Just came across this. for some who were under the impression if you use 89 octane you would crater your motor. JFYI

http://www.nytimes.com/2008/08/03/au...o_interstitial

 

was just about to post this.

 

me too i was gonna post this up
so can the evo handle 87oct?
the owners maunal must state something about it?

 

Right by the gas filler cap.

"PREMIUM FUEL REQUIRED"

Why would you buy an evo and then put in 87 octane to save 3 bucks a tank???????

 

Yeah it's pretty interesting. The whole time I was thinking, "Yeah but what about turboed or supercharged cars?" Then I read the part about all of Porsche's modern production cars being able to run on 87 with no problem...

 

the question is, would we be willing to take the plunge and use 87 octane gas now?

 

I really didnt post this for the 93 octane VS the 89 octane. that is posted elsewhere but really as just info on people who were under the impression you could/would have motor damage. the facts remain. you will loose performance, who cares what you run. why put 93 octane then drive it like a granny. For some people this is an extra car, who would by and EVO and then garage it. to each his own. just have fun thats the bottom line with cars.

 

cheaper gas is ok if your just cruisin/not getting into boost

but i dare one of u fools to try to boost on it.....49 counts of knock later,dont come crying to evoM

 

I'm still not going to put regular in my car...

 

though its not recommened, if u absolutely had to you could run a lower oct and be ok, obviously stay out of boost.

and if u didnt know, some gas stations run higher oct then what is listed. so when you use 87, it might actually be 89, 89 might be 91 and so forth. there are hefty fines when a gas station uses a octane rating that is lower then what is listed, aka you bought 89 but it tested at lower.

so most stations to combat that will use a higher octane then what is listed. so thats why when you go to a station, on the octane tag on the pump, it says minimum octane rating.. meaning its atleast 93 oct but could be higher.

 

hmmm, interesting good to know. No more premium or even mid grade for the lease, 87 it is!

 

I read that article in the Sunday Times and it attempts to lull the reader into thinking, Yeah, I do not need to run Premium, Regular is fine because no damage. This is totally misleading. There are fuel maps in the ECU for running low octane fuel but they are there in case of an emergency, like you ran out of gas in the middle of Nevada and this station you are at only has 88 Octane fuel. The engine was designed to run on high Octane fuel and as another post stated earlier, why would you buy a $35-40K car and worry about saving a couple of bucks of fuel? Makes no sence to me. If you want fuel economy, go buy a Honda Fit.
Additionally, when asked about damage to the engine, the so called experts within the article hedged their response by saying they don't think there would be any harm in running Regular Octane fuel. This sounds like an opinion and as we all know opinions are like *******s, everyone has one!

Later, Ken

 

I'm willing to bet that the reduced engine timing you would get out of 87 octane would drop engine output a good 10-20 HP on a turbocharged car that runs relatively high boost like the Evo X. While cruising around you only need 87 octane but when at full throttle, your power will be effected if the car is tuned to the higher octane.

I guess since I turn my boost up higher than stock and modify the car to put out more "safe" horsepower, using lower octane gas just wouldn't make sense. I can just imagine trying to run 30 PSI of boost on 87 octane... the stock engine control system can only account for so much knock before causing damage. It might not be instant failure but over time it's going to catch up with you.

 

...and they stink.

Figured I'd finish that for you.

 

Ask some of the VIII and IX guys how their logs look on 91 nevermind 89 or 87. 6-7 counts of knock on the stock tune running 91. Sure the ECU responds to this and corrects it, but the initial knock is still present. I'm not sure I want all that knock in my engine. Use 93 or take the bus.