Premium or Regular?

[wesscamrywagon]

I have a 1990 camry with a V6 in it. In the owners manual it says either 87 octane, or "for better performance" 91 octane or better. I was thinking about trying a tank of premium to see if it pays for itself in gas mileage. If it does, then I'd be running a better great gas to keep my engine in good shape, and it would pay for itself in mileage. Sounds good right???

My most important question is, will i have to reset the ECU in order for the premium to even make a difference? Some newer cars get the fuel MAP stuck until it is reset. So if you had a car that was supposed to run on premium and you put regular in, it would retard the timing. But once you put premium in again, the timing stays the same. This has actually been documented by dyno in a car magazine i read on a WRX. Do our/my camrys do this to?

Has anyone tried this?

What do you guys like to put in your cars?

Thanks guys.

[javolin13]

I put the mid grade stuff in it... less lead/crap your engine doesn't need. And ive never heard anything about your ECU reset or whatever you're talking about... i would just suggest you get octane booster and fuel injector cleaner, then perhaps change your fuel filter, then while your at it just get a full tune up... after that you should notice a slite difference... as for your fuel mileage... that has nothing to do with anything... it all depends on how you drive your vehicle and how high you run your RPMs while accelerating and maintaining a high speed. If you keep your RPM's around 2500-3000 while doing both you shouldn't have a problem in gas mileage after the full tune up. If you do... then you need to take the lead sole out of your shoe and drive the car like it was meant to be driven...

[Cyorke]

this has been discussed many times on here. I also run regualr in my 94 V6 and it has no problems with pinging or anything of that nature. IT runs fine with any grade gasoline I put in it. Running premium over regualr is not going to increase your fuel mileage by enough to make a noticeable difference. I have run both and have never noticed a difference in performance or fuel economy. ON my Sienna I have not noticed a difference in fuel economy but it pings to high heaven if I run regualr in it and not premium. It is a 1MZFE with vvt-i.

If you decide to run premium and you want to reset the ECU all you ahve to do is remove the EFI fuse under the hood for about 15 seconds and then put it back in.

[ASG14]

I have a '96 V6, and the owners manual says the same. I just use 87, from whatever brand is the cheapest. No problems after 18k miles in a year. Just get regular and save the money. Plus Premium just pollutes more, haha.

[CCCP]

^^ I got 80km less on a tank of regular gas. But V6 runs perfect on 89 no powerloss, if there is it's probably so minimal so it wount matter in your race against some v8 LOL will get owned anyway

[atobe]

i doubt it's gonna make a difference if it doesn't knock on 87 it'll be fine... but i got a 88 camry i run 89 gas only though no need for 91

[rayprog]

It might sound weird. The best mileage I’m getting when I mix in the tank 2/3 89 and 1/3 91 in southern Ontario (ESSO or Shell). I do not even know how to explain that, but it get’s me + 30 to 50 km on tank. That’ probably more related to the quality of gas. The difference more noticeable if I’m fuelling up 89 south of the border (NY or Michigan) or in northern Ontario (Parry Sound and up) it gives me + 60 to 80 km on tank comparable same brand taken in southern Ontario.
I’m diving Camry V6 92. All experiments related to highway driving. I did not compare anything for the city driving.

[rat42]

the 1990 ECU wasn't that smart. my experience is that cars are individuals. run a few tanks of high test and figure cost/mile for gas.

[te51levin]

Well, my '85 MR2 will relearn the fuel map. I'm sure a few people will argue that it doesn't ("my brother's roomate was a Toyota tech and he said" etc), but I've reset it a number of times and satisifed my curiosity, and proven to myself that it does. It has an oxygen sensor to get feedback on the fuel mixture, but it doesn't have a knock sensor to get feedback on the ignition curve. Your VZV21 does, so perhaps it will also relearn the ignition map. Resetting the ECU will send it back to its baseline maps and will probably speed up the process of getting it back to a curve that will take advantage of higher octane fuel.

javolin13: There is no lead in automotive fuel anymore. In fact I haven't seen it in my area for about fifteen years. And higher octane will/should enable more spark advance, which very definately equals more efficient combustion, hence significantly greater fuel economy.

ASG14: Be careful. Your athlete of an engine is being fed a diet of off-brand junk food. Cheap gasolines can be blended inconsistently, can have more impurities (dirt and water, for example), and can clog fuel injectors and create deposits inside the engine. You may not have seen it in 18K miles and you may never see it, but why take a chance to save 50 cents per fillup? And...higher octane fuel pollutes more? Where did you hear that?

rayprog: in order to be anything close to useful, you really need to figure miles (or km) PER GALLON (or per liter), not miles, days, burgers etc PER TANK. An average of three or four tanks, preferably filling up at the same pump for greater accuracy when the pump kicks off, is enough to get a firm grasp of your actual fuel consumption.

rat42: Are you sure? Where did you hear that? I would not be surprised to find that it is fully capable of remapping fuel and ignition curves based on feedback from the oxygen and knock sensors.

I'm not trying to be a know-it-all here, but I am so tired of rumor and old wives' tales ruling every forum I visit. I'm pretty careful to make sure that what I say is true, and most of what I read in this thread runs dead contrary to things that I have learned from personal experience and real authoritative sources (i.e. NOT internet "wisdom"). Toyota mechanics can be wrong...high school or college auto shop teachers can be wrong...engineers that are out of their depths can be wrong...books and magazines and, yes, even The Almighty Internet, can all be wrong.

Knowledge is power. Ignorance is bliss. Ignorance being passed off as knowledge is what most people accept as gospel, and is worse than useless.

[HoboJoe]

My 93 camry v6 runs fine with whatever I put in it. Regular, plus, premium... diesel, the thing loves the stuff.
OK, seriously, I put regular in the camry but will try plus and maybe premium on my next fill up. Now, in my 73 Lincoln, there is a noticeable difference between gasoline types. On regular, the thing idles rougher than it does on plus. And when using plus, I have noticeably more power to the wheels and the car just sounds quieter overall. I'm gonna try premium soon.

[auzcam]

Don't know what you yanks are using, but in Australia or at least most of it, the lowest octane is 91, and the highest is 100 octane. I put a tank of 100 octane premium in the other day to my 2002 2.4l 4cyl camry sportivo. Don't know if it was because of the ECU or because of compression ratios but it didnt give the power i expected from 100 octane. The 98 octane I use every now and then, performs much better. Anyone got any ideas? In fact I worked it out I got like 16l/100km fuel economy which is absolulty shite. This is city driving. I put the 100 octane stuff in a 4cyl honda CRV on highyway driving and got shite milage outta that too. Is 100 octane too high for normal cars like these?

[sasair]

At 20 cents per gallon difference for 87 and 91 octane, that would be more like $3+ per fillup, which for me would be like $18+ per month or $216 per year, and thats only on my camry. Doesn't include my wife's and daughters vehicles which use much more gas. So I figure I'm saving at least $700 per year, which could easy be used to clean out my fuel system on all 3 vehicles and still have enough left over for other camry toys....

BTW, I track my mileage on every tank of gas, and I have tried 87 and 91 octane, and see no difference in mileage. I average about 22mpg, and there is alot of bumper to bumper traffic in my area on a daily basis. Haven't taken the camry on any long highway trips yet, as we usually take the big SUV, but interested to see what my mileage would look like then.

Originally Posted by te51levin

You may not have seen it in 18K miles and you may never see it, but why take a chance to save 50 cents per fillup?

[JMSinMD]

I put premium in my 99 S/C V6 Camry. In my mother in laws 95 Avalon she normally puts the lowest grade, when I fill her's up I put premium and I can definitely tell a difference. The car is smoother and feels that there is the hp that is supposed to be there. I guess when she puts in regular the system retards itself to prevent knocking which cuts down on the power. I need to try midgrade and see if I feel a diff. I haven't even monitored gas mileage for difference. Jon.

[Eye8Pussies]

^ werd

the 1mz can run fine on 87, but it was made for 91+
if driven lightly on 87, it won't ping, but once you drive it hard, it pings like nobody's business and when compared to using 91, you can feel the difference- there's no power all the way to redline

nothing below 91+ goes in my car
sure it costs a bit more, but such is the cost of wanting to drive your car (semi-)hard and get as much performance out of it

[te51levin]

Originally Posted by auzcam

Don't know what you yanks are using, but in Australia or at least most of it, the lowest octane is 91, and the highest is 100 octane. I put a tank of 100 octane premium in the other day to my 2002 2.4l 4cyl camry sportivo. Don't know if it was because of the ECU or because of compression ratios but it didnt give the power i expected from 100 octane. The 98 octane I use every now and then, performs much better. Anyone got any ideas? In fact I worked it out I got like 16l/100km fuel economy which is absolulty shite. This is city driving. I put the 100 octane stuff in a 4cyl honda CRV on highyway driving and got shite milage outta that too. Is 100 octane too high for normal cars like these?

Ahhhh yes, here we are again...the old Australian/JDM/UK octane myth, including the famous belief that "JDM engines make more power because they're designed to run on 100-octane gas and we only get 91 to 93 in the US". Nevermind the fact that Japan uses a different ratings system to determine their engine's power output than the US does. Nevermind that fact that manufacturers - yes, even Toyota - have been known to fib more than a little with their horsepower and torque ratings. The fuels themselves are also rated differently in different markets and can't be fairly compared number-to-number.

It's not that easy. Autsralia, Japan, etc rate their fuels using Research Octane Number (RON) only. The US (and Canada, I believe, and I'm sure some other markets) use an average of Research (measurement of the fuel's resistance to detonation during a 600rpm test with cooler intake temps) and Motor (measurement of the fuel's resistance to detonation during a 900rpm test with much hotter intake air temperatures) octane numbers; look on any gas pump in the US and the octane label reads (R+M)/2. These tests are always conducted on a very specialized and very standardized single cylinder engine with a variable compression ratio, designed just for this purpose.

What's it mean? It means you can't directly compare Australian or Japanese octane ratings with what we get in the US. A generally accepted and relatively useful benchmark is that pump octane, or (R+M)/2, ratings will be about four to five points lower than RON ratings on the exact same fuel. In other words, if I bought a gallon of 98 RON Australian fuel, flew it to the US, and had it tested, it would warrant a pump octane number of roughly 92 to 94, or maybe even less, depending on how honest the Australian refineries had been.

And it's still true that higher octane than your engine can take advantage of will not improve power. Octane is merely resitance to detonation. It is not power. If your engine can run an optimal spark advance curve without detonation, it cannot take advantage of higher octane fuel and will not benefit from it.

It can, however, always benefit from a higher quality fuel. Just as you would rather drink a glass of clean, filtered water than slurp out of a mud puddle, your engine and fuel system would rather have good quality brand-name gasoline (Chevron, 76, Shell, etc) than Costco, USA, AM/PM discount stuff.

Why people always think they're getting a bargain just because they're spending less money is beyond me.