Unleaded Vs Vpower nitro

Unleaded Vs Vpower nitro

Author
Discussion

si easter

Original Poster:

219 posts

212 months

Saturday 24th January 2015
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Hi all, I always use Vpower nitro in my Griffith, but I was told by a TVR specialist I only need unleaded ? Any thoughts , Simon

carsy

3,018 posts

164 months

Saturday 24th January 2015
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They are probably right. However being a 5ltr they run a lot higher compression ratio than the other engines. So to be on the safe side of "detonation" i would carry on using Vpower, especially if it gets a bit of stick.

QBee

20,905 posts

143 months

Saturday 24th January 2015
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I have a V8D 5 litre engine, new in 2013. rob told me to run it on 95 standard unleaded, only upgrading to super unleaded for track days. Seems to run fine doing just that.

shake n bake

2,221 posts

206 months

Saturday 24th January 2015
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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!

si easter

Original Poster:

219 posts

212 months

Sunday 25th January 2015
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Thanks for the replies ,I'll stick with the V power for now ! Simon

blitzracing

6,387 posts

219 months

Sunday 25th January 2015
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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.

Dr Wolff

2,203 posts

222 months

Sunday 1st February 2015
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Timing for the V8 is (and always was) set for 97 octane fuel. 95 won't harm it in an emergency, I was told, but...

blitzracing

6,387 posts

219 months

Monday 2nd February 2015
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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.

macdeb

8,493 posts

254 months

Monday 2nd February 2015
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V Power nitro????
FFS, what will they come up with next?

Sardonicus

18,928 posts

220 months

Wednesday 4th February 2015
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macdeb said:
V Power nitro????
FFS, what will they come up with next?
How about Shell Formula? oh yeh they did that in the 80's hehe ...... and they had problems with that one ....... whistle

blueg33

35,590 posts

223 months

Thursday 5th February 2015
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macdeb said:
V Power nitro????
FFS, what will they come up with next?
Shell Viagra "for when you want to drive hard"

QBee

20,905 posts

143 months

Thursday 5th February 2015
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blueg33 said:
macdeb said:
V Power nitro????
FFS, what will they come up with next?
Shell Viagra "for when you want to drive hard"
I always assumed that was what the "V" in "V Power" stood for.....idea