UK fuel question

w_orbit · 11-05-2003, 03:40 AM

Picked up a '84 924 Lux last week. The seller told me to run it on Shell Optimax - is this OK or should I go for Lead Replacement petrol or Optimax with additive.

I believe that the post '81 engines can be timing adjusted to run on unleaded, and I assume that's how this has been tuned, but can the valves cope ok ?

Oh, while I'm here.. Looking for a black glove compartment and black gearleaver (standard 5speed insert )with gaitor in good condition fo 924.

Cheers
Martin

Dark Skies · 05:11 AM

Quote:

Originally posted by w_orbit
[B]Picked up a '84 924 Lux last week. The seller told me to run it on Shell Optimax - is this OK or should I go for Lead Replacement petrol or Optimax with additive.

B]

I wrote to Porsche on this very subject when the UK was told it was going to do away with leaded fuel.

Porsche said the important factor was the octane rating which must be 98. Consequently it's okay to use 4 star (and given they wrote to me in 1998 I took this to mean the LRP that replaced REAL 4 star) or superunleaded. LRP is only 97 RON but for ordinary road use that ought to be okay. That superunleaded is permissable tells me that Porsche had the foresight to design the valve seats to cope with the weak piss that the Americans and Europe use.

and that the seats will not suffer unduly from recession. However ... because cars produced after 95 (UK) had to be designed to run on unleaded (95 RON) by law and as more old cars are hitting the scapyards LRP is gradually being phased out due to falling demand. I gather it will have left the forecourts by the end of 2003.

I don't know about you but I've found few garages actually stock superunleaded. Consequently you might find it best to use either ordinary unleaded with an octane booster once the LRP is gone. I've noticed Esso garages in the Oxfordshire area aren't stocking LRP now.

By the way - you can still get the REAL 4 star from a few garages -it's a little more expensive and garages are far and few between but you can still get it. Here's a link to a page that lists stockists:

http://www.leadedpetrol.co.uk/list.htm

I'm not au fai with Optimax - is that a fuel or an additive?

w_orbit · 11-05-2003, 04:38 AM

Optimax is Shell's new Unleaded Petrol..Major breakthrough, best ever, washes whiter than white blah blah. Advertised on UK TV with speedy fishes if that helps.

Still unleaded tho, so I wonder if I should use an additive to boost the octane rating? If I start using an additive I assume I'll need to have the timing reset ?

http://www.shelloptimax.co.uk/
if you really want their advertising blub

w_orbit · 11-05-2003, 04:46 AM

Actually, just read their advertising blurb. Apparently Shell Optimax has an Octane rating of over 98RON and has replaced their SuperUnleaded.

From their FAQ.

"Shell Optimax has the highest octane specification of any petrol in the UK. It is greater than 98 Research Octane Number (RON).
"

Dark Skies · 04:54 AM

I've amended my last post a little. By the way - Porsche say you don't need to alter the DMA at all. So I'm sure you'll be fine with octane additives in either unleaded / LRP or just Optimax on its own. I've been using just LRP (superunleaded when available) and my car has run fine for some two years and 50,000 miles.

Dark Skies · 11-05-2003, 05:00 AM

Quote:

Originally posted by w_orbit
Optimax is Shell's new Unleaded Petrol..Major breakthrough, best ever, washes whiter than white blah blah. Advertised on UK TV with speedy fishes if that helps.

Oh, yeah ... I recall ... Quinten Wilson does the voice over.

Maybe I'll give it a shot next time I'm near a Shell garage.

flangermog · flangermog's Garage

Yeah Optimax is good. But it's just so expensive. Luckily for me mine will run on 95RON.

What I do with my Polo (which is too old to have even heard of unleaded) is alternate between super (or optimax) and ordinary unleaded. For daily commuting etc. this shouldn't cause any problems but if your gonna blow the dust off some B roads, get some optimax in there.

If all you do is pleasure driving (i.e. not sitting in traffic every day commuting) in your '44, then I would stick with Optimax and even consider an additive every couple of months also.