Leaded petrol or not for 308 GT4? | FerrariChat
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Leaded petrol or not for 308 GT4?

Discussion in 'Technical Q&A' started by rmdferrari, Mar 14, 2005.

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  1. rmdferrari

    rmdferrari Formula 3

    Jan 6, 2005
    1,383
    Gatwick, UK
    Full Name:
    Richard
    #1 rmdferrari, Mar 14, 2005
    Hi Guys,

    I've done a quick search on previous threads on petrol choices, but nothing conclusive has emerged.

    Reason for post is I've noticed two garages within 20 min drive from me who stock good old fashion leaded petrol. I've only owned the car just over a month and the previous owner told me he put high octane unleaded (ie Optimax) and an addative (Millers I think) in the car.

    What do other GT4 owners do, and have any swopped from unleaded/addative to leaded and what was the outcome if any? Where there any official guidence notes from the factory when unleaded took hold?

    Thanks. Richard
     
  2. tomoshea

    tomoshea Formula Junior

    Dec 29, 2003
    541
    Ireland
    Full Name:
    Tom O'Shea
    #2 tomoshea, Mar 14, 2005
    OK Here is the bottom line from Ferrari in the UK I have spoken to many people about this and this is the concensus I have obtained

    (see Ferrari technical bullitin 966 - ring Ferrari UK technical dept and they will tell you)

    1) you can use unleaded 95 (does not have to be high octane) in your engine without any additives as long as you are not driving prolonged at high RPM or a lot of Motoroway driving, if you are doing short jaunts the engine is just fine - as long as your engine timing is set up correctly!!!

    2) If you plan on track style driving or lots of long journey high RPM travel (motorway etc) then 95 unleaded with a fuel additive is fine (You should use shell Millenium) - recommended by Ferrrai and tested by them on old 308 Engines potassium based I think.

    3) High octane unleaded such as optimax is fine without any additive as long as you are not drving for prolonged periods like an F1 driver! - you can add an additive if you want for belt and braces

    4) If you have access to leaded petrol and cost is not prohibitive use it until they stop making it - why not!


    Finally I am in the process of replacing my exhaust valaves in my gt4 as they are still Sodium filled - (everyone I have spoken to in the business has said there is no need to replace the valve seats for an unleaded conversion (tough as old boots) - unless they are excessively worn. - no one I have spoken to has seen pitting on these seats (which is why additive is added)

    Hope that helps - lets see if anyone else has a different view
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,785
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Mar 14, 2005
    It really hasn't been a widely-reported problem issue here in the US where virtually every 2-valve 308 has been forced to use unleaded fuel. Would the extra lubricity of a leaded fuel be worth it on a non-cat car? -- minimal IMO. Is there a significant cost difference between the two for you (other than the 20 min drive ;))?

    Is that Ferrari TSB related to the unleaded vs leaded issue or more towards the 95 RON vs 98~100 RON octane difference?
     
  4. GavC

    GavC Formula Junior

    May 9, 2004
    492
    Lincolnshire, Englan
    Full Name:
    Gavin Culshaw
    #4 GavC, Mar 14, 2005
    Difference in unleaded and leaded is quite a margin in costs. I have been to Shell R&D in the uk and for off the record conversation with a very highlevel tech guy (current F1 experience). The 308 engine will run happily on unleaded as it is not a high compression so the octane is ok. As for valve seats the heads are made out of alloy and have hardened seats in ,America has been on unleaded for over 30 yrs now. I am in the position that I have my engine stripped at present. No wear on valve seats or valves only thing that was worn was valve guides have replaced these with new ones phosperous bronze. With regards to sodium filled valve I have heared that they can break. However Porsche 944 turbo use these and they run on unleaded I have owned one of these in the past never had any problems. If you want to use a additive keep with one type don't mix potassium ones with sodium etc type can cause problems. Given that most cars cover small mileages put Optimax in,I run my Saab 9000 Aero(slightly modded) and it responds better than standard Tesco stuff. Good Luck with the gt4 great car.
     

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