Tarrant64

You're right on the alternative fuels. Absolutely you can run something other than 91, but you should use 91 as per recommendation. I have on occasion used 89 when I felt 91 on that day was just too outrageous but most times I suck it up. I tell myself I drive a Lexus, no need to be cheap on the gas. It's really not that much more. I haven't had any issues switching between either, but my recommendation is still use 91 whenever possible.

The Acura SH-AWD system is superb. My father has the '13 TL, absolutely fantastic car. I don't know that you can rule out Lexus as not having a good AWD system though. Not all AWD systems are created equal. More to my point here's a link that goes over the different variations of AWD setups (http://reviews.cnet.com/2300-10863_7-10007878.html). You'll find that each system has it's pro's and con's - but each were designed to achieve a certain goal. For Lexus it was performance orientated for their RWD based cars (IS).

keyframe13

You guys should not use anything other than premium. Lexus does not recommend using premium.. IT REQUIRES premium, Huge Difference. On the gas cap it say "Premium Unleaded Fuel ONLY" not recommended.
Of course the car won;t break if you put once. Sometimes premium might not be available but running a long period on that can cause serious damage to your engine.
Read owners manual.

Nikon

iTrader: (2)

the AWD rides like a monster truck. only thing i don't like about AWD models.

Tarrant64

The serious damage part is generally not true though. Which is why people have reported going 100k without it. It's not that huge if a difference on most cars. Lexus states it's required because it is preferred to get optimum performance. It's a luxury "tax" you pay to meet expectations of a higher performing engine. You lose a slight amount of power which most drivers will never notice.

The serious damage part is an extreme but most engines today can cope with any gas. Experts in automotive industries have always stepped out and said basically "premium may be stated as required but it's really only to ensure the engine runs at it's best". Scaring people into not using it at all is silly. If it were a problem we would see people complain that their car broke down from use of non-premium, which I've never seen from a Lexus. Even Mercedes has cars which state premium is required but reality is these cars must run anywhere int e world and in some places regular is your only option.

Cars are more advanced than people give them credit for, but to ensure engines run the best the trick is put a sticker on it that says premium only.

keyframe13

I think you need to educate yourself more into this matter.
The reason why premium is REQUIRED is because of the engine high compression ratio, it squeezes the air and fuel mixture to higher pressures — which can improve both fuel economy and power output.
Because regular contains less concentration of detergents in the mix than premium you are more prone to carbon build up than using premium.
Of course if you don;t put your car to work hard and drive normal it might not affect it much but driving hard, extreme hot condition or with big loads might cause serious damage to the engine. Hence why the manufacture is cautious about it.
The lose in performance, MPG, carbon build up and the risk to damage your engine doesn' worth saving few dollars per fill up in my opinion. Of course people can test their car for 100k miles putting regular in their Luxury Expensive cars that calls for premium ONLY but that denote cheapness IMO and they should own a Toyota instead which is a low compression ratio and premium is not required.
Don't get me wrong, I hate they use that expecially when I know low compression engines provides the same great performances and better gas mileage maybe. I really don;t get why luxury cars prefer to use this high compression.

NYKnick101

I am going to have to agree with Tarrant on this one. If you do a little research on the 2GR/3GR/4GR engines, there is a but of a confusion on this whole octane rating thing which leaves the gas thing forever up in the air. Lexus says that it requires premium at all times BUT when you look at its sister cars where the 2GR is in like the toyota camry, RAV4, or Sienna minivan, they require 87 minimum. Of course there are slight differences in the engines but compression ratio isn't one of them.

Also the mark X in japan which uses the 3GR/4GR-FSE engine, they require 89. But I think in japan, the lowest octane rating is 89 therefore they will be fine. So you really have to make your own educated decision on what you want to get out of your car. Are you gonna do what the manual says, OR are you educated in mechanics enough to make your own octane rating decision at the pump.

Therefore, 91/premium isnt REQUIRED, although under american octane ratings, it is HIGHLY RECOMMENDED. For all i know, american oil companies could be treating their gas differently than other countries

keyframe13

Correct me if I'm wrong but Camry/RAV4/ SIenna uses 2GR-FE which has a compression ratio of 10.8:1's while Lexus IS350 uses 2GR-FSE which has a compression ration of 11.8:1.
Lexus IS250 uses 4GR-FSE with a compression ratio of 12.0:1. How is the compression ratio not a difference between those engines?

Tarrant64

Even if the compression ratios are different, the damage you're talking about is unlikely with the car in question. Because I've educated myself on this I am speaking up to say it's not as big of a deal as you're making it out to be. Most newer cars have the knock sensor or whatever that assists the engine in dealing with lower compression fuels so it doesn't fail. Hence, you can drive 100K on 89 octane. The biggest impact these days is loss of performance because the engine is retarded to compensate for the lesser octane fuel.

91 (in my mind) is required because Lexus wants people who drive their vehicles to say that it absolutely runs great and is a good performer. The engines rated at 91 octane will do best on 91, so the only way to guarantee most people will be pleased with their car purchase is to require they use 91. In reality, all the bells and whistles are built-in to allow the car to run a lower octane just fine.

Valkyrie00

Responding to the original post, I would look at one owner cars with a clean maintenance schedule. This should be available through Lexus.com if car was serviced at local Lexus dealer. We bought our 1st Lexus this year : 08 IS250 RWD, Matador Red Mica, with 52k miles and are pleased with almost everything, especially compared to the Accord we drove the previous 5 years, but can't compare it to the Audi's and Beemers. The only real issue was the graphite alloy rims were cosmetically damaged by a cleaner or brake dust or something ? ! The dealer "promised" to refinish them, but we got screwed on that - it was not a Lexus dealer though. Next time I would shop around more to find a car with more options; no memory seats or heated/cooled either on ours; I run synthetic oil AND we alternate gas fillups with regular(89) and premium (93) and do not notice any type of diff in performance or mpg. If I wanted a higher HP engine, would have bought a 350 or a Shelby Mustang !! I think the ECU knows the octane and compensates for it. Our friends have a LS400 with 150k on it and have always used regular ! Good luck shopping and keep us updated.

carlos3366

alternate gas fillups with regular(89) and premium (93) and do not notice any type of diff in performance or mpg. If I wanted a higher HP engine, would have bought a 350