isking99

ik it says 93 is the only gas for the 2014 is250 but mines a lease so is it really that big of a deal to use 87?

Justin2JZ

People will own your car after your lease is up. Dont be a idiot this topic has been covered many times, put the right gas in the car.

unowned

A continuously detonating engine will eventually crack a piston easily before your lease is up, which will bounce all over the cylinder, valves destroying them.

4TehNguyen

iTrader: (1)

try it and watch how bad it runs and how bad the mpg is. Coworker tried it in his 08 IS250, ran like ***

frmUkraine

You are right, detonation is killing engine, but this process is very slow. I live in Ukraine, we have enough quality European gas, like your 93 octane (it costs 5usd per gallon). But in our neighbour Russia, they have very poor quality 93 gas. That is why most of people use 87 octane even on high powerful cars like Lexus, Mercedes, BMW etc. They use 87 instead of 93 and higher because they have a lot of dangerous additives that increase octane number, but kills ignition sparks. They use low octane for a long time, without problems. But! As for my observations, using low octane (87) is useless, because consumption increases, plus power is decreasing. There is no sense in such economy.

davyjordi

agreed. if you're leasing a lexus you should be able to afford the few cents more for the gas that the manufacturer recommends will keep the engine running without problems. never forget that after your lease is up someone else will be purchasing that vehicle.

FinaLpeace

He obviously can care less about maintaining the car well since he's leasing it, as he mention. That said, which is why I never recommend anyone to buy used car with high mileage.

CtSFox

Yes, human nature being unfortunately what it is, I would never buy a car off lease or a demo/loaner.

isking99

Personally i have found that its just more expensive and that 93 in a 250 is pointless? Why pay more for gas when you only have 200 hp? who are you racing? and the chance of blowing a piston from a decrease in octane is just unlikely.

carderoni

Spend $40k on a car and yet you worry about $4 per tank. If the money is that important you bought the wrong car. Sorry to sound harsh.

CTLG

Horsepower has NOTHING to do with what kind if fuel the engine needs to run properly (as designed).

The 2.5L in the IS250 has a compression ratio of 12.0:1, which is actually higher than the 3.5L in the IS350 (11.8:1). It needs 93 octane to run properly. End of story.

That said, you can run a lower octane fuel for a SHORT period of time and the ECU will pull timing at the onset of knock (which will happen if you run a lower than premium octane). This will cause of loss of performance and an even bigger loss of efficiency. You will probably lose more in engine efficiency than you stand to gain in the cheaper gas price. Case in point, it is stupid. Don't do it.

Maybe you should have bought a Honda Civic? Nothing wrong with that.

Side note: The 2.5L's actual crank HP is closer to 220-230HP, it is de-rated by Lexus, just as the 3.5L's actual crank HP is probably closer to 340HP. These engines should be close to 1:1 displacement/HP engines.

forum429

Cars nowadays have equipped with octane sensors.
In another word, your car will adopt your cheapass behaviour.
However, it won't have the full 200hp you are already looking down at and it will have worse fuel consumption. You will end up using more fuel than you should so you are not saving up any better and you are loosing power.
Do your car a favor, just put in the recommended octane.

forum429

Source?
It does behave like a 300hp car.

salvadorik

iTrader: (1)

Highly doubt about IS350 is 340HP at crank. I dont feel even 300 horses at high RPMs. Can someone confirm dyno results?

l5JLlll

LMAO, HOW? using our Seat butt dyno?