'89 328 intake to airbox hose...RifleD? | FerrariChat

'89 328 intake to airbox hose...RifleD?

Discussion in '308/328' started by mike996, Feb 21, 2020.

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  1. mike996

    mike996 F1 Veteran

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    #1 mike996, Feb 21, 2020
    Was wondering what RifleDriver recommends for the intake-to-airbox hose on the '89 328. The foam in my original hose deteriorated some years ago and I used a piece of black clothes dryer hose in it's stead. It works fine, of course, but it doesn't look all that great!

    So I'm curious, RD,, what do you typically use to replace the original foam-covered hose when folks bring their '89's to you for service?
     
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  2. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #2 Rifledriver, Feb 22, 2020
    Same as you. A friend in Florida makes a beautiful concours correct replacement but it is very expensive and for normal use few find the expense worth it. I typically install Dayco wire reinforced plastic duct hose. Its black and not too noticeable. It fits great and can be removed and reinstalled without damage unlike the foam covered hose.

    Ferrari was fighting increasingly rigid noise regulations in Sweden and Switzerland and to a lesser degree the USA. Thats why the hose change.
     
  3. Freddie328

    Freddie328 Formula Junior

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    #3 Freddie328, Feb 25, 2020
    I used a piece of flexible air duct that I carefully wrapped with a sheet of Sticky backed Armaflex. Join at the bottom, so it can’t be seen.
    Same with the oil cooler duct.
    Not perfect, but much better than what was on there.
     
  4. mike996

    mike996 F1 Veteran

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    #4 mike996, Feb 25, 2020
    I thought about trying to find the hard parts that the pre-89 used but then decided it was a waste of money. It doesn't actually work any better that a piece of hose and, originality-wise, it would still be wrong. I will change the type of hose I'm using to the Dayco RifleD suggested, which looks better than what I've been using and that will be the end of that...
     
  5. yelcab

    yelcab F1 World Champ
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    #5 yelcab, Feb 25, 2020
    If you find the Dayco hose to work well, please post the part number.
     
  6. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #6 Rifledriver, Feb 25, 2020
    Sorry, wrong brand. Its Gates 23864.
     
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  7. Mule

    Mule F1 Rookie
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    #7 Mule, Feb 25, 2020
  8. mike996

    mike996 F1 Veteran

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    #8 mike996, Feb 25, 2020
    The hose from aircraft spruce is really good quality, of course, but I prefer solid black color of the Dayco.
     
  9. Freddie328

    Freddie328 Formula Junior

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    #9 Freddie328, Feb 25, 2020
    The hose on these cars was originally insulated, well at least mine was as was the oil cooler duct. Gimmick or not I guess the idea was to keep intake air unduly rising in temperature whilst in traffic etc.
    Also, the ribbing in some of these alternative hoses is quite significant, which causes pressure drop.
    So technically, a smooth bore insulted hose is the best option.
    Just my opinion!
     
  10. mike996

    mike996 F1 Veteran

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    #10 mike996, Feb 25, 2020
    As stated earlier in this thread, the reason for the insulated air intake hose was for noise reduction. US regs - and perhaps other countries as well - required a 3db reduction in intake noise for 1989. The earlier 328 ducting could not meet the regs. Ferrari was clever, they found that insulated hose was an easy and cheap (at the time) way to drop intake noise by 3db.
     
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  11. Freddie328

    Freddie328 Formula Junior

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    #11 Freddie328, Feb 25, 2020
    I take your point, but why was the oil cooler hose also insulated unless there is some benefit to keeping the air cooler?
     
  12. mike996

    mike996 F1 Veteran

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    #12 mike996, Feb 25, 2020
    There is, of course, benefit to having cooler intake air but if you look at the path for the intake air, the 'heat' exposure of the hose or duct between the outside intake and the airbox is insignificant compared to the run of the air from the airbox through all the heat soaked metal of the KJet system, the heat-soaked hose between it and the heat-soaked throttle bottle and then the heat soaked intake manifold itself.

    The advantage of cooler intake air was well known long before Ferrari ever made a car and if there had been an advantage in heat-insulating that short run between the 3x8 outside air duct and the airbox, they could have used the less expensive insulated hose from the beginning on the 3x8 FI engines.

    I don't know about the oil hose you mentioned but the air hose and the reason for it is documented in Ferrari docs and US regs pertaining to 1988 vs 1989 noise requirements. I posted references to the docs here probably 8-10 years ago; a search might locate them.
     
  13. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #13 Rifledriver, Feb 25, 2020
    The intake hose has about 3 times the flow capacity of the throttle body.

    The intake hose design was about noise reduction. Not an opinion.
     
  14. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #14 Rifledriver, Feb 25, 2020
  15. Rosey

    Rosey F1 Rookie

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    #15 Rosey, Feb 25, 2020
  16. JohnnyTS

    JohnnyTS Formula Junior

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    #16 JohnnyTS, Feb 27, 2020
    yeah ! that's the stuff I used, it's similar to rubber foam just more black and I also used black duct tape to close/seal and turned towards the bottom, it came out very nice !
     
  17. Mule

    Mule F1 Rookie
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    #17 Mule, Feb 27, 2020
    Installed it about 17 years ago when the original went to dust. The black one was not really known yet. Never bothered to change it for the black one.

    One thing of note on any new hose. There are some sharp brackets in there, so be careful the new hose does not get a hole rubbed through it.
     
  18. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    #18 Dr Tommy Cosgrove, Feb 27, 2020
    I understand the reasoning based on governmental sound laws

    But doing this on a Ferrari is about like telling your wife or girlfriend to keep it down during sex.
     
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  19. Rosey

    Rosey F1 Rookie

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    #19 Rosey, Feb 27, 2020
    Definitely the girlfriend !! Who has noisy sex with their wife ??!! :) :)
     
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