What you are about to read, may be a total load of bunk. It is basically a detail of a recent experience I've had, which I have chosen to look into further, and as such is more my opinion than anything.

The topic is fuel.....and more to the point, what has happened to Australia's fuel and the effect I believe it is having on our older cars.
At a recent Club meeting, a couple of members were complaining that there cars were performing poorly of late, especially since the introduction of the new "Lead Replacement Petrol" (L.R.P). At the time I dismissed their comments as paranoia about the new fuel. That was before I found my own car starting to run like a dog as well.

The car in question is a 1971 VH Charger 770. It has the 4.3 litre 265 HEMI with T-Bar auto. I tried everything to get it running right. More specifically, it was idling rough, and lacked power, and seemed to struggle on the Freeway. I tried tuning etc but it didn't work.
It was about this time that I started to think about the fuel I was using. I looked into Octane Ratings for the first time, and found some interesting facts that I'll share.
When I looked into it, I found that the Octane rating of the fuels we are sold just aren't up to what the car was designed for.
Now, I'm still not able to give you a text book example of what Octane does to your fuel, but in Laymans terms, and as I remember it from a very reliable source, if the Octane level in the fuel helps determine when the fuel will ignite. If the Octane level is too low, the fuel, upon the compression stroke of the piston, is liable to ignite too early - before reaching the spark plug ignition point. I think this is due to the fact that Carbon builds up in the cylinder and reaches temperatures such that it can ignite the fuel before the plug does.
It was also said to me that if the Octane level is wrong for the car, it can cause the fuel to "explode", rather than burn evenly, again before it's meant to.....this is known as "pinging".

OK, so that's probably a very "Layman" term for it, but it's something like that. Basically, if the Octane level is wrong, the car is not going to perform as it should.


My Charger, when it was new, ran on fuel with an Octane reading of 98.

Todays L.R.P has a general rating of 95.
Unleaded has a rating of 92.
Premium Unleaded has a rating of 95.
SHELL OPTIMAX has a rating of 98.

So I'm at the auto shop, and I'm looking at the fuel additives. At first I glance at the WYNN'S product, at $7.99 a bottle, but end up with the NULON OCTANE BOOST AND CLEAN, at $10.00. It says that it boosts the octane rating by 2-3 points, cleans injectors etc, blah, blah, blah. Adds power and performance. They're the words I wanted to read.
The NULON has to be added every 4th tankful of petrol. I filled up, added the NULON, and waited to see if their was an improvement.

There was......almost instantly.

The car, especially on a long trip seemed to be quieter, smoother, and have better acceleration. It idled better.
Now, I am not usually one to spend money on additives and the like, but this stuff had me sold, so much so that I bought another bottle 2 weeks later. After adding it, I thought I'd give Nulon a ring to find out if there was any more I could do to get better performance, or a better additive - they also make an Octane Booster for $20 per bottle, and I wanted to know more about it.

I spoke to one of their technicians and he was the most enlightening people I've spoken to in a long time. And the reason I know he wasn't spinning me crap was because he actually advised me NOT to use the Nulon anymore.

Not because it didn't work, but because there was a more cost effective way for me to get the most out of the car another way.
He told me that Australia was a dumping ground for fuel and that our fuel ranked at the bottom in world standards and was in the same bracket as Indonesia....which is also very poor quality.

He said that using fuel with the incorrect Octane rating was definitely a disadvantage to our cars, but that there weren't many options for us. Other countries all have fuels with much higher octane ratings than us. We import all kinds of performance cars eg : Subaru WRX Imprezza - but that if the owners use normal unleaded, they are getting nowhere near the kind of performance or running quality that the cars are supposed to have. He said that people generally have there cars timed to run effectively, but this is not the solution.

With regards to older cars, he mentioned that the Octane in fuel was 98 from memory, and that there just wasn't any fuel around these days with a 98 rating - not for leaded cars at least.

He told me that the fuel I should be using is SHELL OPTIMAX - now called V Power. There are other fuels available lately - "VORTEX" by Caltex for one - but they aren't quite in the same league as the OPTIMAX. In all cases another additive must be purcahased due to the occurance of Valve Seat Recession in older engines.
What SHELL have to compensate, and I didn't realise this till he told me, is a syringe type device which is purchased upon filling up, which is squirted into the tank. This is an upper cylinder head lubricant. The lubricant stocked by Shell is called Valvemaster.

Now, for those that may think I'm being paid by Shell for this report, you're wrong. Infact, I've only just started using Optimax in my car, and also their additive. What I am touting is that since I have tried to improve the fuel going into my old Charger, I have noticed a distinct difference in how it runs. It is very noticeable.
It is also one of the ONLY fuels available with an Octane Rating of 98 RON, the other being the BP Ultimate, although it isn't a High Density fuel. The other superduper fuels still only have about 95-96.

So how about some negatives with the Optimax ?? Well for starters there's the price.

Optimax is 7-9 cents per litre dearer than unleaded....meaning it's 3-4 cents per litre dearer than Super - or L.R.P. The thing is that once you've been buying it for a while, you get used to the price....just seems a lot when you start.

Then there's the Valvemaster which is $1.20 per syringe, which they say will do 20 litres. Mind you, the guy from NULON said 1 syringe should be fine, but I'm going to get back to him on that one. Of course the best way to go is to get your engines head reconditioned to suit unleaded fuel.

Other than that, OPTIMAX is widely known as being the best fuel available in Australia at the moment, and that's from mechanics, engineers etc. All I know is that since I added NULON, and now Optimax, my car is loving it. It is definitely worth a try. I intend going into this more, with regards to R&S Valiants, but for now this will have to do. As I said at the start....it might be all bunk, but it seems to be working for me.If you want to know more, contact the various bodies, get as much info on each of them from the others, and make up your own mind.

If you want to read a general rundown of Frequently Asked Questions about fuel, check out the following link to the Caltex web site and learn a little more.


Peter Morthen

Footnote : I rang Caltex to find out a little more about Vortex, and was told it is basically their new Premium Unleaded.....they still don't have a fuel on par with the Optimax. The Rep told me that in the future they no doubt will, but at present it has a lot to do with tank space at Service Stations due to having to supply L.R.P.
L.R.P also has a very limited lifespan, so it may be wise to play around with what fuel is best for you sooner rather than later. Also, with the rubbish they put into the so-called Lead Replacement Petrol, you're actually robbing your engine of any real performance because (my opinion) LRP is dead set crap. I won't even think of using it - poor quality.

BP now has a fuel called ULTIMATE, which is 98 Octane. I've used it a few times and get pretty good performance and economy. It's not High Density like Optimax, but a good fuel none the less. When I can't get Optimax, I buy Ultimate. There's also a new one put out by Mobil which is 98 Octane.

The bottom line is there are some very good fuels around, but in the end it's up to you to decide which is best. I must admit though, that since I started using the dearer fuels, I have not once filled my car with lead free super.

I'm convinced they work.

With regards to R&S Valiants, I use the 98 Octane fuels in my S Series, not because it needs that Octane rated fuel, but simply because it's the best available fuel around and that's what I want in my car. I'm telling you the difference in using a good fuel is incredible.