In the end i think that everyone should try and see what best works for them...

CEO

 

Years of testing and research from the manufacture have already been done, and they tell you quite clearly what octane to use. So why reinvent the wheel?

 

I know this topic has been beaten to death, but I can't resist adding my .02 after spending the time to read all the posts, so here we go.

I use 87 octane in my '93 LS400 with 127k miles on it. I get get around 400 miles before the low fuel light comes on (5 gallons left in tank). From past experience, when my light comes on I still have about 5 gallons of gas in the tank. I'm no advocate for visiting the pump more often then necessary. I can usually get 500 miles out of a tank. Granted, this is using just about every drop of fuel, but come on, It's a 22.5 gallon tank, so I do my best to roll alot of miles before refueling.

 

I dunno if the RON is equal all around the world? Somewhere I heard it wasn't but oh well...

I use 98RON fuel in my Soarer, nothing else. City milage is shocking (450km/tank) but long distance (ie. interstate) it's brilliant (more like 700~nearing 760km/tank!). I've never dared to run it on anything lower than 95RON (normal premium) because the 1JZ was designed for 100RON fuel. Guys with J-Spec 2JZ conversions should remember that as well.

 

did i miss the RON memo? not quite sure what you mean (i.e. 95RON, 100RON) is it just how octane is referred to there?

 

Years of testing and research from the manufacture have already been done, and they tell you quite clearly what octane to use. So why reinvent the wheel?

if years of research has told us this info, why are we still having this discussion?..and why do people have different opinons?

CEO

 

I guess the way I look at it is... some people (including toyota/lexus) think that there is a possibility of damage that can be inflicted by the low octane and high compression. Is it really worth the .15 cents you save per gallon to tease with the line? even if you have been running on 89 octane for a year, how do you know your car has not permanantly changed the timing to deal with the lower octane? just my .02 cents. p.s. 93 octane plus meth injection is good

 

Yeah it's jsut how a lot of people call it over here in Australia So yeah 95 octane, 100 octane. I'm too scared to run anything lower than 95 octane fuel because the Japanese premium is rated at 100 octane, so the closest I can get the better as I've heard that the ECU retards ignition timing to cope with the lower quality fuel.

 

I always use premium, normally 93 octane. I noticed that in California to Iowa, the premium grade fuel is typically 91 octane. As much as possible, I try to put in Mobil or Amoco. However, while in California, Arizona, Nevada, and Utah, I saw a few Chevron stations. They advertise this thing called Techron which supposedly helps your engine run cleaner? Any truth to this?

For those in Sunoco fuel markets, is it worth the extra 15 cents for Ultra 94? Does the car benefit at all from it, or are you just paying for a "feel good" feeling? I put in premium grade fuel because the recommendation is 91 octane or better. Is it worth the extra octane rating?

Also, to the person with the LS400 - isn't it bad to drive your car down to the last gallon? Does that bring up contaminants in the bottom of your fuel tank, clogging your fuel filter prematurely?

-Brian.

 

My friend is a mechanic who swears by Techron, by Chevron. There was a guy with a truck that kept lagging and jerking at higher speeds. He told him to use Techron and, after a month, problem solved.

I don't know if it's a true story, but I hear only good things about it.

 

i used to swear by the stuff until I start running Exxon 87. my car runs much better now.

 

Maybe bacause America is full of egotistical idiots that are highly opinionated?!?!?!?!?

Some people are cheap and will do/say anything to defend their actions, with total disregard for the scientific community. The answer to this whole discussion is clearly stated on the gas cap door!! People have different opinions because they don't have all the facts. Many rely on the butt dyno for hp readings, and forget to remember that there are actual devices to give them exact results....but thats right, it costs money to go to a dyno. The butt dyno is free and regular unleaded is cheaper too. But rather than being honest with themselves and others; its easier to just defend their actions w/ BS. No one wants to be labled as cheap.

No need for this thread to be as long as it is. If diesel was cheaper tha gas, I'm sure someone here would say it gives them great gas meilage and everyone else is a sucker for paying for premium unleaded!

 

115 octane at moroso, or c16 (about 117 octane) if I'm near one of the executive airports. If you pay the guy a little extra at moroso, he'll let you use a funnel (filler nozzle is oversized) to fill up with the NHRA 118 octane they have, but usually they don't want you to.

SR

 

the highest i've seen around here is 91 octane.. which is what I always used and will continue to use.

 

These cars pull from the bottom of the tank anyways, so you're always getting the lowest level of gas thats in the tank.


As for the whole RON and Octane thing. RON is one measure of the fuels performance. MON is another. Octane is (RON + MON) / 2. Octane is really tricky though, because a 93 octane fuel from one place could case knock, and a 87 octane from another could run like a dream. Reason being is if the RON and MON are too far apart (85 MON and 99 RON makes for a 93 octane), but the fuel will be unstable. The IDEAL fuel is to have equal measurements on both, i.e. 93 MON and 93 RON which will equal 93 octane. Once you have higher compression and higher revving motors, it becomes much more important for the MON/RON to be as close to matching as possible.

I can get much more into detail on it if you want specifics on something. Fuel ratings are really confusing.

SR