B15 Sentra Forum banner
1 - 13 of 13 Posts

·
I hide the bodies...
Joined
·
523 Posts
My car has never liked anything other than 89 octane. I put in 92 and it seemed to perform slightly worse. I have also used 87 and I got the same thing. Besides, I live in AZ and I don't want to run 87 octane AND use my A/C and then hope it doesn't detonate.
 

·
Registered
Joined
·
1 Posts
87 is same as 91 RON. RON stands for Research Octane Number. The octane index shown at the pump in North America is calculated by (RON+MON)/2, where MON stands for Motor Octane Number.
 

·
Registered
Joined
·
75 Posts
I run regular all the time except for auto-x or track days, then it's strictly premium. No spark knock in day to day driving with a/c on or off using regular.
 

·
Al, The Ignorant Fcuk
Joined
·
9,081 Posts
I think if you are wasting money...

by going with higher than 87. I used to alternate between the 87 and 89 like SDsr20de858 said to be nice to the car. I believe the higher octane just burns a little slower and that does not appear to really give more power unless you advance, in which the higher octane burns slower and you don't get a "knock". One of my buddies claims he gets bettter milage with higher octane. I think its BS. That's one good thing about a GM product. They have an anti-knock sensor which adjusts the timing as soon as it senses a knock. An '92 Corsica - no less!!! (my Ghetto/Bumper Car:D).
 

·
Registered
Joined
·
119 Posts
Discussion Starter · #8 ·
Actually, that anti-knock sensor can be your worst enemy.

My previous car had completely torn all of its motormounts apart, so I replaced them with solid ones. I think that sometimes the added vibration was setting off the sensor, retarding the timing. I know some people who even removed the sensor.

Trust me, you dont want it
 

·
Registered
Joined
·
1 Posts
Octane ratings were created as a way of signifying the gasolines resistance to knock. Higher octane ratings take a longer time to burn, but that does not mean you'll get more power just by using higher octane. If you have advanced timing, high compression pistons, large amount of boost, the need for higher octane is there, simply because the auto-ignition that will result from a lower octane gas being burned to quickly and unevenly causes detonation. Octane is not a power adder, its more like an engine saver. If your car can run with 87 octane, and it doesn't knock, ping, detonate, etc., then you have no problem. There's absolutely no reason to get higher octane. It's a waste of money.

Unless you have advanced timing, high compression, high boost pressure, etc., there is no point in using a higher octane gasoline. I'm actually thinking of bumping back my ignition timing to 15 degress BTDC so I can use 87 octane again.

[Edited by SE-Rage on 05-24-2001 at 10:11 PM]
 

·
Al, The Ignorant Fcuk
Joined
·
9,081 Posts
Rage...

Yea..that's what I was trying to say. You said it a lot better. Good explanation.

Kevin..That knock sensor is pretty proven technology and someone here could correct me, but I'm guessing that most engines made today have this technology. I wouldn't be a bit surprised if that's what killed the SR20DE. In the 8 years I owned 2 GM Corsicas-I have yet to hear 1 ping. Its pretty impressive that GM with with of their idiotic ideas came up with that one.
 

·
Registered
Joined
·
53 Posts
Just one more vote...

I have been using 87 octane with my 1.8L and it seems to have no complaints as well.
I have been regularly achieving Nissan's own estimates of 32mpg city/45mpg highway using this grade - and these figures are derived from almost exclusively short city trips (2-5km... oops, sorry - that's the Canuck talkin' - 1.5-3 miles) and um... "expedient progress" on the open road.
I recently tanked up after a long, tank-drying trip using 89 grade as an experiment and when the prices came down and the differences are so slight (read, negligible) I'll likely top it next using 87 again, unless some epiphany-toting research surfaces proclaiming higher grades prolong the life of the engine...
Hmm... Won't start holding my breath quite yet...
 

·
Registered
Joined
·
1,978 Posts
With fuel prices so high, I currently try to gas at local Sonic Stations as much as possible and get the 89 octane 5% Ethanol fuel, it feels great and its at the price of normal 87 octane fuel.
 
1 - 13 of 13 Posts
Top