Guys, i was using 94 Sunoco in my car for about a year and a half and now i have to use 91 here in california...it's been about 3 months so far
my engine doesn't seem as smooth as before...and sounds loose

am i just bugging out or could the change in fuel cauz problems?

how would i know if my car is "pinging" "knocking"???

need some help guys...any suggestions?

-boz

 

i feel the same thing. i don't think the fuel is harming anything. i miss 94 octane. but, i'll have it in a couple of weeks.

 

Yes, the engine will probably not seem as 'smooth' because it is not developing as much power. 94 Octane is more resistant to burn than 91 so the 'explosions' are not as harsh. Unless your timing is advanced, I suggest not using octane higher than 91/92, or whatever the manual suggests. BTW, your car cannot ping... it has a knock sensor that automatically retards the timing if it senses detonation. Retarded timing = less power but no detonation. Cars are designed to run on an optimum fuel octane, and anything less than that it will retard the timing so detonation does not occur. The car will NOT advance the ignition timing if there is no detonation, so putting fuel in with a higher octane level than it was designed (stock ignition timing) is a waste and will compromise power...

 

Your quote: "BTW, your car cannot ping... it has a knock sensor that automatically retards the timing if it senses detonation" has already been proven incorrect by numerous drivers that have experienced "problems" with 91-octane gas (And the car's were rated for 91-octane [in the case of the CLS] and 92-octane in the case of the TLS.)


There are some TLS owners (and a very small number of CA CLS owners) that have reported pinging problems that could not be fixed by their dealer (they were in California and running 91-octane petrol). The pinging went away with the addition of a few gallons of 100-octane unleaded (76 carries the stuff and it works rather well and has a great detergent and additive package; it is very expensive).

I was also amused by the dyno graphs of the new Z-car in the latest SCC magazine. The car makes more HP with 100-octane gasoline when compared to the 91-octane crud we get here in California.

The question is: what is the octane that the car was actually designed for and who wrote the specification (engineers, designers, testers, marketers, sales people, so on)?

 

The lower rated fuel must explain the delayed response when i W.O.T the car.

The car was lagging compared to the 94

have any of you guys have problems using 91 here i california?

-boz