Car Maintenance

A Complete Guide to Super Unleaded & Premium Fuels

Fuel is an essential when it comes to driving, but even this isn’t as black and white as it might feel like. When we add premium fuels like super unleaded petrol to the mix, things get slightly more complicated, and quite a lot more controversial, to say the least. The biggest of these usually ends up being about what super unleaded petrol actually is, what it does, and if it’s even worth buying in the first place. Here, we’re looking at answering all of this, and even more.

To give a thorough and educational answer to the questions at hand about premium fuels though, as always, we need to look at the bigger picture. We have to address all of the nitty-gritty that comes alongside such a heavily debated topic and answer all the questions we can. Let’s take a look. See fuel saving tips.

What is Super Unleaded & Premium Fuel?

First and foremost, we actually need us to understand what premium fuel is.

Carbon-based fuels like the ones we use in combustion-engined vehicles are burned to create small explosions in an engine which creates a force to drive pistons to turn axels, as we know. The purity of these fuels is what we look at when looking into their quality, and how pure they are is determined for the most part by its octane rating; how pressured the fuel can be before exploding.

Super unleaded petrol, for example, is simply higher grade petrol vs unleaded fuel. Standard unleaded is 95 octane as it says on the pump itself. Super unleaded, however, takes that up a notch, and can actually be up to a staggering 97-98 octane at the pumps. Why fuel economy matters.

Diesel has a similar equivalent as well as petrol, having its own term premium fuel which again stands at a 5-10 higher octane rating than that of standard diesel.

What does Premium Fuel do?

So, all of that is well and good, but another common question is what do premium fuels like super unleaded petrol actually do to your car? There must be a reason for their existence after all rather than just having a higher number on the pump, and that’s absolutely right.

The higher octane fuel as we brushed over means that the fuel can sustain a higher pressure before needing to burn than that of fuel of a lower octane. As a result, it can create a larger force without the same volume and with less burning occurring as well. In fact, it can reduce some of the damage that standard fuel causes in the long term.

Super Unleaded Vs Unleaded: Is It Worth Buying?

It sounds like unleaded petrol is a done deal than with it being a better burn for a relatively small price difference, but to determine that, you need to have a look at what you’re working with, and carefully too. It boils down to a few pros and cons:

+      Higher MPG

A better burning fuel almost always means a higher mileage per gallon, since we need less of it for the same results and therefore the same will get better results. As a result of those results, we have an increased mileage per gallon which can save you money over time through better fuel economy.

+      Healthier Engine

In addition to your wallet, your car will thank you for using unleaded petrol or premium diesel too. It means that your engine gets an easier ride and can actually help its overall health with better lubrication caused by engine cleaning additives that eat away at some of the excesses.

+      Better Environment

Both of the points above have a knock-on effect, and that is that premium fuel is better for the planet. A less efficient fuel means a worse emission almost always, and that is bad news for the planet, especially with diesel. Premium fuels are kinder to the environment.

–        More expensive

Like all things, it still has its downsides. Premium fuel is still premium, and that means that you are paying extra for the luxury. It is usually around 10p per gallon more which can add up in the long term (unless you save fuel by other means).

–        Difference can be subtle

In addition to that, the difference you’ll see in engine health and performance can actually be subtle as well. In fact, you may not even see the effects of the positives above, and in which case, it might not be worth the extra cost. Might it key work in this equation.

Can I mix unleaded and super unleaded petrol?

If you’re on the fence still like a like of people out there are about how good super unleaded petrol and premium fuels in general are, then it could also be worth looking into the idea of hybridisation. We don’t mean like electric hybrids her, but instead, fuel hybrids. What happens in two different respects here.

  1. Use premium fuel half or a quarter of the time, and standard the rest to counteract the bad with the good and try to make life easier for yourself.
  2. USe both types of fuel in harmony. You’ll end up with octane in the middle of what you had on both ends if you go half and half (i.e. 96 by using 50% 97 & 50% 95). This can negate the good and the bad of both to make things slightly better for slightly more money.

Should You use Super Unleaded Fuel on an Older Car?

Another big misconception when looking at fuel usage is that once the damage is done, then it’s done. That’s not the case for the most part. Engine health is often something that can actually be repaired with methods as well as with parts if need be. We’d still always advise getting an inspection to take place to give a thorough chekc up on a new purchase, but fuel can still be a factor.

In fact, as we said above, adding premium fuel to any engine can do good things if done regularly. Even if you don’t use super unleaded all of the time, it can still help to remove some impurities in the engine with the additives involved and keep things running as best they can.

The same even goes for premium diesel as well. In fact, diesel even has additional additives that can be used every once in a while to do this without the fuel (but premium fuel still does the job just fine where needed).


Ultimately, it all falls down to you and your own personal vehicle needs. Premium fuel exists for a reason, and it does go along way in improving the performance of your car, both long and short term. That is a fact.

The issue people face is actually the extent to which that happens with fuels like super unleaded vs standard unleaded, and the price at which we pay for it. Sometimes, it just doesn’t pay off in the long run to use a more expensive fuel, especially if the car is primarily for saving you money.

Whatever your reasons, being careful with your vehicle is never a bad thing. Engines are seriously temperamental designs, and they need to treat with respect to that.

Remember that vehicle inspections exist for this very reason. If you’re not sure about the state of an engine, don’t be afraid to get it checked over by a professional, even before you commit to buying the car.

Whatever you do, be safe. See how to purchase vehicle safely.