MMmmmmm....Octane!

[jlangholzj]

wel fellas, I did recently post a pinging question and it seems as if the only real solution is less timing or more octance.

of course, less timing is less power. how retarded is that?? (sorry i couldn't help)

well my thoughts went to directly to octane and what can be done. Being a pilot, I though immediately about 100LL or 100 octance (low lead). Of course my next thought was that the older engines liked a little lead, so i set out to find the lead contenet.

As it turns out,

100LL has 2g of lead per gallon

opposed to:

91 premium having .001 g per gallon


so my next question is, will this lead content cause some harm to my engine? i doubt that i would be running 100% of avgas, but a 50-50 mix will produce a 95-96 octane rating. This would be nice, considering that 91 is the the highest available octane around here.

i spose that i wouldn't have to worry about the lead ruining a cat-converter
Even though they lowered the lead content because of the harmful side effects, i think that a 50/50 might be safe.


well if I can't do this, what other options would I have like an octane booster. are these ligit (i doubt it) but do they work?

 

[D.Hearne]

I don't know what the lead content used to be, but the current low lead avgas has a lower content than the old pump gas did. 50/50 will be fine. Just mix it with 87 octane and you'll end up with 94.

 

[mrmustangman357]

whats your price on aviation fuel?

 

[rbohm]

wel fellas, I did recently post a pinging question and it seems as if the only real solution is less timing or more octane.

you have one more option, low the compression ratio. you can do this just by installing a thicker head gasket. as for running aviation fuel, you have one problem. if you get caught using it on the road, the government will hit you up for road taxes.

 

[blown65]

100LL isnt rated the same as auto fuel is. Might still be close. Personally I'd just put 10 gallons 91 and 1 gallon 100LL and see how the car does then. No need to raise octane any higher than needed.

As for price, our local Avgas is at 4.95 a gallon right now. Another reason to only use what ya need. I was going to run it in my car since on the street it would probably be fine with a slight change of timing. Found some Trick Racing 110 though for 5.45 a gallon so just went that route instead. For 50c a gallon more, quite a bit higher octane.

 

[jlangholzj]

I cuaght wind that there might be some 93-94 octane pump gas available in town, definately going to check it out.

still, i need and anwser to my last question, do these octane boosters really do anything? or all they just ....meh.....?


P.s. price of 100LL avgas is about in that 4.50 to 4.88 but i can get a $.50 discount per gal. b/c we store our C-172 there.

 

[blown65]

I cuaght wind that there might be some 93-94 octane pump gas available in town, definately going to check it out.

still, i need and anwser to my last question, do these octane boosters really do anything? or all they just ....meh.....?


P.s. price of 100LL avgas is about in that 4.50 to 4.88 but i can get a $.50 discount per gal. b/c we store our C-172 there.

Octane boosters wont raise you crap and are over priced IMO. Your better off with the 100LL and mix IMO. I'd still do the 10-1 and see how that is and go from there.

 

[D.Hearne]

Ditto on the octane booster additives. I always found they did nothing. That was back in the 80's when I had the 427 Stang. AvGas always worked.

 

[Hack]

You could also put in a bigger cam with more overlap.

 

[CochinoFilipino]

How about water/meth injection?

 

[65fastbackresto]

Look at a Shell station

We got one in town that has 93 octane. Everybody else has 91.

 

[jlangholzj]

You could also put in a bigger cam with more overlap.

considering that i just put one in i've got as big as i dare go, w/o having to replace anything else. its a auto so i'm kind of limited considering vacume. that and considering that it has 67K ORIGINAL miles on it and no rust (thats right, NONE) I really don't want to tear into this one too much, so a stall converter is outa the question

How about water/meth injection?

might work, but I'd get a thrid member for my differential before that!

We got one in town that has 93 octane. Everybody else has 91.

MY point exactly!!! I didn't have time to snoop around today, but definately tomorrow. this could possibly be part of problem, since it has gas in it from last fall, condensation, etc etc.

we did re-time it today, and it seems better.

 

[CochinoFilipino]

:
might work, but I'd get a thrid member for my differential before that!

There are more affordable kits like this one from Snow. You could possibly piece together a system for less