On older cars slight knock under load in high heat can be considered 'normal' but its never an advantage.

whatever, lol... it'* been a while since I read the Nissan (eww) owner'* manual.

I see a lot of talk about octane being about the burn. It'* about the ignition of the fuel as well. Low octane fuel lights off sooner then higher octane. That'* why they want it (high octane) run in sc motors. Higher compression leads to higher heat which leads to pre-ignition with low octane fuel. You go right ahead and tell these cash strapped college kids to save a few pennies at the expense of their engine if you want to. If there that strapped then maybe they should be driving something different. On the other hand, what is more likely to blow their motor? 87 or 91? If your seeing some pre-ignition with 91 then doesn't it make sense that you'll see a lot more with 87? How much of it can the engine take? That'* what your risking. None of this makes any sense anyway. Why buy a car that recommends premium and then run regular? Just buy a car that recommends regular. You have to pay to play. How much have you got?

You said it.

Put 91 minimum in your SC Bonneville, or shop for another car. This is serious business. And when you start modding, be prepared to bump it up a notch.

Jesus this is really sad. I feel like I should respond to this comment in a nice manner, and normally I would, but when you don't even take the time to figure out the difference between pre-ignition and detonation how can I take anything else you say seriously? I mean hell I explained it in this post! I will say though, I've explained a number of times how this will NOT blow your motor. What do you think a knock sensor is for?

Ponder this for a second. One person said the PCM can retard the ignition 15deg. I'm assuming this means -15 as anytime the PCM pulls timing its considered retarding. So with premium you run about 24deg advance at idle. You're telling me that pulling 39deg of timing won't compensate for 87 octane?? Ok but what about WOT? I run about 10-11deg of advance at WOT on 92octane. Take 25-26deg of timing away and you still don't think it can compensate?? Think about that some.


You've said nothing to counter the debate. NOBODY said you won't lose performance. Matter a fact I said several times you WILL lose performance but thats not what we're talking about.

It gets a little frustrating to sit here and read peoples, sometimes cocky, responses about how they lost performance or how "well the label says" or a whole host of other opinions that have nothing to do with what the debate is about or flat out hold no water.

Look if I'm wrong I'm wrong and I'll admit it. But I won't admit it because you tell me about how much better fuel economy you get, what the label says (although aparently the manual says you can use it), or because you think you need to "pay to play." Find an expert or someone mutually agreed upon as an expert that says you will damage your engine running lower octane WITH A KNOCK SENSOR and we can go from there.

OBVIOUSLY this is something that needs discussed because I can (and have) pointed to several 'expert' sources to counter the other side of the debate but all I can get in return is myth after myth....Hey what ever happened to premium being a "cleaner" fuel?? How about oxygenated fuel being "more powerful"??

Nobody is calling you an idiot, far from it. I'm just frustrated that the only debate I get back is all opinion. Throw one or two in there but don't base your whole arguement on "well I think" and "well my friends buddies cousins barber said once.." Know what I mean? Thats what 95% of the responses lately have been. "I'm right because I think so." Meanwhile I'm doing my best to back everything I say up. Right now I'm making a long list of different pages and people that say it won't damage your engine. I wish someone would do the same for the other side.


If you guys think it will damage your engine, prove it! Thats all I'm asking! Find someone that agrees with your opinion!

Jr - If you want I will run 87 in my engine and film the results. For some reason I doubt that will cease the debate but if its what it takes I sure as hell will. I'm not in the least bit worried. Then you can learn at the expense of my engine :o

Sorry bud, I have to call BS on this one. Do you realize how much of a HP gain it takes to be noticable? Your telling us that you felt 2 octane by the seat of the pants. Do you realize it could have been the difference between a good or bad load of gas? I don't doubt that you think you fel it. Let me put it this way. For the next 5 tanks of gas have a friend fill it up for you and randomly switch between 87, 89, and 91 and see if you can tell which fuel was used by this method. The higher the octane, the harder it is to burn and ignite. If you use too high of octane rating then your putting a larger workload on the ignition system. People for the longest time have thought that higher octane equals more power. If your compression ratio doesn't require it then you are wasting your money and taxing your ignition system.

I was wondering when I would get to say this in this thread...

"I agree"

Holy crap that felt good haha.

So we're done now right?

err no? Nobody has proven that low octane will hurt your engine. Its funny that it seems nobody CAN. I mean hell its been weeks now and nobody has proven, or even attempted to prove that it will...thus I will wait