Octane for Jetta 2.5: regular, mid, or premium?

[jetta08]

The gas cap on my auto/clutchless Jetta 2.5 specifies "regular." Recently I tried mid-level and premium octane, and it felt like the ride was a little smoother with each increase in the octane level. For example, when speeding up, I thought I could shift 2-to-3 sooner using mid-level (relative to regular), and shift 3-to-4 and 4-to-5 sooner using premium (relative to mid-level).

Has anyone had a similar experience? I'm wondering whether this might be just a psychological effect.

[lewis@vwdiscountparts]

Probably psychological. Name brand gasolines use the same cleaning and lubrication additives in all grades. The only true difference is in octane. The higher the octane, the higher the point of detonation. (Engine ping) The engine cotrols on your Jetta will also work to prevent detonation. Usually if your electronics detect the onset of detonation, it will automatically retard timing which will cause a slight loss of power. This shouldn't occur if you are using a minimum 87 octane fuel. Some parts of the country have 85 octane. I would not recommend using anything less than 87.

- Craig
Discount Volkswagen Parts