Which gas?

[eap95gt]

I have been told that my 95 5.0 came off the show room floor set up to burn 87 octane gas.

Every time I try to run it, my car pings bad. It has 111K miles with no oil burn or other engine issues.

When I run 91 or better (currently 93 in Alabama), there is no pinging except under load (a/c on) at 4500-5000 rpm.

Which is correct? Can the car be tuned to run 87 or 89 octane without cheating performance?

Eric

 

[GTJake]

Clean the MAF and do an all around tune up. If that doesn't help you may need the higher octane.

Jake

 

[wytstang]

Check your timing a may be set to high. It should be a 10* unless it has be advanced to 14* for the extra hp than you must run a higher octane.

 

[HISSIN50]

dont forget that more compression increases the chance of detonation. if you have a lot of carbon build up in the chambers, your compression can be artificially raised enough to require more octane (slower burning fuel - less volatile).

as for pinging at higher revs, i might also hook up a FP gauge and monitor the pressure at those revs. if you are running low on pressure and thus lean, that does not help.

good luck.

 

[mo_dingo]

You have the classic 94-95 pinging. Do a search on the forum on how to get rid of it.

Running 91 octane will make your car slower, and only "hide" the pinging problem.
Scott