Octane Boosters???? Do they work??

[ruredy]

Originally Posted by dougmcp

Try aviation fuel from your local small airport.
or

The makers of av gas (like shell) recommend you do not use their av fuel in auto type application. They have some legitimate reasons for this, search for, or ask them about it.

[dougmcp]

Here is some more (condensed) info on avgas for your consideration:

Racing Gasoline Verses Aviation Gasoline
byTim Wusz
76 Products Company
Avgas 80/87: this product is used in low compression ratio aircraft engines, contains little or no lead, is red in color, and should not be used in any automotive engine due to a low motor octane number of about 80.

Avgas 100/130: this product that can be used in some automotive engines. It has both research and motor octane numbers slightly over 100. Avgas 100/130 is green in color, contains four grams of lead per gallon, and is becoming harder to find.

Avgas 100 LL: the LL stands for "low-lead" which means two grams per gallon, low compared to the avgas 100/130 that it was designed to replace. It has research and motor octane numbers very similar to the 100/130 product previously discussed. The color is blue. This product sometimes has a high level of aromatics which can contribute to lazy throttle response and dissatisfaction of the consumer.
Avgas is less dense than most racing gasolines. Instead of weighing about 6.1 to 6.3 pounds per gallon like racing gasoline, it weighs 5.8 to 5.9 pounds per gallon. The racer must compensate for this by changing to richer (larger) jets in the carburetor when changing from racing gasoline to avgas.

The other major difference is octane quality. Avgas is short on octane compared to most racing gasolines. Many racing engines with "quick" spark advance curves or with no centrifugal advance have more spark advance at low rpm than avgas and some racing gasolines can handle. The result is detonation, especially during caution periods in circle track racing because all of the spark advance is "in", rpm is low, and part throttle air fuel ratios are too lean for the operating conditions.

The high lead content, green 100/130 avgas is the only thing I would use in a GC.

[tonyton]

Wow!! About half that went over my head, But this is what I'll try. Premium Pump gas first, if there is a need for more we'll try 50/50 premium/ race fuel. Beyond that we'll go with the green avgas.
There are suppliers for all of this within 20 miles of the house, so it's not a really big deal.
Thank you all soo much for your inout and opinions. You all have become a valuable source of information. I've learned a lot here and appreciate it!!

[Flintrock]

Originally Posted by tonyton

Wow!! About half that went over my head, But this is what I'll try. Premium Pump gas first, if there is a need for more we'll try 50/50 premium/ race fuel. Beyond that we'll go with the green avgas.
There are suppliers for all of this within 20 miles of the house, so it's not a really big deal.
Thank you all soo much for your inout and opinions. You all have become a valuable source of information. I've learned a lot here and appreciate it!!

That sounds like a good plan. You may be surprised and find premium works just fine. Listen carefully for pinging at low throttle under load, that's when it's most likely to happen......

[pizzamaker]

anything that runs at or under 200psi will do fine on 93 octane

[DOOmsman]

PM what percentage of squish band do you run in your higher compression engines?

[pizzamaker]

Originally Posted by DOOmsman

PM what percentage of squish band do you run in your higher compression engines?

with the 295 head on a 350@.50 over bore it's around 30%
and clearance is bewteen .20 to .28 using .38 solder
the compression runs out at 190psi