which causes the 'knocking' sound. Prolonged detonation can cause pistons to melt, engine temps to get high enough to cause a bearing to spin, or can even cause connecting rods to break. All of which require the lower end of the engine to be rebuilt.

The other problem with detonation is that it's only audible at lower RPMs, after you're above 2K or 3K RPMs, you couldn't hear it if you wanted to, but it's still there and every bit as dangerous.

I would normally say these extreme results of detonation would be hard to witness as a result of running regular fuel in the TL, but the fact that it's compression is so high is enough to scare me into only ever running premium.

The average compression ratio in a turbo/super-charged engine is around 8.5:1, this is because the air/fuel mixture is already being compressed, thus a higher compression ratio can be unstable. The average naturally-aspirated engine has a compression ratio around 10:1. It is not uncommon to find high performance engines, most often custom built, with compression ratios as high as 12.5:1, but these engines generally run race fuel, 100+ octane. Diesel engines have compression ratios ranging as high as 22:1, but diesel engines are built without spark plugs, and rely on detonation to operate. I'm sure we've all heard a diesel engine, and the distinct knocking sound it makes.

You should be able to see that the TL's compression ratio is at the high end of what is considered 'normal.'

HowStuffWorks tends to have decent information and little flash video diagrams that can show a four-stroke engine in action, or a manual/automatic transmission.

 

I just want to point this one out.

The reason the compression ratio on a turbocharged engine is 8 (or 8.5) is because as soon as more air is introduced by the turbo (boost), the compression ratio goes up to around 12., 13, even 14:1 in some cases. higher compression ratio on a turbocharged engine is possible (ive seen instances where a 8.5 or 9 is stock), this is to give the turbo engine some "legs" at lower RPM, but thats about it. my Evo (and all evos) had measly compression ratio off-boost and that made it sluggish at lower rpms, but once the turbo starts pumping, it gets better

 

That guy is charlatan. I can’t say about surface tension from top of my head, but I can say that 35% improvement would bring him a Nobel Prize. Final touch on his BS is “to much octane” part.

 

I kind of figured this was one of those "If it sounds too good to be true, it probably isn't" type of deals, otherwise, some automotive aftermarket company would have bottled it and it would be on the selves of every Automotive Parts House in the country! The potential damage to the fuel system components is enough to prevent me from trying it!

 

ok, so here's how I understand it in laymans terms (and I could be wrong). Using a higher octane fuel allows the combustion chamber to fill up fully with fuel/air before it needs to ignite. This 'full' or complete detonation cycle produces more power. Using a lower octane fuel, the engine needs to compensate and detonate earlier (because the fuel is more volatile) with a partially full fuel/air mixture. This 'partial' detonation cycle produces less power. Sorta like running with baby strides instead of full.

Once you understand this concept, you will realize its not so much about the type of fuel generating more or less power as it is to how the engine is calibrated to work with the fuel provided. I.e. an engine will work more efficiently with the fuel octane it was designed for. Higher performance vehicles are designed to use the higher octanes because they can derive more power out of each combustion cycle.

In my opinion, deviating from the octane designed for your engine is always a risk. You're relying on your car's computers & sensors to reactively adjust itself (determining octane, and i'm guessing oxygen temperature/density) to each and every detonation, and when you push the car to its extremes (flooring it) it can potentially fail and cause damage to the engine (knocking)

Now are you even actually saving money? I would guess you're burning the lower octane fuel faster because your car needs to compensate to produce the same amount of power with the less efficient combustion cycle, so while your gas refills are cheaper, they will also be more frequent. Plus the engine isnt running in the way it was efficiently designed for, so who knows how much is wasted there.

 

leedogg,

The air/fuel mixture will be compressed regardless of the octane. Higher octane fuels are LESS volitile so they resist the initial burn.

High compression ratios will yield high combustion chamber pressures. The higher the pressure, the more likely the air/fuel mixture will PRE-IGNITE or KNOCK. High octane fuel resists this. Octane is an organic compound that is added to Heptane to decrease the volitility of the gasoline.

By added more spark timing (spark advance), the engine can sometimes make more power. This cannot be done without using higher octane fuel. On a supercharged engine, 1 degree of spark timing can be worth 4-5 HP and 8-10 lb.-ft. of torque. So if the engine is knock constrained (all supercharged engines are knock constrained by nature) at 89 octane, but not at 93 octane...then using 93 octane and adding 3 degrees of spark added 15 HP and 30 lb.-ft. of torque.

Most straight gasoline engines cannot detect fuel octane. The PCM's that detect octane are really looking at O2 content in the exhaust stream so it's really retro-active.

You will always produce the most power from an engine that is running closest to it's adiabatic efficiency and on the lowest octane it WAS programmed to run on. Using high octane fuels on a engine tested to run on 89 octane is a waste!

110 octane fuel in a lawnmower DOES NOT get the grass cut any faster.

A-Train

 

Well, almost. Octane is the eighth hydrocarbon. Methane, ethane, propane, butane, … , octane. It is the most resistant to detonation. If you have 100% octane it will be 100 octane gasoline. You mix it with air at mass rate 14.5:1 during aspiration cycle, compress it 11 times in TL’s engine, ignite it by sparkplug, it BURNS developing heat, which generates pressure that push pistons … But, if it is low octane fuel it DETONATES before sparkplug, creating knocking sound and overheating pistons. BURNING fuel front travels 20 yard/sec, while DETONATING fuel front travels 2000 yard/sec. Piston can not be pushed that fast so that energy is just heating it and ultimately melting it. So part of fuel energy is used to overheat pistons instead to push them creating useful power.

Smart engines try to prevent knocking by retarding ignition and ENRICHING mixture. So IF it succeeds in preventing detonation it is burning more fuel because of richer mixture, developing less power because of retarded ignition.

Some smart guy performed an experiment, as I red here, and concluded that it is more expensive to use regular than premium. I strongly believe that his conclusion is right. But some other guys, ignoring him, still calculate non existent savings.

 

First off a high compression engine will run better on high octane, and get better MPG. It burns more efficient. Its worth the extra 8%. Don't let anybody upset you. They are trying to help Some people come off without thinking. I use to be like that. Until I read a book-(Think about what you are thinking, and think before you talk) Its just a question that is asked way too much. If you can afford a nice car, spend the few extra cents. If an extra $4.00 per tank is a real problem, pack your lunch 1 more day a week. Buy food and drinks in quantity at Sams or Walmart. Save somewhere else. BUT DON'T neglect your poor engine. If you drive A LOT OF MILES every day, get a used Civic with a stick. This way you will save on gas and keep the resale value on your TL HIGH. Excessive miles on a car is worse than the cost of premium fuel. Everything is relative. Do what you have to do for YOURSELF But ignore sarcastic comments, its not worth the stress on your mind or body. Have a great day Jeff D.

 

lol it's funny reading these last few posts everyone correcting each other..
i have no clue what any of this means

 

DAMN!

 

lower octane fuel predetonates from heat that is added called heat of compression. This is why in a high compression engine, High octane fuel is needed. High octane fuel has a higher ignition temp, so the heat of compression in the TL's engine is not enough to ignite the high octane fuel. high octane fuel also has a slower more uniform burn.

 

I say if you can't afford the gas, i don't think the car is for you. Try something that requires regular...

 

Conclusion: Just use premium. 91 +

 

 

I like twinair's definition of what a higher octane fuel is. It's the same explanation I use when trying to convince someone that they don't need high octane in a lower compression engine.
Now I need to get my wife's TL-S back to the dealer. It has about 4500 and has been pinging since new, and has never had less than 91 to drink. Let you know what they find out.

 

Not the OLD DISCUSSION again! This one is so old it like has flies on it! Search my friend....you will find no less than (oh....lets see...let me do it for you I guess) ok

on just a search of premium fuel I find.... https://acurazine.com/forums/search.php?searchid=534720

in just a quick cursory glance I find at least a handful of the same exact thread and same exact discussion more or less. Search first!!

http://gprime.net/flash.php/postingandyou (just messin' with ya)

 

These engines (in fact I think all modern gas engines) have knock sensors. These are little piezo-electric devices that are 'bolted' to the head at strategic locations. They produce a signal relative to the vibrations of the motor. A knock causes a spike to occur, just like regular ignition. The computer can then see if the 'bang' is occuring before the desired time, or not and adjust the timing (retard it) to match.

As discussed above, retarding the timing lowers the power/torque. This makes the car feel 'lethargic'.

Level cruising will not be effected much. But any acceleration (passing, etc) and you'll definitely feel it.

Even with regular, mine would not ping. Or it would not ping for more than a half second since the computer would quickly retard the timing. If yours is pinging constantly, I'd look at EGR or the knock sensors. IF you can get a tech actually look and not just trust what the diagnostic computer tells him.

 

I don’t agree with you. This forum is supposed to be fun and fun is communicating with people. Searching is not fun. And Google is better anyways.

 

weedeater,

DO NOT assume that all cars have knock sensors (KS). I was shocked to see the 1999-2004 5.4L Ford Lightning SVT and 2003-2004 Cobra both have KS, pigtails, wiring and are connected to the PCM. However they are CLEARLY turned off in the program.

The Eaton M112 supercharger produces enough noise/frequency to trigger the KS into coming on when it shouldn't.

While most engines use the KS, not EVER new car has them.

twinair,

This is incorrect. Octane DOES NOT change the burn rate of the AIR/FUEL mixture. There are 4 things that control knock sensitivity in any engine:

1) Fuel octane RON
2) Combustion chamber design
3) Cylinder pressure (higher static compression ratios have higher cylinder pressures).
4) AIR/FUEL mixture temperature. The hotter the air and fuel...the more knock constrained the engine.

A-Train

 

That gif cracks me up@!# It's hypnotizing.

 

So I followed your first url and here's what I got:

"Sorry - no matches. Please try some different terms."

certainly not a handful - thanks for nothin'.

 

You got the "Sorry - no matches" because that was a link to a search, and such links expire after a variable time period determined by when the site refreshes itself. I have never noticed one expire this quickly, but anyway that's what happened.

The search smilie, gif, or other method of promoting the search ethic, sometimes backfires and should be used judiciously and with compassion. If a person continually shows that he is too lazy to search and just wants others to do his work it can be invoked, but for people asking for help it should be suggested along with a link, which was done here so all is not yet lost.

 

i never put anything below 93
but sometimes, i wonder if some gas station cheats the costumer by putting regular fuel into their premium tank..
thats why i change my gas station preference to shell. lol

 

Ya....I am just playing with him Ron....you know we have all been there once as we all were newb's at one time or another and did the exact same thing. (hense the just messin' with ya' statement) I tried to do the search for him to get him started.... didnt know they expired though. Sorry dude.....tried to point you in the right direction though....

 

Hmmmm..... sales weasel who wants you to spend $36k tells you what you want to hear while a trusted and certified source (who has nothing material to gain) tells you the truth. Who woulda thunk it? :-)

 

I want to make sure people understand that octane does not change the burn rate of the A/F mixture like some people think.

weedeater,

DO NOT assume that all cars have knock sensors (KS). I was shocked to see the 1999-2004 5.4L Ford Lightning SVT and 2003-2004 Cobra both have KS, pigtails, wiring and are connected to the PCM. However they are CLEARLY turned off in the program.

The Eaton M112 supercharger produces enough noise/frequency to trigger the KS into coming on when it shouldn't.

While most engines use the KS, not EVER new car has them.

twinair,



This is incorrect. Octane DOES NOT change the burn rate of the AIR/FUEL mixture. There are 4 things that control knock sensitivity in any engine:

1) Fuel octane RON
2) Combustion chamber design
3) Cylinder pressure (higher static compression ratios have higher cylinder pressures).
4) AIR/FUEL mixture temperature. The hotter the air and fuel...the more knock constrained the engine.

 

Firs time you were correct as well.

I can add just:

5) Sparkplugs. They have different heat rates. Higher rate can cause difficult start, while lower gets too hot and ignites mixture before spark.
6) Valves, especially exhaust that can be glowingly hot.
7) Carbon deposits that can be very hot.
8) Pistons, if not properly cooled with oil from below.
9) Mixture quality. Lean mixture tends to detonate way earlier than rich.

Also important is that detonation can occur after ignition but in front of regular burning front. Since that it burns 100 times faster it creates hot spots and can melt piston or exhaust valve.