Fuel Selection

[Stan]

Question:
What grade of fuel does everyone use with a carburetted CS?
I have been running regular and it seems to work fine.
Stan

 

[HB Chris]

Fuel

Stan,

I use Premium, in California it is only 91 octane and it helps prevent the ocassional run-on when shutting down the motor.

 

[Bill Riblett]

US 3.0 engines only have 8.3:1 compression, so regular works just fine.

All 2.8s and rest-of-the-world 3.0 have 9.0:1, while CSi's have 9.5:1 and should use premium.

 

[Stan]

Hmmmm
I have the block from a 1986 635CSi minus the FI stuff.

 

[Bill Riblett]

Hmmmm
I have the block from a 1986 635CSi minus the FI stuff.

If it is a US car, it is still low compression. I have a stock US 635 and it runs quite happily on regular.

 

[BluE9]

Hi Stan,

I have been running my 1971 2800CS on 91 Octane (dual Weber set-up) with great success. The Weber’s are a though set-up and I think the 91 keeps it a bit cleaner and helps to maintain proper timing with decent combustion. But that’s with the timing set at 18* BTDC at idle and without the vacuum advance connected…so go figure?

Greg