A test here - http://www.thorneymotorsport.co.uk/ - click on Fuel test results.
I'll be conducting my own economy tests soon. Watch this space!
I'll be conducting my own economy tests soon. Watch this space!
regular vs hi-octane petrol
- Thread starter Tomsk
- Start date
Soldato
- Joined
- 7 Sep 2005
- Posts
- 3,312
merlin said:
Its an old test, I'm sure its been on before!
I too like the V-power stuff, even before my bike was mapped on it.
Aren't the M3 and VXR already mapped for 98 RON or better anyway? In which case the ECU isn't advancing the ignition timing for the good fuel, it's mearly retarding it for the lesser?
For most cars I still can't see higher RON fuels being worth the while unless specifically mapped for it.
For most cars I still can't see higher RON fuels being worth the while unless specifically mapped for it.
Also Tesco 99 won't give you the economy benefit as it has less energy in it. The reason it makes more power more likely due it running 'leaner'.
Ethanol (Tesco 99 has 5% of it in, needs an AFR of about 8.9:1 for stoichiometric compared to normal Gasolines 14.7:1. Ethanol has about 30MJ/kg vs 44-45MJ/kg.
Ultimate and optimax both are similar as they are around 98ron and are what the car's are mapped to run on, as Lowe says
Ethanol (Tesco 99 has 5% of it in, needs an AFR of about 8.9:1 for stoichiometric compared to normal Gasolines 14.7:1. Ethanol has about 30MJ/kg vs 44-45MJ/kg.
Ultimate and optimax both are similar as they are around 98ron and are what the car's are mapped to run on, as Lowe says
housemaster said:
I did do a search before posting and couldn't find a previous reference to the website.
Their test just proves what anyone with a bit knowledge knew - that hi-octane fuels would only work if the car was capable of using it.
I'll be trying it in a VW Golf MK4 2.3 V5 10V 150bhp (with an auto box). I'm running regular Shell for the next couple of tankfuls and then I'll switch to V-power. No performance testing, just a fuel economy comparison.
Not trying to pick holes more like "yea, that's the one"I believe you will typically need to run a couple tank fulls of any given fuel for a modern car (with a knock sensor) to fully take advantage of it. So when people talk about putting 1/4 of a tank full in and seeing a difference I would question this. My GT3 actually 'seems' less affected by fuel types than the Golf GTi, though I never put normal unleaded in the GT3 on occasion my wife puts normal in the GTi. When she does this the difference is noticeable as the sharpness of response is duller, especially if she does it 3 or 4 times in a row. The fuel consumption also reduces on normal unleaded by up to 50 miles a tank full.
Simon said:
Yup..
and
If you advance the ignition timing, the burn time is longer so your AFR meter shows less fuel in the exhaust gas...
It doesnt use less fuel always, it just makes it appear its using less as it has burned more...
A reading of the fuel flow is the only way to measure the consumption, not afr ratio...
