[s-cars] Exhausts

Tue Dec 8 16:18:21 PST 2009

Taka you are thinking of the boundary layer FYI, and you are right. On a 
dual system you are going to lose more there as well as have more welds 
impeding on joints (unless it's good TIG work) causing an even larger 
boundary layer. I'd say, without doing any math, that in reality a dual 2.5" 
is roughly equal in flow to a single 3". I still like a dual 2.5" because 
you can tuck it up closer to the driveshaft and gain ground clearance. For 
my car I'd do a dual 2.75".

-Cody

--------------------------------------------------
From: "Taka Mizutani" <t44tqtro at gmail.com>
Sent: Monday, December 07, 2009 5:48 PM
To: "Robert Myers" <bob at chips-ur-s.com>
Cc: <s-car-list at audifans.com>
Subject: Re: [s-cars] Exhausts

> The OE system is not 2.5" per tube, IIRC.
>
> Also, with a single vs. dual setup, you also have to take into account
> losses from wall friction or whatever it's called.
>
> That said, I don't think the Stromung flows any better than the OE system-
> you need to go to a 3.5" setup to really see big gains, but you will at 
> the
> expense of a lot more sound.
>
> Taka
>
>
> On Mon, Dec 7, 2009 at 5:25 PM, Robert Myers <bob at chips-ur-s.com> wrote:
>
>> *This message was transferred with a trial version of CommuniGate(r) Pro*
>>
>> Do the cross sectional area calculation for one 3 inch diameter tube
>> vs.  two two and a half inch tubes.  The dual system wins out.
>> 9.82 vs. 7.06 square inches.
>>
>>
>>
>> Bob
>>
>>
>> At 05:16 PM 12/7/2009, pmische wrote:
>> >*This message was transferred with a trial version of CommuniGate(r) 
>> >Pro*
>> >Has anyone actually done a Stromuuuung v. OEM back-to-back on the dyno?
>>  I'd
>> >love to see the data.
>> >
>> >I will say the Stromung does seem to deliver better throttle response
>> (hard
>> >to measure that), and there's that unbeatable, unquestionable sonorous
>> >mellifluousity...
>> >
>> >PJM
>> >
>> >-----Original Message-----
>> >From: s-car-list-bounces at audifans.com
>> >[mailto:s-car-list-bounces at audifans.com] On Behalf Of djdawson2 at aol.com
>> >Sent: Monday, December 07, 2009 4:58 PM
>> >To: dlandaeta at gmail.com; alexander_witham at yahoo.com
>> >Cc: s-car-list at audifans.com
>> >Subject: Re: [s-cars] Exhausts
>> >
>> >
>> >
>> >"...and allows for 'real' tuning that requires moving a lot of exhaust
>> >- of course, it's nice to move a lot of air on the intake side as well!"
>> >
>> >
>> >
>> >Just to be clear... an exhaust like the Stromung, while they do sound 
>> >very
>> >nice, is certainly not required to do "real" tuning or to extract big
>> >horsepower from the I-5 20v engine.  Dyno tests have proven on more than 
>> >a
>> >few occasions that the OE exhaust is not limiting power output, and
>> >installing an aftermarket unit does not improve power output.  That is
>> fact.
>> >
>> >What you are buying is a cool sound, less weight, and fewer parts.
>> >
>> >Dave
>> >
>> >
>> >
>> >
>> >
>> >-----Original Message-----
>> >From: Douglas Landaeta <dlandaeta at gmail.com>
>> >To: alexander witham <alexander_witham at yahoo.com>
>> >Cc: s-car-list at audifans.com
>> >Sent: Mon, Dec 7, 2009 1:59 pm
>> >Subject: Re: [s-cars] Exhausts
>> >
>> >
>> >Alexander,
>> >
>> >Stromung. Nice quiet low thudding on idle in a confined space, (rattles
>> old
>> >house windows from the driveway) but cruises very quietly, until full
>> >throttle boosts just open up and create a low throaty roar that is
>> >uncomparable for an Audi - almost P-car like. The tuning of the sound is
>> >excellent and allows for 'real' tuning that requires moving a lot of
>> exhaust
>> >- of course, it's nice to move a lot of air on the intake side as well! 
>> >Do
>> >the bigger turbo as a package and your 'tuner' can customize chips to 
>> >pull
>> >all the performance out of the package. 'll let others describe ther
>> >versions - Mine's from 2004 or '05, generation IV, I think.
>> >Yes, the lower attaching bracket is broken at the weld joint, but it 
>> >gives
>> >me no trouble and I hear that the latest version with a flex pipe has
>> fixed
>> >that issue.
>> >
>> >Doug
>> >94 'S4 rolling over 25k miles on the Stromung
>> >
>> >On Mon, Dec 7, 2009 at 3:29 PM, alexander witham <
>> alexander_witham at yahoo.com
>> > > wrote:
>> >
>> > > Hi all,
>> > >
>> > > So, I just picked up another UrS6 and I love it. I'd been toying with
>> the
>> > > notion of doing exhaust on my previous 2 UrS cars and looked into it
>> >pretty
>> > > seriously before backing off due to financial constraints.
>> > >
>> > > Well, the urge is back and I thought I would pick your brains as to
>> what
>> > > the best course of action is. In case it's relevant, the car is
>> currently
>> > > equipped with K&N, MTM Stage +, and RS2 exhaust manifold.
>> > >
>> > > I'm looking for a pretty aggressive sound that's really going to 
>> > > bring
>> out
>> > > the I5's bark. But I don't want that highway droning that's so common
>> with
>> > > aftermarket systems.
>> > >
>> > > So what do you folks recommend?
>> > >
>> > > Thanks,
>> > >
>> > > Alex
>> > >
>> > >
>> > >
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