[928uk] Advice and parts - intake tubes
Simon Watson
simonwatson at unitelconsultants.co.uk
Sat Jun 8 20:31:38 UTC 2024
Intake noise is good! In my opinion. And on BMW M3 e46 cars when fitted with the CSL air box. It sounds amazing!
Thanks for the information Smiffy, I never knew that and had always wondered why the 928 has the strangely shape tubes.
Best Simon
Sent from my iPhone
> On 8 Jun 2024, at 20:07, Paul R Smith via 928uk <928uk at lists.928.org.uk> wrote:
>
> 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
>> >>>>
>> >>>>
>> >>>
>>
More information about the 928uk
mailing list