Has anyone used a lower grade gas on a 1994 viper?

[Qualitywires.com]

Why does the Viper need 93 octane? It's fairly low compression engine right? What are the thoughts on this?

 

[Marv S]

9.6 c.r. (or even 9.0 for yours) is not that low for that type and design of head. Also, Agressive spark timing is also a factor in needing 92 or higher ron/mon. Example is the Dodge truck with a 5.9L. In stock form reg unlead is "ok". Put on the Mopar performance ECU and you are now required to burn premium fuel -- and the compression didn't change.

 

[Vip-RT10]

In chemistry class, we learned that the higher octane has less engine knock properties, so it should burn better. I have always used the Amoco 93 octane gas here. And remember to fill up in the morning too. Since in the afternoon it is thought that the heat that is transferred to the ground heats up the gas enough to make it closer to the gaseous state, hence less dense. I don't know if this is true here, but it is in Italy. I do notice a difference in liters/cost.

 

[phiebert]

Vip RT/10,

Gas pumps in North America usually say on them "adjusted to X degrees" or something like that. They take into account the temperature and adjust for the density.