Does the lower octane stuff you tried contain ethanol by chance? On the DD I run 87. 89 here is 10% ethanol and results in less power and fuel economy. The 87 actually costs a little more. I haven't yet done the math to see which costs more to run though.

fwiw my 'Bird got 30 mpg on the highway this last weekend trip I'm amazed and don't understand how my car does so good... especially for a cam, gears, AC running, etc. It doesn't seem right but I can't argue with the math. Yay for me!

 

Where I live, we only had one station with 93, then they quit carrying that in May. I always used to put the 93 in. Now the highest octane available is 91, which they have at several stations. Can i dump a bottle of octane boost in my tank when i fill up with the 91 to make up the difference or will i not notice anything?

 

Octane boost in a bottle is a joke and a waste of money. It will only raise the octane rating of a tank of gas a fraction. It is good at ridding people of money though

91 probably runs good. If you had to run higher octane you could make your own. There are recipes out there but keep in mind that many are not safe for all your fuel system components.

 

It's not the money.....I was just told by some car people that it's not absolutely necessary to run 93 in my car.

 

Sorry. So your saving $0.006 per gallon, assuming regular is $2.40 and premium is $2.60. (Don't ask how, or why I figured that out, lol. I guess i'm just that bored.)

 

My current 94Z is my second LT1, and it's 93 only for me.

When I purchased my 95 Formula at a dealership years back, I pushed it hard on the test drive and it was fine. They filled it up while we did the paperwork, and suddenly it was pinging under heavy load, and wow it was so much slower. Needless to say, that salesman got an earful about them ignoring it's need for decent octane. It took about a tank and a half until it behaved normally again. And it was a real Pontiac dealer, car was slightly used still under warranty.

10.5:1 compression means higher octane fuel, that simple.

 

oh yeah!

 

if you dont have the money to put the high octane gas in, try using fuel additives... octane booster works well also, but always try n avoid the low octane gas, it really does take life off of your motor and makes ur car run like .....just an idea...

 

87 works for me.
Yeah it was made for premium (91 technically)...but an engine with minimum deposits should be fine, at least at part throttle, on the stock tune. I look at it this way - the mail order tunes seem to crank up spark advance for better performance. Well, I left the SA stock, but used a lower octane. And if I drive easy, I still get 22mpg. And that's with a low end problem (The Hesitation, I think).

 

I have found that the PCM responds REALLY fast to knock. Fast enough that I NEVER hear it.

You're not going to hurt anything on a stock engine (meaning stock heads and cam). Hell, I read one guy in the tuning forum turned off PE mode and ran WOT at 14.7:1 to dial in his VE and MAF sensor. If the engine can tolerate that, then it can deal with a few inaudible pings before the PCM does something. Now, if you want to talk heads/cam, or forced induction, that's an ENTIRELY different animal and you don't want to play around. But at stock performance levels, which really aren't that exotic at all (~275hp from 350 cubes people), I don't see a problem.

Bottom line, try it, see what you think. Some cars respond differently than others.

 

It's cheaper to just use premium and not buy the octane booster, which is junk anyway.

 

I've been running 87 in mine for the three months I've had it, and I haven't had any problems with the engine. I'm going to try 93 next time I fill up, to see if I can notice any performance increase. All my ****'s stock. Bone stock.

 

its just a few more dollars to run the gas that the motor is built for, oh well

 

I ran 86, 87, or 88 in mine (until the supercharger). It ran fine, but I would use better gas when I went to the track.