Quote:
Originally Posted by TacomaOffRoadGrl
Is the FJ engine not the same as the Tacoma?
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It's exactly the same. The 1GR can run on 87 octane or higher. Toyota recommends 91 for best performance, however. With any octane, the ECU will determine how far it can advance the ignition timing. Obviously since 87 octane is more explosive, the ECU cannot advance the timing as far as 91 octane and the knock sensors actively detect pinging or detonation. Since 91 octane can let the engine achieve more timing, it creates more power, therefore, 87 octane runs the timing retarded since it cannot achieve the maximum amount of advance the ECU specifies. As the compression ratio of an engine increases, the more performance you'll lose between 87 and 91, but since the 1GR only has a 10.0:1 ratio, it's not too terrible.
So:
87 octane
236hp @ 5200rpm
266lb-ft @ 4000rpm
or
91 octane
239hp @ 5200rpm
278lb-ft @ 3700rpm
You get 12lb-ft more 300rpm sooner. Trivial, but it helps. Most dynos I've seen of the 1GR on 91 octane show 285lb-ft though.