Outer Limits 4x4 Board

About to do a trip were there isn`t much Fuel stations that have leaded fuel
Wondering if theres any bad things about the octane boosters available for unleaded to run in leaded motors and is it important to get the ratio mix spot on

We've got an unleaded tank here that I always fuel my Rangie up from, and I usually throw in one of those 50 ml bottles of octane booster for good measure - have never had any probs.

Mind you, the compression on the old Rover engines is so low that you can apparently "safely" use unleaded.

Take a look at this to see if your engine is also safe* to use with unleaded:

http://www.bp.com.au/globalchoice/about ... de-new.pdf

* Note that I still use the valve seat retention additive 'cos I figure it's bugger all $$$s for a bit more protection... I rarely use LRP in my Rangie.

the lead (or lead replacement) in leaded/LRP fuel has nothing to do with octane rating and the octane rating of most LRP fuels available now is not much or any higher than that of regular unleaded (around 90 - 92 RON), the lead is far more important for valve seat protection - on older engines with soft valve seats, if you do not run a lead replacement additive or LRP you risk expensive damage to your valve seats whjich can only be corrected by a complete top end overhaul.

the best thing you can do to keep an old leaded fuel engine alive and running well is to use the highest octane fuel you can get, and using a lead replacement additive, like valvemaster or redex or whatever. if youre travelling in an area where higher octane fuels are not available it may be necesaary to retard your ignition timing a couple of degrees to minimise detonation/pinging.

cheers

Brian

dumbdunce wrote:the lead (or lead replacement) in leaded/LRP fuel has nothing to do with octane rating and the octane rating of most LRP fuels available now is not much or any higher than that of regular unleaded (around 90 - 92 RON), the lead is far more important for valve seat protection - on older engines with soft valve seats, if you do not run a lead replacement additive or LRP you risk expensive damage to your valve seats whjich can only be corrected by a complete top end overhaul.

the best thing you can do to keep an old leaded fuel engine alive and running well is to use the highest octane fuel you can get, and using a lead replacement additive, like valvemaster or redex or whatever. if youre travelling in an area where higher octane fuels are not available it may be necesaary to retard your ignition timing a couple of degrees to minimise detonation/pinging.

cheers

Brian

Just to clarify...

The RON (Research Octane Number) for LRP is actually 96, its a higher octane rating than Premium which is 95 and Unleaded which is 91.

Hope that helps someone.

RAY185 wrote:

dumbdunce wrote:the lead (or lead replacement) in leaded/LRP fuel has nothing to do with octane rating and the octane rating of most LRP fuels available now is not much or any higher than that of regular unleaded (around 90 - 92 RON), the lead is far more important for valve seat protection - on older engines with soft valve seats, if you do not run a lead replacement additive or LRP you risk expensive damage to your valve seats whjich can only be corrected by a complete top end overhaul.

the best thing you can do to keep an old leaded fuel engine alive and running well is to use the highest octane fuel you can get, and using a lead replacement additive, like valvemaster or redex or whatever. if youre travelling in an area where higher octane fuels are not available it may be necesaary to retard your ignition timing a couple of degrees to minimise detonation/pinging.

cheers

Brian

Just to clarify...

The RON (Research Octane Number) for LRP is actually 96, its a higher octane rating than Premium which is 95 and Unleaded which is 91.

Hope that helps someone.

Most of our Premium Unleaded down here in Vic is now 98 RON

Yeah, in Qld there are some brands that offer 98RON but they are not branded as Premium Unleaded, they are Shell Optimax, Ampol Gold, Caltex Vortex and BP Ultimate

RAY185 wrote:Yeah, in Qld there are some brands that offer 98RON but they are not branded as Premium Unleaded, they are Shell Optimax, Ampol Gold, Caltex Vortex and BP Ultimate

Yep same down here.

I think you'll find Vortex is only 95 or 96 octane- not 98.

murcod wrote:I think you'll find Vortex is only 95 or 96 octane- not 98.

Yep, you're right, Vortex and Gold are just premium (95) with extra additives.

fightara wrote:We've got an unleaded tank here that I always fuel my Rangie up from, and I usually throw in one of those 50 ml bottles of octane booster for good measure - have never had any probs.

Mind you, the compression on the old Rover engines is so low that you can apparently "safely" use unleaded.

Take a look at this to see if your engine is also safe* to use with unleaded:

http://www.bp.com.au/globalchoice/about ... de-new.pdf

* Note that I still use the valve seat retention additive 'cos I figure it's bugger all $$$s for a bit more protection... I rarely use LRP in my Rangie.

well going by that chart I can use any unleaded or leaded fuel in the 2F

dumbdunce wrote:the lead (or lead replacement) in leaded/LRP fuel has nothing to do with octane rating

Sorry but this is complete crap. Most of the anti-valve-seat-recession (VSR) additives boost octane. The invention of tetraethyl lead was as a way of increasing octane (and reduce engine knock) rather than a way to reduce VSR.

Tetraethyl lead boost octane (RON) by 5 points. MMT (common additive to LRP) boosts octane by 1 point, Valvemaster (LRP additive - organic phosphorous compound) is the only one that has no effect on RON. These values are for the usual concentrations found in fuel.

An important point to note, is that valvemaster and MMT (the 2 most LRP anti-VSR additives), do not have a combined effect. This means, that if you fill up with half a tank of LRP containing MMT, and half a tank of LRP containing valvamaster, you will end up with 2 - half diluted additives that together will HAVE NO EFFECT ON VSR.