What kind of gas do you guys run in your car's engines? I know it says to run 93 but it seems to run just as good on 89. So is there any harm in running 89 or even 87?

 

The LT1 are high compression engines which run optimally on high octance gas. Having said this it is best to run on 93, but wont do any "major" damage running on a lower(87) gas. When i get cheap i will fill with 87. most times i fill up on 87 then add a octance boster. I find doing this cheaper than filling up on 93. Plus with the booster its more like 97 octance.

 

Here in CA 91 octane is the highest available and my car runs fine. I would not run 87 or 89, you bought a performance car and you're lowering your available HP by introducing engine knock...yes the knock sensor will keep your engine safe but at the cost of HP because it pulls timing.

Octane booster is snake oil; do a search on the subject, you may bump your octane by 0.4, certainly not by 4.0!

 

if you're using the commercial octane boosters, you have to take the points they advertise and divide by 10. So a 7 point octane boost would raise the octane level from 87 to 87.7 - MAYYYbe

Compounds like xylene or toluene have octane levels in the 114-118 range. You can mix those with gasoline and calculate the final octane by simply stoichiometric means.

eg. 10L toluene at 114 octane + 40L gasoline at 90 octane would give you a 50L solution with an octane rating of: 114 x 10/50 + 90 x 40/50 = 94.8

For more information, you can see http://www.team.net/sol/tech/octane_b.html

It is not economically feasible to raise the octane of 87 gasoline using this method. It would be cheaper to just buy premium. You should run the lowest octane gasoline that does not result in knock retard, as the lowest octane gasoline burns most readily and is cheaper. Some claim it has more energy per liter than than higher octane gasoline, but I dont know for sure if this is true. In theory, less branching (lower octane) would give a higher heat of combustion but this assumes complete combustion - and dozens of other factors probably come into play as well.