Just to clarify VP C16 is a leaded racing gasoline having a motor octane (M) of 117. M is more difficult to achieve that research octane (R). The test used to establish M is felt by some to be more representative of race conditions. You can read all about it on VP's site.
VP sells fuels having M up to 120.3, which is ("mathematically") as high as M goes. However, you must be certain that the fuel you use is intended for turbocharged applications. To be sure, octane is NOT the only characteristic of fuels that matters. Contact VP with your specific application for their recommendations.
BTW, all these fuels are leaded.
I do know that VP makes Import, M = 120.3, and it is for what I'll call ultimate turbocharged applications. This fuel is not readily available, but they'll make you some if you have the wallet. Last I knew it was north of $20/gallon, and I'm sure it's more now.
Your might find Import to be overkill, but if you have a boner for octane, be my guest. Practically speaking C16 will likely be fine - to my understanding it's been run sucessfully are very high boost levels, much higher to 30 PSI.
strike
