I know I'm going to get so much flak on this forum for asking this but has anyone ever experienced any knocking on the 2gr-fxe engine when using 87 octane (regular fuel)?

Just curious because the same engine in a tacoma or highlander hybrid comes goes with an 87 octane recommendation but lexus insists on 91 and warns of knocking dangers? Any experience with knocking?



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Nope. I also don't put 87 in. 91+ only.

Not saying that 87 octane is the course of your knocking, but it seems the simple answer if that's all you're putting in.

 

Never had a knock either, but just wondering why the exact same engine across three different (even classes) of vehicles gets different "required" fuel in their manual and a knock warning for 87 octane fuel in the case of the lexus

 

The GS450h is a high compression ratio NA engine, 13.0:1. Eve​n the GS350 is only 11.8:1 although interestingly, the RX450h has the same engine code but is 12.5:1 and only recommends 91 instead of stating requires.

The ECU will dial back so you can survive 87 but it'll likely be lightly knocking (not to mention power and efficiency losses) even under nominal power. Not really worth it.

 

I ran 91 for a while, then i went to 85, didn't see any downfalls to getting the cheaper gas. I really like the savings too. Mines never knocked. It shouldn't as the knock sensor will richen up the A/F ratio to cool down the combustion chamber if a knock is detected. Our Engines have a real high compression ratio but a shortened intake stroke so the actual PSI isnt as high as you would expect.

The RX450h does not have the same engine. At Least not until this last year. Ours are unique as it has the (2) different fuel injection systems but also combined with the Atkinson cycle. I came across a paper toyota circulated or the 2GR-FSE GDI PFI engine. It's a long read but interesting on why they did the dual systems. Let me know if anyone wants it.