Is this even possible to detect? Shouldn't the ECU just pull timing if you have lower octane fuel than the tune calls for? I swear I've heard people complain about knocking around here before yet how is that even possible in the first place?

 

I think once the tune is set to a certain octane, the air/fuel ratio is set as well. Using a lower octane will cause the knock.

 

I was running 87 and heard a slight ping here and there. Switched to 89 on my last fill up and no more ping. Shell 89.

I dont care what that manual says, this car should not run on 87.

 

I guess I don't understand how you are experiencing knock due to low octane fuel. Your ECU should pull timing automatically. Or so I've heard.

 

My 07 only gets 91, she pings like a bitch on any thing lower, oh yeah, running 91 tune.

 

on my 05 its VERY audible

stock tune, jump on the gas in 2nd, 3rd and 4th and you can hear, for a split second, slight knock, then it goes away

just get an aftermarket tuner and you are set

 

I was hearing something similar but it had nothing to do with the fuel, asked around and it ended up being a cam phaser.

 

MY 07 does not like 87 octane fuel at all. It gets crappy fuel economy with 87 anyway. I had bad fuel a few months back that was 87 and the engine bogged at 3k rpm like I lifted off the throttle. The engine sounded like crap too. I took it easy on it and filled it with 93 and I kept it there. I used to fill it with 93 then like I said before when gas prices got high here I switched to 87 for a few tanks. Then after getting bad gas I switched back to 93 and have been filling it with 93 since. The way I see it is, my car worth me spending the extra 2bux per tank.

I really don't care what the manual says. 87 octane with 9.8:1 compression ratio is a bad idea.

Now I am awaiting for my 93 tune an cai from Doug. Should be here any day.

 

My buddy has a WRX. His ECU will pull timing in the event he gets gasoline in there that is not at the octane level rated for his tune.

Why do our cars not do the same thing? Shouldn't our ECU pull timing if it senses detonation? I don't understand how you guys are even experiencing pinging/knocking in the first place.

Does noone know?

 

Our engines are close to 10:1 compression ratio and the timing is already substantially pulled from the factory. The knocking and pinging is not something you hear in our engines at idle, or even under normal driving. It will be apparent once you are climbing the rev range during spirited driving where the car suddenly stops pulling and bogs down due to the ecu pulling timing and making the engine run extremely rich. That is a safety feature. The simple point remains that the engine does not perform like it should especially in the summer where the temps are high.

Put it this way, my intake air temp during the summer is around ~140f with the stock box on. I cant wait to see how my bama tune works out in combination with my c&L. During heavy traffic where you sit for 5minutes and move 10feet I have measured the intake air temp at ~190F with my dash hawk. Lets just say a combination of NY traffic and low octane fuel results in a very suprided driver when he finaly clears the traffic and wants to hit it. However these conditions I encounter almost on a daily basis, and they really do not apply to highway use. If you are crusing on the highway allot then the fuel can be lower octane because the load on the engine is minimal.