THE IMPORTANCE OF HIGH OCTANE FUEL - 98 RON

[IC]

Hi, seems to be a balance of what you are prepared to pay on a day to day basis and what you want to do with your car. What's the point of paying extra money for petrol if you can't realise the potential. For everyday driving to and from work in town driving the extra money that you pay for higher octane petrol is simply a waste of money if there is no discernable difference in mpg (I know that there is supposed to be an improvement, however is that improvement enough to justify the extra that you pay for it) however different people have different purposes for their cars.

It is interesting to read a previous comment that a chipped car will under perform with lower octane fuel - I'm sure that there will be lots of opinions on this - it is an interesting point. Most people use their cars for a multitude of purposes - how much of their cars potential do they use? To some people there is a balance of cost-effectiveness and performance.

It makes sense that if you chip your car the programming is optimised for higher octane fuel and if you drive in a manner that you feel justifies using higher octane (and feel that your engine will benefit from it)fair enough - however does it mean that if you are using the car for general purpose work that the car will underperform when you use choose to use standard 95 lower ron - in other words is it a compromise that will affect the choice of fuel that you use in that you feel that you must use higher ron fuel with the obvious implications of paying that extra for fear of under performance?
Being involved in the performance section I do see the benefit of chipping and upgrading, however I do see chipping as being a complex subject that needs to be addressed according to individuals' needs!
In the end we have indeed got the freedom of choice to use whatever mediums we feel will improve our cars performance and practicality - it would be good to have both!

Iain Collinson ;-)

Ian,

Absolutely agree with you!

This is why the heading for this topic is "Importance of High Octane Fuel". It's not a must if you don't want it - an upgraded car will still perform much better than if it was standard even on 95 RON fuel, but simply won't realise the full potential. Like you say, it's freedom of choice. A standard car is less of an issue.

But the bottom line is that yes, any car that has been designed to run on 98 RON fuel or higher will under-perform if you use 95 RON fuel. Classic examples are many of the Japanese imports.

Adam.

[Ross9]

Many words of wisdom from Ian there.

I always get a bit horrified when I hear of people putting "normal" petrol, ie 95 RON, in turbocharged cars etc, I think it's because the majority of my friends etc have turbo'd cars, and doing aall the upgrading and competetive use of our cars we do, it rubs off on our on the road driving as well, and it's pretty much necessary I guess to use the higher octane fuel. To be honest, when the Rover was standard I could have put 95 RON in it no problems, it was built in 1994, long before Optiplop and BP Ultimate etc, did you even get Super Unleaded in those days? (showing my youth, lol, I was 14 at the time), but I never ever did, it ran on Optimax since I got it, and BP Ultimate mostly now apart from a recent trip to the highlands wherte finding any 98 RON was a challenge and ESSO Super unleaded had to do. These days it needs higher octane fuel though, as a safety feature more than anything else, no knock sensor, and no ECU control of the boost apart from a 1 BAR boost cut that it never reaches.

I do have one friend who has a ridiculously fast car, thats in a very high state of tune, and during the week when he's just pootling to work and back, he will as Ian says, just put 95 RON in, personally I think this is madness seeing as the reason its so highyl tuned is that when the engine was rebuilt it was rebuilt with a fortune worth of goodies in it, it first died through detonation from using 95 RON and flooring it apparently. At the weekends and for 1/4 mile and track days, it gets its diet of 98 RON to allow all 350 horses to be used.

I'd still definately say that it's worth shelling out the extra few pennies all the time when filling up, the handbook for Jacqs T4 says 95 RON minimum, 98 RON recommended( or it might have been 97) either way, that tells me it should always have at least Super Unleaded in it, she was forced to put 95 RON supermakret petrol in once, and it was hesitant on acceleration for the first wee bit until the ECU knocked the timing back etc I assume. You wont catch me using anything less than 97 RON if I can help it, and BP Ultimate 98 ROn at all opperchancities, it showed better mpg on a run to Inverness up the A82 last weekend even with spirited driving, and is a better quality fuel if nothing else. As with optimax it cleans the valves etc as well (I know people who've had engines run only on Optimax for many miles, and you can see where the fuel has cleaned the valve's etc when they've opened it up) It's a compromise obviously for most people as no hamr will come of using 95 RON in most standard cars, the additional coss is more than outweighed by the benefits and peace of mind personally.

Hi guys,
I live in ireland the price of petrol is expensive here at €1.25 per litre for 98 ron superunleaded (which is very hard to find a garage that sells it) and 95 ron unleaded at €0.88-0.93 cents a lawnmower is expensive to run,so i tried using an octane booster the performance levels are still retained,although when the weather gets cold and boost increases when driving the car hard the car does pink/knock a slightly (boosting at 1.4 bar +) the octane booster is "millers" it costs me around €7.00 per bottle and at fill up i add about one and a quarter bottles per tank it does seem to work but also leaves a rusty brown colour on the plugs and internal parts of the engine which i am told is ok.

Hope this is of some help.

jason

[Steve 60]

Originally Posted by Matt_Watkins

As I work at cardiff airport, The main (sorry only) fuel company there is BP. Do you reckon JETA1 fuel will do the trick?? If it was good enough to power concorde to silly speeds think what it can do to your car!!!!

Any how, when I swithced to usuing optimax I didnt notice any difference in performance at all. The only difference I noticed was a thinner wallet after paying for it.

Jet A1 is kerosene so would only work in a diesel car. And you would need to add some 2t oil or similar to look after the pump etc.

[XC90Mk1]

Originally Posted by Matt_Watkins

As I work at cardiff airport, The main (sorry only) fuel company there is BP. Do you reckon JETA1 fuel will do the trick?? If it was good enough to power concorde to silly speeds think what it can do to your car!!!!

Any how, when I swithced to usuing optimax I didnt notice any difference in performance at all. The only difference I noticed was a thinner wallet after paying for it.

Funny post lol. Sure you know Jet A1 is actually kerosene based not petrol.

[dingov70]

Also avoid using AvGas as it has a lead compound added as an anti knock component & this will poison your cat , leading to an MOT failure .

The suggestion for toluene is also fraught with problems as it damages your central nervous system .

I know these facts as I have stored & used
Nitro methane
Isopropyl nitrate (avpin )
methanol

The only thing I would recommend to improve fuel is premium grades & a small dash of octane booster

[cyclogenesis]

Many moons ago before i converted to LPG i did a trial on running with 98 RON. Not only did it provide better throttle response and acceleration but the engine felt smoother too. I also noticed that economy improved as well which went some way towards offsetting the cost.

My only experience of 100 RON was in Germany when it was minus 7 Celcius and I got 137mph out of the car, still accelerating when someone pulled out in front and I had to get off the gas.

Now I run on LPG, I only use unleaded for the first few minutes when starting from cold. I always use “Super”.

[Dash300]

Originally Posted by XC90Mk1

Funny post lol. Sure you know Jet A1 is actually kerosene based not petrol.

Indeed it is. Same as my boiler runs on. Its what is known as 28 second oil so thinner than Diesel which is 35 second oil. The denomination being the speed at which the oil flows down a measured smooth incline. The Kerosene will run a diesel but it won't do it much long term good.

[Coachwhip]

Just out of interest.
Does the 98 octane work on a 4.4 car? Standard tune that is.
I know they will make a difference with more modern engines as they'll have anti knock sensors and the like. But I'm thinking the throttle cable models are much more basic on sensors, so will the car learn it's got better fuel and adjust? If so how long is it likely to take. , would we be talking a fairly quick change after filling with 98. Or would it take a few tankfulls before any difference is noticed?

Thanks