I always tried getting Shell V-Power in thePlus 8. I used to get very occasional intermittent random misfire triggering the MIL light. The V-Power cured that. The engine is deemed ethanol safe but not so sure about ancillaries. Pump, fuel lines etc.
I got 1-2 extra mpg with it too. The extra cost was not a real issue due to relatively low mileages but the misfire removal was nice.
A few years ago I had a Focus Turbo diesel. Long commutes so needed for them. I tried Millers Octane boost and it gave increased mpg. Bottle cost £12. It dosed several tankfuls. Net better mpg saved £37 so net £25 saving. A colleague tried it in his golf diesel but it didn’t work, maybe marginal but nothing worthwhile. Looks possibly like the ecu map worked differently.
I’ll be sticking to E10 in the Plus Four until mileage has built up then try E5 to see if any effect. A bit soon to test with a new engine.
