Unleaded Vs Vpower nitro
Discussion
This comes up quite often, some see it as snake oil, others claim to feel an improved response. I use v power, mine certainly idles better and behaves better at low speeds on it. I tried esso 98 stuff before I put it away for the winter and it ran like crap. So I believe it's better for these big old engines, but I'm no engine builder!
You need an adaptive ignition timing system that can detect knock if the fuel octane is changed, and the RV8 distributor and timing control is stone age on this front. You could set the timing manually on a rolling road with Vpower, but then you would have to stick with it, otherwise there is little point.
Having read on the RPI web site that peak ignition timing could be set by ear at the point of knock, I strapped an amplifier and headphones onto a knock sensor (that's really just a microphone) with I set off as passenger in a mates 5 ltr. We hammered up and down the road for some time whilst I listened for knock after we keep advancing the ignition- but it never came. Move ahead some years Ive now putting mapped ignition on my engine, so I can alter the timing at ease- back out with the headphones- no knock what ever I did. OK- maybe its just too noisy to here, so I buy two knock sensors and an tuned electronic knock sensor box- I know it works as it triggers if you tap the sensors to make them ring. Still no sign of knock. This makes little sense-
That is until I have a conversation with Mr Adams, who causally says you cant get the RV8 to knock easily with over advanced ignition timing- the torque just drops off. Any "pinking " you hear is mostly due to an over lean mixture causing the combustion chamber to pre detonate as it now running too hot (in particular the 5ltr).
So the moral of the story is, don't believe anything RPI tell you, and even if the timing is over advanced for low octane fuel, the worse you are going to do is loose some peak torque. How ever if you do hear knock or pinking, (technically two different things) then reduce the amount of throttle ( to reduce the compression and reduce heat) as this causes real damage under load.
That is until I have a conversation with Mr Adams, who causally says you cant get the RV8 to knock easily with over advanced ignition timing- the torque just drops off. Any "pinking " you hear is mostly due to an over lean mixture causing the combustion chamber to pre detonate as it now running too hot (in particular the 5ltr).
So the moral of the story is, don't believe anything RPI tell you, and even if the timing is over advanced for low octane fuel, the worse you are going to do is loose some peak torque. How ever if you do hear knock or pinking, (technically two different things) then reduce the amount of throttle ( to reduce the compression and reduce heat) as this causes real damage under load.
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