Thread 28564381

Australians

Should you use 91, 95 or 98 in your petrol car and why? Does it really make a difference?

>>28564381 (OP)
Depends on the car, most will have a sticker near the fuel cap or in the manual. There will either be a requirement or a recommmended rating and a minimum rating

My old camry took 91
My civic type R took 95 with a minimum of 91.
My Supra took 98.

If you use lower than recommended the car will have significantly reduced power and it can fuck it up

>>28564381 (OP)
You're a retard, try reading the owners manual.

>>28564381 (OP)
Put diesel in and send it mate

>>28564381 (OP)
kinda surprised that we don't dilute all our petrol with 10% ethanol like the burgers do. apparently they have to go to stations that advertise as being 100% ethanol free if they don't want any ethanol in their fuel.

>>28564381 (OP)
there is literally no difference in terms of heat energy, the only thing octane rating matters as far as engine operations is concerned is flash point, which is important in performance engines that run higher compression or/and faster revolutions per minute which means higher cylinder temps which means potential pre-ignition or detonation
if the engine is tuned for low octane then you are wasting money for no benefit with high octane, and if the engine is tuned for high octane then you can grenade it with low octane

>>28564434
Don't they also tune some cars for the fuel available in each country?
At least some fancy Mazda high-compression engine being slightly down-tuned in its US version because the car itself was fairly cheap, and cheap car buyers were probably going to end up putting cheap fuel in it. US "Regular" is pretty low octane by international standards.
Maybe they didn't want the car to get a rep for grenading the engine or whatever.

>>28564444
>being
>ended up being
ffs. Not deleting because of the digits.

>>28564434
>if the engine is tuned for low octane then you are wasting money for no benefit with high octane,

Does the high octane last longer?

>>28564444
you also can't compare ocatane numbers across coountries because there are different ways of calculating it, 91 rating in one country could be the same as 95 in another

>>28564434
>you can grenade it with low octane
Not an issue with any car designed for premium in the last 25 years, it just detects knock with the knock sensor and the ECU adjusts the timings for standard fuel instead of premium. You'll get 5-10 percent less power but that's about it.

>>28564447
Yes higher octane is slightly more fuel efficient, but not enough to where its worth the price difference

>>28564447
No, a car that's tuned for standard only will compress higher octane fuel to the exact same pressure before ignition and therefore gain zero extra power or efficiency.
It's not "slightly" more fuel efficient, there is literally no difference besides the higher price

>>28564448
Sure, but isn't regular US "87" roughly 91 on the international scale? That's quite low.
The US scale might actually be a better measure of the fuel's (anti-)knocking properties, but the numbers are fairly convertible if the fuel isn't anything too weird (a completely synthetic fuel with just a few kinds of different molecules could give wildly different results on the two tests).

98 from Costco for my classic car and my (modern) daily since it's only about 15 cents more a litres than regular 91 is at the cheapest place.
91 in my beater ute (from the cheapest place).

E10 never EVER.

>>28564433
consider yourselves lucky

>>28564381 (OP)
The real question is, why is e85 so scarce and the same cost as 98? It used to be half of the price. It's a bio fuel, why doesn't it get all the greeny environmentalist points?

Modern cars have these things called KNOCK DETECTORS that retard (just like OP) the ignition timing as soon as any pinging happens.

So any car from the early 00s onwards should be fine to use 91. I'd be more weary on forced induction applications though.

Its the older stuff that can't retard itself enough (like OP) where you run into issues and get detonation.

I use diesel myself because it's not a Jewish fuel.

I put 98 in my car because that's what the sticker says

>>28564484
I have to drive for like an hour if I want e85. Fucking sucks

>>28564551
jerry can?

>>28564566
He can what?

>>28564381 (OP)
Didn't know 91 was still a thing in high HDI countries. They phased that shit out in Europe at least 20 years ago.

>>28564678
>in Europe
they pay government for carbon dioxide and consider that normal
What did you expect from retards

>>28564433
once we GMO corn to grow in Alice Springs you can guarantee it will happen to you

>>28564381 (OP)
what is the 85% ethanol for? the abos?

>>28564978
Isn't the US boner for corn ethanol, corn syrup and so on mostly just a product of absolutely retarded tax/subsidy policies (and certain corn-growing districts having early primaries) ?

Don't they drive on sugar in Brazil?

>>28564447
Octane rating is the fuels tendency to ignite. It also affects burn speed (and burn patterns). Higher octane actually burns slower and produces less power, that is if the engine is designed for the lower octane.
If an engine is designed for 98 but changes spark table to compensate for lower octane than it will of course lose power with the lower octane.

>>28565010
Yes.

>>28564492
>knock sensor
My newest vehicle is a '95.
My oldest is a '64.
You dont live in my world so kindly eat a dick and fuck off.

>>28564447
Strictly speaking, no. See
>>28564452
and
>>28565314
However, it's quite common for "regular" to contain ethanol and for "premium high octane" to be ethanol free. In which case, yes high octane would be more fuel efficient due to the lower energy density of alcohol.

>>28565324
Energy density is compensated for in A/F ratios.
If youre at 14:1 with E10 in a lower compression vehicle then 14:1 with non-eth 98 will deliver less power.

>>28564434
>there is literally no difference in terms of heat energy
if i remember correctly, higher octane gas actually has lower energy than low octane gas. It's just that it allows higher compression ratios, which massively increases power despite the tiny loss from running less explosive fuel.

>>28564447
no, retard.

>>28564492
Kek knock detectors are there to protect the engine.
Unwanted burn can still happen and it will sooner or later destroy the engine.
>just get the correct fuel, no more and no less

My car says "premium only" not sure if I should be using 95 or 98.

>>28565965
What car is it? Check the manual, if its not a sportscar or european its probably 95, if its a sportcar its probably 98

>>28565967
Manual only says "premium"

>>28565968
if you're worried than the only thing higher octane will hurt is your receipt

>>28565968
Contact the manufacturer or go to a local dealership

>>28564381 (OP)
Fill the rainbow!

pozzies smell of bum poo and cannot drive to save their lives

>>28564381 (OP)
Which one is best for sniffing ?

>>28564387
>FPBP
I've been telling people for years this simple shit, "Plus" "Supreme"
etc...fucking marketing

There is a legal standard of quality they have to reach, (additives withheld), the numbers refer to the octane and each engine has its rating

>>28564387
>If you use lower than recommended the car will have significantly reduced power and it can fuck it up
Over time yes, that includes using higher ratings than listed for the engine, too much pressure; although at your typical gas station you wont find more than 100 unless your near a track, damage will take years but will also take years off the lifespan of the car

At best, each realtor has maybe better additives

>>28564576
Match box

>>28564433
why does the carb on my motorcycle gum up if I forget to start it for a while then? This has happened multiple times, I give it 91

>>28569256
i dunno. but from what i can find, the only ethanol-containing fuels are E10 and E85, everything else is unadulterated

>>28566000
They're not gonna know