93 to 95

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Pointing1

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So the fuel price is going up:cry: again tomorrow (fill up tonight) and just noticed that 95 will be a few cents lower than 93...:erm:so am thinking of changing save a few cents per litre - is there any fuss or issue with that. Have always used 93.
 
No NO NO NO NoNO nO NO please man! You'll litterally save like R5-R8 ona fill up! GO 95, burns better and gives car better performance, its 2 rons more!!! 93 is only good coz it burns slower...makes you go further, I've tested it, and I'll fill up with 95 all the time!

You won't save much if you fill up tonight like all the uninformed people, its not like you saving R50 per fill up! I cannot understand how people will bum rush to the filling station tonight, and then afterwards go eat out, and have desert and then complain that the petrol price has gone up...lol I guess I'm just being biased coz I work for a petrol company, so the more prices go up, the better my share dividends in Sept/October!!!YAAAY!
No, seriously, go home tonight, spend time with your family, and when the light comes on...go fill up...oh, 95 has ALWAYS been more expensive than 93!
 
95 is good/required for turbo and supercharge cars. Excess O2 - higher octane - better performance and efficiency.
Also, according to a scientist that explained this, 95 burns cooler (cant remember how) so better for the turbo/supercharger.

I always fill 95 (had a turbo, now a super).
 
superskully said:
95 is good/required for turbo and supercharge cars. Excess O2 - higher octane - better performance and efficiency.
Also, according to a scientist that explained this, 95 burns cooler (cant remember how) so better for the turbo/supercharger.

I always fill 95 (had a turbo, now a super).
Click to expand...

Benz?
 
ALFAHOLIC said:
No NO NO NO NoNO nO NO please man! You'll litterally save like R5-R8 ona fill up! GO 95, burns better and gives car better performance, its 2 rons more!!! 93 is only good coz it burns slower...makes you go further, I've tested it, and I'll fill up with 95 all the time!

93 goes further????? How further are we talking few metres, kilometers, few hundreds of kilometres......i will fill up today drums and all
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Yep, and i noticed a difference between 93 and 95 (both 2.0T and C180k).
I know combustion but not much about cars.
In a naturally aspirated car, in the highveld, low O2 (air pressure much lower) - so 95 octane not necessary (when compared to coast).
Also the reason why they say these type of cars are 'slower' in the highveld.
With Turbo and Super - excess O2, so higher octane.
But if there is excess O2 in exhaust gases - there must be excess O2 in air intake. So my whole argument does not make sense (and just lazy to look it up).
I have though NOT noticed a difference between 93 and 95 on my wife's 1.4 Getz.
 
I have just done some reading.
Higher octane burns slower (also probably why it burns cooler).
Since it burns slower - require higher O2 (thus 95 in coast and 93 in highveld).
So there is no reason as to y we should use 95 - rather 93. Probably could cause more harm. This also depends on compression ratio (O2/fuel) - so stick to the manufacturers manual.
As mentioned difference for turbo and supercharged as excess O2 - and burns cooler.
 
Manufacturers manual doesn't say anything about it dealer who sold said it really doesn't matter......apparently it only matters on your fancy cars M3, etc and its been known to matter on the 335i...everywhere else u can pretty much go with the cheaper one
 
Pointing1 said:
Manufacturers manual doesn't say anything about it dealer who sold said it really doesn't matter......apparently it only matters on your fancy cars M3, etc and its been known to matter on the 335i...everywhere else u can pretty much go with the cheaper one
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I would not trust the dealer.
On your petrol cap or manual, it should state what RON.
My cap says 91-98.
Not fancy cars - but turbo or super. I know the 335i is turbo but older M3's were straight 8 (like a V8) - think the new one is also turbo charged.
 
Yes! 93 goes further lol...with my wife's yaris we had...going 160km trips to JHB, we'd use about 30% less on 93 doing 150kph than we did using 95 doing the same speed...with my 2.0 16v, 93 also lasts longer than the 95, but th 95 is just way better in terms of response etc...that's just me and my theory, and it works for me! YOu should however, try every theory you intend t adopt out yourself!
 
ALFAHOLIC said:
Yes! 93 goes further lol...with my wife's yaris we had...going 160km trips to JHB, we'd use about 30% less on 93 doing 150kph than we did using 95 doing the same speed...with my 2.0 16v, 93 also lasts longer than the 95, but th 95 is just way better in terms of response etc...that's just me and my theory, and it works for me! YOu should however, try every theory you intend t adopt out yourself!
Click to expand...

That actually might make sense though 30% is too big a difference. In the getz, the difference was a few %, thats freeway driving at 120 - 200kms per day.
It should also depend on compression ratio - thus follow the manufacturers guide. Higher ratio's would provide more O2 - thus higher octane (but its all relative as cars can take RON from 87 to >100) - so 93 might already be high enough.
95 will burn slower - so higher fuel consumption - but when it burns - it will provide more energy - so better performance.

P.S. I am making educated guesses - dont take my word for it.
 
....I adopt theories that result in me saving money in the short to medium term...thats mostly what its about for me except of course where it comes to driving a chery or a gonow
 
Wow, where did you guys get some of this stuff?!

The higher the octane number, the less explosive it is. The explosiveness is important because under conditions of high compression, the mixture could explode prematurely (i.e. before being ignited by the spark plugs) and cause detonation, which could cause engine damage.

Modern engines have knock sensors, and if they sense detonation, the engine's timing is retarded to reduce the detonation. This reduces the power the engine delivers, so if the fuel you're using is too low an octane, you'll be losing power, but only if there would have been detonation!

What that means, practically speaking, is that most modern normally aspirated engines have no problem with lower octane fuels; 93 at the Reef's altitude is just fine. The exceptions are those cars with particularly high-compression engines, or turbo/supercharged engines: they need the higher octane fuel to maintain the same timing and still not experience detonation.
 
100% Claymore, except fuel should never explode, it burns. Explosion = detonation. Detonation strictly speaking is when the fuel was ignited by the spark plug but as it started burning other pockets of fuel started ignition by themselves (IE. rapidly expanding gas, IE. explosion) If the fuel explodes prematurely that is known as pre-ignition and not detonation. They are not the same thing although it sounds the same, pre-ignition is much more harmful to an engine.

Also the ONLY way you can get increased performance and fuel consumption is if your car has a knock sensor. It doesn't stop there, ignition timing is determined by a ignition map. At most a knock sensor can usually deviate about 2 or 3 degrees from the ignition value set for a given map position. If for example you are running 93 octane and the ignition map is already at it's maximum advance because the ECU detects no knock that means filling up with 95 octane will have no effect as the ECU will not allow the ignition timing to be advanced any further.

It's a protective feature because highly retarded ignition timing in itself can lead to detonation regardless of RON and too advanced ignition leads to increased engine output and heat. Although it would be beneficial from a performance stand point not to limit ignition advance that would mean that a normal N/A standard engine could far exceed it's rated factory output by use of high octane fuels (which is kinda like modifying your engine without actually modifying it).

Other than that there is no benefit to higher octane fuels. That cleans and burns better nonsense is marketing jargon. So long as the engine is not experiencing detonation or pre-ignition it's running 100%
 
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Yea - I was about to mention compression too.

I remember in the days of owning 1.6 and 1.8 high compression RSIs, I was always told to use 95
 
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