Gas Premium or regular?

[TheVoiceOfReason]

Originally Posted by buckyislucky

Hey guys .... I was just trying to get a better idea about which brand of gas to use... ultra 94. Shell 91,Esso 93. Etc.... obviously the car takes premium gas. .. don't need to read the manual to know thay

For some know it all out there on the forums not everyone is a 86 junkie

I have actually wanted this car for 2 Years and now finally have it and want to make the best of it by getting as much info from everyone here.

I'm gonna stick to the 94... thx for the help...

Also, gas seems to vary place to place, station to station, brand to brand, month to month, etc. Shell 93 here may not be the same Shell 93 in another place. So unless you are going to log data on each fuel in your area, I would just pick a premium fuel that's convenient to you.

[Koa]

THIS CAR IS KNOCK EVENT HAPPY. Whether it is actual knock or misattributed, the knock sensing system seems to be dialed in to the 'safe' side and reports even non-knock events.

Even stock, there is common exhibited knock (FBKC, FLKC) from the 2600-3500rpm and low load range, and for some in the upper RPMs and heavy loads as well with users using American 93 octane. Aussies, UK, and places in America with 91 only/shit gas options have it worse.

Run the most QUALITY high octane gas you can.. try to determine a fueling source that limits the amount of reported knock events given you're stock, or know your tune is dialed in well. This is almost impossible to discern without logging tools

[Tcoat]

Originally Posted by HunterGreene

Well, sure, but seeking out anything above 94 is likely to get expensive and for minimal benefit. I know that's probably what you were thinking, but I thought I'd just clarify it for you.

Originally Posted by Koa

THIS CAR IS KNOCK EVENT HAPPY. Whether it is actual knock or misattributed, the knock sensing system seems to be dialed in to the 'safe' side and reports even non-knock events.

Even stock, there is common exhibited knock (FBKC, FLKC) from the 2600-3500rpm and low load range, and for some in the upper RPMs and heavy loads as well with users using American 93 octane. Aussies, UK, and places in America with 91 only/shit gas options have it worse.

Run the most QUALITY high octane gas you can.. try to determine a fueling source that limits the amount of reported knock events given you're stock, or know your tune is dialed in well. This is almost impossible to discern without logging tools

Yes!
and
Yes!
I have had some Shell 91 that rocked my world and some Petro Can 94 that just sucked!

[Muaddib]

I noticed that i could only get 27-28mpg with the Chevron 94 octane. But with Shell 91 octane i could get up to 31.5mpg. The choice is clear.

[billwot]

Originally Posted by Koa

THIS CAR IS KNOCK EVENT HAPPY. Whether it is actual knock or misattributed, the knock sensing system seems to be dialed in to the 'safe' side and reports even non-knock events.

Even stock, there is common exhibited knock (FBKC, FLKC) from the 2600-3500rpm and low load range, and for some in the upper RPMs and heavy loads as well with users using American 93 octane. Aussies, UK, and places in America with 91 only/shit gas options have it worse.

Run the most QUALITY high octane gas you can.. try to determine a fueling source that limits the amount of reported knock events given you're stock, or know your tune is dialed in well. This is almost impossible to discern without logging tools

12.5:1 CR tends to do that!

[FRSBRZGT86FAN]

Originally Posted by Hanakuso

To answer your question, yes regular will run but why risk damage to the engine to save a few pennies.

The job of the knock sensor is so that NO damage will occur....

[Koa]

Originally Posted by FRSBRZGT86FAN

The job of the knock sensor is so that NO damage will occur....

Not true.. the job of the knock system is to prevent serious damage from occuring, but a significant knock event such as pre-ignition knock can flare and cause damage before the feedback or learned knock systems (FBKC and FLKC) can pull timing. Alternatively, it's possible that the system can hurt you: In the event of the sensor detecting false knock events that end in pulling timing, one's track times could be damaged which can cause loss of position, ego deflation, and sads in general.. so damage is relative to the situation here..




And to finally answer the OP:
None of the above

[buckyislucky]

Great input koa and everyone else. ..

also if I decided to change from 94 to 91 (for more mileage) is there anything I should do before I do so?

[Tcoat]

Originally Posted by buckyislucky

Great input koa and everyone else. ..

also if I decided to change from 94 to 91 (for more mileage) is there anything I should do before I do so?

Nope! Just open the cap and pump 'er in. I run 91 most of the time and am very happy with the way it runs. The ECU will take a tank or so to adjust but it will do all the work for you. The only advice I would add is to make sure you get it from a station that sells enough that it is reasonably fresh in their tanks. I had a bad time once when I went to a little neighbourhood station that had it in their tanks for months.

[Packofcrows]

Premium, no crickets, asks to be driven harder... treat her like a lady.

[FatFree]

Sorry to revive this thread but I couldn't find anything about using 90 octane gas.

It seems that many people believe that using as low as 91 octane is just fine. There's an ethanol free station by my work but they only offer up to 90 octane. I just filled up with the 90 octane ethanol free to give it a try and my car is sooooo much quieter during idle. As far as I can tell from my butt dyno there is no loss in performance either.

Should I just be safe and continue to use the 92 octane gas at shell and try to ignore the crickets? Or would it be ok to use the 90 octane ethanol free? The ethanol free would also cost me about $25 more a month. The crickets really don't bother me that much but it's so nice to have silence while at a stop light...

[Shankenstein]

Originally Posted by FatFree

Sorry to revive this thread but I couldn't find anything about using 90 octane gas.

It seems that many people believe that using as low as 91 octane is just fine. There's an ethanol free station by my work but they only offer up to 90 octane. I just filled up with the 90 octane ethanol free to give it a try and my car is sooooo much quieter during idle. As far as I can tell from my butt dyno there is no loss in performance either.

Should I just be safe and continue to use the 92 octane gas at shell and try to ignore the crickets? Or would it be ok to use the 90 octane ethanol free? The ethanol free would also cost me about $25 more a month. The crickets really don't bother me that much but it's so nice to have silence while at a stop light...

As others have mentioned, listen to the car (or watch the datalogs). The most knock-free fuel I found in Houston was Chevron Supreme 94. The best I've found in Boston is Sunoco 93.

You can usually tell the fuel quality by listening during cold-start warm-up. When the engine is operating in open loop, bad fuel will cause an audible lope in engine rpm and some timing adjustment. "Puuht" + 100 rpm dip. The frequency this happens at is a good indicator when you're trying a new fuel.

[FatFree]

Does engine knock sound different than the knock you hear from cooling and heating?

[Vincenttam]

Originally Posted by FatFree

Does engine knock sound different than the knock you hear from cooling and heating?

Cooling and heating meaning when a car is off? Thats the sound of the metals in your car shrinking because they're getting cooler. Knocking in your car with low octane has sounds like someone hammering your engine while your driving. Not the most attractive sounding bit and your car's performance diminishes. You want to use as ethanol free as possible since these engines were originally designed to not have ethanol as part of it's combustion process. Don't ever use anything less than 91 unless your running very low and the next gas stop only has low gas 87,89. But only get enough to get you to the next stop to fill back up properly.