[s-cars] Re: wrt pushing RS2 to the edge...
Bruce Mendel
brucem105 at comcast.net
Sat May 10 14:17:56 EDT 2003
Exactly.....at certain heat/octane/negative conditions, whatever more power
is dialed in gets dialed back out by the ECU via timing or boost retard due
to negative engine conditions.
Since it's almost always heat that is the culprit, a lot of folks go with
bigger FMICs or water injection.
B
----- Original Message -----
From: "Calvin & Diana Craig" <calvinlc at earthlink.net>
To: "Mihnea Cotet" <mik at info.fundp.ac.be>; <QSHIPQ at aol.com>;
<robert at s-cars.org>; <pizzoman at yahoo.com>; <s-car-list at audifans.com>
Sent: Saturday, May 10, 2003 1:01 PM
Subject: RE: [s-cars] Re: wrt pushing RS2 to the edge...
> Mihnea,
>
> You say more boost=more torque. Yes, if you discount heat. What we are
> really interested in here is n in the old equation PV=nRT. So you can
> increase cubes, pressure, or decrease temp. What doesn't gain you
anything
> is increasing pressure and temperature from a heat soaked IC at the same
> time. I am sure you meant boost = torque WHEN the temp. stays the same,
> right? I think what some people are arguing here is that you might be
> peeing in the wind with the extra 2-4psi because the rest of the system
> can't handle it efficiently from either a flow perspective or a heat
> perspective. I don't know. I run a stock S4 so I have no experience at
28
> psi boost levels with these particular cars, but I am 100% sure there is a
> point where more boost does not equal more torque because of the
> aforementioned circumstances.
>
> --Calvin
>
>
> -----Original Message-----
> From: s-car-list-admin at audifans.com
> [mailto:s-car-list-admin at audifans.com]On Behalf Of Mihnea Cotet
> Sent: Saturday, May 10, 2003 10:43 AM
> To: QSHIPQ at aol.com; robert at s-cars.org; pizzoman at yahoo.com;
> s-car-list at audifans.com
> Subject: Re: [s-cars] Re: wrt pushing RS2 to the edge...
>
>
> Scott et al.,
>
>
> 28 psi *does* gain over 26 or 21 in terms of torque IMHO/IME (I can't but
> exist on the Experience part, especially in tuning myself a few RS2
engines
> recently).
>
> And, I know of several RS2s running 28 psi (i.e. almost 2 Bar boost or PR)
> overboost for a massive 530-540 Nm of torque (dyno measured), while stock
> RS2 torque is 420 Nm at max. 1.4 Bar. I know 28 psi isn't efficient, but
> for torque no one needs 100% efficiency. So what does your statement of 28
> psi being almost double the factory boost levels mean? Stock AAN boost?
> Maybe, okay but what's the point? What's the point in comparing apples
with
> oranges?
>
> So, sorry to insist, boost means torque and if timing is properly
> programmed (sorry to insist on that point again), 28 psi will be a lot of
> times better than 21, I've personnally BTDT many times.
>
> Then, according to several serious tuners here in Europe (what do you say
> of Dupre Motorsport's racing engine management director during the 90's?
> He's the guy that helped me with most of what I know about chip tuning),
> stock rods (including the crappy AAN units which are the worst Audi ever
> used, i.e. the thinnest) are known to break at 600 Nm crank torque,
meaning
> in excess of 2.5 Bar or PR. This also means that running 30 psi (or 2.0
Bar
> or PR) won't break rods, except if the timing/fuel chip is done by an a$$
> and if knock sensor function is suppressed or the threshold raised.
>
> Furthermore, maximum boost people are stating doesn't mean anything to me
> in terms of HP, what boost levels are you guys seeing at 5500, 6000, 6500
> and 7000 RPM? This is more relevant than maximum boost you see for a few
> seconds during overboost.
>
> HTH and my 0.02 Euro,
>
> Mihnea
>
> At 12:27 10/05/2003 -0400, QSHIPQ at aol.com wrote:
> >Hmmm... I personally think running 28psi on an S-car is silly (I'd say
> >stupid, but long nerdy posts about effective compression ratios I don't
> >need). IMO, you are "safer" increasing the Density Ratio than the
> >Pressure Ratio. I'd also venture to say that 28psi probably isn't
gaining
> >any performance over 26psi, which means Motronic is probably saving a lot
> >of butts here. I'd also venture to say that the difference between 24psi
> >and 26 psi is barely measureable. I'd also venture to say that the
> >difference beyond 21 psi (RS2 equipped only) comes at a massively
> >diminishing rate of return.
> >
> >I'd further venture to say that rods are known to pop at 30psi, which
> >means the closer you get to it, the higher the danger.
> >
> >All anecdotal "evidence" so noted, 28psi is almost double the factory
> >boost levels. For street driving, probably not there long enough to
worry
> >about it. The long straight and intense 30minute track session? I'd be
> >worried about it.
> >
> >Boost, specifically Pressure Ratio, is only part of the equation in
tuning
> >for performance gains. Cars *can* run at maximum parameters, but small
> >hiccups in any of the ancillary systems can cause catastrophic failures
> >because of boost. The good news Joe, is that you can respond in the
> >"takes one to know one" concept. Specifically, if it's stupid to run
> >28psi, in reality, with no other changes, it's really no "smarter" to run
> >it with race gas.
> >
> >HTH and my .02
> >
> >Scott Justusson
> >
> >
> >In a message dated 5/10/2003 8:07:52 AM Central Daylight Time,
> >mik at info.fundp.ac.be writes:
> >
> >Joe,
> >
> >Someone stating 28 psi without race gas on an RS2 motor is stupid simply
> >doesn't know what this motor/turbo is. Period.
> >Then, you can log timing advance and IAT with VAG-COM, I don't remember
> >where exactly but you can.
> >
> >HTH,
> >
> >Mihnea
> >
> >At 05:00 10/05/2003 -0400, Robert Myers wrote:
> > >--
> > >[ Picked text/plain from multipart/alternative ]
> > >At 08:16 PM 5/9/2003 -0700, Joseph Pizzimenti wrote:
> > >
> > >>Well, this was sparked by a rather vocal argument I
> > >>had with someone about water injection recently. I
> > >>was asking his advice and he has experience with B5
> > >>S4's and 3000GT VR-4's, etc...he basically said I was
> > >>stupid to run 28psi without race gas.
> > >>
> > >>Is there any way I can datalog ignition timing or
> > >>intake air temperature with VAG-COM?
> > >>
> > >>Joe
> > >
> > >
> > >I dunno, Joe, but I betcha you could get an answer on the VAG-COM list.
> > >
> > >Mailing-List: list VAG-COM at yahoogroups.com; contact
> > >VAG-COM-owner at yahoogroups.com
> > >
> > >
> > >
> > >
> > >____
> > >
> > >I've been wondering... Who would Jesus bomb?
> > >
> > >Bob
> > >*****
> > > Robert L. Myers 304-574-2372
> > > Rt. 4, Box 57, Fayetteville, WV 25840 USA WV tag Q SHIP
> > > '95 urS6 Cashmere Grey - der Wunderwagen ICQ 22170244
> > > http://www.cob-net.org/church/pvcob.htm
> > >*****
> > >--
> >
>
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