I was in a tizzy and a hurry yesterday and so I filled up with 87. Well I did notice a difference. It's mainly when cruising at low rpms and then hitting the gas. There is a defined smaller amount of throttle response. Otherwise I don't see much difference. Anyone else did this and notice anything different?

 

i didnt notice a bit of difference when i ran it in my car.. i dont make a habit of it but it seemed to be fine on 87

 

The computer will compensate by retarding the timing (I think) which results in some loss of power, but it shouldn't hurt anything.

 

Yeah, the manual says you could use a lower octane gas if there is no higher one availible. They also "recommend" premium only.

 

Keep in mind the computer won't start retarding the timing until after the car has already knocked. It's not like the computer "reads" the type of gas you have and retards the timing.

That being said, if you always drive like a granny then you might be okay with regularly using 87, but if you drive like the car like you should then you better stick with Premium. Remember this car has a fairly high compression ratio. Besides, paying the difference to get Premium will only cost you about $120 annually (based on 15k miles).

 

Or more like $300 extra here in Germany We have to use 98 SuperPlus in these cars here. I haven't noticed any knocking whatsoever, track included, but I'm not willing to try the 95 Super stuff either.

Then Shell is selling that 100 octane stuff (another 10% more cost) and took out their 98 pumps No more Shell for me!

///Robin

 

The ECU can only retard timing so much. If you push it hard enough, the engine will knock despite the ECU's best efforts.

 

Anyway, the car must be running fine, I just got an 89 in a 65 speeding ticket today

 

I dont think the engine will knock once the ECU starts to retard the timing significantly. Retarded timing kicks in fast and powerful, almost like hitting the rev limit fuel cut. I believe it compensates significantly to be on the safe side, and with today's lowest 87 grade gas, the engine won't knock. Unless you're putting in mexican fuel!

Now getting the engine to kick in the retarded timing is another matter. On my maxima, especially when going WOT on a dyno, the power just flat out drops when the knock sensor kicks in. (because the engine did knock due to bad ignition coils). But on normal days, with the engine in ultra high load (like going up hill on a hot day in 3rd gear), it sometimes starts to ping and the knock sensor fails to pick it up. In which case you just immediately let off gas.

 

i would try to avoid running lower oct gas cause of my hot weather (socal) and high compression ratio of the engine. and my impression is that the engine is running very hot (which isn't helping much in this prevention of knocking) so i rather pay a little more and prevent any engine knocks.