Added to the fleet; OCTANE QUESTION

inspiredsports

I bought an excellent 2002 Toyota Avalon yesterday for my youngest daughter to drive to and from college/work. The car has the standard 3.0 Liter DOHC 24-Valve V6 Engine which runs perfectly and does not knock or ping with 87 Octane.

I've heard conflicting reports however that all of these Toyota 3.0 liter 24 valve engines "prefer" 91 octane. I also understand there were 2 versions of this engine; a 1999 and earlier that "required" 91 octane and a 2000 and newer version where 87 is "OK", and 91 or higher suggested for higher performance.

The original Owner's Manual confirms that for 2002, 87 octane is OK and 91 or higher can be used for "better performance".

I guess at today's pump prices 91 octane is about 4% more than 87.

Will my daughter get 4% better gas mileage using 91 octane?

nguyendot

It really depends on how the engine is designed. The knock sensor may **** timing and give you worse mileage, but make your engine not blow up.

I've run 87, 89, 91 in my Cadillac CTS 2009 - and from my experience I've gotten better mileage - 2-3mpg or so on 91 than 87, 3mpg is pretty good, considering I average 20-30mpg... that's 10%.

This is with a high compression 3.6L Direct inject engine, so you may see less (the 4% you quoted).

My uncle has worked for shell, arco, and now Maersk, all large oil producers. He's a senior engineer - he states the different levels of octane really don't make a huge difference, but... I dunno. I see a difference so I go on that.

My dad sells cars, and he says the same thing - you actually get decent mileage on some cars with better octane - specifically the ones with high compression that will **** more with lower octane gas. The less sophisticated the engine, generally the less you'll gain, if there is a gain at all.

concealer404

Going off my experiences with my Toyotas, yes. You'll see a 4% improvement in economy.

But there's no way to tell until you try for sure.

Jstas

Short answer: No.

Longer answer: depends on tuning, fuel maps, ignition timing aggressiveness, compression ratio...yada yada yada.

For a 2009 CTS, I can see octane levels making a difference because the ECM programming is going to be designed to take advantage of higher octanes when available due to the car's "sporty" intent/nature. Hell, my Lightning has a very aggressive ignition tuning program and will handle as much as 110 octane fuel without a problem. Runs like a raped on it too. But, again, completely different vehicle with a completely different intent.

A Toyota Avalon...beige mobile with a dash of geriatric thrown in for good measure. It's made for economy, comfort and reliability. If the manual says 87, use 87. You might see SLIGHTLY better mileage with a higher octane but, not enough to justify the cost premium. Run 87, keep up with maintenance and it should be a reliable, comfortable and uneventful term of ownership for you and your daughter.

edbert

Ape. You forgot the word ape Jstas. I know in my wife's Altima, it definitely gets better performance and mileage with the higher octane fuel, but since most of her driving is in town and for the most part not aggressive, we have found the lower octane is better. If we are planning on a road trip though, I generally will fill up the tank a few days before with higher octane and then use it throughout the road trip where we are driving at higher speeds and mostly highway and have noted a marked increase in mileage versus regular octane.

TNRabbit

I get 1-2 mpg better on 93 octane than 87 octane in my 94 Yota 4x4 Pickup...

Joe08867

The octane won't make 4% difference in fuel economy. Maybe 1-2% on the average.

I would stick with 87 and just keep it serviced regularly.

kawizx9r

I'm not even allowed to run anything lower than 91 octane, must be nice :rolleyes:

But to answer the question, in my experience I didn't notice much of an improvement if any. Use Fuelly and track your MPG's and compare if you're really curious.

camp21178

I looked all over the internet and did not find one article that said a higher octane fuel would give your car higher mileage or more power. Here's one http://www.squidoo.com/regular_or_premium

Sherardp

91 all the way in the 7 series, I also add the fuel injector stuff too. Not sure if it helps or even works. BMW parts/labor is rediculously expensive so the less I see of those people the better. Congrats on the new ride, my family owns part of Toyota in Japan.

mole'

inspiredsports wrote: »

I bought an excellent 2002 Toyota Avalon yesterday for my youngest daughter to drive to and from college/work. The car has the standard 3.0 Liter DOHC 24-Valve V6 Engine which runs perfectly and does not knock or ping with 87 Octane.

I've heard conflicting reports however that all of these Toyota 3.0 liter 24 valve engines "prefer" 91 octane. I also understand there were 2 versions of this engine; a 1999 and earlier that "required" 91 octane and a 2000 and newer version where 87 is "OK", and 91 or higher suggested for higher performance.

The original Owner's Manual confirms that for 2002, 87 octane is OK and 91 or higher can be used for "better performance".

I guess at today's pump prices 91 octane is about 4% more than 87.

Will my daughter get 4% better gas mileage using 91 octane?

if the car does not Knock or ping with the 87 gas i would stick with it unless you have modded it in some way. like the timing table/maps. IMO you would get better MPG by adding a simple better intake filter like a K&N one.

i would run 87 for a week and then 91 for a week and see how the MPG are.

mole'

kawizx9r wrote: »

I'm not even allowed to run anything lower than 91 octane, must be nice :rolleyes:

But to answer the question, in my experience I didn't notice much of an improvement if any. Use Fuelly and track your MPG's and compare if you're really curious.

once you get your DSP, you can make a 87 octane map. you will have to lower the timing by alot. i have a 87 map, 91/meth map, 110/meth map and a q116/meth map. only take a few minutes to switch them out.

Sherardp wrote: »

91 all the way in the 7 series, I also add the fuel injector stuff too. Not sure if it helps or even works. BMW parts/labor is rediculously expensive so the less I see of those people the better. Congrats on the new ride, my family owns part of Toyota in Japan.

BMWs hate 87, my girl put 87 in ours and it ran like total DOG POOOO!!!!

kawizx9r

mole' wrote: »

once you get your DSP, you can make a 87 octane map. you will have to lower the timing by alot. i have a 87 map, 91/meth map, 110/meth map and a q116/meth map. only take a few minutes to switch them out.

Well, I don't complain honestly about the price I pay for gas (91 octane+ required) it's just the gas mileage as well as my heavy foot

Least it's fun to drive! But I can't wait til it's tuned to 93 when I do get it! Think the Stage 1 (he now says he's available Saturday) and bigger fuel injectors will lower my gas mileage though :eek:

Back on topic, +1 to a drop in K&N filter! I have an extra one if anyone wants it ($48 retail) for a PT Cruiser GT (2.4ltr turbo). Has less than 350 miles, and it's just sitting in the garage in the stock airbox.

dorokusai

I run 87(E85 if possible) in my Avalanche and 91+ in the Audi. If it wasn't for BG products I'd wonder about my truck but everything runs fine and internally looks clean as a whistle. I take the Audi more seriously...plus it carries my wife so there you go.

mole'

kawizx9r wrote: »

Well, I don't complain honestly about the price I pay for gas (91 octane+ required) it's just the gas mileage as well as my heavy foot

Least it's fun to drive! But I can't wait til it's tuned to 93 when I do get it! Think the Stage 1 (he now says he's available Saturday) and bigger fuel injectors will lower my gas mileage though :eek:

Back on topic, +1 to a drop in K&N filter! I have an extra one if anyone wants it ($48 retail) for a PT Cruiser GT (2.4ltr turbo). Has less than 350 miles, and it's just sitting in the garage in the stock airbox.

post the part # for it so peeps can see if it will fit.

remember your car wont be tuned to 93. the tune that comes with it is called the "93 octane tune" but i will mod it so you can run 91 gas. did you know that you can data log with the DSP too? oh ya, i dropped my cell. so its OOC for a day or two

kawizx9r

mole' wrote: »

post the part # for it so peeps can see if it will fit.

remember your car wont be tuned to 93. the tune that comes with it is called the "93 octane tune" but i will mod it so you can run 91 gas. did you know that you can data log with the DSP too? oh ya, i dropped my cell. so its OOC for a day or two

Yea I remember, but that'll be after Stage 1, pipes, cut out, etc

And I wondered about that, I called you after I got home and it went straight to voicemail :eek:

Will get the part # in just a bit......

Edit:Part number is 33-2153. K&N says it'll fit from 2000 to 2005 PT Cruisers, both N/A and Turbo. Like I said, it's VERY low miles and they come with a million mile warranty!

inspiredsports

So I think I've been able to answer my own question . . .

I've spent a lot of time reasearching and learned a little more. The engine in this car is a 3.0 liter 24 valve Dual Overhead Cam "VVT-i" engine that Toyota designates at the "1MZ-FE". The VVT-i stands for "Variable Valve Timing intelligence" and the ECU Computer (Electronic Control Unit) senses load variable to control the timing.

It can sense the performance boost of 91 octane fuel and output 210 BHP at 5,800 rpm or "detune" itself to **** the spark and produce just 190 BHP at 5,400 rpm. It has a 10.5 to 1 compression ratio so engine really can take advantage of the octane boost when it optimizes itself for 91 octane.

They suggest running multiple tanks of 87 octane and then multiple tanks of 91 octane, driving as consistently as possible while carefully recording fuel usage and mileage over and above what the onboard computer provides. A simple calculation or cost per mile will show which octane is most economical.

I'm going to run 3 tanks of 87, and then 3 tanks of 91 and compare notes.

Jstas

OK, I'll put it this way then.

2007 Lincoln MKX: 20 gallon gas tank. 17.5 gallon fill up of 87 octane: $38.50...lasts about 12 days.

2001 Ford F-150 Lightning: 25 gallon gas tank. 17.5 gallon fill up of 93 octane: $57.00...lasts about 8 days.

In one year, provided gas prices were actually static, gas alone costs:

Lincoln: $1,171.04
Ford: $2,600.63

Difference: $1,429.59

You will not gain enough in fuel economy to offset price differences between 87 and 91. You will gain power because timing advance can be increased to provide a better air/fuel burn. You'll also burn more fuel as the computer richens the mixture to keep NOx emissions in line and prevent an over-lean condition from blowing up the engine. Whatever efficiency you might make will be offset by the higher fuel usage of the engine due to the more aggressive tune. Power don't just materialize out of thin air. It needs a fuel source to be created. More power uses more fuel and air. I will be very surprised if you get more than a 2-3 MPG increase. To make a switch to 91 worth while, you will need more than a 5 MPG increase to realize any cost benefit. It'll be paltry at that as well.

Jstas

BTW, even if mileage was the same for both grades, it'd still be a $1,733.75 yearly bill with an almost $600 a year difference.

If gas cost $3 even a gallon on average and your car got 20 miles to the gallon that'd be 350 miles in a single fill up. With 30.41 fill ups a year, that'd be $6.57 a fill up for the difference. So, in order to actually make up that $6.57 a fill up difference, you would need to make up the mileage of 2.2 gallons of gas. We are getting a 20 MPG average fuel economy, right? 2.2 times 20 is 44 miles per fill up. That 17.5 gallon fill up? Yeah, 350 miles plus 44 miles is 394 miles per fill up. That means you have to make up an average of 2.25 miles per gallon, rounded up. That's average, not peak. It does not take in to account things like stop and go traffic tie ups, city driving from traffic signal to traffic signal or that 80 MPH blasts down the highway to pass the stinky trash truck or puttering old man. Making up 2.25 MPG at a peak is easy. Follow a tractor trailer down the highway. I've seen as much as a 9 MPH increase doing that. But to get an average is much harder. Maintaining that average fill-up after fill-up takes biblical levels of patience and concentration. Then again, the 2.25 MPG is what you need to break even. You need 2.3 or better to see any difference. To make a reasonable dent in the $600 a year difference, you'd need over a 3 MPG average increase. Good luck with that just changing fuel grades.

Bubinga99

Putting it even more simply, if any significant fuel economy improvement could be had by just switching to higher octane fuel, car manufacturers (especially of sub $25k cars where fuel economy is a big selling point) would spec their cars for it, so they could claim higher mpg than their competitors in their advertisements. It would be the cheapest possible way for them to claim higher mpg (no tooling or development costs).

In turn, their competitors would do the same thing to catch up, and by now there'd be little demand for 87 octane fuel, and the price of 91 might have even dropped to where 87 was.

inspiredsports

Jstas wrote: »

OK, I'll put it this way then.

2007 Lincoln MKX: 20 gallon gas tank. 17.5 gallon fill up of 87 octane: $38.50...lasts about 12 days.

2001 Ford F-150 Lightning: 25 gallon gas tank. 17.5 gallon fill up of 93 octane: $57.00...lasts about 8 days.

In one year, provided gas prices were actually static, gas alone costs:

Lincoln: $1,171.04
Ford: $2,600.63

Difference: $1,429.59

You will not gain enough in fuel economy to offset price differences between 87 and 91. You will gain power because timing advance can be increased to provide a better air/fuel burn. You'll also burn more fuel as the computer richens the mixture to keep NOx emissions in line and prevent an over-lean condition from blowing up the engine. Whatever efficiency you might make will be offset by the higher fuel usage of the engine due to the more aggressive tune. Power don't just materialize out of thin air. It needs a fuel source to be created. More power uses more fuel and air. I will be very surprised if you get more than a 2-3 MPG increase. To make a switch to 91 worth while, you will need more than a 5 MPG increase to realize any cost benefit. It'll be paltry at that as well.

Your presenting a comparison of your 2007 Lincoln MKX using 87 octane to your 2001 Ford F-150 using 93 octane makes me think you do not understand apples, oranges or mathmatics.

Today's delta between 87 and 91 octane in my neighborhood is 4%.

The early line according to the fuel computer is the car gets about 24 mpg on the driving circuit my daughter will typically travel.

So . . . if the mpg increases to 24 X 1.04 = 24.96, the use of either octane is equivalent. If she gets 24.97 mpg, 91 octane wins.



P.S.: Good luck with your Linclon Sedan, your Ford truck and your fruit basket.

inspiredsports

Bubinga99 wrote: »

Putting it even more simply, if any significant fuel economy improvement could be had by just switching to higher octane fuel, car manufacturers (especially of sub $25k cars where fuel economy is a big selling point) would spec their cars for it, so they could claim higher mpg than their competitors in their advertisements. It would be the cheapest possible way for them to claim higher mpg (no tooling or development costs).

In turn, their competitors would do the same thing to catch up, and by now there'd be little demand for 87 octane fuel, and the price of 91 might have even dropped to where 87 was.

You missed my post (#17) where I learned about this specific engine mating VVT-i with it's ECU.

It is true that a "dumb" engine will probably not achieve better mileage with 91 octane.

Jstas

inspiredsports wrote: »

Your presenting a comparison of your 2007 Lincoln MKX using 87 octane to your 2001 Ford F-150 using 93 octane makes me think you do not understand apples, oranges or mathmatics.

Today's delta between 87 and 91 octane in my neighborhood is 4%.

The early line according to the fuel computer is the car gets about 24 mpg on the driving circuit my daughter will typically travel.

So . . . if the mpg increases to 24 X 1.04 = 24.96, the use of either octane is equivalent. If she gets 24.97 mpg, 91 octane wins.



P.S.: Good luck with your Linclon Sedan, your Ford truck and your fruit basket.

Fine, you know more about it than I do.

Combustion engines do not work that way and if you read the 2nd post I posted, I addressed your knee-jerk response already.

You switch to a higher octane, the engine is going to use more fuel even if the computer can "compensate" for it. You will not see a difference in mileage worth the extra expense. This is experience talking, not math. But it's fine, you obviously have the money to burn and know more than I do so, have fun wasting it in your Toyota. I hope your daughter is as disciplined of a driver as you seem to think you are.

BTW, better take that Toyota in for the recall service if it hasn't been in already.

No, not that recall:

http://www.intellichoice.com/1-201-2002-709-10v345000/2002-toyota-avalon-recall-10v345000.html

xj4094dg

The Jag REQUIRES premium. Kinda sucks because I only get about 14 mpg city but, I work from home so I don't really give an S and I love the ride.

In my last life, as a certified Cadillac service adviser, rule of thumb was follow the manual. Many GM engines are tuned for 87. FOLLOW THE MFR RECOMMENDATIONS and you will be fine as wine.

Cheers!

camp21178

Here's another octane link. You do not need higher octane fuel than your manual recommends. http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf

bikezappa

inspiredsports wrote: »

I'm going to run 3 tanks of 87, and then 3 tanks of 91 and compare notes.

Great idea-get the real data between the 87 and 91 gas and compare milage results.

Please share the results.

mole'

dorokusai wrote: »

I run 87(E85 if possible) in my Avalanche and 91+ in the Audi. If it wasn't for BG products I'd wonder about my truck but everything runs fine and internally looks clean as a whistle. I take the Audi more seriously...plus it carries my wife so there you go.

e85 is awesome stuff. way cheap too.

inspiredsports

camp21178 wrote: »

Here's another octane link. You do not need higher octane fuel than your manual recommends. http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf

Correct. This owner's manual clearly states you can use both because the the VVT-i Variable Valve Timing technology allows you to use either. The manual also says 91 yields a performance boost, but it does not say what happens to mileage, so that's why I will test both grades.

bikezappa wrote: »

Great idea-get the real data between the 87 and 91 gas and compare milage results.

Please share the results.

It will take a while as she drives fewer than 200 miles per week and a tankful will cover about 430, but I will definitely post results (probably mid December).

inspiredsports

Here's the low down over the first 2600 miles:

55.5 gallons 91 octane at an average cost of 2.899 per gallon = 1,405.6 miles = 25.33 mpg

48.7 gallons 87 octane at an average cost of 2.819 per gallon = 1,190.2 miles = 24.44 mpg

Mileage was 3.64% better with 91 octane for a cost that was 2.84% higher so we are better off at these price levels burning 91 octane.

ratster

mole' wrote: »

e85 is awesome stuff. way cheap too.

How many cents per gallon cheaper than regular 87?

inspiredsports

ratster wrote: »

How many cents per gallon cheaper than regular 87?

I don't know much about alternate fuels, but also should have added that we can sometimes find slightly cheaper prices here, but have a deal through Giant Eagle Grocery stores where "Fuel Perks" at their "Get-Go" stations gives us 1% off of our grocery bill for every 10 gallons purchased.

We go through over 50 gallons of fuel per week with 6 drivers at home and 5 cars on the road. We go through about $200 of sale/coupon items from Giant Eagle in the same time period which are discounted to $180. We might overspend on gas by 3 cents per gallon ($1.50 per week), but it saves us $20 because our family is so large and it's rare the kids don't have at least 1 extra guest at dinner (we're traditionalists in that we have a home-cooked, sit down family dinner at least 6 nights per week).