Car and Driver tested it at 8.1 seconds 0-60 for the 5-speed car...but that's on the higher end of most normal, stock S13s.
They typically run roughly 15.9 @ 86-87mph in th 1/4 mile...C&D got 16.3 @ 84.
See the article here (.jpg scan of the page):
Car and Driver 240SX Article from Nov '90
240SX.org has a few 240SX magazine articles uploaded here:
http://www.240sx.org/links/magazine/index.html
- Brian