Who's the first to put regular octane gas on their GX550?

[rgsiii]

I do not have a GX. I have three other Lexus vehicles that call for premium fuel. The LX570 calls for premium and the essentially identical 200 Land Cruiser says regular is fine. I have used regular with the LX, a GS350 and a NX300 after evaluating both regular and premium, I have found no difference in MPG or acceleration.
Will this be the same with the GX?

 

[steveperry]

Now, on the question of whether Regular would actually do any damage to the GX.... Toyota specs Regular for the Tundra, which uses the same engine. So why does the GX need Premium?

I've wondered about that as well. We have a tundra that's happy to run 87. I've wondered if it's something with the tuning or if the turbos are different or what.

 

[killy]

it is well known that the tundra and the GX have different turbos.

It is likely emissions related, running lower octane gas will require more fuel to prevent the AF mixture being too lean and knocking on the more efficient tune.

the cost of premium fuel is offset by the increase in mileage and you get more power to boot.

 

[cloey701]

As someone that's calibrated engines, I would highly recommend against regularly using lower octane fuel. While it's true the ECU has ignition timing and boost tables to compensate for knock and other adverse conditions, you don't want to constantly rely on that to keep the engine safe. This is especially true under higher load conditions like rapid acceleration or towing.

Keep in mind that all else being equal, (e.g. air and coolant temps) the knock sensor(s) have detect knock before the ECU reduces ignition timing. So there's a real chance of premature wear and/or damage if that's regularly happening.

On maximum effort racing applications, "riding the knock sensor" can allow the engine to run closer to MBT but that's not a strategy for a daily driven car where the operational target is 150k+ miles. Can you run lower octane fuel occasionally and get away with? Sure. There's just little reason to do so.

Finally, the GX550 is priced between 65k - 83k. If the small additional cost of premium fuel is too much for your budget, then you bought the wrong car.

Well, I have both the new and old GX. I know the new GX is completely different from the V8 in my 2014, and maybe that’s why I’ve been lucky with regular gas. I have had no issues and I’m at 190,000 mile. The new one is my husbands and does use the premium. I’ll take my risk and continue with the regular. I’ve had it for 10 years and if starts giving problems then I’m fine trading it in, I got my money’s worth anyways

 

[YellowLab]

Only reason the manufacturer recommends premium is to meet their power and mileage claims. You can use regular. Yes their will be less power, hardly noticeable, and yes a little less mileage, hardly noticeable. But the computer will take care of any possible detonation.

You mean it's possible to get worse than 13mpg???