• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

is 92 bad for my engine ????

Pharaoh XJ

NAXJA Forum User
Location
Cairo, EGYPT
I always used 90 octane which was more like 87 or 89 untill the prices rose so I filler my 94 HO auto with 92 octane this is what I noticed:
1- smelled different
2- Higher mpg
3- Better performane
4- (this is the strange one) it Wont start as easy as before when the car is cold it doesnt start from the 1st time unless I keep cranking for 10 sec.
I tried to turn the key twice so I can force more fuel from the fuel pump but still.

Is the higher octane level detonates later than the lower one so it needs more compression to start the engine or I need to change my wires , spark plugs.
ps: just changed my battery with a Varta 65 Amp instead of my usual 55 Amp ( installed it the day before I filled her with 92 )
 
i think high oct gas helps carburated cars, fuel injecter xj's are recommended to use 87 unless you have worked on the engine and need it.

why not just 87 octane?

maybe replace the fuel filter too.
 
POSXJGuy said:
why not just 87 octane?

X2

Higher octane rating means lower volatility, i.e. it's harder to ignite, therefore it is recommended for engines with higher compression ratios. This may be why you are having problems starting (fuel doesn't have enough heat/compression to ignite immediately). If your engine has alot of miles on it as many of ours do, and it has not been rebuilt specifically with higher compression, then you are wasting your money on the high octane stuff. Only use it if you are having problems with detonation (knocking and pinging) and most of us will never have that problem. The compression in our engines typically gets lower as the miles go up due to wear and tear.
 
Back
Top