Unleaded for S1's

[AndrewL]

I have heard that some people have problems running their S1's on unleaded petrol, my 1988 S1 seems to run well on unleaded but I have never tried superunleaded, has anyone any advice? Does in need advancing/retarding and is there any benefit?

[shpub]

It's covered in the S bible and in the unleaded FAQ on my web site. www.tvrbooks.co.uk

Make sure you have compatible heads and you might need to adjust the timing.

Steve

>> Edited by shpub on Tuesday 23 July 17:41

[bills1]

I run my S1 on Shell Optimax and it is much better.
The difference is very noticeable especially if have to use ordinary unleaded when on a trip and cant find a Shell garage. It usally costs 76p/litre but gives better consumption, I now get 26-28 mpg blasting the local roads, no doubt better still on motorways
Every 4th fill up or so I add Millers VSP plus lead additive, usually if I have had to put ordinary 4* unleaded in.

[f402mlr]

Two factors, octane rating and valve seat recession.

As Steve says there is a way of identifying the unleaded (hard valve seat) heads by the code.

When I first got my S1 I asked the dealer, who gave me a copy of the (c1990) Factory note. To run on 2 star unleaded (standard unleaded) the timing needs to be adjusted. I found that above 4000rpm on unleaded the engine didn't have the same urge. So I haven't tried it again. So I used 4 star or Super Unleaded when it was cheap. When Super went 10p/L more I used 4 star and now LRP. As Steve says Super is now at a lower premium, but rare.

A local garage sells the real 4 star, but at over £1/litre! I treat my 1926 Alvis every now and again.