What Octane Gasoline For sc430? Premium fuel required? (Merged threads)
09-09-16, 02:51 AM
#152
Lexus Test Driver
91-93 when offered...
You mean you can get 98 unleaded?
You mean you can get 98 unleaded?
09-09-16, 05:24 AM
#153
The posted octane numbers in the USA are 4-6 counts below those posted in many other parts of the world including Australia. So 91-93 octane in the USA is displayed as 96-98 in Australia. The US displays the (RON + MON)/2 or (R+M)/2) method while many other countries including Australia displays just the MON method. So, yes, we're all using the same grade of "premium" gasoline.
09-09-16, 05:57 AM
#154
The posted octane numbers in the USA are 4-6 counts below those posted in many other parts of the world including Australia. So 91-93 octane in the USA is displayed as 96-98 in Australia. The US displays the (RON + MON)/2 or (R+M)/2) method while many other countries including Australia displays just the MON method. So, yes, we're all using the same grade of "premium" gasoline.
Since many "premium gas" engines can compensate electronically for lower octane with only a slight degradation in performance, Edmunds breaks out into "premium recommended" and "premium required." It looks like our engine is on the "required" list indicating possible damage from extended use of non-premium gas.
http://www.edmunds.com/fuel-economy/...g-premium.html
I have no idea of their methodology. They just post this as a fact. Although I did read somewhere that everything on the Internet is true.
09-09-16, 06:24 AM
#155
I have been told that buyers of "premium" cars key off of whether the engine uses premium fuel. Dumb - yes - but that is one reason that premium is specified. Our engines have knock sensors that adjust the ignition timing advance to get the most out of higher octane fuels so "premium recommended" it what our manuals say. With premium fuel there is a slight performance increase and slightly better fuel economy. The key word being slight. However, in my opinion there isn't enough difference to justify the cost difference. The Lexus V8's have always been "premium recommended" engines with their knock sensors taking care of you.
09-09-16, 07:32 AM
#156
Most modern engines can adjust detonation to avoid pinging. The bigger question is whether the fuel's lower octane will result in elevated exhaust-gas temperatures, reducing engine life.
While some Lexus engines are on Edmonds "premium recommended" list, ours is on the "premium required" list. Where the manufacturer suggests premium fuel, I don't know what criteria Edmunds uses to then differentiate between recommended/required.
While some Lexus engines are on Edmonds "premium recommended" list, ours is on the "premium required" list. Where the manufacturer suggests premium fuel, I don't know what criteria Edmunds uses to then differentiate between recommended/required.
09-09-16, 01:53 PM
#157
You're quite right. I mis-remembered what I had read in my owners manuals. I checked both my 2001 LS430 and my SC430 manuals and neither one says "premium recommended". I had quite a few LS400, SC400 and ES level cars and perhaps it was on one of those. That said, over the years I have used all grades with the 430 engines and haven't heard a ping yet. The knock sensors seem to do a great job.
09-09-16, 03:13 PM
#159
Lexus Test Driver
09-11-16, 09:36 AM
#160
Since purchasing my car in June 2002, I have only used Premium (93) octane (usually with ethanol additive-unfortunately). Never had a problem, no engine knocks, no pinging, no engine vibration, nor rough idle. I do throw Seafoam into the gas tank approx every 10k miles.
09-11-16, 11:50 AM
#161
Premium recommended, is for engines that are tuned for 89 octane, but can compensate for 87. Premium required is for engines tuned for 91 octane fuel, but can compensate for 89 octane. It varies in what state your in weather you get 91 or 93 octane fuel. That I'm not sure why it's that way.
09-11-16, 12:29 PM
#162
Always use 93. I would consider 91 but the price difference at the Sonoco station I use is 2 cents a gallon. for 2 cents it get the 93. You can cheap out and use 87 (or worse). Yes the engine sounds OK but how much harm are you really doing? Treat your car well and it will treat you well.
09-14-16, 10:29 AM
#163
I don't think this car requires premium gas. On my manual it says Unleaded 95 (EU). I however always use 98, because the 98 has no ethanol while the 95 has 10% (called SP95E10).
Its economy is really good for a non-DI gas car. Doing mostly highway driving, I get around 9.5 l/100km (24.7 mpg). On road trips, I get even 27 mpg (measured at the pump).
Of course, it's still no match to DI engines with higher compression ratios (turbos, on the other hand, are only good for reducing the tax bill).
Its economy is really good for a non-DI gas car. Doing mostly highway driving, I get around 9.5 l/100km (24.7 mpg). On road trips, I get even 27 mpg (measured at the pump).
Of course, it's still no match to DI engines with higher compression ratios (turbos, on the other hand, are only good for reducing the tax bill).
09-14-16, 06:05 PM
#164
Pole Position
Not true. On your gas cap, there is the sticker that says "Premium Unleaded Fuel Only". BTW, 95 is premium.
There are plenty discussion about this
https://www.clublexus.com/forums/sc4...emium-gas.html
There are plenty discussion about this
https://www.clublexus.com/forums/sc4...emium-gas.html
09-16-16, 07:28 PM
#165
Compression ratio is 10.5. Needs 91 or better