Regular 87 octane vs premium 91-93 octane
 

Why does the manufacturer recommend 87 octane gasoline when the engine run like crap with it. When put regular gas, the engine makes rattling noise and pinging noises and acceleration is horrible. Gas mileage also suffers. The same thing happens in my wife's Rav4 which has the same 2.4 engine. When I put premium fuel the engine runs smooth, gas mileage is better as well as power and acceleration. I called Scion and Toyota and the couldn't give me a direct answer. Any feedback would be helpful.

I have seen many vehicles recommended fo 87 that ping on it (Ford Ranger, Chevy Full Size, my current Hyundai Sonata).

My xB however, runs great. I actually did some comprehensive testing and it gets worse mileage on 93 vs 87. Not sure what your issue is.

My Sonata is OK on 87 most of the time, but when it starts the pinging I have to run 89 to get it to stop. Once I take it into Firestone or something like that, let them run the upper intake cleaner liquid into it, it will stop for awhile. I guess it gets buildup or something. Both of our Chevy Z71's at work (2003 and 2007) have to have 93 or they sound bad.

Maybe it's the fuel in our area that makes the engine rattle and ping. We live in NJ and the fuels have a summer blend mixture and a winter mixture. That could be the issue. But for now I will continue to use premium fuel. For some reason my xb does not run well on regular 87.

Hmmm this is interesting. I have always been running 87 and hearing the pinging noise. Next fill up I will try 91 and see how that goes.

It sounds like the fuel in your area is bad - specially when you have 2 cars that ping and rattle. Try the mid-grade first.

In Arizona, the weights and measures department actually posts reports on how good the fuel is on a regular basis - you need to do a search and see if your state does that.

Here's a link to the AZ site for comparison - bug your state to post these results also. My cars run fine on the regular stuff. There was one time they didn't, I checked the site and the RON was 3 points below the nominal across the board.

Inspection Search
Type in Phoenix and select fuel quality from the drop down

I have to agree with MarcusJDM. I have been using the recommenced 87 ever since I bought the car but because of this thread I decided to try 89 on last fill up. Some things I noticed when switching to 89 is much smoother starts, better acceleration, no more pinging noise and smoother idle. Gas mileage didnt seem to be affected at all though.

I went back to 87 yesterday to see if maybe it was just a placebo effect but sure enough the pinging noise has returned and starting the car seems to be rougher. Next fill up I am going to try 91.

This engine deff runs better on higher octane. My 2010 w/ 80k pings on 87 no matter where I buy it from.

Weird. Im in the camp maybe it is the area. Like I said, my box is at 86k miles and has drank 87 the whole time without issue.


I do run an aftermarket intake, not sure that it would matter.

I've been running 87 in my 08 for 125K no issue at all. Just switched to 91 today but that's due to new engine mods which will require it.

Running 87 didn't necessarily cause me any issues really, it still runs fine when using it but just seems to be better with higher octane.

What did you get Greg?

Unichip to go with my intake, headers, and exhaust. Haven't put it on yet though. The switch to 91 actually got rid of some morning hesitation I had before engine warm up and things seem to run smoother now.

You should try a different gas station

Modern engines are designed to ping to some extent, since they try to extract as much energy from the fuel as possible. It's not a good thing in general but engines are designed to handle it.

You can use any grade, but you should stick with it, otherwise the computer will have to readjust every time you change grades. Changing grades is arguably worse than using the wrong grade over and over.

A vehicle will usually make more power running 87, as it has *slightly* more BTU per gallon. And it is cheaper - so why pay more for less.

I'm a new xb2 owner (july) and i've been using 87 from the beginning. Maybe because this engine is soooooo much quieter than my 08 Mini that I don't notice. However, the car is peppy and quiet in my eyes/ears. I've been using arco in the scion since they now claim "top tier" and recently costco. Costco from what i've been reading has even better gas than most.

It will make absolutely no difference in power or engine lifespan filling up at costco vs arco.

Cost wise you would be better served spending less on gas and more on regular maintenance.

I'm more concerned about the Ethanol in the fuel than Octane. If I was running a turbo or supercharger then I would consider the octane. If you enjoy your car more with higher octane fuel, go ahead. Different parts of the country have different fuels.

I use to have a TDI Jetta and I could tell the difference between difference brands and regions of diesel. I use to keep a bottle of cetane boost in the trunk for those times I felt I got crappy fuel. The car got 700+ miles a tank full so it was really not much of an issue to make sure I got fuel from my favorite station.

Buying anything other that 87 is stupid. Unless you have a high compression car that requires the higher rated fuel you are wasting money. Here this will explain it better than i can....................................

If you plan on keeping your car for a long time, just make sure to use top tier rated gas. The 2AZ can adjust timing, so it doesnt really matter what octane you fill up with. You might get a little more performance with 91 octane, thats only if your racing all the time.

Anyone try to run E85? I've been reading up on it, and supposedly it's safe to run in non-flex fuel vehicles. In some vehicles the check engine light will come on because of how clean it burns, the computer basically thinks the o2 sensor went bad. E85 is 107 octane......could give a little boost in performance.

Any thoughts?