I posted the following e-mail a few months back when the whole fuel thread started. This e-mail was sent to me after I e-mailed Sauber asking them about the fuel they use.
The Petronas/Sauber partnership started at the begining to the 1997 Season...but fuel supply only started at the end of the 2002 season or begining of 2003 season! Not sure...I think the answer is also posted somewhere in this thread.
Dear Mr. Correia,
The Sauber-Petronas team is using both PETRONAS fuel and engine lubricant.
However, both the PETRONAS fuel and lubricant have to be approved by
Ferrari,
and therefore undergo the same Ferrari approval process as the Shell
products
have to undergo on the Ferrari engine.
I hope this answer is satisfying.
Best regards,
=====================================
Marc Bongers
SAUBER PETRONAS ENGINEERING AG
Engine Development
Wildbachstrasse 9
CH-8340 Hinwil
TEL +41 1 937 91 00
DIR +41 1 937 92 87
FAX +41 1 937 91 04