108 octane....

[macino62]

Drove down to southern Indiana today to go look at a BSA. On the way home, I stopped at a gas station about 20 miles from my house....they had 108 octane fuel for sale. Only $4 a gallon!

 

[jerrybny]

I'm not sure my TR6 would know what to do with any octane over 93 other than to burn a hole in my wallet. Now if I still had my 69 Firebird it would surely like it.

 

[macino62]

i think my turbo-charged TR4 will like it *muwhahahaha*

 

[Simon TR4a]

At the local race track they sell Sunoco, I think one unleaded at about 107 octane and leaded at somewhere over 110, but the price is $3.25 a LITRE! (3.8 litres per U.S. gallon)
I would think that as it is for race use there would be no government highway tax, like fuel sold in marinas or diesel for agricultural tractors, but perhaps the distribution costs are high because of the small quantities sold.
Simon.

 

[Russ Austin]

Hey macino62; Where in Southern Indiana was the BSA, and where are you from.

 

[macino62]

pm sent

 

[Guest]

You would need much higher compression ratio to take advantage of the high octane fuel. I think the average US TR can run well on 87 octane, unless you get too much pinging, then you might bump up to 89. I run 93 octane only because my car has been bumped to 9.5:1 cr from 7.5:1.

 

[macino62]

correct, there would be no benefit to using 108 octane in a low compression, normally aspirated car. I ran a couple of tanks of 100LL av gas, and noticed no real difference (except a lighter wallet).

forced induction needs the higher octane levels to prevent detonation. higher octane and intercooling should add about 10 hp per psi. (IE: if I'm running 5 pounds of boost in my TR4, it's not unreasonable to expect an increase of 50 horsepower). I used to have a Porsche 944 Turbo which ran 13 psi from the factory. I replaced the EPROM with an 18 psi chip. There are current chips that allow 25 psi, without fear of overboosting.

I'm about to put an end up my turbo-charging project, and focus on the FI/ITB/Megasquirt project.