tsopranoMB

Shame on that salesperson!

I always show my customers the requirements and if they do use 87, you will get poor economy and performance and potential for problems down the road.

JC6180

Can someone confirm if this is correct.... the NX200t recommends premium 91 fuel, and the 300h only says regular 87. So if Lexus themselves state 87 for the 300h, would we get lower mileage if we were to use anything higher than 87 ?


http://lexus2.custhelp.com/app/answe...xus-vehicle%3F

Mr645

Won't make a difference. Going from 87 to 93 is not enough of a change. More and more cars that use 87 octane will make more power with 91/3 octane. Not saying the 300h will but many cars do. Volvo 2.5L turbo calls for 87 but if you read through the owners manual there is a line that says *Rated power was obtained using 91 octane fuel.

Mr645

I find it unlikely that using 87 octane would cause a problem. Perhaps slightly less power but since a majority of Lexus drivers would never notice a drop of 10 hp and will use 87 octane for 100k miles it's fine. Most cars that specify Premium still run perfectly fine on 87 octane just will not reach the boost levels under certain conditions that can be reached using premium fuel. I've dyno'd several cars trying different fuels and some make a difference, some don't. Lexus and almost all brands now use engine knock detection that monitors each cylinder at every revolution and can make adjustments very quickly. I did try a 2012 Subaru WRX and was surprised to see a single sensor for 4 cylinders and the system did not reach very quickly. But the latest GM engines can reach to engine knock in a single RPM to protect the engine. Perhaps a Lexus F car will require premium only, I have a Cadillac V that required premium and the manual says using lower octane fuel can cause engine damage that may not be covered under the powertrain warranty. VW GTI is rated at 220 hp, requires 87 octane but on the dyno the car made 16 more HP with premium fuel then 87 octane. A 2008 VW R32, NA 3.2 V6 says required premium. Yet on the dyno the engine delivered the same power with 87 octane as it did with 93. I sometimes wonder if some of the fuel requirements they state are influenced by marketing. A relative just sold a 2012 Mercedes C250, 1.8L turbo, says premium required. 45k miles and that car never had a drop of premium in it's engine. No problems

JC6180

So basically, to save fuel and achieve the best fuel economy, I might as well stick with 87 then? Thanks!

Joeb427

iTrader: (1)

You may say that to your customers but most sales people won't do the same.
So, yes...shame on the sales person!

Lex2000TL

If the engine is designed for 87, it will not make more power with higher-octane gas. In Volvo case, if this is what the manual said, it most likely meant that its engine can tolerate 87 without harm, but is built for 91.

Torii

wonder if the whole reasoning for higher octane is just the tests...better stats. my old lexus IS ran for 10+ years with NO issues on 87 octane, great car.

Mr645

The Volvo had a sticker on the fuel door, said 87 octane required, also the window sticker was marked 87 octane.
My 2017 VW GTI is the same way, fuel door is marked 87 octane, specifications in the manual say requires 87 octane but reading a little online and it seems that the VW 2.0 TSI motor makes more power with higher octane. I took it to my friends dyno an the power was identical up to 4500 rpm at which point power built 16 hp greater with 93 octane E10 compared to 87 octane E10 fuel. No where in the manual does VW say anything about premium

GoHuskers

If this is TRUE with Lexus 2.0l then it is awesome news. How often do you stay above 4500 rpm?

Mr645

This dyno test I did was with a 2017 VW GTI. I never put the NX on a dyno. You can try a simple test, with premium fuel in the tank go to a local 1/4 drag strip test and tune night. Just look at the MPH and the end. There go back the week after once you have run through 2-3 tanks of regular fuel. See if the MPH drops on the 1/4 mile runs. Keep in mind if the temperature change more then 5-10 degrees that can affect the performance. Cooler temps will yield faster times

Lex2000TL

Your car engine designed for 87 will not make more power using 93. Perhaps it is placebo effect that makes you feel that way. Please read couple of articles (links below). You can find a lot more on line about this topic.

https://cars.usnews.com/cars-trucks/...gular-gasoline
http://oppositelock.kinja.com/the-tr...ter-1487358722

Mr645

Not sure about Placebo but my VW measured more hp and more torque on a Mustang MD150 dyno. It made 16 hp more peak and 11 ft lb torque at higher RPM. Never put the Volvo on a dyno, but for some reason it stated that 227hp was measured using premium fuel. in the owners manual. Maybe it made the same with 87 octane, I don't really know. A 2008 VW R32 which says Premium required made virtually the same power burning 87 octane E10, 93 octane E10 and 90 octane pure gasoline. The power output was within margin for error on the dyno.
My Cadillac says Premium required and in the manual states that using improper fuel may cause engine damage which is not covered by the warranty.

Mr645

100% true there is no difference in fuel quality, just the resistance to burning. In fact most brands all use the same base stock, order fuel from tree same facilities and the additive package unique to each brand is added just before the fuel is delivered to the station.

LexBob2

For their CX-9 Mazda shows the ratings when using regular or premium. It takes the guesswork out of things for the driver. Other cars have done this too but Mazda it the most recent.

Regular 87 octane: 227 hp/250 ft. lbs.
Premium 93 octane: 250 hp/310 ft. lbs.