[928uk] Advice and parts - intake tubes
Paul R Smith
smiffypr at gmail.com
Sat Jun 8 19:06:01 UTC 2024
Correct, from the 1981 service tech info:
"These tubes are now designed as venturi nozzles to effectively dampen
the engine’s intake noise.
Due to the aerodynamic shape the air stream is not restricted.
Sound waves, which are pressure impulses from the engine against the
direction of air stream flow,
are reflected “inward” on the inside walls of the tapered nozzles and
prevented from reaching the
intake opening in the car’s front end.
As on earlier models air is drawn from housing (2) through opening (1)
for cooling of the toothed
belt (3)."
I suspect only test equipment can detect the difference in the noise.
Smiffy
On 08/06/2024 19:42, Ben Hodges wrote:
> Isn’t the Venturi shape of the plastic ones an attempt to reduce noise
> too?
>
> On Sat, 8 Jun 2024 at 18:48, Simon Crowe via 928uk
> <928uk at lists.928.org.uk> wrote:
>
> I could never hear any difference between the plastic on my S4 and
> the foam on my GTS.
>
> When they did finally fall apart (I think the inner wires rusted
> heavily and the foam detached itself) I bought a pair of
> plastic/rubber hoses from an Italian company, specially designed
> for the 928. A perfect fit and I still have them.
>
>
>
> > On 8 Jun 2024, at 18:15, Paul R Smith via 928uk
> <928uk at lists.928.org.uk> wrote:
> >
> > According to PET, they started in 1987 for Switzerland, 1992
> for all markets.
> >
> > Smiffy
> >
> >> On 08/06/2024 17:25, phil rick via 928uk wrote:
> >> learn something new every day, i thought the crap foam hoses
> only came with
> >> the GTS, but must have started on the 91 model year
> >>
> >> On Sat, Jun 8, 2024 at 5:21 PM jonathanrackowe--- via 928uk <
> >> 928uk at lists.928.org.uk> wrote:
> >>
> >>> Oh yes, thanks, I'd forgotten that. Can't say I noticed any
> difference in
> >>> noise level when I fitted the Samco silicone tubes, but maybe
> that's due to
> >>> my de-catted custom exhaust system! :-D
> >>>
> >>> Best regards,
> >>> Jonathan
> >>>
> >>> West London, England
> >>>
> >>> 1991 928 GT Amethyst Metallic with Blueflame custom exhaust
> and Porsche
> >>> 18" Sport Design wheels
> >>>
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: 928uk<928uk-bounces at lists.928.org.uk> On Behalf Of Paul
> R Smith
> >>> via 928uk
> >>> Sent: 08 June 2024 15:24
> >>> To:928uk at lists.928.org.uk <mailto:To%3A928uk at lists.928.org.uk>
> >>> Subject: Re: [928uk] Advice and parts - intake tubes
> >>>
> >>> The official reason for the foam hoses was to reduce noise:
> >>> "All 928 GTS vehicles are fitted with noise-reducing intake
> hoses of the
> >>> same type used previously on export vehicles
> >>> for Switzerland."
> >>> From the 1992 service tech info document.
> >>>
> >>> Smiffy
> >>>
> >>> On 08/06/2024 14:07, jonathanrackowe--- via 928uk wrote:
> >>>> My 928 GT has a pair of Samco SHL77 Silicone Hoses 77x640mm
> installed -
> >>> that
> >>>> I fitted back in 2006. They're still perfect.
> >>>>
> >>>> The foam hoses that Porsche fitted to the 928 GT and GTS were
> rubbish!
> >>> The
> >>>> insulation was intended to keep the intake air cool, but it
> disintegrated
> >>>> badly. Given the speed of the air rushing into the 32V V8
> engine I doubt
> >>>> that the foam hoses made any significant difference to the
> intake air
> >>>> temperature anyway.
> >>>>
> >>>> Best regards,
> >>>> Jonathan
> >>>>
> >>>> 1991 928 GT Amethyst Metallic
> >>>>
> >>>>
> >>>>
> >>>> -----Original Message-----
> >>>> From: 928uk<928uk-bounces at lists.928.org.uk> On Behalf Of Ian
> Marsh via
> >>>> 928uk
> >>>> Sent: 07 June 2024 16:06
> >>>> To: 'Cengiz Ali'<cengizali at btinternet.com>; '928 List'
> >>>> <928uk at lists.928.org.uk>
> >>>> Subject: Re: [928uk] Advice and parts
> >>>>
> >>>> Cen,
> >>>>
> >>>> I can't help with much of what you require but I gave up
> looking for
> >>> decent
> >>>> intake tubes and bought a pair of Mercedes Tubes modified to
> fit 928's
> >>> from
> >>>> Roger and 928rus.
> >>>>
> >>>> The genuine Porsche replacements were about twice the price
> in in my
> >>> opinion
> >>>> inferior in design.
> >>>>
> >>>> Hope this helps
> >>>>
> >>>> Regards
> >>>>
> >>>> Ian
> >>>>
> >>>> Ian J Marsh
> >>>> Regional Organiser
> >>>> 07976 242344
> >>>> West Country Region
> >>>>
> >>>>
> >>>>
> >>>> -----Original Message-----
> >>>> From: 928uk<928uk-bounces at lists.928.org.uk> On Behalf Of
> Cengiz Ali via
> >>>> 928uk
> >>>> Sent: Friday, June 7, 2024 4:01 PM
> >>>> To: 928 List<928uk at lists.928.org.uk>
> >>>> Subject: [928uk] Advice and parts
> >>>>
> >>>> Hi All,
> >>>>
> >>>> It was good to see some of you at Simply last weekend.
> >>>>
> >>>> A few things please:
> >>>>
> >>>> Does anyone on the list know if the warning triangle
> originally came in a
> >>>> storage bag (similar to the jack)? If so are they available
> or does
> >>> anyone
> >>>> have one they are willing to sell?
> >>>>
> >>>> Also, I have an old Porsche tyre inflator, the one that is in
> its own
> >>> black
> >>>> plastic box and runs off the cigarette lighter. It runs but
> is pretty
> >>> weak
> >>>> and not producing enough air to fill a tyre, can these be
> repaired?
> >>>>
> >>>> Also, does anyone have a very good black plastic intake pipe
> that runs
> >>>> either side of the air box to the front of the car ducts they
> want to
> >>> sell?
> >>>> Many thanks
> >>>> Cen
> >>>> S2 auto 86.5
> >>>>
> >>>>
> >>>
>
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