What is the "official" currently recommended spark plug for the 5.2 Motronic F355? | FerrariChat
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What is the "official" currently recommended spark plug for the 5.2 Motronic F355?

Discussion in '348/355' started by f355spider, Sep 6, 2012.

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  1. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
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    USA
    #1 f355spider, Sep 6, 2012
    Last edited: Sep 6, 2012
    Obviously the originally spec'd plug is the NGK PMR7A. But off and on, I have heard rumors that FNA had switched several years ago to recommending either the PMR8A or PMR8B, which are both one heat range colder.

    I recall a quote from Rifledriver on the subject of F355 plugs, and he said use the colder if you can get away with it. I had a "miss" that developed about two years ago and replaced my PMR7A plugs with PMR8A and my car runs terrific, with no fouling or issues with the colder plugs.

    I emailed NGK just to ask what the differences were between the PMR8A and PMR8B (I was curious, as Ferrari uses both of these on newer cars) and it sounds insignificant to them: "The difference between the PMR8A and the PMR8B is very small. They are physically the same, except the shape of the platinum chip that is welded on the ground electrode. They will both work great...
     
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  2. bobzdar

    bobzdar F1 Veteran

    Sep 22, 2008
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    #2 bobzdar, Sep 6, 2012
    I think the 5.2's are recommended the colder PMR8 plugs while the 2.7's are PMR7. My 2.7 car has the PMR8B plugs and will occasionally misfire on long downhill decels and one time fouled a plug when I ran it up to revs and then did a long decel before the oil temp was all the way up. I plan to put the PMR7's in this winter and keep the 8's for the track. I don't think A or B matters, indexing the plugs would likely have a bigger influence on performance than the shape of the electrode.
     
  3. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

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    #3 f355spider, Sep 24, 2012
    Last edited: Sep 24, 2012
    Anyone else have information on the correct NGK spark plugs for the 5.2 Motronic F355? Someone recently posted (in another thread) that the correct plug is the PMR8B...
    I have also heard that the 1995 2.7 Motronic is still spec'd for the original (hotter heat range) PMR7A plug

    Thanks.
     

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