Finding super unleaded petrol stations

Gixer · 29 Jun 2018 at 07:57

I'm going to be heading to Newport in Pembrokeshire and after the fun I had finding a garage which sells super unleaded in Cornwall was wondering if there's a way to find garages before I leave. Using super unleaded petrol station as a search on Google maps isn't coming up with anything confidence inspiring!

Gixer · 29 Jun 2018 at 12:17

I have a Revo remap on my Audi. I rather not risk getting knock by running lower octane fuel. Not sure if the 1.8T BEX engine has a knock sensor or not? The one downside to having a remap. I should have put this info in my earlier post to save the debate about higher octane fuels

Thanks for the replies all.

Gixer · 29 Jun 2018 at 12:25

Looks like I'll need to plan my fuel filling!

Gixer · 29 Jun 2018 at 15:21

Frozennova said:
Octane rating doesn't affect combustion temperature, it's a fuels ability to resist detonation.

There's far more than compression ratio that affects how likely an fuel is to detonate too.

Engines are also as a rule less likely to detonate at high RPM as cylinder pressure is generally lower than at peak torque for example

Exactly. It slows the burn. With a remap it's likely the ignition has been advanced so you need a slower burn to prevent the knock.

Gixer · 29 Jun 2018 at 15:34

Cookeh said:
Haverfordwest has a Tesco that has super-unleaded, think the Morrisons offers it too. There are several Gulf/Texacos etc that have higher ron fuels (97 iirc) on the A40 from Fishguard to St Clears. There's an Esso on St Peters Road in Haverfordwest that has Synergy Supreme+. There's another Esso in St Clears (Tenby Road) that has the same fuel.

Thanks. I'll keep an eye out whilst driving around but at least I have two dead certs and one is on my way so I'll top up then. I thought more would have premium fuels when I stayed down in Polperro, Cornwall, but most didn't have anything above 95ron.

Gixer · 29 Jun 2018 at 17:53

sigma said:
Buy some octane booster?

Could do but then I have to bother to work out how much to put in. I should for emergency purposes but I can't recall if octane booster goes off, as petrol does.

Gixer · 30 Jun 2018 at 09:03

Frozennova said:
1 Litre of toluene per 10 litres of 95RON would give you 97.6 RON fairly easily (Its the main component in a lot of octane boosters)

It's stoich ratio of 13.6:1 means the fuel mix will have a stoich ratio of 14.59 meaning less than 1% change to air-fuel ratiio compare to regular petrol

Found 1ltr of toluene for £5. I have a 70ltr tank so filling at light would roughly be 50ltrs of fuel + 5ltrs of toluene (wouldn't quite be a full tank but close enough). That's an extra £25 and having to carry around a fair bit of toluene. I guess 1ltr for an emergency 10ltr top up would be OK. I'll just plan my journey accordingly on this holiday. It's not something I have to worry about in Southampton, there is premium fuel pretty much in every station.