# Mileage test results **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [August 7, 2007, 5:22pm UTC](https://boards.straightdope.com/t/mileage-test-results/414756 "2007-08-07T17:22:50Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Mollie\_Magill](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mollie_magill/32/20882_2.png) [@Mollie\_Magill](https://boards.straightdope.com/u/Mollie_Magill)\ **Post date:** [August 7, 2007, 5:22pm UTC](https://boards.straightdope.com/t/mileage-test-results/414756/1 "2007-08-07T17:22:50Z")
This is in response to these threads: [Do I really need premium gas? (VW Passat car question)](http://boards.straightdope.com/sdmb/showthread.php?t=418888) [Premium Gas](http://boards.straightdope.com/sdmb/showthread.php?t=413329) [Gas in Diesel Engines](http://boards.straightdope.com/sdmb/showthread.php?t=276918) And [Una’s Staff report](http://www.straightdope.com/mailbag/mdieselvsgas.html) from 2004, and this [Car Talk column](http://www.cartalk.com/content/columns/Archive/1997/June/09.html) from this past spring. I have placed it in this forum per Rico’s suggestion. In the first thread above, I had mentioned that I would run my tests and gather more data again. In short, I was gathering data on mileage using different grades of gasoline. I waited until summer started and school was out, so my A/C usage and traffic patterns would all be similar. [1] Method: Vehicle: 2004 VW Passat. Manual Transmission. 4 cylinder w/ Turbo. VW recommends 91 Octane. Prep: I waited until summer, so A/C usage and traffic would be consistent. Conditions: Daily commute. Mostly suburban driving. Very Little Highway. Some start/stop. Blend: I would fill up after using a quarter tank alternating between 89 and 93 octane averaging about 91 octane.[2] Results: ```auto Octane Miles MPG Time Average Fuel Fuel Price per Costco/BJ's Costco/BJ's Rating Driven Driven Speed Used Price[3]500 miles Price[4] Price per 500 Miles 87 521.5 28.6 19.617 27 18.234 $2.822 49.336 $2.795 48.864 89 568.1 28.6 19.183 30 19.864 $2.995 52.360 93 570.6 29.3 17.55 29 19.474 $3.126 53.345 $2.859 48.788 Blend 424.2 30.3 14.6 29 14 $3.061 50.503 ``` Conclusion: Due to the better mileage with the blend, the cost per distance 87 octane and the blend (91) is negligible. While I could save money using 87 octane, I did experience sluggish acceleration and lessened performance. Personally, I’d rather spend a dollar more every 500 miles and know that my car will take off if necessary. [1] We have had a heat wave here for the last week, which may have skewed the 89 Octane results. [2] The Blend Data is not as complete, as we were about to take a road trip, and I didn’t want to skew the data with an additional 100 miles of Highway driving. [3] Price take from AAA website for the Charlotte, NC region. [4] Price recoded from the sign outside BJ’s last night.