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Discussion Starter · #1 ·
i have a 72 silver shadow, and it carries with it a plaque underneath the fuel cap stating 100 octane. as i live in lovely Los Angeles, the highest octane i have access to is 91. what are known good subtitutes of octane booster? personal accounts would be great. Thanks Dominic
 

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Stirling has pointed you to a very useful article. Any indication of 100 octane pretty much tells you that the car came from a country where RON was the octane measurement method.

In any case, if you do lengthy reading about the fuel requirements for the Shadows and derivatives you'll find that they were designed to allow for the use of what is "regular" in the U.S. system (R+M/2) because that's all that was available in many places these cars were destined for.

I have a Shadow II that I haven't put a drop of premium fuel in for about 3 years. It has made absolutely no difference in the way the car runs.
 

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Discussion Starter · #4 ·
thanks alot guys, car finaly is turning over. but fuel pumps are bad gotta rebuild them. 17 years of sitting in the garage is never good
 

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Just finished rebuilding my dual SU fuel pump. The rebuild itself is a very easy job, the extraction of the pump and getting it back in is where the adventure lies.

Rebuild kits are available from Burlen in the UK as are straight replacement dual SU fuel pumps (Part #: AZX 1405).

I hate to tell you, and am not trying to discourage you, but you're going to have much, much more to contend with than the fuel pump if this car has been in storage for 17 years. I would absolutely not start the thing again unless you've checked out what the contents of the hydraulic/brake fluid reservoir look like first. That system is sure to need a fluid purge at a minimum and all the rubber hoses will likely need to be replaced in short order as well along with rebuilding the accumulators. The hydraulic systems on these cars are definitely a "low point" in terms of requiring very high maintenance.
 

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There is no need to run a Silver Shadow at 100 octane. There are thousands of SS in the UK all running happily on standard unleadded. Some folk have retarded their ignition timing by a couple of degrees to prevent "pinking".
Lower octane petrol will not harm your engine, but you get nothing for nothing. The engine will deliver less power: maybe one horsepower of the two hundred or so that the car was born with. That is 0.5%. You cannot tell the difference.

Phil
 

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100 octane not needed

The low octane doesn't harm the engine, but just looses some performance power.

In The Netherlands the unleaded 98 is recently disapeared from all gasstations, but i was told the 95+substitute is good replacement.
Shell V-power, Esso-Extra and in UK i use the BP-Ultimate.
The engine really loves it and performs so much better :)

Hemmo
 
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