Is Higher Octane Fuel Really Necessary?

[decypher]

Hello folks,

I have a 95 SC300 that I absolutely adore. I want what is best for her. So naturally the topic of what fuel I should put into the car comes up, especially in this day an age of the high price per gallon. When I bought this car it had a measly 131k miles on it, just broken in if you ask me. The previous owner told me they only put Regular in her. I was shocked. The car runs so well! It runs like a dream, no funny noises in the engine, smooth starts and acceleration.

When I first got it I put Premium in her but with prices so high I have been giving her Regular for the past month and I haven't noticed any difference. Am I very lucky?

Should I just put Mid-Grade in and be happy with the middle ground?

What do you put in your car and why?

[jzz30]

if you fill your car with 16 gallons what is the difference between regular and premium? about $3.20. your going to put in fuel that was not designed for the engine putting it at risk for premature failure just to save an amount of money that cant even buy a #1 at Mc Donalds. sell your car and get a geo metro.

[decypher]

if you fill your car with 16 gallons what is the difference between regular and premium? about $3.20. your going to put in fuel that was not designed for the engine putting it at risk for premature failure just to save an amount of money that cant even buy a #1 at Mc Donalds. sell your car and get a geo metro.

Oh I think I will do that, along with running you over with a tractor. Thanks for quip!!!

[GrnHrnt]

Hello folks,

I have a 95 SC300 that I absolutely adore. I want what is best for her. So naturally the topic of what fuel I should put into the car comes up, especially in this day an age of the high price per gallon. When I bought this car it had a measly 131k miles on it, just broken in if you ask me. The previous owner told me they only put Regular in her. I was shocked. The car runs so well! It runs like a dream, no funny noises in the engine, smooth starts and acceleration.

When I first got it I put Premium in her but with prices so high I have been giving her Regular for the past month and I haven't noticed any difference. Am I very lucky?

Should I just put Mid-Grade in and be happy with the middle ground?

What do you put in your car and why?

All SC300 and 400 motors are equiped with engine knock sensors. These sensors !Removed! engine timing to prevent low octane fuel predetonation from damaging the engine. Retarded engine timing means lower performance and lower gas mileage. Soooo.... save $ at the pump and get less HP and lower MPG. Not easy to quantify, but likely an even trade off.

[JIBBBY]

I've recently been putting regular in my SC400 and I don't see a difference...I go back and forth between premium and regular.. No knocking, but then again in California regular gasoline is 87 octane while in many other states 85 octane is regular....

[Air Force Rascal]

Hello folks,

I have a 95 SC300 that I absolutely adore. I want what is best for her. So naturally the topic of what fuel I should put into the car comes up, especially in this day an age of the high price per gallon. When I bought this car it had a measly 131k miles on it, just broken in if you ask me. The previous owner told me they only put Regular in her. I was shocked. The car runs so well! It runs like a dream, no funny noises in the engine, smooth starts and acceleration.

When I first got it I put Premium in her but with prices so high I have been giving her Regular for the past month and I haven't noticed any difference. Am I very lucky?

Should I just put Mid-Grade in and be happy with the middle ground?

What do you put in your car and why?

All SC300 and 400 motors are equiped with engine knock sensors. These sensors !Removed! engine timing to prevent low octane fuel predetonation from damaging the engine. Retarded engine timing means lower performance and lower gas mileage. Soooo.... save $ at the pump and get less HP and lower MPG. Not easy to quantify, but likely an even trade off.

I have been using 87 Octane for the past 2 yrs in my SC400 and I have not had any problems at all with my engine..nor have I had any problems with performance....the only thing I have found with premium gas is...burns faster and hotter then regular and less miles per gallon..just like E-85 does in the newer cars..with automatic timing there shouldn't be a problem...and by the way I have had the heads off the engine to check to see if there was any build up of carbon in the engine...NONE..as far as I can see the Oil companies are in with the automakers and want you to burn High grade gas because it makes them more money..the bottom line...the only cars that need premium gas are cars like formula 1's, Ferraris etc. I've had many mechanics tell me this over the years...but I was so afraid to try it thinking it would ruin my engine, but like I said with the New automatic timing in cars controlled by your ECM, shouldn't be a problem.. It's ok if you don't believe me..it's your car, Im just telling you my experience. Good Luck

[JIBBBY]

I have read that with the Q45 Infinity V8 motors that are some what comparable to the Lexus V8 motors that if you run regular octane fuel the spark plugs burn out within 1000 miles.... I was thinking maybe that theory can be applied to the Lexus motors.. I run cooler running plugs on my SC400 because of my nitrous system so I was never concerned..

I am a little confused on this statement in accordance with the last post... Q45 owners claim this spark plug burn out to be true as those motors call for premium fuel aslo...

[Demented Sc400]

I have read that with the Q45 Infinity V8 motors that are some what comparable to the Lexus V8 motors that if you run regular octane fuel the spark plugs burn out within 1000 miles.... I was thinking maybe that theory can be applied to the Lexus motors.. I run cooler running plugs on my SC400 because of my nitrous system so I was never concerned..

I am a little confused on this statement in accordance with the last post... Q45 owners claim this spark plug burn out to be true as those motors call for premium fuel aslo...

Why not just pay the extra 20 cents? i mean yeah it sucks n all but id rather pay the extra 20 cents den need a new engine

[jzz30]

Oh I think I will do that, along with running you over with a tractor. Thanks for quip!!!

you own a tractor...that says alot.

[JIBBBY]

A smart man always looks for easy ways to save money...So he can later use that money to build his car up and go faster

[mburnickas]

you own a tractor...that says alot.

What is wrong with that? It cost more then cars around here...

[Demented Sc400]

you own a tractor...that says alot.

What is wrong with that? It cost more then cars around here...

I think your tractors sexyyyyyyyyy!!!!!!!!! and a smart man wont chance messing up his engine, to save a couple cents. but i guess you could say that, lets save the 20 cents and that way by the time the engine stalls from havin the wrong gas, ull have enough money to buy/build a new one..smart idea :chairshot:

[JIBBBY]

Ok, I got the lowdown on Regular or Premium fuels...

If you do not run the recommended fuel in the Lexus motors you will run the risk of damage. It is not a sales advantage for a car to require premium fuel it is and engineering reality...

Let me further explain - A "knock sensor" listens for detonation and if heard retards the timing to reduce cylinder pressure and supress said detonation. They only work properly if there is detonation to supress. Detonation is BAD period... mild can be tolerated but it cycle stresses parts and it is cumulitive.

Reduced timing creates other problems and is to be avoided. It is far less damaging then detonation but it is something you don't want.. Lower then recommended octane fuels for our motors do this...

I WILL NEVER RUN REGULAR GAS IN MY LEXUS AGAIN... This information was aquired from a very reputable source....

Don't go cheap fellas, it will bite you in the !Removed! in the long run... I am now a believer...

[mburnickas]

Don't go cheap fellas, it will bite you in the !Removed! in the long run... I am now a believer...

Again, my oil testing house states other then 87 is a waste. I add Fp3000 to my fuel and gives it more BTU's, burns cleaner, added needed lubricity due to ethanol in gas and more MPG.

For me, it is nothing to do with being cheaper. It comes down to doing the samething better/less cost. I use FP3000 in fuel to regular fuel (87) and it cost me $0.50 a tank to add (no knocking in any car). A 93 octane would over $4 to $7 and not get the same benefits as the lower fuel with additive (and gets small pinging in another car I own).

[mburnickas]

I think your tractors sexyyyyyyyyy!!!!!!!!! and a smart man wont chance messing up his engine, to save a couple cents. but i guess you could say that, lets save the 20 cents and that way by the time the engine stalls from havin the wrong gas, ull have enough money to buy/build a new one..smart idea :chairshot:

Sorry, see above.

[JIBBBY]

Well, for alot of us are cars run perfect, we pull into a gas station and see a $.20 difference in price between regular and premium fuel... We think man does it really matter just because it says "premuim fuel only" on our cars... It's a legitimate thought for some of us that aren't that well paid... An extra $5 with every fill up can add up...

Apparently, there is significant meaning to the label "premium fuel only"... Too bad though because gasoline is expensive if you drive alot....

PS.. Tractors and Geo Metro's aren't sexy....Austin Martin Vanquish is though..get it right guys...

[mburnickas]

Well, for alot of us are cars run perfect, we pull into a gas station and see a $.20 difference in price between regular and premium fuel... We think man does it really matter just because it says "premuim fuel only" on our cars... It's a legitimate thought for some of us that aren't that well paid... An extra $5 with every fill up can add up...

Apparently, there is significant meaning to the label "premium fuel only"... Too bad though because gasoline is expensive if you drive alot....

PS.. Tractors and Geo Metro's aren't sexy....Austin Martin Vanquish is though..get it right guys...

If you use the right addative, there is no diff between 87 and 92/93 octane. I have stated that.

I never said tractors are sexy but neither is an Austin Martin. Problem is you can do more with a Tractor then any car...

[JIBBBY]

Well what is the right additive then and how much does it cost with each full tank of gas? Curious, I've never used a fuel additives...... I've used the oil, radiator, and power steering fix leaks in the bottle but those don't always work... I am always a little skeptic about those quick fixes in a bottle or power in a bottle... Even the concentrated fuel injector cleaners in bottle I don't think are all that effective but do help..

I don't know enough about the fuel additives to comment on that, so I will take your word for it....

[mburnickas]

Well what is the right additive then and how much does it cost with each full tank of gas? Curious, I've never used a fuel additives...... I've used the oil, radiator, and power steering fix leaks in the bottle but those don't always work... I am always a little skeptic about those quick fixes in a bottle or power in a bottle... Even the concentrated fuel injector cleaners in bottle I don't think are all that effective but do help..

I don't know enough about the fuel additives to comment on that, so I will take your word for it....

The right add is what you like. For me, it is Fp3000 from Lube control based on my UOA's and testing house comments. Cost was noted on previous post. As I noted before with ethanol and its crappy lube properties I would always use Fp3000. Chevron makes a nice cleaner but it is only a cleaner. No burning cleaner, no lube properties, no "more btus", fuel stablier etc. I can look at my tailpipe and there is no black soot for over 1 year inside.

[JIBBBY]

So then which is a better fuel as a whole for your motor...91 octane (premuim) or 87 octane with an additive with each fill up? It looks like the costs would be around the same when comparing the two.... I would still venture to guess the Premium fuel by itself may still be the better call... Plus when you think about it you got to carry around all these bottles go to the store and buy them and then remember to use one with each fill up... I think I will just stick with what works for me and that is using premium fuel as the dealership recommnends....

Good info. anyway... I am sure the fuel additives help and don't hurt though....

[mburnickas]

As noted prior, 87 with an add is all you need. Putting in 91 or 93 is a waste. Again, as noted before a Premium fuel is not going to do the things an good fuel addative will. Again these are things I have going through and a dealership know jack $$%&^ on UOA and fuel addatives. Hell Lexus is still 15 years hehind the times on oil.

I do not put any bottles in my car. I put in the proper amount (1oz) and go to gas station. Takes about 10 seconds and the bottles you need you get for free when you buy certain addatives.

Premium fuel will not burn cleaner, add more BTU to fuel burning process, less NOX, adds UCL to fuel. WIth the 10% corn in fuel ,you need a nice fuel add since corn is worse then MTB's.

[JIBBBY]

Well it sounds like you know what you are talking about...I will take your word for it....Thanks for the info....