From: darling@simlab.arc.nasa.gov on behalf of Dave Darling [darling@simlab.arc.nasa.gov] Sent: Wednesday, April 07, 1999 4:36 PM To: aschwenk@direct.ca Cc: 914 Subject: Re: [914] Octane requirements for 2.0L with 8:1 CR? At 5:15 PM -0800 4/7/99, aschwenk@direct.ca wrote: >I am considering installing the European pistons with 8:1 compression >ratio in my '73 2.0L when I rebuild it. The engine will be otherwise stock >and I was wondering what fuel octane level this rebuilt motor would >require. Right now, with 7.6:1 cr, it requires 91 RON which corresponds to >87 AKI. From what I understand AKI is what is listed on US gas pumps. After >the rebuild, will 91 AKI be sufficient to avoid detonation? The specs listed for the European 2.0 list 95 RON octane. That cor- responds to about 89 (R+M)/2, which is what I assume AKI is. Some people have reported no problems running on 87, but that may not be typical. Also, remember that the only way to be sure of your compression ratio is to measure all the pertinent volumes and then add them up. Jim T. has an Excel spreadsheet that will do the adding and dividing for you. --DD Dave Darling 74 914 2.0 (VROOM!) darling@simlab.arc.nasa.gov <--- OR ---> ddarling@wgss.com "914: The Porsche Picnic Basket. A lid that opens on each end, and a handle in the middle.." -- CHD