Hi guys

While since i posted sry still need to post some pics, lazy me lol

Anyway just quick thought, i have been running 98 vortex in my car for last three months basically since I had it, I know my engine doesnt have a knock sensor as that is what I get from the forums.

Know no power increases with the knock sensor absent will running the higher octane fuel be worse then regular 91RON for the engine no better or same? I know stupid spending extra 14c a litre for delusions of granduer frankly I dont care just like the best fuel avaliable.

no power increase, but they say premium fuels help keep your fuel system cleaner for longer.
i found my car liked premium a bit, always seamed to run better on it. wait till your tank is allmost empty, and fill to brim with regular, and see if you can feel a difference once your back to the low fuel level again.

I always get better fuel consumption on 95/98 compared to 91/E10. I am sure the higher knock rating creates a better burn even without the knock sensor.

As lowrider said mate, no power increase using 98 but if you are prepared to pay the etra then you may as well do it. If nothing else, it will help kep your fuel system cleaner as the premiums have more detergent based cleaners in them.
But really, if it is hurting paying the extra then dont bother. It wont really be making that much difference to your car. Go a Steve Knight tune mate then un the 98 then you will feel the power increase.

probable good to run 95 or 98 every 5th tank or so just to keep fuel system clean. I run 95 all the time and did an oncar injector clean and it made no differance at all...as they were already clean

I was told by a Mitsubishi service manager that the best fuel to run in my TW Magna was 95 as the 98 does more harm than good. That doesn't sound right to me, But I get best econ on E10.

E10 def wont hurt it, any mits from '98 onwards can handle it no worries.

I stick to 95ron as I have found that 91ron has worse consumption rates and seems to be lacking a bit of power. It could just be a placebo effect but I still prefer to run 95ron. However I don't see a point in running any higher then 95 as there is no knock sensor to tell the difference. I will use 91ron if it does NOT contain ethanol however (Most places don't have this anymore though).

Never got a perceivable benefit out of 95 in my TL, may have got ever so slightly better economy but not enough to make up for the cost difference.


I will use 91ron if it does NOT contain ethanol however (Most places don't have this anymore though).

Every servo I go to has both :eh:

I stick to 95ron as I have found that 91ron has worse consumption rates and seems to be lacking a bit of power. It could just be a placebo effect but I still prefer to run 95ron. However I don't see a point in running any higher then 95 as there is no knock sensor to tell the difference. I will use 91ron if it does NOT contain ethanol however (Most places don't have this anymore though).

To a certain extent I agree, knock sensor or not. We have O2 sensors, if a car injection system was to put in as much 98ron fuel as 95ron fuel, the O2 sensor would pick it up, in theory anyway. Higher octane fuel has a higher volume per litre output of BTU(energy) than a fuel with less RON.
So wouldnt this inturn make the car run richer on a higher octane fuel? And then the O2 sensor picking up the richer fumes and telling the ECU to run a leaner mix?

(I may be wrong, please dont make out im a total cockhead due to my opinions, just going by chemistry understandings this should theoretically be correct).
Feel free to disagree if im wrong, but in a constructive way.

Luke

I stick to 95ron as I have found that 91ron has worse consumption rates and seems to be lacking a bit of power. It could just be a placebo effect but I still prefer to run 95ron. However I don't see a point in running any higher then 95 as there is no knock sensor to tell the difference. I will use 91ron if it does NOT contain ethanol however (Most places don't have this anymore though).

Im pretty sure that I have never seen 91 with ethanol, only 95 or 98.

Im pretty sure that I have never seen 91 with ethanol, only 95 or 98.

E10 is 91RON fuel with 10% ethanol. The ethanol acts as an anti-knock additive in the fuel, increasing the RON figure to around 95.

To a certain extent I agree, knock sensor or not. We have O2 sensors, if a car injection system was to put in as much 98ron fuel as 95ron fuel, the O2 sensor would pick it up, in theory anyway. Higher octane fuel has a higher volume per litre output of BTU(energy) than a fuel with less RON.
So wouldnt this inturn make the car run richer on a higher octane fuel? And then the O2 sensor picking up the richer fumes and telling the ECU to run a leaner mix?

(I may be wrong, please dont make out im a total cockhead due to my opinions, just going by chemistry understandings this should theoretically be correct).
Feel free to disagree if im wrong, but in a constructive way.

Luke

Not sure about that theory. Fuel with a higher RON rating is used to advance or retard timing in modern engines to increase economy and output.

To a certain extent I agree, knock sensor or not. We have O2 sensors, if a car injection system was to put in as much 98ron fuel as 95ron fuel, the O2 sensor would pick it up, in theory anyway. Higher octane fuel has a higher volume per litre output of BTU(energy) than a fuel with less RON.
So wouldnt this inturn make the car run richer on a higher octane fuel? And then the O2 sensor picking up the richer fumes and telling the ECU to run a leaner mix?

(I may be wrong, please dont make out im a total cockhead due to my opinions, just going by chemistry understandings this should theoretically be correct).
Feel free to disagree if im wrong, but in a constructive way.

Luke

This is correct Luke. Thats why many report better fuel economy with 95/98 octane fuels. Both are a denser (heavier) fuel so contain more heat producing molecules per litre than normal unleaded due to the addition of heavy aromatics like toluol and xylene. The oxygen/Lamda sensor only works to lean the mixture when cruising though in closed loop mode. When the ECU goes open loop then the fuel is metered by injector duty cycle (time) so the same volume is injected accelerating, starting, idling etc.


Im pretty sure that I have never seen 91 with ethanol, only 95 or 98.

A lot of E10 is only 91 octane. Mostly from Caltex and some BP. Shell is 94 and United and most independants use ULP Plus which is 95.


E10 is 91RON fuel with 10% ethanol. The ethanol acts as an anti-knock additive in the fuel, increasing the RON figure to around 95.

Not correct. Caltex E10 is generally only 91RON, and BP are also doing the same at many outlets.

Cheers,
Alan

Not correct. Caltex E10 is generally only 91RON, and BP are also doing the same at many outlets.

Cheers,
Alan

hang on, I thought the Ethanol content upped the RON rating? Regardless, all E10 fuel starts off as regular 91RON before it is processed with Ethanol.

hang on, I thought the Ethanol content upped the RON rating? Regardless, all E10 fuel starts off as regular 91RON before it is processed with Ethanol.

Yes, Ethanol does increase the octane rating.

No, not all E10 starts off as regular 91 unleaded. Refiners like Caltex selling 91RON E10 start out with lower octane unleaded that only rises to 91 after the ethanol is added.

Refiners can produce/buy fuel at all sorts of octane levels, even as low as 80RON if its only lightly refined and still has a lot of oil, wax and tar left in it. They can blend in whatever is required to get the octane up where they want it, or even down where they want if they have an excess of high octane fuel in storage.

Prior to the advent and of use of t.e.l. in the 1920's petrol was around 60-65 octane and comp ratios only 6:1. As refining process got better then octane numbers rose but it burns a lot of energy to get big octane numbers without the use of lead or aromatics and alkylates.

Typically even to get only 91RON refiners add 25% aromatics and for 98 it can be close to 40% in summer. Aromatic content in winter is less to improve starting so the fuel has to be more heavily cracked, so is a lot more costly to produce.

Cheers,
Alan

Yes, Ethanol does increase the octane rating.

No, not all E10 starts off as regular 91 unleaded. Refiners like Caltex selling 91RON E10 start out with lower octane unleaded that only rises to 91 after the ethanol is added.

Refiners can produce/buy fuel at all sorts of octane levels, even as low as 80RON if its only lightly refined and still has a lot of oil, wax and tar left in it. They can blend in whatever is required to get the octane up where they want it, or even down where they want if they have an excess of high octane fuel in storage.

Prior to the advent and of use of t.e.l. in the 1920's petrol was around 60-65 octane and comp ratios only 6:1. As refining process got better then octane numbers rose but it burns a lot of energy to get big octane numbers without the use of lead or aromatics and alkylates.

Typically even to get only 91RON refiners add 25% aromatics and for 98 it can be close to 40% in summer. Aromatic content in winter is less to improve starting so the fuel has to be more heavily cracked, so is a lot more costly to produce. This is caltex btw.

Cheers,
Alan

Actually Alan, currently the E10 being pumped out of the Newcastle and Sydney refineries atm is exactly 94.4, my Wifes father is a petrochemical engineer there, it gets RON and batch tested every 3 days. Also the 98 Vortex is reading very healthy at 101.6, as some clown didn't switch the loading pipe correctly.

cheers alan, as always you have shown a wealth of knowledge :) i didnt even know less than 91 was freely available to distributors!!

Potent, interesting about the Caltex 98! If only 3rd gen Magna could use it's benefit

Actually Alan, currently the E10 being pumped out of the Newcastle and Sydney refineries atm is exactly 94.4, my Wifes father is a petrochemical engineer there, it gets RON and batch tested every 3 days. Also the 98 Vortex is reading very healthy at 101.6, as some clown didn't switch the loading pipe correctly.

Most refiners ship fuel that is above advertised octane. Typically its more like 0.6RON over. There are many reasons for this like the switching "accident" you mention. But there is also the need to take into account other factors such as different batches being mixed in the same servo tank and reducing the octane. Adding a batch of 95 with another batch of 95 may result in something that isn't 95, and if its less than 95 they are fined heavily. Fuel octane changes with age and light exposure too. Sometimes there's a loss of octane, and for others the octane increases. So the refiner has to allow for both possibilities.

Then there is the servo operator factor. He has to guess how much fuel to order and pay for days in advance. When the tanker arrives if the entire order won't fit down the ordinary unleaded hole then the excess that might be anything up to 800-1000 ltrs, will be dropped into any tank with space. That might be a 95 tank or a 98 tank. So the 95 or 98 must be over-octane to still be legal after a lower octane dump. The reverse happens too. 98 and 95 gets dumped into the 91 tank. When Avgas was shipped by common tanker pre-unleaded days it was dumped into the "super" hole. As was diesel and kerosene.

Cheers,
Alan

Dumping Alan you not legally able to do anymore, 91,95 and 98 are different weight to L ratios, so it will seperate and cause issues, if its been an over order most big tanking companys just compensate it out with the next order for the next servo (most tankers run the same types per compartment, or they get a blow out and dry with high pressure steam)

Any yes Alan all fuel direct out of the refinery is always higher octane as you said for legality purposes. That is generally why its a good idea to fill up at busy servos, or if the tanker is unloading and you need to fill up.

And E10 is advertised at 94+ so what your saying is true, then the 91 E10 people are buying isnt legal at all. (exception being BP as they advertise it as 91)

Have got some MSDS sheets here.

http://www.msdsonline.com.au/msds/msdsview.asp?SynonymCode=ACRU300&msds_format=00&in_langcode=&uselogo=TRUE

http://www.shell.com/static/au-en/downloads/e10/shell_e10_tds.pdf

http://www.exxonmobil.com/Australia-English/PA/products_fuels_ethanol.aspx


Will add the others in a tick

Dumping Alan you not legally able to do anymore, 91,95 and 98 are different weight to L ratios, so it will seperate and cause issues, if its been an over order most big tanking companys just compensate it out with the next order for the next servo (most tankers run the same types per compartment, or they get a blow out and dry with high pressure steam)

Any yes Alan all fuel direct out of the refinery is always higher octane as you said for legality purposes. That is generally why its a good idea to fill up at busy servos, or if the tanker is unloading and you need to fill up.

And E10 is advertised at 94+ so what your saying is true, then the 91 E10 people are buying isnt legal at all. (exception being BP as they advertise it as 91)

I think you should re-read what I posted about E10 octane values. Many have assumed that E10 is 95RON. I said that Caltex E10 is mostly 91 according to what is on shown their price boards and pumps, and some BP E10 is also marked as 91. Shell is 94 and Plus ULP E10 from United and independants is 95RON.

Technically dumping shouldn't happen but it does. Perhaps not in the city anymore, but in the country its not uncommon. There is no issue with different octane fuels separating or fuel weight affecting fuel blending. Actually specific gravity changes from batch to batch because different % of aromatic content, and fuel temperature alters the SG anyway. One batch of 98 might test 0.725 and another with more aromatic might be 0.77SG, or anywhere between at the standard test temp of 15 deg C.

Cheers,
Alan