I noticed the other day the local garage are selling four star LRP.
Ron rating of 97.

Now If I am correct, Four star cars could not run unleaded as the higher ignition temps could burn out the valves. And unleaded cars should not run four star as these cars usually had catalytic converters that could get clogged up with the leaded petrol. But in a scooby, with a decat exhaust, would Four star LRP help or hinder?
Just a query as I thought leaded petrol used to help and seal the piston rings.

Stop laughing at the back there.................Just a puzzle.

And I don't want to see or or even

But I will accept , or

 

 

I've wondered this as well

 

The lead in the old 4-star would not only have the effect of raising the octane rating but would also "lubricate" the valve seats, which on older cars were unhardened. Running these cars on unleaded would cause eventual valve seat recession or "pocketing"
LRP has an additive that replaces the lead for the purpose of this "lubrication" LRP is quite rare now and for use in a Scoob (which of course has hardened valve seats) is rather pointless if SUL is available.
JohnD

 

I doubt whether the lambda sensor would like it very much.

I suppose if that packed up you could claim that you'd got your petrol from Tesco...