What fuel do you use?

[gromit]

Just had my 2nd fill up since getting the car with mobil super unleaded which i assume is 96 octane. Just thought about this afterwards...

What are your experiences with 98 octane?
Is it really superior to 96 on a tangible level for stock cars?
I hear its 'good for your engine' and may be more fuel efficient.

[dtrang]

recommended to use 98 octane for vtec engines i think

[Vinnie]

premium is actually 95 octane. i honestly dont think ude notice any difference moving up to 98...

also get the feeling this has been covered before sumwhere...

[BiLL|z0r]

Covered 1000000000 times. I'm running off 95 BP all the time now, can't justify the cost difference. I find more difference in power and economy just keeping the air con off as much as possible.

[Euro76]

I'm using Premium Unleaded, however which one's better? BP Ultimate or Shell V-Power?

[mastcell]

If you engine is designed for 95RON, using 98RON is not likely to result in noticeable fuel saving. Considering the price premium of 98 over 95, there is virtually no cost saving either!

However, you will notice fuel saving if you use regular 91RON in a car designed for 95RON.

Most modern engine management system will detect premature detonation of the fuel-air mix and adjust the ignition timing correspondingly. However, the engine will produce much less power and uses much more fuel. This is why it is false economy to use regular (cheaper) fuel, when the car is specified for 95/98RON. You will probably damage the engine too.

On the other hand, unless the engine management system can advance the ignition timing to make use of the higher 98 RON fuel, this is also a waste of money. There is no harm using it however.

It is a myth that higher octane equates to more power. The octane rating of a fuel is a measure of how well the fuel resists spontaneous combustion in the engine. Power of an engine is defined by the fuel-air mixture. High performance engines specify higher RON fuel because to derive more engine power, more fuel-air mix must be crammed into the engine at much higher compression ratio. Lower octane fuel will prematurely detonate at this compression ratio so higher octane fuel is required.

It is really this simple! Don't be fooled by unsubstantiated advertisements.

[Mr_will]

If you engine is designed for 95RON, using 98RON is not likely to result in noticeable fuel saving. Considering the price premium of 98 over 95, there is virtually no cost saving either!

However, you will notice fuel saving if you use regular 91RON in a car designed for 95RON.

Most modern engine management system will detect premature detonation of the fuel-air mix and adjust the ignition timing correspondingly. However, the engine will produce much less power and uses much more fuel. This is why it is false economy to use regular (cheaper) fuel, when the car is specified for 95/98RON. You will probably damage the engine too.

On the other hand, unless the engine management system can advance the ignition timing to make use of the higher 98 RON fuel, this is also a waste of money. There is no harm using it however.

It is a myth that higher octane equates to more power. The octane rating of a fuel is a measure of how well the fuel resists spontaneous combustion in the engine. Power of an engine is defined by the fuel-air mixture. High performance engines specify higher RON fuel because to derive more engine power, more fuel-air mix must be crammed into the engine at much higher compression ratio. Lower octane fuel will prematurely detonate at this compression ratio so higher octane fuel is required.

It is really this simple! Don't be fooled by unsubstantiated advertisements.

some of the stuff you are saying is correct, but some of it is not.

read this thread.

http://www.ozhonda.com/forum/showthread.php?t=26880&page=2

[Merlin086]

Mr will
"some of the stuff you are saying is correct, but some of it is not."

Mastcell sounds at least 80% correct to me, and according to you if the other 20% is just crap that's irrelevant.

Mr will, I see you have had a heated debate over this issue before so I suppose you should know..........good to see you are so tactful in a grown up discussion and only stick to the facts....lol

[Mr_will]

Mr will
"some of the stuff you are saying is correct, but some of it is not."

Mastcell sounds at least 80% correct to me, and according to you if the other 20% is just crap that's irrelevant.

Mr will, I see you have had a heated debate over this issue before so I suppose you should know..........good to see you are so tactful in a grown up discussion and only stick to the facts....lol


do you have a point? the thread is about fuel, and the thread i linked to raises some very valid points.

[jeffske]

depends how many $2 coins I can collect before refueling, some weeks I put in v-power and other weeks i put in the reg. unleaded

[Merlin086]

do you have a point? the thread is about fuel, and the thread i linked to raises some very valid points.

My point is I am at least 80% agreement with Mastcell..

Did I deny you made valid points?
You may possibly be 20% right or more, I am not enough of a expert to say, and I do not profess to be.
Neither did I call you a idiot or any other derogatory name for you largely unsubstantiated opinions.

I was agreeing with Mastcell over his comments on fuel.

My apologies if I have offended you by not being in agreement 100% with your comments but I have found many of your opinions to be without basis.

IMHO.............lol

[040501912]

dont you guys had a 101 ron ?? in eastern states some where ???

[Merlin086]

Apparently some BP and Shell depots have 100 ron available........apparently

[jeffske]

Apparently some BP and Shell depots have 100 ron available........apparently

yeh its true, its just 98RON fuel with ethanol in it

[gromit]

some of the stuff you are saying is correct, but some of it is not.

read this thread.

http://www.ozhonda.com/forum/showthread.php?t=26880&page=2

ahh will use the search butt next time :p
Looks like 95 it is.

[BusterSonic12]

fuel topic stuff, hasn't it been talked about LOADS and LOTS and heaps of times?

i use shell v power.

[Omotesando]

Despite some rumours going around that Optimax 98 is exactly the same formula as V Power 98, I find that V Power 98 is much more responsive than the Optimax 98 version.

For me its either Mobile Synergy 8000 or V Power 98 now. V Power 100 seems to be smoother on power but I can't feel any noticeable power difference, except it gives me crap mileage.

I don't think the Euro works well with BP Ultimate 98 at all. It becomes so sluggish. And Vortex 98 is to me, less powerful than Mobil 98 and V Power 98 to me too, despite revving quite cleanly.

Of course, I haven't put this particular car on the dyno to prove what I say. However over the years I've been comparing the different fuels I still like Mobil the best. Pity no supermarket fuel discount and less and less outlets.

[040501912]

when does perth have it :( ... always be eastern states first .. sob sob :(

[sendok]

when the price of fuel increase again apparently they dont even open the hose for 100ron.. damm!

[Honda_Euro84]

in my opinion i had some problems with bad batches of Shell fuel so i switched to BP premium. but i just recently used shell v-power and noticed a remarkable improvement in economy, but no power difference...

[curik]

I have been using Leaded Petrol for sometime and I noticed a slight improvement on economy, could it be because the cat is burned up and the exhaust flows more freely? :P

[J-TODA]

fuel topic stuff, hasn't it been talked about LOADS and LOTS and heaps of times?

i use shell v power.

lol yer...3rd thread ive seen....search is key ;)

btw i use bp ultimate

[tony1234]

Caltex Vortex 98.:thumbsup:

[blk05gli]

caltex vortex 95 gives me 600+ km's every tank and a meaty rev.

[gReY-oNe]

lol yer...3rd thread ive seen....search is key ;)

btw i use bp ultimate

LMAO and who told ya??
LOL

umm im using synergy

[mastcell]

some of the stuff you are saying is correct, but some of it is not.

read this thread.

http://www.ozhonda.com/forum/showthread.php?t=26880&page=2

Thanks, Mr_will for pointing out the thread.
I can't say I know all there is about automotive technology, but I believe what I said to be mostly correct, with a few omissions. I have read the thread and I disagree with Mr_will's assertion on two points:

1. It is somewhat misleading to state that '98 ron burns far more slowly than 95 ron' (Mr_will, 14/11/2005 5:12PM), as all vaporized gasoline burn at about the same rate, as advised by the BP reply in yfin's post (17/11/05 11:19AM)

To be more technically correct, one should think about the 'autoignition point' of petrol, which is the lowest temperature at which it will spontaneously ignite without an external source of ignition (see Wikipedia). For petrol, the autoignition point should be as high as possible so that it will not auto ignite/detonate/ping/knock in the hot engine as the fuel-air mixture is undergoing compression (note: the main determinants of detonation here are temperature and pressure).

Fortunately, the autoignition point of gasoline can be modified by adding various additives (octane booster) to make it more resistant to pinging.

2. Therefore, it is erroneous to state that 98RON will produce less power because of slower burn. This is because octane rating has nothing to do with the rate of burn of petrol. Instead, it is related to the autoignition temperature as mentioned above.

Remember, we are not talking about flammable liquid in liquid form, which has entirely different thermodynamic stoichiometry, we are talking about petrol in finely atomised vapour with significantly higher molecular kinetic energy. The burn of the fuel-air mix in the combustion chamber will be instantaneous once there is a spark!

3. I am in agreement with Mr_will that using 98ron in a stock engine is possibly unnecessary (exceptions granted).

Please correct me if I am incorrect:
On one hand, it is plausible that the VTC feature in K series engine will advance the ignition timing so that there is a slight increase in power output (aarong 14/11/05 9:20PM) - VTC will allow an increase in the compression ratio because 98 ron petrol can handle higher compression without detonation. This equates to more power.

An alternative position is that the engine is probably already finely tuned for 95 ron such that the 'peak cylinder pressure' (the maximum compression) is at the top of piston up-stroke, thus further advancement in the ignition timing will actually result in lower compression and hence lower power.

In either case, there is only a small range from TDC which VTC can advance or retards. The actual power gain or loss is probably minimal.

Petrol contain about the same amount of chemical energy regardless of octane rating, BP claims that Ultimate has higher energy contents, possibly because of different additives they add to it. Perhaps there are more double and triple carbon-carbon bonds in these additives, so more energy is liberated during an oxygen burn.