110 octane
 

So i went down to my local napa, bought five gallons of 110 octane put it in on E. more power, better response. filled it up the rest of the way with 91, lost some of the power and response. what im wondering is what is the limit where its a waste for octane level? Anyone have an opinion on this?

Interesting but at the actual price of fuel i might stick to 91 if u dont mimd

Our cars aren't going to gain much more over and above 94 octane. If good 93 to 94 octane is used the car should run the maximum timing it is capable of.

Sent from my Galaxy Nexus using Tapatalk 2

The stuff you bought, does it says "Unleaded"? If not, the lead in the fuel will destroy your catalytic converters.

What that guy said. Sounds like more of a placebo affect than a thing else. If the cars are like other Subarus there are Self adjusting maps which get more agressive without knock events happening by just dump

Yes, higher octane = less energy. Thus if you're not already getting any knock and such, the car isn't going to default to exceedingly aggressive timing or a/f ratios to take advantage of the anti-knock potential of the gas...

...Which will equal no added power if not potentially even a loss...

Sorry, getting used to posting w/tapatalk...

http://www.ft86club.com/forums/showthread.php?t=9265

No, I didn't post this because it has the funniest quote I have ever read...

Hmm, well the temperature here in the Phoenix metro area was in excess of 111 degrees Fahrenheit, and I'm sure the extra six gallons or so effected the weight of the car enough to change the readout of my butt-dyno.

In the absence of tuning, or at least datalogging options (e.g., of ignition timing), you have no way of knowing what, if any, gains were made.

Put in on a dyno, first with 93, then reset ECU, then run with 100+, then post results.

Real Dyno > Butt Dyno

No, higher octane = less likely to autoignite.

You will still make the same torque burning the same amount of high octane petrol -- it still is stoichiometric at 14.7:1.

Almost a complete waste of money on a stock car. This exact subjuct is already being discussed here and has been dicussed on every car forum on the internet since the begining of the internet and probably before that. This horse has been beatin for so lung we're just pounding on dust now.
:reposthorse::reposthorse:

I am the link ninja!

http://www.ft86club.com/forums/showthread.php?t=8691

for those that are too lazy to read...

Factory fresh datalogging...

Run the lowest octane you can without knock! Otherwise you can foul plugs, o2 sensors, cats and so on. Octane boosters like to foul things as well.

You dont seem to understand what octane does in a fuel. Higher octane prevents detonation. It burns slower and more controlled. That allows you to run more ignition advance and/or boost in an FI car. That's what makes more power, running more agressive profiles - profiles that would damage the engine otherwise with detonation.

You dont benefit any from running 110 octane over premium as that is what the factory tune is done on. The ECU isn't going to run a more aggressive map than the one meant for premium because there ISNT one programmed.

Even if you went to the dyno and extracted as much power as possible from that fuel you're not going to net much of anything over premium without rebuilding the engine with much higher compression pistons for a higher static CR or boosting the hell out of it.

:popcorn:

Ah but note that he said he filled it with 91. Now it's probably just the placebo effect in this case, but 91 vs. 93 should have a small difference.

Only if knock is detected and the ECU retards the ignition advance.

So honestly... probably no difference in reality.

The owner's manual says fill with 93, 91 is okay if that's all you have, but you may hear slight knocking. If the manual admits that you may get some knocking with 91, then I think it's safe to say there should be a small difference, easily perceptible or not.

Again, only if you actually knock and the ECU detects and retards timing. There's a whole lot of factors involved.

This doesn't tell us much. We would need two to compare. Whether you would like to call this a placebo effect, or whatever negative response, I noticed a difference in output and throttle response in very hot weather. What is a condition that would cause an engine to knock? I'm sorry I forgot, it's hot weather, low octane, high boost, and high compression. Now in case y'all in the Midwest have been living under a rock, aren't aware of the climate around the country, or flat out have a low reading comprehension, I live in one of the hottest regions in North America, I do not have access to a pump that produces an octane higher than 91 octane, and guess what? It is approaching the hottest time of the year for un in the northern hemisphere. So having said all that nonsense, I currently am experiencing conditions that meet two of the criteria that would cause an ecu to retard timing due to knock. The temperature is in excess of 110 Fahrenheit all day, and my vehicle has a high cr. I am not saying that my car can make full use of the higher octane, I'm not saying that this gas is by any means anything that could be considered economical, but hey we didn't buy a Prius, at least I didn't, and I'm having fun, in my book that is all that matters.:thumbup: