What fuel to use for long drive? 10 August 2021 at 11:21PM edited 11 August 2021 at 8:38AM in Motoring 21 replies 923 views

izawa

Hello,

Driving London to Edinburgh. Thinking of filling up with Premium fuel to get more MPG. Alternative is to have normal fuel + Redex or Premium + Redex.

What are your thoughts? Car is a 1.6L 7 seater.

Options

1. Normal Fuel + Redex
2. Premium Fuel + Redex
3. Premium Fuel

Not worried about difference in price since. This exercise is just meant for long drive, while in Scotland it will be normal fuel all the way.

izawa

Hello,

Driving London to Edinburgh. Thinking of filling up with Premium fuel to get more MPG. Alternative is to have normal fuel + Redex or Premium + Redex.

What are your thoughts? Car is a 1.6L 7 seater.

Options

1. Normal Fuel + Redex
2. Premium Fuel + Redex
3. Premium Fuel

Not worried about difference in price since. This exercise is just meant for long drive, while in Scotland it will be normal fuel all the way.

cymruchris

4. Normal fuel

Why pay extra to get a negligible, if any improvement in MPG?

Save your money - unless you have a performance vehicle that would benefit from a higher octane.

cymruchris

You've already asked this on another part of the forum:

https://forums.moneysavingexpert.com/discussion/6289467/what-fuel-to-use-for-long-drive

And my answer is the same: 4. Normal fuel, no additives.

izawa

Is it not a good idea to atleast have Redex to clean up injectors?

cymruchris

It'll depend on lots of factors - how the car has been driven the last year or two, the service history, the types of journeys it does - there's negligible benefit to adding a fuel system cleaner once in a blue moon. I recently bought a car that had done very sporadic mileage since 2016 when it was last serviced, then gave it a complete service of all fluids and filters, and just for good measure put a dose of something similar to Redex through it - didn't see any discernible difference between before and after. In my mind I now know all the fluids are fresh, and everything is clean, but did any of it make a real world difference to MPG or drivability? No.

AdrianC

Enough fuel. That's it.

You don't say what "1.6l 7-seater", but very few will have a knock sensor to allow the ignition map to change, so can't take any benefit from the higher octane. If it's turbocharged, then there's a slightly higher possibility.

If you think Redex will make a difference, use it regularly, not just on a long journey. It's intended to clean your fuel system... which if it IS gunked up, will take a lot longer than a couple of hundred miles. But since there's a very good solvent (mixed with detergents) already going through your fuel system all the time...

You want to save a bit of fuel? Driving style. Not just speed, but anticipation and smoothness.

But, really, even a 10% improvement is only going to be a fiver.

The_Fat_Controller

I concur, just use your normal fuel.

Nobbie1967

If you want more MPG just drive slower, make sure your tyres are pumped up to the right pressures and remove unnecessary junk from the car before the journey. Try to avoid any roof rack type storage.

jimjames

You missed off item 4 - normal fuel.

Unless it's a performance car there is no need for performance fuel

peter3hg

AdrianC said:

Enough fuel. That's it.

You don't say what "1.6l 7-seater", but very few will have a knock sensor to allow the ignition map to change, so can't take any benefit from the higher octane. If it's turbocharged, then there's a slightly higher possibility.

I'd be amazed if you could find a mainstream petrol car engine from the last 20 years that didn't have a knock sensor. They all use them so they are protected if ran on lower octane fuel.

The important point though is that most cars (especially a 1.6 in a family car) won't be tuned to take advantage of higher octane fuel, so there will be little to no benefit from running on high octane fuel or using an octane booster.