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Same 0ld Testarossa Questions

Discussion in 'Technical Q&A' started by gfrench, May 27, 2025.

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  1. gfrench

    gfrench Rookie

    Mar 14, 2006
    20
    #1 gfrench, May 27, 2025
    About to do a few jobs on the very rarely used garage queen and would be grateful for some latest advice / guidance on matters that I know have been previously aired on this site.

    Gearbox Oil
    Changing the oil and proposing to use Redline 75w 90ns with 3 fluid ounces of Redline modifier for limited slip diffs. Has anyone found an oil that works better than this and helps with what is otherwise a typical recalcitrant Ferrari box of the period?

    Rear Engine Lid Sound Deadening / Heat Shield Material
    Despite the cosseted garage life the underside of the engine lid has turned into a disintegrating greenish sticky mess. I understand that this is no longer available from Ferrari. Does anyone know the source of a close replacement to the original?

    Front Bonnet Struts
    I despair with these! I have replaced them on three occasions with struts from Kent High Performance (I believe these were genuine Ferrari), D K Engineering (probably aftermarket) and lastly Superformance (definitely aftermarket). All utterly useless, with the best lasting no longer than a few weeks. Is there such a thing as a strut that is strong enough to hold the bonnet up without bending it in half?

    Fuel
    All fuel from garages in the UK now contains minimum of 5% ethanol. I have been storing the car with specially purchased drums of ethanol free long lasting storage fuel. This however is not practicable for journeys of any distance. I would welcome any advise on what others are doing to negate the effects of ethanol on a 1990 car and what problems to expect long term.

    As noted, I am in the UK hence if anyone is good enough to respond could you please provide full addresses for any non UK suppliers.

    Thanks in advance. This is a superb site and I remain indebted to Steve Magnuson for all his past help. An absolute credit to the Ferrari Community.

    Regards
    Greg French
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    36,873
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #2 Rifledriver, May 27, 2025
    Why put in any positraction additive? Many make no noise without it and you do not know until you try. It inhibits syncro action so none is better.
    The transaxle holds on the order of 2 1/2 gallons of gear oil. 3 ounces is a drop in that bucket.
    Engine lid insulation. That foam rubber was not installed for any insulating properties. It was sound deadening for the North American market only. The ROW cars were black painted fiberglass and many US cars were delivered that way just like the US sound deadening found its way to other markets like yours. Clean it off and paint it black.
    Front hood use Mondial trunk struts. They actually have enough gas pressure to work.
    My cars, all of them have been using alcohol gas additive since it was mandated. I don't even think about it.
     
  3. raemin

    raemin Formula 3

    Jan 16, 2007
    2,307
    Lyon (FR)
    Full Name:
    R. Emin
    #3 raemin, May 27, 2025
    I've rebuilt my k-jets with ethanol compliant diaphragms. Also replaced the non ethanol compliant cohline braided fuel hose with cohline non braided but ethanol compliant hoses. As I was there I also replaced the injectors with the new type (metal is different), new filters and complete flush of the tanks. All in all that's not expensive, and an opportunity to review all the k-jet pressures. Car has been running on E10 (10% ethanol) for 3 years now.

    No horror story so far. I've opened the tanks last week in order to replace the fuel gauge sender, It's much more clean than what it used to be. Will keep on monitoring the aluminium tanks.
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,630
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #4 Steve Magnusson, May 27, 2025
    Last edited: May 27, 2025
    My particular ex-TR was very unhappy with the Redline 75W90NS, even with the friction modifier, and had an intolerable amount of LSD clutch chatter during low speed turns. I settled on using Ravenol VSG 75W90 GL-4/GL-5 Gold:

    https://www.ravenolamerica.com/gear-lube-transmission-differential-fluid/gear-oil-75w-90-gl-4-gl-5-ravenol-vsg/

    AFAIK, the best alternative found so far (and what I used) is an Aeroflex EPDM sheet insulation in a 1/2" (or 12mm) thickness:

    https://aeroflexusa.com/aeroflex-sheet-insulation/

    Its color is more a charcoal grey (than the stock light grey), but looks very OEMish/appropriate IMO. The biggest problem might be buying something less than a huge amount. I got a piece from Brian Crall so you might check with him to see if he still has more. Here's a thread/story showing my result:

    https://www.ferrarichat.com/forum/posts/147033546/
     
  5. jgmblair

    jgmblair Formula Junior
    Silver Subscribed

    May 27, 2010
    788
    Winnipeg, MB Canada
    Full Name:
    Jeff Blair
    #5 jgmblair, May 28, 2025 at 7:42 AM
    This is the most up to date info regarding struts for the front and rear on the testarossa, both readily available and reasonably priced if sourced from non-ferrari vendors like rock auto. The shorter front struts do have the increased lifting power like the Mondial ones suggested by Rifledriver. I just did mine 2 days ago and they are a perfect fit.

    https://www.ferrarichat.com/forum/threads/rear-decklid-struts.700014/

    Front - Stabilus 5B-1829BK
    Rear - Stabilus 4F-251003
     

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