[Healeys] Gasoline Octane

Bob Spidell bspidell at comcast.net
Sun Jun 7 21:37:05 MDT 2009


Hi Ron,

There are precious few real 'experts' on gasoline, and I don't know if there's 
any on this list.  I recommend you do your own research and draw your own 
conclusions.  Try net searches on 'gasoline additives,' 'octane boosters,' 
'octane rating,' 'tetraethyl lead,' etc.  I think you'll find the bulk of 
opinion on fuel additives is that they're little to no help at best, potentially 
damaging at worst (as you've already discovered).  My Mustang's owner's manual 
specifically states not to add anything to the gas or oil and that it could void 
the warranty.

Is your DB's requirement for Motor, Research or R+M/2 octane fuel?  If it's for 
Research method--as is often given in European literature--91-octane R+M/2 may 
be adequate for your DB (Research method is typically 3-4 octane higher than 
R+M/2).  If not, adding 100-octane--as long as it's unleaded--as you're doing is 
probably the safest and most beneficial way to raise fuel octane.  Your car may 
be fine on 91-octane pump gas--since your DB is electronically controlled it 
probably has a knock sensor that will change the engine tune: retard timing, 
enrichen mixture, etc.--to prevent damage.  Of course, you won't be getting the 
last few HP out of it--you'll just have to manage on, what, 500HP?

Regards,
Bob



Ron Davies wrote:
> I've always just used premium and the lead additive and no problems in my 67
> BJ8.
> However, I had some serious expense with an octane booster in my DB7 after
> an idiot had put the wrong plugs and wrong gap in.  I had been told to use
> the additive since the DB needs 92-93 octane.  The dealer said the additive
> fouled the plugs and burned out two sets of coil packs (because of the wrong
> plugs). (one coil to each cylinder $$$$). No problem since the right plugs
> and gap but I'm nervous about the additive again.
> 
> I now add one gallon of 100 octane to each tank of 91 and it works but I
> would like to know the experts' views on the list on octane boosters in
> modern cars with electronics, high compression and superchargers.
> Any comments?
> TIA
> Ron Davies
> Laguna Hills, CA

> 


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Bob Spidell           San Jose, CA            bspidell at comcast.net

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