harvey

iTrader: (48)

Can someone please explain the difference between SUL & 4 star Facts pls not theories Regards Harvey

Jon Jonzz

Do you mean LRP?

Although 4star (leaded) is still meant to be available (in minute quantities), I have never seen a pump dispensing it on any forecourt I have visited.

brickboy

"Old" 4-star uses a chemical called tetra-ethyl lead for two purposes: 1. to raise octane level to 98 and 2. to protect non-hardended valve seats from wear & erosion.

Although stocks of leaded fuel are still available for classic / vintage car users, old 4-star has now been replaced by LRP, which uses a different compound to protect valve seats (potassium based, I think) and has added high-octane hydrocarbon compounds to make it 97 octane.

SUL is basically the same as LRP, but without the valve-seat protecting compound.

Blackscooby

In that case can I put LRP in my UK94 (de-catted) ?

Mark

brickboy

Forgpt to add that using LRP in any car with a cat or oxygen sensor will kill either / both components, as the potassium salts that are the byproduct of combustion will contaminate them.

Also LRP is not much cop at protecting valve seats, apparently.

mutant_matt

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Blackscooby:
<B>In that case can I put LRP in my UK94 (de-catted)[/quote]

<B>NO NO NO - DON'T DO IT!!!!!</B>

LRP has no real quality control or British Standard (notice at the pump there is no BS number) and can be really nasty stuff.....

I've spoken to several mechanics who have taken apart (broken) engines running on LRP and were horrified at the carnage inside....

Leave it along...

Matt

HunterB

Premium Unleaded petrol (commonly referred to on Scoobynet as Normal Unleaded or NUL) has a minimum octane rating of 95RON and contains no lead.

Super Unleaded (commonly referred to here as SUL) has a minimum octane rating of 97RON (despite any BP petrol pump stickers claiming 98RON , it's not) and contains no lead.
Four star is no longer generally available in the UK but can be obtained through some "special interest groups" such as classic car clubs. It has a minimum octane rating of 98RON and contains lead as a lubricant.

Lead Replacement Petrol is the general replacement for Four Star. It has a minimum octane rating of 97RON, using SUL as a base (this is why SUL dropped from 98RON to 97RON last year) and contains no lead but does contain a proven anti-wear additive to protect your engine in the same way as lead did previously.

Ultra Low Sulphur Petrol (ULSP) is what the Government is trying to get everyone to use by announcing a discount in the March budget. Because it hadn't reached the forecourts by then, though, they gave the discount to NUL petrol until June. Expect the price of NUL to go up accordingly then. It contains about 50% of the sulphur content of current NUL so should produce less pollutants. It has a minimum octane rating of 95RON and contains no lead.

Brian

2wdcossie

i was told not to put LRP in my cossie cos the potassium rots away at the turbo splines - not sure if this is right or if it applies to scooby turbos but there you go

Blackscooby

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by mutant_matt:
<B> NO NO NO - DON'T DO IT!!!!!</B>

LRP has no real quality control or British Standard (notice at the pump there is no BS number) and can be really nasty stuff.....

I've spoken to several mechanics who have taken apart (broken) engines running on LRP and were horrified at the carnage inside....

Leave it along...

Matt <HR></BLOCKQUOTE>

Hmmmmm in that case I'll stay with SUL, or NUL + Millers CVL

Paul Wilson

Wouldn't use Millers CVL, IIRC it uses the same stuff as in LRP, either Potassium or Sodium. What you want to use is Millers Octane plus, same bottle different label.

FYI old style leaded 4 star is available all over the country, but NOT from any major chains, the distributer