mannyfold

Hi

after all the petol threads sorry to ask another question but this has been playin on my mind...

the local sainsburys still sell real 4 star leaded petrol, which unless i have been well misinformed is ifact 100 ron.

since i have the benifit of not having a cat to worry about killing, what, if any damage would be done to the engine/turbo or anything else for that matter, if i ran it on for star rather than super + ob?

p.s. my95 wrx jdm

probably wishful thinking but hay ho.

pps on questioning the tanker driver on where his fuel came from etc etc, well i may have well asked him for the key to the crown jewells!!!!

mannyfold

even if nobody has any cold hard definative answer some hyperthetical conjecture is welcome, does any one know what the procedure was to convert a car from 4 star to unleaded?

perhaps the logic may infer some suggestion whether or not it is the worst idea i ever had?

davedipster

I though that LRP was 97 octane with some lead replacement stuff in it.

Dipster

mannyfold

oh right so when they said it was "real" 4 star then they were talking rubbish, ah this would make sense.

shouldn't they call it lrp and not 4 star then?

i thought it really was the real thig cos i saw an old xjs filling up with it and thought it was the V12.

davedipster

Real 4 star was outlawed years back, you need LRP or unleaded with an additive for those old cars, may need to adjust the timing as well.
As for your JDM I would use super if it's mapped for uk fuel and super and booster if not.

Dipster

Carl2

Unless the law has changed again, they actually allowed something like 10% of the petrol stations to keep selling it for those old and other cars that needed it. But the day after it went this way it also went up 10p a ltre at the garage I bought it from.

4star was never 100ron it was 97 I think

It'll kill your lambda sensor too, (which the ecu relys on a little)

mannyfold

yeah, cheers dipster.

sound advise that i already adhear to but i have'nt seen (well noticed) a sign saying 4 star for a long time and then i just got a little bit too excited!

anyways did someone say N.O.S.? hhhmmmm

one day

mannyfold

so if it is real 4 star then the lambda is all it would affect? how much is a new lambda, and how often would it go i wonder?

Fuzz

5 star was 100 ron not four star, but that was wwwwwwwwwwwway far back


Andy

ALi-B

iTrader: (1)

The only problem you would have is contamination of the oxygen sensor by the lead (seeing the cats are removed).

Genuine leaded fuel is still available at selected outlets which are very few and far between.

It won't be 100ron. 4 star was about 98Ron....5 star was around 100RON, and that hasn't been around since the 70's (although if you have a friend who works at an airfield you can still get some nice 100+ron Avgas).

Jag V12's never needed leaded fuel, as they had hardened valve seats from day one of production. However, XJ-Ss and late SIII XJ12s with HE cylinder heads needed high octane fuel due to the very high compression ratios (upto 12.5:1 - compare that to a modern cars compression ratio).

mannyfold

oh! poo i'm old!

willipdarling

To do a conversion from leaded to unleaded, you have to replace the heads on some engines. The way i see it is that the lead in the fuel also acted sort of like a lubricant, hence the hardened valve seats. All i know is that you cant put u/l in a 4 star car, coz the engine will go bye bye, the other way round is ok i think, but emissions will be high, and with the mapping on the new engines, personally i wouldn't recommend it.

mannyfold

nice one boys

looks like i'll forget that idea since optimax can match or better it and not damage stuff, and as for anyone who needs "real" 4 star fuel give Sainsburys "marsh mills" petrol station a bell cos they mey just have what you're looking for.

anyone with access to aviation fuel in the SW and a genous disposition pm me pls.

David Lock

5 Star was about 101 Ron in the days of the decent Astons etc

4 Star was 98 then reduced to 97

LRP is around 97 but no British Standard

Lead content was also reduced considerably a few years back from .4 g per litre to .15 g per litre IIRC

5% of sales can be leaded which is at least £1 per litre when you can find it

As above Jags like a decent octane and heads have been OK for unleaded from around 1969 onwards.

LL Avgas also has lead in it (Low Leaded Avgas).

punkie

Graham Goodes in Leicester still sell it........i think!

petrol magnet

we still sell i, last time it was checked it was 99.8 octane it sells 4 106.9 per litre. bayford thrust 01937 541111 is north of england distritutor.