Luquanda

Hi i just got my car (2015 ct f sport) a week ago. Idk which unleaded gas to put. 87, 89 or 91?

Idk if i should put the regular gas or premium.

The manual said 87 or higher

StillLine

Our cars use the Prius engine and are designed to run on 87 octane gasoline. Using any higher octane fuel is a waste of money.

User 41924

Do they put any additional additives in the higher octane fuels to reduce carbon build up, clean injectors, etc.?

GSteg

iTrader: (15)

I highly doubt it. Additive package depends on the retailer. As long as you're buying from a top-tier company, you should be okay. I run fuel injector cleaner in my car every 5,000 miles since the additive in gasoline is not as concentrated.

Trexus

The manual stated 87 but you can go higher if you like. I have used the mid-grade and premium grades and noticed slightly higher mpg's but you'll be fine using 87 regular gas. From time to time be sure to pour in a bottle of fuel injector cleaner for good measure. I like to use Redline fuel injector cleaner. You can get a bottle at O'Reilly Auto Parts, Pep Boys and Advanced Auto Parts...

KKM

Using 87 is fine, better to use the stations that are qualified Top Tier listed here:

http://www.toptiergas.com/retailers.html

Most gas comes from the same refiners, it's the addition of detergent additives by the individual companies that makes a difference in the long run.

I have a 21 year old '93 Volvo that I've only used 87 octane, even though they suggest higher, since new, that still runs like a champ.

Raidin

Hey guys, I noticed something about the octane rating for the CT, and wanted to bring it to your attention in case you haven't seen this.

In the manual, every instance that speaks about what type of unleaded gasoline to use always says to use 87 octane or higher. It never says 87 is recommended, only that it is the minimum we should be using. It never states that using premium (91 octane) will increase performance. Engines usually have to be designed to make use of higher octane gasoline, and most non-performance cars will not see any advantage using higher octane than what's recommend.

But...

I was looking at my 2014 CT 200h brochure from Lexus, at the final section, where it mentions the 0-60 mph time of 9.8s. There were two footnotes next to the number. I looked at the fine print, and the first footnote said the following (direct quote):

Ratings achieved using the required premium unleaded gasoline with an octane rating of 91 or higher. If premium fuel is not used, performance will decrease.

Many cars can run on 87, but recommend 91 for the engine to produce all of the power the manufacturer claims it can produce. This line seems to suggest the opposite, that the car is supposed to take 91, but can accept 87 with reduced performance.

Obviously there's nothing wrong with running 87, but has anyone tried 91 and noticed any real difference? I think I may run 91 for a week and see what sort of MPGs I get, since I drive a nearly identical trip every day and can see small differences better than most.

StillLine

Yep, I found the reference regarding the use of premium fuel in the CT on the Lexus website as evidenced by the following screenshot.


Check out note (2).

Raidin

I've been putting premium in my car this whole week (93 octane, we don't have straight 91 here). So far, no difference at all in mileage (really didn't expect anything, but worth a test). Also, I didn't feel any difference in terms of power when accelerating hard.

StillLine

The only time I've seen an appreciable difference in fuel economy was when I burned 100% gasoline, as opposed to the widely available petrol with 10% ethanol. Even with the increase in gas mileage, the extra cost of the 100% gasoline was still more expensive than just burning the cheap stuff. For the CT200h, the cheapest gas represents the best value.

sonnyhood

Damn your octane is low.
Here in australia fuel is...
E10 91 octane (can sometimes get 91 without ethanol)
95 octane
98 octane
We use 95 in the CT and i use it in my GS.
CT gets over 700kms and doesnt ever fully fill the tank i think theres about 10+ litres still in the tank.
We get 4.8-5.0 L/100km, or 49-47MPG very regularly without really trying to save fuel.
My car says Premium Fuel only on the cap, which means here 95 octane at least.
I will never run ethanol fuel as it leaves residue on spark plugs and in cylinder.
Unless a car is specifically designed for it to work you shouldnt use E10.
Camry Hybrid for example is designed to work on E10.

DarkMastyr

Not the same rating in Australia.
http://wikicars.org/en/Octane_rating

sonnyhood

It says there 98 RON is equal to 93 Super Unleaded.
I didnt see anyone mention 93.
I think my wife fills that in about 50/50 with 95.

Raidin

I did, in my second post.