What kind of gas are you guys putting in ur Solara?

[Jon11582]

Ok I'm going to dispel a few myths here.

Higher Octane = LESS bang. The whole point of higher octane is to prevent detonation at high compression.

Lower octane fuel cant be compressed as much before it detonates, which is the direct cause of engine knocking.

Now....what octane do you need? let me start with the I4s since thats easy. The 5S and 2AZ both take regular gas. You gain nothing by using higher octane fuel. You dont get more power, you dont get more mileage, it doesn't "clean your engine better", nothing. The engines doesnt compress the fuel enough for it to detonate before full compression, so 87 is just fine.

Now for the V6s, the compression is higher, and its premium recommended. What this means is that testing was done with premium gas on that engine. What happens if you put regular in? The ECU in all modern cars are smart enough to retard timing when it first senses early detonation. Retarded timing does mean reduced power, and possibly reduced mileage. Its important to note that this will NOT harm the engine in any way.

Whether or not this difference in mileage is enough to make up the difference in price, I dont know since I havent seen raw data about how much mileage decreases when running regular on a premium recommended engine. I'll reserve judgement until someone draws up some real data, but my guess is on the 1MZ/3MZ, its not all that much, since its not a extremely high compression/forced induction engine, and you would still save money by filling up on regular than filling up with premium at a ~15% premium.

And finally..the 2GR. Im pretty sure the 2GR-FE, in all its Toyota variants (Avalon, Camry, Rav4) is rated for regular gas and not premium gas. Toyota.com doesnt say, Edmunds says regular, and In the Lexus variants (ES350, RX350), it produces more power and is rated for premium, probably due to advanced timing for premium gas.
Its kind of suprising because its high output and high compression at 10.8, but what I'm thinking is toyota took it easy with the timing on the 2GR at the expense of some horsepower in the Toyotas, enough so that regular gas was all thats necessary.

onefiend - Can you verify if the 07 Camry V6 is premium recommended or not? If its not premium recommended, then theres no benefit to using premium on the 2GR-FE in Toyotas either.

My recommendation is use regular if your on a budget on the I4 or V6, and use premium if your not living paycheck to paycheck and have a 1MZ/3MZ V6. I'm not entirely sure how ECU engine timing adjustments play with forced induction, so this recommendation is only for N/As. If you have enough money to afford a turbo or S/C, then you have enough money to afford premium gas and you shouldnt put anything else in your engine.

[MCOjerry]

I have been running premium (I guess that's 94) since reading the last post on this topic.

I have found that I do get a little better gas mileage, and a little more power. Engine seems a little more responsive with the premium.

[onefiend]

but what I'm thinking is toyota took it easy with the timing on the 2GR at the expense of some horsepower in the Toyotas, enough so that regular gas was all thats necessary.

onefiend - Can you verify if the 07 Camry V6 is premium recommended or not? If its not premium recommended, then theres no benefit to using premium on the 2GR-FE in Toyotas either.

I think marketing/advertising has alot to do with it to. Camry needs to compete with the Accord which uses regular for its i4 and V6. The 2GR in my Camry is exactly the same as the 2GR in the ES350, the ES350 gets 272hp because it requires premium. Camry is rated at 268hp because of regular, that's my thinking.

This is what my manual says:
Fuel type: Unleaded gasoline, Octane Rating 87 (Research Octane Number 91) or higher.

I've had a full tank with 87, a full tank of 89 and a full tank of 91. The 2GR I feel responds better with 91 octane, the engine feels smoother with better response.

[made in china]

Jon11582,

You are pretty much right. I just had to correct your math a bit...currently in my area, gas stations still use the +$0.10 per grade. So, at $3.00/gal avg, the cost for premium over regular here is 6-7% more, not 15% like you stated. So, the gap at current prices is much smaller. 15% would've been a few years ago.

So, my car gets about 15% better MPG on 91, which is only 7% more expensive. Therefore, the Solara gets 91.

My wife's Max, same MPG whether it be 87, 89 or 91. Max only gets 89 or 91 cause it has a bad case of the "pings" sometimes....otherwise we'd run only 87 in it. It has 200k...so I take my cars case by case.

And I was gonna say I assumed that the 4cyl's won't benefit from premium grades, as you confirmed.

My point is, you're right. And, furthermore, probably most any gas OBD-II car these days can safely tolerate lower grades...they all have ways of dealing with pinging. But, Solara owners with V6's should perform a test with their cars...run a few full tanks of 91 and run a few full tanks of 87 while recording your avg MPG in fair driving conditions. Check what is the price "premium" of premium, and just compare the % gain in efficiency directly to the % premium of 91. I bet most people will find 91 is actually CHEAPER with the 1MZ. And peppier too.

BTW, my car is labeled "UNLEADED FUEL ONLY".

[Somedude]

I put regular gas in my Solara because it requires regular gas. If I put premium I probably get less gas milage.

[onefiend]

I have been running premium (I guess that's 94) since reading the last post on this topic.

I have found that I do get a little better gas mileage, and a little more power. Engine seems a little more responsive with the premium.

94 octane!!?? you are so lucky.

[MCOjerry]

I have been running premium (I guess that's 94) since reading the last post on this topic.

I have found that I do get a little better gas mileage, and a little more power. Engine seems a little more responsive with the premium.

94 octane!!?? you are so lucky.

It's either 94 or 93, I can't remember. Why lucky?

I have never seen 91 anywhere, it's either the 87, 89 or the premium which is the 93 or 94. I'll look next time I fill up.

Gas here is the same as someone said in one of the previous posts, .10 difference between grades. Currently, the 93 (or94) is anywhere from $2.97 to $3.05/gal, depending on where you go. 87 is around $2.77 to $2.85/gal.

[JMSinMaryland]

I4 put regular, anything above regular will not add power or help in any way, will not hurt anything except wallet

V6 will accept regular through premium and will operate fine, power on regular will be reduced due to engine pulling back on the timing to prevent knock, to truly 'unleash' all the power you need to put in premium

The V6 in the Lexus and Toyota Camry are the same. The only reason Toyota recommends/'allows' the use of regular is to keep competitive with Honda. Honda's sell based on the fact that they 'recommend' regular gasoline, therefore people believe in the long run they are saving money.

If Toyota only recommended premium for the new Camry, it would definitely give Honda a nice little bump in Accord sales. Also the 'extra' power for the Lexus ES350 is a little puff of smoke up the Lexus owners a$$ so they believe they are getting a 'better' vehicle.

[QuickSEV6]

93 Octane

Used to get gas from Mobil

Now I switched to QuikTrip... more conveinient

[Turbosolara]

did you guys read your user manual at all? it says for better performance, premium fuel is recommended. my is300 is strictly has to use premium fuel

[DatSRBoi]

93 octane and getting 270 on a tank.... Thats driving slow..

93 octane and getting 200 sometime less on a tank.. Thats releasing the superchargers power and still driving slowly.

[Jon11582]

If Toyota only recommended premium for the new Camry, it would definitely give Honda a nice little bump in Accord sales. Also the 'extra' power for the Lexus ES350 is a little puff of smoke up the Lexus owners a$$ so they believe they are getting a 'better' vehicle.

Can you explain why the ES350 gets worse mileage than the Camry V6 at 21/30 vs 22/31? In theory, on an engine that is made to use premium gas, mileage and HP should increase when using premium gas.

I have two theorys.

One is that I think the valve timing is tuned differently on the two cars, and the Lexus is tuned more aggressively for premium and the Toyota is tuned for regular.

Second is maybe theres something different about the intake or exhaust piping as well that is causing a mileage decrease (Maybe a different muffler or intake to lower cabin noise?)

As far as this research octane thing. I just read up on it, and it actually makes alot of other things make sense. Stop reading now if you dont want to learn something.

I noticed this before but didnt think much about it, but when you go to a gas station, near the octane numbers, youll see something that say "octane calculation method = (R+M)/2". "R" stands for Research octane, "M" stands for Motor Octane, and apparently all gasoline has TWO octane ratings.

Research octane is pre-iginition resistance of a gas under controlled conditions.
Motor Octane is the pre-iginition resistance of a gas heated up, under load, higher RPM, and with variable ignition timing. Basically, near worse case scenario.

Modern gasoline has about 8-10pts difference between Motor Octane and Research Octane. Gasoline that is rated as 91 octane at the pump in the US is probably something like 87 Motor Octane/95 Research Octane. Of course, you dont run you car under the worse-case conditions of Motor Octane, nor the ideal conditions of Research octane. The way most people run thier cars is somewhere in between, so the method that gas companies use to rate gas in the US is an average of the two. In reality, people run thier cars closer to research conditions than motor conditions - Light load, standard ignition timing, low to mid RPMs.

What this means is the octane you need on a premium-recommended engine depends on how hard you drive your car. If you keep the revs low, the gasoline will have pre-detonation resistance closer to the research octane rating, which is genrally 4-5pts higher than the pump octane number.

On the other hand, if your doing repeated runs down the 1320, then its probably near the worse case scenario, and you will operating closer to the conditions for the motor octane rating, which is 4-5pts less than the pump octane rating. This would be why higher octane racing fuel helps at the track.

The US generally uses the average of research and motor octane, and some countries use just research. So when you see a pump with 98 octane in another country, its might be the same stuff as our 93 octane.

So what to use in the V6? Depends how hard you drive it. You can get away with regular with no retarded timing if you keep to flat roads and the RPMs low. If you do a fair amount of reving, then plus will be fine. If your going uphill alot, or your living in your powerband at ~5K RPMs, then even putting in 91 premium might cause some retarded timing, but obviously not as much as if you put in 87.

This circles back to what TurboSolara said - On a premium recommended engine, try each out and see what works. It depends on the driver, the environment, the health of the engine, etc. Theres many variables, and theres no way of finding out what you need without giving each a try. Putting in a gas of higher octane than you need is still a waste of money and offers no benefits.

[Sebas007]

Jon11582
nothing to add to your 2 posts...you just tell everything and broke those myths...high octane doesn't detonate before it has to be proctecting your engine of early detonation that would mess with the normal steps of a full engine revolution.

Great writing !

[NeFaRiOuS_SLE]

91 all the way... If there was 94 I'd take it, but I'm in California.

By the way, thanks for the write-up, Jon... When I researched foreign gas prices, I was thinking that the Europeans got it made, with close to racing fuel octane gas!

[shocar4]

premium....93 octane and i get 27+mpg all the time!!!