unleaded petrol, 95 or 99

Technical MGB discussion
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Remyd
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unleaded petrol, 95 or 99

Post by Remyd »

Hi,

I guess this has been asked before but could someone explain which is best for my GT, 95 or 99 octane? What is the difference and what does the Octane level means?
I currently use 95 with Tetra Boost additive which works fine. For those who use 99, do you still put additive with it?
Just curious on what it all means as I don't have much knowledge in this area.

Remy
Remy Dubois
1971 MGB GT
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Paul Scott
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Re: unleaded petrol, 95 or 99

Post by Paul Scott »

99 is going to be the best as it will be E5 also..

I use 99 & valvemaster plus

The car was designed to run on 5 star fuel back in the day.

Regards
Paul
1975 MGB Roadster
Webguru for MGB Register
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Remyd
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Re: unleaded petrol, 95 or 99

Post by Remyd »

Thanks Paul,

I am guessing that it is fine to switch from 95 to 99 without having to drain the tank?

One of the garage in town still sells 4 star but I don't really want to go down that route as it is the only one I know of that is still selling it. Don't want to go low and not being able to reful!
Remy Dubois
1971 MGB GT
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Paul Scott
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Re: unleaded petrol, 95 or 99

Post by Paul Scott »

Remy you do not need to remove the old stuff

I was told to rum on Tesco 99 super unleaded by John Watson (MGB Register Chairman) quite a while back.
So that is what I put in, I use the Castrol additive as I'm unsure about unleaded conversion. But the additive has something in it for E10/E5 ethanol protection.

Are you going to the picnic at Millets on the 8th Aug?

Hope to see you there.

Paul
1975 MGB Roadster
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Remyd
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Re: unleaded petrol, 95 or 99

Post by Remyd »

I'll try it next time I refill.
Not sure if I'll be going to the picnic as I don't know if I'll be off yet. I still have to fit the passenger seat back in and the interior restoration will be finish for now. Still got a few things to do with it but nothing that can wait.
I've kept my place for the spring run next year so will be there for that!

I'm definitely going to the Stony Classic at the end of August!

I'm thinking of doing a feature on the restoration but not sure where to start! I've taken lots of pictures of it, some I might put on the forum, but need to put words to them.
Remy Dubois
1971 MGB GT
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Paul Scott
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Re: unleaded petrol, 95 or 99

Post by Paul Scott »

Where did your last post go for the interior.

I was going to remove a few of the hadle shots for you, but it is no longer here :0(

Paul
1975 MGB Roadster
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Remyd
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Re: unleaded petrol, 95 or 99

Post by Remyd »

I deleted it as I realised that there was a lot of duplicated pictures. Just trying to do another one. I've got too many pictures to choose from!
Remy Dubois
1971 MGB GT
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Charles Farran
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Re: unleaded petrol, 95 or 99

Post by Charles Farran »

Hi,
I''ve used Shell VPower ((previously named Optimax when i think it was slightly modified) since its' introduction + castrol valvemaster plus (which has ,in the last 12 months or so been modified to stabilise Ethanol petrol E5 & E10). The engine ran much smoother ,whereas previously it used to pink under load.
If not going via a Shell garage, then Tesco 99 super unleaded is to my view on a par..My engine is unmodified, with the original head on,having completed about 85K.
No need to drain the tank if you have previously been using standard unleaded., just put 4 star in the tank at next fill up. (If the head hasn't been modified to take unleaded then an additive such as valvemaster is advisable ).
Cheers,
Charles
1980 Roadster
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Remyd
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Re: unleaded petrol, 95 or 99

Post by Remyd »

Thanks Charles, I'll start next time I fill it up and will check if the additive I use is good for E10 and E5
Remy Dubois
1971 MGB GT
Dave Wheatley
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Re: unleaded petrol, 95 or 99

Post by Dave Wheatley »

For what it is worth I use the cooking E5 stuffwith ignition retarded to 6 degrees btdc. I use the Lucas (not Joe) additive, and haven't noticed any problems apart from an occasional 2 bumps run on. I'm going to have to think again though when E10 comes in. No super available in my neck of the woods.
1978 MGB GT
1931 Austin 7 RM
1955 Standard 10
1972 Ford Cortina
No modern!
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