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4 Weeks Of Regular Fuel


2rotor
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Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine?

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Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine

running on 87 octane will not make your car run slower, if u put octane boost in it it doesnt go faster, it just gives u better milage, i would think that running on 87 might be bad for your knock sensors and ur intake system as well as the injectors, so saving a few pennies at the pump might cost u in the long run

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Actually the fuel does make a difference. I have several High output cars that fuel makes a big difference. 93 octaine fuel burns faster and hotter making the reaction in the chambers faster, thus the burning reaction happens faster and more efficiently. The LS DOES accelerate faster on 93 octaine. The ecu is programmed for higher octaine fuel so the fuel curve is programmed for fuel to burn as does a higher octaine.

I have noticed no change in fuel economy but the accleration has suffered a little.

High output cars (such as the LS, Mustang GT's, Nissan Z cars ect) do react to octaine, but putting high octaine fuel in your honda civic wont "make it faster".....

Please educated responses only, I have done a 4 week run on regular so I have something to base my statements off..

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Oh no not another thread on the same topic!

Humans tend to igrore long term effects in favor of short term. (Just like eating junk food)

Running with lower octane will.

a ) Knock engine as knock sensors dont work 100% of times. Knock is very bad for your piston-rod-crank apparatus.

b ) When knock sensors do work, delayed spark will result in lower performance and bad gas mileage.

But HEY you save 4 bucks. Have a big-mac.

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this issue has been beat to death in just about every car forum on the net *haha*

here is my "web research" --------------------------------

the computer will pull back your timing (to a certain point) if knock is detected and lower grade gas will increase the possibility of knock...pulling back your timing definitely affects performance and acceleration

from one site:

"engine knock occurs when fuel in a combustion chamber ignites before it should...Octane, by definition, is the resistance to burn or detonation. The higher the rating, the slower the burn when ignited during the compression burn cycle of the piston. The higher octane allows for better control of burning for high compression engines. So we want to match the correct octane rating of the gasoline to the engine design to ensure complete burning of the gasoline by the engine for maximum fuel economy and clean emissions."

sounds to me like cheaper gas might decrease fuel economy in the lexus since it was designed for premium as it nstructs us in the owners manual

Exploding is bad, burning is good. If you are running too low of an octane for your motor, you will get

pinging. Pinging in its extreme form is also known as detonation. The

fuel/air mixture is igniting all at once and exploding instead of igniting

as a flame wave.

as for gunk buildup - the US EPA requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits, I think I even read somewhere that higher octane actually burns hotter (not sure though) which may help prevent gunk buildup better than the additives alone

I also agree that high hp tuned cars NEED higher octane...i would NEVER EVER put anything less than the highest octane I could find in my Supra...forced induction cars (turbos/superchargers) are especially susceptible to knock due to "cheap gas" because of the tremendous pressure over normally aspirated engines...I will use premium in high hp cars (which includes the lexus)...i want the least chance of engine knock and I dont want the computer to pull back my timing...i want all my power ;)

but here's the kicker...all the websites pretty much end on the same note...

"Check your owner’s manual to determine the right octane level for your car. Regular octane is recommended for most cars. However, some cars with high compression engines, like sports cars and certain luxury cars, need mid-grade or premium gasoline to prevent knock."

and

"Most cars are designed to burn regular unleaded fuels with an octane rating of 87. If the vehicle needs a higher octane rating of 89-93, there is documentation in the owner’s manual, as well as possibly under the fuel gauge and by the fuel fill hole. Usually you will see this rating for high performance engines only."

well guess what folks??? we have a luxury car and our owners manual says use premium and I dont know the exact compression numbers on our engines, but I would consider it a high performance engine, i'm sure it benefits from the higher octane...in a pinch, i might try mid-grade, but then the savings arent much off using premium anyway...

not trying to start an argument or some long debate...just going by what I'm finding :P

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Wow another trying to use regular gas??? If people are really that worried about a few bucks per tank, go ahead, but you're just asking for trouble considering Lexus specifies CLEARLY to use ONLY PREMIUM fuel.

Read and learn. Maybe this topic can finally be put to rest over here at LOC :D hahaha

http://www.clublexus.com/forums/showthread.php?t=334846

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I NEVER run regular in an LS430. But, I will burn mid-grade occasionally when the price difference gets ridiculous. Most stations used to separate fuel grades consistently by $0.10: E.g., Premium = $2.09, Mid-grade = $1.99, Regular = $1.89. However, in northern VA last Wednesday, the neighborhood station was $3.06 premium, $2.97 mid-grade and $2.87 for regular. Not much difference at the "high end." But by Friday, there was a $0.20 difference between premium and mid-grade and the same $0.10 between mid and regular.

When the difference is a dime I'll always spring for premium, maybe even 12 or 15 cents. Already over $3 per gallon, it doesn't make much of a percentage difference. But at 20 cents plus more for premium, I'll sometimes spring for mid-grade, especially on a long drive in flat country.

What burns me is the changes are so erratic and cannot POSSIBLY be related to the cost of the fuel already in the in-ground tanks. It is pure gouging. And Exxon/Mobil turns the greatest quarter profit of any business in US History while the market crashes.

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"93 octaine fuel burns faster and hotter making the reaction in the chambers faster, thus the burning reaction happens faster and more efficiently."

".........putting high octaine fuel in your honda civic wont "make it faster"..... "

Please educated responses only, I have done a 4 week run on regular so I have something to base my statements off..

I am trying to give you an educated response, but your statements contradict themselves. Your first statement tells me that putting high octane fuel in a car makes it goe faster because of it's burn speed and temperature.

Your second goes to tell me this will not make my Honda Civic faster.

Why not? Does the speed and temperature of this "high octane rated burn" change when put into a Honda Civic?

I find this statement interesting....

"Octane rating has no direct impact on the deflagration (burn) of the air/fuel mixture in the combustion chamber. Other properties of gasoline and engine design account for the manner at which deflagration takes place. In other words, the flame speed of a normally ignited mixture is not directly connected to octane rating. Deflagration is the type of combustion that constitutes the normal burn. Detonation is a different type of combustion and this is to be avoided in spark ignited gasoline engines. Octane rating is a measure of detonation resistance, not deflagration characteristics."

Are they wrong?

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Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine?

Only thing that comes to mind to me is, if one can afford to drive a Lexus vehicle, one would probably be able to pay the extra 20 cents per gallon at the pump. I am a cheap and thrifty person when it comes to most stuff, but I never think twice about putting premium gas in my car.

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Not going to get in a *BLEEP*ing match over this.. But those who quoted me are leaving out an important part..

"The ecu is programmed for higher octaine fuel so the fuel curve is programmed for fuel to burn as does a higher octaine."

Your honda civic is not "programmed" to accept the higher octane fuel, which is why it will not "go faster"....

Regardless, i haven't heard any pinging (and I am a seasoned boosted vet so I know what detonation sounds like)..

I have 318k on my Lexus, if it was a newer Lexus I would for sure not take a chance (as I don't take any chances with my Mustang GT or my Turbo Rx-7's...) But for goodness sake the car is a beater LS400 worth maybe $4000... It's not a $48,000 car anymore..

I guess this thread can be closed, I have not recieved any info I wasn't already aware of (knocking/pinging, slower acceleration, alleged fuel economy sufferage) and I have only expereinced slower acceleration, so I may continue using 87 as the prices of fuel seem to be skyrocketting. If I notice any mal effects I will let you guys know.

Other then that this thread might as well be closed.

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why even get on a forum, ask questions and then try to answer them ur self 2rotor? good way to get no response to any help u might need in the future! octane booster is not made to make ur car go faster, it may have an effect on the knock sensors and then your timing will restrict, i had my knock sensors go out and it made my transmission shift funny because of the timing! tell me how u know thats not possible! keep ur smart remarks to urself,or go elsewhere to get help, and keep running 87 octane in ur bucket....also u said u wouldnt take chances in ur mustang? thats cuz ur mustang will never see 318,000 miles, unless its towed by your lexus

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Your honda civic is not "programmed" to accept the higher octane fuel, which is why it will not "go faster"....

Please enlighten me 2rotor..... I am very curious about this. If I had a honda civic, the ecu would be programmed to run on lower octane rated fuel, so putting a "faster, hotter burning, higher octane rated fuel" into it's tank will actually not burn hotter or faster in it because of the ECU?

Please help me out here, I apologize for my ignorance.

Question for 2rotor.... What about my non-ecu naturally aspirated regular compression engine? Will the fuel burn faster and hotter in that since there is no ecu to tell it not to accept that higher octane rated fuel?

Does this mean that octane rating in fuel can translate to more speed if the vehicle has no ecu?

Does my lexus have a sensor that knows what the octane rating of it's fuel is?

Once again, I am here to learn, please help me out.

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I had considered putting 87 in my 91', but since it has only had 93 in it since new (according to the original and previous owner), I will continue to put in 93 I guess..... unless gasoline goes up to $5 per gallon... then I will start walking I guess. <_< BTW, my 91' LS400 gets 21 mpg in town. Not too bad I guess.

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Usually in CA there's about a 20 cent difference per gallon (although the spread seems to be widening lately) so at about 18 gallons a pop its another $4. After almost 60 bucks another 4 isn't going to break the bank. :)

I suspect that most modern engines are fine with either; the Camry V6 (which is pretty much the same V6 as the ES 350) runs on 87 octane while the ES recommends 91+. They have the same 10:8-1 compression ration. The Camry has 268 hp while the ES has 272. I'm sure running the ES on unleaded would probably net you an output of about 268.

I can't imagine using regular gas is going to destroy your engine (as long as it's not obviously knocking); over time the variance in effective octane etc. between different grades of gas is something engineers have to account for. However the knock sensor will !Removed! your timing; giving you less power and poorer mileage; so you may end up saving more at the pump but visiting more often.

Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine?

Only thing that comes to mind to me is, if one can afford to drive a Lexus vehicle, one would probably be able to pay the extra 20 cents per gallon at the pump. I am a cheap and thrifty person when it comes to most stuff, but I never think twice about putting premium gas in my car.

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I have owned my LS400 for three years. Drive it for work. I purchased it with 60K miles and now have 130. I have only put 93 in it three times. Runs fine on 87 and I average 28mpg. I am now getting a V V T warning code 1349 which has something to do with timing.

Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine?

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As I mentioned Python I am not going to get in a great debate, i am not an engineer, I never even mentioned OCTANE BOOST nor did I claim it would make the car go faster.. So you can stop trying to prove that point wrong, cause I never said that.

Bottom line the car accelerates faster on 93 then it does on 87. FACT. If it is beause of retarded timing fine, bottom line it does.

As to the gentleman who mentioned that i will have a hard time getting help in the future- Check my previous posts, I asked for help once, and then took that help and wrote a writeup with my experience to assist other members (how to set your timing/belt replacement) so go ahead and threaten me and see how it effects the forum.

I was doing this as an experiment, and will continue to do so until i see reason not to.

I never claimed that the Mustang was a super reliable awesome car, therefore I do make sure that it has 93 (as it is supercharged and requires it or it will die and be towed by the Lexus)

From MY EXPERIENCE (NOT A POULAR MECHANICS ARTICLE) putting 93 in non High output car shows no difference (like my xterra, or my wife's old 04 civic) but when used in a car that has an ecu set up/ higher compression (like my motorcycle) it is benificial.

I still get 24mpg on 87 as I did on 93 and have only noticed a difference in acceleration.. my findings, do what you want with them.. Enjoy your day.

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THE FINAL WORD....

When I picked up our 2001 911/996 C4 at the Porsche factory in Germany I was told that throughout our travels in europe we would not always be able to fuel with preminum but I should NEVER fuel with LEADED. The explanation was that leaded fuel would contaminate the catalytic converter and it would have to be replaced, $1000 cost to me, before shipping to the US.

Now the 911/996 engine is unquestionably a high compression and high performance engine, so I asked how it was possible to run on regular fuel.

I was told that the engine ECU would "learn" what fuel was being used by "pushing", leaning out, the A/F mixture to the limit, the point wherein the knock sensor would go off, essentially saying "enough, already". By that method the ECU would know just how rich to run the mixture to avoid knock/ping due to fuel octane being (too??) low.

In other words if you fuel a modern day engine that has a high compression AND knock sensors no damage will result since the ECU will avoid the A/F mixture range, more lean mixture, that would otherwise result in knock/ping.

He did point out that with the engine in the rear I would not be able to readily hear the onset of engine knock/ping due to lugging (six speed stick) so I was to avoid loading the engine up, asking for acceleration torque, below 1500RPM.

So fueling a high compression engine with knock sensors with regular will result in increased fuel consumption but no damage will result. Our '92 LS400 has been running on regular only since ~2001, 60-70,000 miles and is still running STRONG.

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As I mentioned Python I am not going to get in a great debate, i am not an engineer, I never even mentioned OCTANE BOOST nor did I claim it would make the car go faster.. So you can stop trying to prove that point wrong, cause I never said that.

Bottom line the car accelerates faster on 93 then it does on 87. FACT. If it is beause of retarded timing fine, bottom line it does.

From MY EXPERIENCE (NOT A POULAR MECHANICS ARTICLE) putting 93 in non High output car shows no difference (like my xterra, or my wife's old 04 civic) but when used in a car that has an ecu set up/ higher compression (like my motorcycle) it is benificial.

I still get 24mpg on 87 as I did on 93 and have only noticed a difference in acceleration.. my findings, do what you want with them.. Enjoy your day.

I do not know whom your post is directed but I have noticed zero in acceleration of 87 to 89 to 91 (or 93). All three, perform the same in my cars and even my gsxr. Un-treated fuels turn all injectors to crap, carbon up plug ends, carbon crowns of cylinders.

As I noted in other posts I can use Fp60 (or FP3000) and get better results WITHOUT using 91 and save money in various ways. This is not commercial on the product but from what I have read, seen, data, it works WITHOUT spending the worthless money at the pump.

Even if your car accelerated better on untreated 93, does that does not mean anything in engine performance, durability, MTBF etc.

I am not starting a debate here but 100 to 1, without any supporting data you are getting a placebo effect.

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I have owned my LS400 for three years. Drive it for work. I purchased it with 60K miles and now have 130. I have only put 93 in it three times. Runs fine on 87 and I average 28mpg. I am now getting a V V T warning code 1349 which has something to do with timing.
Well I have been pinched lately due to the increasing fuel costs. I drive 75 miles a day to work and have been trying to save on my fuel costs. I started running 87 octaine fuel exactly 4 weeks ago (aka 4.5 tanks of gas ago), to see if the car would run ok on lesser grade fuel.

My reaction has been that the car will run well on regular fuel, it is not as fast on 87 but it does not exibit any "ping" or "knock". I think that I may start to run 87 unless there is a super scary reason not to...

Anyone else run regular fuel? Anyone have definitive reasons why I should go back to 93 octaine?

Come on - 28 MPG, are you serious? REALLY? I drive mine conservative and can get no better than 24 combined city/hwy.

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Less than proper octane places a higher load on all parts of the rotating assembly because the ecu retards ignition timing. Piston tdc algorithm will not coincide precisely with ignition timing as per design spec of the ecu. Therefore, as piston is still rising to tdc, ignition is occuring. This increases a downward pressure as the piston is rising to tdc. ie, downward force on the crank, main bearings, and rod bearings. Silent death over time.

Ferd

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Less than proper octane places a higher load on all parts of the rotating assembly because the ecu retards ignition timing. Piston tdc algorithm will not coincide precisely with ignition timing as per design spec of the ecu. Therefore, as piston is still rising to tdc, ignition is occuring. This increases a downward pressure as the piston is rising to tdc. ie, downward force on the crank, main bearings, and rod bearings. Silent death over time.

Ferd

Good post mossyoak, If people still don't get it, they never will.

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