Do octane boost additives work?

[bud45]

I have a '69 GMC p/u with a '65 283 V8, which doesn't like the gas we've been able to get lately! I was told by someone to get an octane booster & add to the fuel to improve the engine's ability to use the crap from the pump. Since gas has come down in price, this sounds still less of a monetary outlay, even once a week (when I fill up), but is it worth it or safe to use? What do I have to watch out for and what's best to use, if at all?

Thanks a bunch! Bud

[Longhorn Man]

They work great if you actually need it. Have you tried tuning the motor a little? Onless you have like 10 to 1 compression, pump gas should do the truck.

[70shortnphat]

High octane means it resist detenation better. Use the lowest octane your vehicle will run on for best performance.

[Jim_PA]

When the bottle says it raises your octane by 4 points, that means by .4 points. E.G. 93 octane plus 4 points octane booster = 93.4 octane... NOT 97 octane.

As said above, run the lowest octane you can. Otherwise, you're wasting $.

[13lazer]

here in california they sell us some awful gas. i have a mild 383 stroker and some cast iron world products heads in my 1970 blazer. i was constantly moving my timing back and fourth to stop all the detonation. the warmer the day the more it would ping. i threw in the cheapest octane boost i could get on a recommendation from a buddy that runs a 12:1 datsun motor around. i was instantly convinced. i started to get much better mileage and my motor runs much smoother. if you are running a 283 from 1965 i think you need some lead substitute and some octane boost because of your old valves and your smaller combustion chambers. the extra $ is worth it to me mostly to avoid detonating and all the damage that causes inside the engine.

[junkyardjohn]

Originally Posted by 13lazer

if you are running a 283 from 1965 i think you need some lead substitute and some octane boost because of your old valves and your smaller combustion chambers. the extra $ is worth it to me mostly to avoid detonating and all the damage that causes inside the engine.

THOSE OLD MOTORS THAT WERE DESIGNED TO RUN ON LEADED REGULAR WON'T LAST VERY LONG ON UNLEADED WITHOUT DESTROYING THE VALVE GUIDES & SEATS. LEAD WAS A LUBRICANT FOR THESE & THEY HAD SOFT SEATS. ON THESE OLD MOTORS YOU EITHER HAVE TO ADD A LEAD ADDITIVE OR GET THE HEADS REDONE TO BE COMPATABLE WITH MODERN FUELS. YOU CAN ALSO ADD 3 OR 4 OUNCES OF MARVEL MYSTERY OIL TO A TANK OF GAS TO LUBRICATE THEM, BUT CHANCES ARE THAT THE DAMAGE IS ALREADY DONE. JOHN

[MrC1]

Bottled octane boost is crap. Adding a gallon of race fuel will increase your octane as much as 4 bottles of that stuff.

I had a ping issue on my toy car, but swapping to a 160* thermostat fixed that problem. It's either that or pull 2* of timing out of it.

[Longhorn Man]

Yeah, we all have access to race gas.
Bottled octane booster will in fact increase your octane, it isn't crap.

[neonlarry]

Get some Toulene from your hardware store. Works way better and way cheaper.
Read here: http://www.gnttype.org/techarea/misc/octanebooster.html

[Alex Hayley]

I tried Toulene in my car and noticed a big difference. However, on that link neonlarry provided, notice that you need 10% of the total volume of fluid in your tank to be Toulene to increase the octane rating from 92 to 94.2. I used about a gallon in my 12 gallon tank.

[hogrocket]

Like Longhorn said--you only need the higher octane if you're running high compression--10 and up--otherwise it's probably a tune up or engine temp issue.

[MrC1]

I say again, octane boost is crap. What I mean is, a bottle will give you about half a point of octane increase for $4-6, depending on brand. A gallon of race gas will give you about 2 full points of octane (mixed with 10-12 gallons) for the same $6. That's 4X return per dollar.

Unless you're located in BFE, it's fairly readily available. Maybe not as easy as the auto parts store, but most areas have places that sell it.

[alemck]

What octane is racing fuel? We have one station offering 101 but it's a drive to get to it

[bryanw1968]

On that 283 I'd first try to take a degree or two out of the innitial timing.
I don't really have much of an opinion on additives as I haven't really tried them on anything high performance. I have however added a gallon of race fuel to a full tank and it does make a difference. It also cleans the crap outta your carb and plugs. My local performance shop has anything from 101-112.
I'd start out with the lowest first to see how it affects things. Also, as mentioned before, those old school heads really need to be updated or replaced. New gas is mean to them

[nate68]

are you filling up at the same place or are you trying different gas stations? i know many people who simply bought gas at a different station and their problems went away.

[MrC1]

Different places have different grades of race fuel. I've seen anywhere from 100-118 octane.

[bud45]

I've settled on two main places where I buy fuel...the previous station has lower prices, but since it changed hands, the gas smells like sewage and all three of my vehicles ran badly, until we ran it out. My wife also gets good gas from two of her favorite places. BTW, we DON'T buy Citgo gas (raspberries to Chavez!). I'm going to have to change plugs soon, but even so, the truck is NOT detonating, just seems a little sluggish....

I use Lucas products as well. The truck had a new cam put in it less than 10K miles ago & everything's been adjusted. The engine was rebuilt before I got it. After it was installed, it was found to have a knock & I took it back- the folks thet rebuilt it had the crank turned .010 but put standard crank bearings in it! They corrected this free of charge. So, I feel the heads were rebuilt using up-to-date componants

I just feel some little "oomph" may be needed...I'll change the plugs & see, but I feel like our gas isn't what it should be....Thanks!