good fuel

[sam011]

i am about to start running my 3.4 s-type after an 8 year lay up. As this was pre-unleaded fuel days i am interested to know the best unleaded fuel/un leaded fuel+addative to start with.

many thanks for any help

dave

[sweller]

What fuel? The cheapest....

My understanding is it's fine for it to run on unleaded - I use 95 RON in my 3.8s

It has an aluminium head - already has hardened valve seats so valve seat recession isn't a problem. Mine doesn't suffer from detonation on the UL95.

Simon

[sam011]

thanks for your help simon i will have a go.

[stuarthardy]

I agree with Simon. I run my 420 Sovereign on either 95 or 98 unleaded, without additives. Either seems fine. Compression ratio is 9:1.

When I use 98 octane, the car's fuel economy (?) improves about enough to justify the extra.

Regards
Stuart

[sam011]

thanks stuart, thats even better the 98 oct improves the economy.

[stuarthardy]

Dave

When I said improved economy I didn't mean drastically, but 5% or so is worth having, especially at 18 or 19 to the gallon!