Octane rating for 3.4 [Archive] - GrandAmGT.com Forum

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MegaHyp
05-22-2005, 01:33 PM
I'm sure this is a topic that has been discussed many times, i searched and didnt find an answer. But for the 3.4 engine(SE Model) is there any benefit to running 89 vs 87? I know some cars PCMs do not recognize the higher octane and its just a waste of money. I've always filled with 87, just wondering if i should use 89.

xxbackhillxx
05-22-2005, 01:56 PM
No.

Mike Jung
05-22-2005, 02:04 PM
...is there any benefit to running 89 vs 87?
I know some cars PCMs do not recognize the higher octane and its just a waste of money.
I've always filled with 87, just wondering if i should use 89.

If you use gasoline that is blended with up to 10% ethanol; I would use a minimum of of 89-octane.

But unblended gasoline: use a minimum of 87-octane.

About 87 vs. 89 Octane Gasoline ? (http://www.grandamgt.com/forum/showthread.php?t=10606)

intrikitemo
05-22-2005, 08:48 PM
unless u have a supercahrger then u need to run 91 octane ;)

which kinda sucks when its almsot near $1/litre :nono:

atc3434
05-22-2005, 09:42 PM
If you are running with something like a timing advance mod, such as DHP, then they suggest 91+ octane. If your car is experiencing any knock retard, higher octane gas usually will solve that, and restore any power you were lossing to knock retard. Its actually pretty often that these cars will experience a fair amount of KR with cheap gas.

1hotgagt
05-23-2005, 08:18 AM
what is knock retard?

MagusXIII
05-23-2005, 12:15 PM
what is knock retard?
That is where the car's knock sensor detects knock and sends a signal to the ECU telling it to retard the timing. This of course has the effect of reducing maximum power but it saves the pistons from knock damage.