LRP / Optimax / Unleaded?

[image][/image]I have a garage 10 metres from work which sells unleaded and LRP, whereas the Optimax top up is lots further to get to. - Question: As my Exige has the cat removed, does anyone know if LRP (Lead replacement Petrol)can be used in it? Is the octane rating higher than standard unleaded and/or lower than Optimax?I run a Triumph Bonneville '78 on LRP as old fashioned 4 star is NLA. I ws told that as soon as ‘super unleaded’ became NLA (31/12/01)then LRP has certain additives in it to prevent detonation. Does anyone have the knowledge to save me phoning Shell/BP’s technical dept.Thanks Guys (& Girl(s)) Hope you can helpPhil GT

Phil, I do not know of the technical details of octane rating for the different types of fuel but from practical knowledge over running this car for almost 2 years now (wow, doesn’t time fly by when you’re driving fast!), the best fuel to go for would seem to be Optimax. Used to use super unleaded, but switched to Optimax as soon as it became available. Same levels of power as ‘super’ but made running around urban areas MUCH smoother. Run a search on this bbs for notes on LRP, we seem to have a few rocket scientists on this board who know what they are talking about.

Maybe the “new” ECU mapping will be more fuel friendly [image][/image]

The first time I used Optimax, I though it was a marked improvement. Since then, I can’t really tell the difference between Optimax and Super.Nick Adams reckons the Elise (and presumably the Exige) don’t have a knock sensor, and so won’t take advantage of the higher octane rating. He felt that the only benefit of Optimax would be it’s superior detergents which keep the valves nice and clean.I guess it’s worth using Optimax occasionally, but there’s no reason to use it exclusively.