I recently asked the question about what grade gas to put into my car, with recent gas prices i put 87 in it.. and u guys said it might cause engine knock.. today i was driving and everytime i pushed the gas i would get this clicking noise coming from the engine.. is this what u guys were talking about?

 

Knock sounds like a bunch of marbles ratting around inside a can, and if thats what it sounds like, then its knock.

 

yea, that sounds like it... im not ganna hurt the engine by using the rest of this gas am i? i have about a half tank left...

 

I would top the tank off with some 93 octane, to balance it out, and also drive it easy until that tank was gone

 

How did that seem like a good idea to you???

 

by filling up with 87 vs. 93 you are only saving about $2-$3 per fill up if that. so you have to ask your self is it really with risking hurting something just to save $2? sure it might add up after a while but thats the price you pay for having a high performance car. just my $.02

 

i agree with you, i just wasn't sure if the 87 would work in it, and if it did then it i was ganna use it to start out, but ill just fill it up wiht 93 from now on to keep things nice and smooth.. im just glad that clicking noise or knock is from the low grade gas and not something serious

 

Do yourself a favor, run the premium gas at all times, it is well worth the extra money you'll spend. If you have ever seen what knock can do to a engine, then I'm sure you wont take the chance. My other car is a supercharged grand prix, and like many other owners of these cars, we try to push as much boost as possible out of a lousy supercharger with no intercooler and knock is our biggest problem. To make a long story short, not only does knock rob us of power, but too much will easily destroy a motor.

 

You say you have half a tank left?

OK, I'm going to assume that's about 8 gallons.

Go to Sherwin Williams and buy 2 gallons of Toluene and dump it in your tank.

(87*8) + (114*2) = 92.4 Octane

If you have more of that cheap gas then add more toluene, trying to maintain a 4:1 ratio.

After you dump in the toluene, go to the gas station and top it off with the premium stuff.


Don't worry about the toluene hurting anything. It's a pure hydrocarbon, wont hurt your sensors or cats; and is already used in pump gas as an octane booster.

 

When my dads car started knocking for using regular unleaded what we did is went to autozone and bought an octane booster by ''nos'' its the strongest octane booster you can get, it has nitro methane in it, it boosts you octane level up to 60 points which equals 6 full octane numbers. So we bougth it and poured it in the tank with the gas it had and we filled the rest of the tank off with premium and it stoped know almost immediatly after we did that.

 

You can run regular BUT you have to have the pcm tuned for it. I did this for winter once and the power difference was so minor I could not feel it so I stuck with regular. The b-body tuning is based on 87 octane but I had had a custom tune for 93 octane and the cam and such that is why I was able to say I had a winter tune for 87 octane. Yes the b-body motor is .4 points lower compression BUT it is also iron heads so with tuning 87 on a stock f-body motor should be no problem.

 

And I will say yet another time, mine runs just fine on 87. Just needed some tweaking at high load. Anything below 90kPa manifold pressure had no consistent knock retard, even in warmer weather. I almost feel dumb for asking, but, are you guys driving your cars hard enough?

 

Heh my GF is smart, she was telling me about this thing she saw on the news about how most cars don't need more than 87. I tried to be smart and give her a technical explanation of why. I started to explain flash and fire points and how it relates to octane numbers. She told me to shut up and said that she knew more about flash and fire points then I ever will, and that she already knew that.
serves me right for arguing about fire with an ordinance tech in the USMC

wow that was off topic.

 

a lot of this has to do with your altitude.

I have a higher altitude than most, and before I got the supercharger I ran on 86-87 all the time with no problems...

 

Well I am at sea level...