[78 monte]

I'm starting to believe theres a government conspiracy to lower octane without telling us.I've never had this much trouble setting my timing.In order to rid my self of detonation I have to retard the timing till the car has no power.With the timing set were I normaly have it it pings like a mother.I run 93octane pump gas.Have approx 9.5:1comp.
Now what I'm wondering is how much octane boost is tomuch.Or do I just keep dumpin it in till it stops clattering/pinging. Or would I e better off adding a mixture of Cam2 & 93oct??At $3.98 a gallon that would suck.
Last time a posted this I was told that tomuch cam duration would cause detonation.But its allways been my understanding that the more duration the more compression bleed off.The less cylinder pressure the less octane (to a point).

[Tom]

octane booster is waste of money for what you'll pay for it, it only raises the octane a few points and a point is one tenth of the number, meaning if the booster says raises octane 6 points and the fuel is 92 it becomes 92.6 and the stuff they make it with, for for what they charge you could make gallons, and buy it from your local hardware store.punch in octane in your search engine see what you come up with. I run older heads and 10.5 compression and always mix in a few gallons of race gas it gives me the lead for the valves and boosts my octane to the point where I can enjoy what I'm driving, instead of worrying about pinging and timing. smells great too!

[4 Jaw Chuck]

Maybe she's a little lean? Try going up a few jet sizes if the plugs are showing a lean condition.

[Strick]

Tom's right. My experience comes from motorcycle racing. Octane boost is not the product it leads you to believe it is.

The only true way to boost octane is buy octane rich fuel. I just put together my 307 with all the performance goodies. Stock Compression was 9:1 with stock heads (75cc - 3998993 - '72-'73). I just put on 461's (62cc heads). A somewhat calculated guess puts my compression between 10.25 - 10.875. That means race gas.

I only plan of driving my street rod around 1500-2000 miles a year. So, $4.50 a gallon for Sunoco purple (111 octane) won't be too bad.

[TheZaZ]

Hey, I live at almost 7000ft here. usually around 6500 ft where I drive my cars the most.

I am going to be pretty high up there in compression. in the 11's. How much is the altitude gonna affect the compression? And where can I get that high octane racing gas at??

[78 monte]

I'm gonna check the plugs.But it seems to run rich at times so I don't think thats it.
I hope I don't have to run race gas cause in the summer I have to drive it atleast 20mi. a day.

[Tom]

You don't need much just maybe a gallon to your tankful, race gas has an octane rating anywhere from 106 to 114. another option would be AV gas this is a low lead aviation fuel with an octane rating of 100 to 104 at a slightly lower cost. Av gas should be available at smaller commercial airports but bring a regulation gas can,they don't allow you to pull up to the pumps in an automobile or put it in milk bottles,anti freeze jugs ect.Now race gas can be gotten at race tracks,speed shops and some gas stations(usually near race facilities)or from the fuel companies like citgo or sunoco but only in 55 gal drums(average cost per drum 250 to 300)or companies like ERC, CamII and VP.another thing to remember is; if you are running catalitic converters don't use leaded fuels because it will plug them up

[2.3mgb]

Heard good results from toluene and xylene, both paint cleaners. Turbo guys swear by these.

[Strick]

I agree with Tom once again on mixing the two. Mixing oxygenated pump gas with Sunoco purple yields great result in dirt bikes. I just mixed the gas in my '36 - 2:1, pump:race gas. This will give me around 98 octane. Purple gas also looks real cool going through a clear fuel filter.

I buy my gas from a local petroleum company. The type that sells heating oil, and construction companies fill their service trucks at such places. Look in your local phone book and you should be able to come up with something. OR it is a little more expensive, but you can probably get it at a local motorcycle shop. Especially ones that specialize in dirt bikes.

[78 monte]

I'll have to try a little at a time to get rid of the det. Maybe I'll pickup a few gallons.A gas station in another city has a pump of 110oct Cam2.So I'll try like 1gal(race) to 10gal(pump).Then go from there.

[78 monte]

OK,put Cam2 motor is completly detonation free!
Throttle response is better,idles more evan,sounds more lopey,revs quicker and allot more powerful.Thats definitly what it needed.
Now my problem is I'm addicted to the smell.I found myself going w/ the intention of 1gal.1 turned into 2,2turned into3 etc...I wound up putting almost half a tank in w/ 94sunoco.

[Strick]

Ah yes, the evil addictive smell. In a desert race it smells so good the faster guys will stay behind me just to enjoy

I'm glad you found it, and I am glad it helped

Strick