Chevron gasoline

[Brett Dikeman]

On Apr 27, 2005, at 3:21 PM, Dave Head wrote:

> Any car with a knock sensor and a turbo will benefit from a higher  
> octane rating.
> Most cars with knock sensors will benefit from a higher octane rating.

The ECU is programmed with timing and boost tables designed for a  
specific octane minimum octane; it won't take advantage of a higher  
octane just by throwing it in the tank.  Running a higher octane than  
what is recommended will in fact hurt performance because overall  
efficiency drops; higher octanes burn more slowly, so that detonation  
doesn't occur.

Knock control is designed purely for TEMPORARY running on inferior  
gas or with engine problems (severe deposit buildup, for example).   
It doesn't magically see "oh, the owner filled me up with 94, when  
all I need is 89...well, let's advance the timing a whole bunch,  
whoopeee!"

> Try running race gas in a V8 - it loves it!

Then you have internal engine problems- like the wrong plugs, or a  
lot of carbon buildup...or your gas station is shorting you on octane  
levels.  Check with a scan tool to make sure the ECU isn't retarding  
ignition more than it should be.

Quite a bit of race gas is also leaded, which is a sure fire way to  
destroy the cat and O2 sensor in very short order.

Brett