Re: Interesting Reading regarding 2.9 vs. 2.8 VR6 from C list

["S. Joseph Mann" <joem@pswtech.com>]

Do you have Dave Baker's email address??  I would be very interested to know
what he thinks of Audi's 5 valve design.  Which we now see in the new Passat in
both the V-6 and 1.8T.  And very soon you will see the 1.8T in the new Jetta,
Golf and Beetle.

Joe


ken r weidmann jr. wrote:

> Ken Weidmann Jr
> GLXTASY@Juno.com
> Checkered Flag Automotive Components
> 95 Black Jetta GLX M3 wannabe
> 85 Show Scirocco
> --------- Begin forwarded message ----------
> From: lleff@imisys.com
> To: glxtasy@juno.com, jdw8@po.CWRU.Edu
> Subject: Interesting Reading
> Date: Mon, 12 Oct 1998 10:29:22 -0400
> Message-ID: <8525669B.004F6144.00@smtpmail.imisys.com>
>
> Hmmmm... Some of this post (from the C list) is rather interesting.
> Especially when you consider that I'm now getting 183hp (wheel) from my
> 2.9l.  Also, it seems as though our 15% driveline loss estimate is pretty
> dead-on.
>
> Read on, Bruthas -
>
> Date: Fri, 9 Oct 1998 10:47:53 -0400
> From: Vincent Shek <vincent@algorithmics.com>
> Subject: [VR6] 2.8l vs 2.9l
>
> I found an interesting post on the vw newsgroup from an engine builder
> in England:
>
> -
> ---------------------------------------------------------------------------
> ---
> (beginning of original message)
>
> >Subject: Re: VR6 2.8 VS 2.9?
> >From: racerbob911@my-dejanews.com
> >Date: 02/10/98  19:43  BST
> >  "dave.leahy" <dave.leahy@mci2000.com> wrote:
> >  Does anyone know the difference between 2.8 and 2.9? As many specifics
> as
> >  possible please. TIA, Dave
> >
> >        AAA engine - 174 bhp (europe) 81.0 mm bore - 90.3 stroke 2792 cc
> >        10.0:1 CR
> >
> >        ABV engine - 190 bhp (europe) 82.0 mm bore - 90.3 stroke 2861 cc
> >        10.0:1 CR   bigger throttle plate - revised ECU programming.
> Some
> of
> >        the horsepower difference is due to a different exhaust system
> on
> >        the synchro.
>
> In my experience and those of colleagues with dynos there is very little
> difference in power between the two engines. 2.8s show perhaps high 160s
> bhp
> and 2.9s show low to mid 170s. At the driving wheels perhaps 140 bhp
> from the
> 2.8 and 145 bhp for the 2.9 with 25-28 bhp transmission losses.
>
> The engines were rated at 174PS (172bhp) 2.8 and 192PS (189 bhp) for the
> 2.9.
> Common sense alone would indicate that 70cc increase in capacity does
> not make
> an extra 17 bhp when the engines are otherwise identical internally.
> That would
> be a power gain of 240 bhp per litre of extra capacity.
>
> If anyone has accurate dyno data to either confirm or refute the above I
> would
> be interested. Preferably engine dyno data unless you have some
> particular reason to believe that your wheel dyno is dead accurate.
>
> As an aside the V6 is a horrible engine  from the design point of view
> with insufficient valve area, poor low rpm torque and weird port design.
> Very
> hard to get any decent power per litre out of it without spending a
> fortune.
>
> Both the  8 valve and 16 valve have always suffered from similar
> breathing restrictions. They both have less valve area per litre of
> capacity than
> nearly all other modern engines and pathetic port design. If any of you
> VW
> enthusiasts want to see a properly designed engine have a look at the 16
> valve
> Peugot M16 engine. 160 bhp from 1.9 litres in standard trim back in the
> late 1980s.
> 34.6mm inlet valves compared to 32mm for the VW. Even better is the new
> 2.0
> litre iron block engine in the Citreon Xsara.
>
> 275 bhp is possible in road tune with modified head, cams and 4
> butterfly throttle body system. Try getting that from a VW.
>
> It's about time VW designed some proper engines with a bigger
> bore/stroke ratio and more valve area. Other manufacturers seem to
> squeeze larger bore
> engines into front wheel drive without problems.
>
> My favourite big capacity engine: the Opel Monza 6 pot 3 litre. 95mm
> bore, 69.8mm stroke, 37mm inlet valves. Easily stretched to 4 litres and
> 300
> bhp plus in road trim. Bullet proof bottom end, revs like a banshee, goes
> like stink. Bring back rear wheel drive.
>
> Dave Baker at Puma Race Engines (London - England)  - specialist flow
> development and engine work.
>
> (end of original message)
> -
> ---------------------------------------------------------------------------
> ---
> >From another of his post:
>
> I'm considering designing and having made a batch of big inlet valves
> for the VR6 at 41mm or perhaps 42mm. It depends on what size works best
> on the
> flowbench in the end. If anyone is interested post on here and if demand
> is high enough I'll do it. Most of the valves I see around are not
> designed
> right for flow or are of poor material quality or inaccurate dimensional
> tolerances.
>
> By the way - on the VR6 - I'll put the before and after power figures
> too. The customer has already had the car dynoed independently at 145 bhp
> wheel
> figure (170 flywheel). This is the 2.9 engine and from my (and others)
> experience the claimed 192 PS is rubbish. The engines are basically
> identical apart
> from 70cc capacity and theres no way that makes 20 bhp difference. I
> would rate
> the 2.8 engine at 165 to 170 bhp and the 2.9 at 170 to 175 bhp.
>
> Transmission losses are about 25 bhp. If anyone has other data I would
> be most
> interested.
>
> Dave Baker at Puma Race Engines (London - England)  - specialist flow
> development and engine work.
> -
> ---------------------------------------------------------------------------
> ---
>
> Interesting huh?
>
> --------- End forwarded message ----------
>
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