91 vs 93 without tune and all stock

[MAPerformance]

Can't be. I have been running BP 93 since new. I have not had crickets in over two years.

Originally Posted by steeloyangster

In my area it is very difficult to find 93 Octane. (I have a list of gas stations that have 93 octane saved in my google maps.) For the first couple of weeks I was running 91 Octane and was averaging around 27-28 MPG. When I finally discovered that we did have 93 Octane I've started filling her up with the higher grade stuff. Now I get an average of 30-32 MPG depending on driving habits. I certainly don't drive her hard but when getting on interstates I do tend to rev her up to 5k - 6k RPM. I suspect that if I were to drive her super conservatively then I'd be able to squeeze 35 MPG out of her.

One downside to the 93 Octane that I've run across is that they have ethanol in it (BP "TOP TIER GAS") and I suspect this causes the crickets in my gas pump because I didn't have those crickets when I was filling them up with 91 Octane which did not contain ethanol. (Do gas stations have to state that there is ethanol in the gas? And if they don't state it then does that mean there is no ethanol?) Maybe I'll hop the border to Canada to fill up on some ethanol-free gas and get back to you guys.

[steve99]

Originally Posted by strat61caster

Less, biggest difference I could find evidence for was ~4hp peak. I won't argue that you loose some more under the curve but to imply that 91 vs 93 is 190 vs 200 hp at the crank seems exaggerated.

93 vs 91
http://www.fiestastforum.com/forum/t...ctane-OTS-maps

http://forums.themustangsource.com/f...octane-487398/

87 vs 91:
http://forums.vwvortex.com/showthrea...91-octane-dyno

87 vs 93 seems to give the numbers you stated on a Focus ST:
http://2gfusions.com/index.php?topic=2928.0

Was just a guestimate worst case senario for worst 91 formulation to best 93/94, your fuel in usa is superior to most in australia these car will pull 4 degrees timing and have IAM at 0.7 on our 98 ron octane fuel on stock tune we need to run 100 ron to get best results on stock tune

[roddy]

Originally Posted by J_kennington

No offense but unless you can data log tip in knock. There's no way to truthfully say there is less. Sounds like you are undergoing pure placebo effect. In essence, "I spent more on gas, and it says it's better for the car. So it must be better". Even on my turbo eclipse, data logs show no discernible difference between 91 and 93. That's running a tune off of 93, at 25 psi of boost. Now when you get into 87 and 81....there is most definitely a difference.

No offence taken. If I ever get around to picking up a tuner/tunes, or the ability to data log by some other means, I'd be very interested to see what it shows. It's definitely not the placebo effect...the difference is audible. To such a degree, that I put up with the crickets to run 94. Damn crickets...

[steeloyangster]

Holy shit, Cottage Grove!? Where do you get gas and where can I find it?

Anyway, the crickets are definitely intermittent for me and aren't really that loud even with the window opened at a drive through it's usually going in and out. Maybe the crickets don't have anything to do with fuel quality but this was only something I noticed once I put in 93. Not a causation but to me felt like some sort of correlation. I don't have the balls to go back and put in 91 Octane just to see if the crickets will disappear but I'd be willing to drive to find some ethanol-free 93 Octane.

Any tips on winter driving this car bro? Last winter scared the shit out of me and I don't know what to expect with this car.

Originally Posted by MAPerformance

Can't be. I have been running BP 93 since new. I have not had crickets in over two years.

[MAPerformance]

I always get my 93 at BP. I have driven the car through two winters now. Its not the greatest, but I managed. Do you have winter tires? That's a must. And I am going to try sand bags this year to see if that will help.

Originally Posted by steeloyangster

Holy shit, Cottage Grove!? Where do you get gas and where can I find it?

Anyway, the crickets are definitely intermittent for me and aren't really that loud even with the window opened at a drive through it's usually going in and out. Maybe the crickets don't have anything to do with fuel quality but this was only something I noticed once I put in 93. Not a causation but to me felt like some sort of correlation. I don't have the balls to go back and put in 91 Octane just to see if the crickets will disappear but I'd be willing to drive to find some ethanol-free 93 Octane.

Any tips on winter driving this car bro? Last winter scared the shit out of me and I don't know what to expect with this car.

[Priapus]

Air temperature rises as it is compressed. The FA20 has 12.5:1 compression ratio, which is very high. This leads to the need for fuels that can withstand higher compression/temperature before self-igniting. Our engines are designed to work with high octane gas.

I really don't think $2-3 extra every full tank can do that much of a damage to anyone's bank account. Take care of your car, buy her expensive things

Just my 2 cents. If you don't like it, throw it right back, I'll use it to buy more premium gas for my car.

Dramatic exit:

[Ubersuber]

Originally Posted by SpeedyJay

I just switch from Shell 91 to Husky 94 and I was able to tell the difference. The engine definitely felt more alive and happier on 94, however the crickets are much worse with the E10

You'll have a tough time measuring that on anything more sophisticated than your butt dyno.

Seriously, at 1,000 metres elevation you cannot get more power from this engine by using 94 until you supercharge it.

[Ubersuber]

Originally Posted by Priapus

Air temperature rises as it is compressed. The FA20 has 12.5:1 compression ratio, which is very high. This leads to the need for fuels that can withstand higher compression/temperature before self-igniting. Our engines are designed to work with high octane gas.

I really don't think $2-3 extra every full tank can do that much of a damage to anyone's bank account. Take care of your car, buy her expensive things

Just my 2 cents. If you don't like it, throw it right back, I'll use it to buy more premium gas for my car.

Dramatic exit:

That high cr works because of direct injection which cools the compressed air in the combustion chamber because the fuel is not compressed.

The engine is designed for 93 but at sea level air pressure. Only at seal level with 93 will it produce 200 bhp. The higher you are the less it matters.

[makesdrivingfunagain]

I think this a great question. We would probably be able to figure this out relatively inexpensively. I think if we were to dyno a car on 91octane and make 3 passes on it and use a fixed standard such as the SAE correction or Standard correction etc we would have a quality baseline. Then we have the same car and make sure there is no more 91 remaining in it and do what you need to do to get 93 or a 93 mix and run the car on the SAME dyno and with the same correctional factor SAE or Standard etc. and we should have some high quality data (accurate)

[Rocket.BRZ]

Originally Posted by BRZJunkie

I also noticed the pinging almost every time I blip the gas pedal and its hot outside. Manual says it might ping lightly and its not harmful as long as you don't use less then 91. Personnaly I think they are to close to the edge in many area and we get a car which is almost right but not quite. High compression of 12.5:1 and 2.0L and 200HP = pinging + crickets. Same old, same old. Lots of people will start to say, its only some minor sound, etc.... no damage done....

I'm starting to sound like I'm ranting. I guess I am.

Get a professional tune. Case closed. I actually have a 91 tune just so I can drive my car to the west coast. Might be a problem on a 93 octane tune with a supercharger.