The mathematics of the 8Vvs16V problem

[drew at scirocco.cs.uoguelph.ca (Drew MacPherson)]

I don't think the TDI pistons would fit in your 2L very well Patrick, 
given that they're 79,5mm and your 2L is 82,5mm.

The 1.9TD(i) is a stroker (95,5mm) like the 1.6D before it (which had a
76,5mm bore and 86,4mm stroke)

Drew


On Mon, 20 Oct 2003, Patrick Bureau wrote:

> thank you for this information...I really enjoyed reading it..
> 
> Now to get a TDI crank and pistons and add more torque bandwidth :)
> 
> 
> ATS - Patrick Bureau
> 
> 
> ->-----Original Message-----
> ->From: Jason Cammisa [mailto:jcammisa@alwaysonline.net]
> ->Sent: Monday, October 20, 2003 11:26 AM
> ->To: ATS - Patrick Bureau; _Scirocco Mailing List
> ->Subject: RE: The mathematics of the 8Vvs16V problem
> ->
> ->
> ->Heya Patrick,
> ->         Thanks for posting that graph.  Your torque curve illustrates
> ->exactly what I pointed out in my last mail:
> ->
> ->Even though your engine pushes out a very, very healthy peak of
> ->around 118
> ->lb-ft of torque to the wheels, it manages only 98hp.  Exactly as I said,
> ->the 8V concentrates its torque output down low in the rpm range - yours
> ->peaks at around 2700rpm.  This is ideal for a daily driver -- around town
> ->at leisurely rpms, your car is at its happiest.  It'll squirt off
> ->the line
> ->like a beast...
> ->
> ->As you can see though, the torque curve peaks early and then falls off
> ->gradually as you approach redline.  Horsepower is nothing more
> ->than torque
> ->at high rpms.  Since your car is making relatively little torque at high
> ->rpms, its Horsepower number is so much smaller.  Horsepower isn't my
> ->favorite number when used to gauge the overall driveability and
> ->feel of an
> ->engine, but it's the only number you need when you're talking
> ->about all-out
> ->acceleration.  At full-tilt, if geared correctly, a 240hp, 3000lb Honda
> ->with 180 lb-ft of torque will still be even with a 240hp, 3000lb V8 with
> ->double the torque.
> ->
> ->The reason why is simple:  Under full acceleration, you're between, say,
> ->4000rpm and redline all the time... save for the initial launch, which
> ->admittedly, if done properly, will be in that range, too.  Ignore what
> ->happens at low revs on your chart, and you'll see why a stock 1.8
> ->16V with
> ->the same gearing will outrun your car... it puts more torque down
> ->at those
> ->speeds and can rev 1000rpm more.
> ->
> ->Now, with that said:  Driving your car and driving that stock 1.8
> ->16V will
> ->feel completely different.  Let's say you and the 16V are puttering along
> ->in 2nd gear at 2500rpm next to each other, and you both realize that your
> ->two lanes are about to turn into one, and you both gun it.  The
> ->16V will be
> ->eating your hard-earned 8-Valve dust.
> ->
> ->Now, if you both kept your foot in it, the 16V would eventually catch up
> ->and walk away from you.  But your subjective impression from the
> ->short race
> ->will be of course, that your car is faster than a 16V.
> ->
> ->This is why I say quite clearly that the 8V is certainly not without its
> ->merits.  The 8V versus 16V war is certainly akin to the V8 and big
> ->displacement versus VTEC and revs debate, albeit on a lesser scale.  Flat
> ->out at the 1/4 mile, the VTEC Honda can keep up with the V8s.  The reason
> ->is because the high revving motor will let you take advantage of gearing,
> ->where the big V8 just pulls and pulls from low revs.  You have to work
> ->harder to keep up in the Honda, but if you do, you'll be rewarded
> ->with the
> ->same acceleration times as the big boys.
> ->
> ->So yes, your car will, without a shred of doubt in my mind, be a
> ->whole lot
> ->more fun around town than a 1.8 16V would.  Low-end torque is what the
> ->American public wants -- that's why we have Buicks with pushrod 3800
> ->V6s.  They give fantastic acceleration off idle and feel
> ->powerful, smooth,
> ->and fun -- until it's time to really get moving. When it comes to the
> ->stoplight race - or racetrack - or 1/4 mile track - or high speed
> ->race - or
> ->Autobahn cruise, all of that advantage is lost, and indeed a stock 16V
> ->would be faster than your fun-to-drive, torquey and happy built 8V.  It's
> ->just a matter of physics... not me trying to diss ya!
> ->
> ->Jason
> ->
> ->
> ->
> ->
> ->
> ->
> ->
> ->At 10:40 AM 10/20/2003, ATS - Patrick Bureau wrote:
> ->>jason how about this 8v (mine) I think my torque curve is quite
> ->broad, you
> ->>got 133ft'lbs, I got 118ft'lbs torque and in the same manner of
> ->the 16v it
> ->>instersecs the HP curve. stock JH head and 2L bottom end with
> ->only a g Grind
> ->>in it.
> ->>
> ->><http://www.longcoeur.com/scirocco/various/dyno/dyno%5Fatsgtx01%2EJPG>
> ->>
> ->>is this what you where looking for ? or perhaps I did not understand the
> ->>question.
> ->>
> ->>
> ->>
> ->>ATS - Patrick Bureau - txrocco@sbcglobal.net
> ->>----------------------------------------------
> ->>MSN:ATSGTX@hotmail.com |YAHOO:ATSGTX@yahoo.com
> ->>ICQ:32918816           |AIM:Texasscirocco
> ->>----------------------------------------------
> ->>
> ->>
> ->>=>-----Original Message-----
> ->>=>Case in point, please see the following curve:
> ->>=>http://www.scirocco16v.org/dyno/16V.jpg
> ->>=>This is a dyno plot from one of our veteran list members.
> ->It's a 2.0 16V
> ->>=>with a slightly P+P and shaved head; Schrick 260/276 cams, and an
> ->>=>exhaust.  That's a relatively stock motor in my book -- the
> ->entire bottom
> ->>=>end is completely stock.
> ->>=>
> ->>=>You'll see that not only does it peak out at 144whp and almost
> ->133 lb-ft
> ->>of torque, but the torque curve itself is tremendously broad and
> ->>=>beefy:  This engine puts more than 120 lb-ft of torque to the
> ->wheels from
> ->>3000 until 6250rpm.  That is a simply awesome number from a 2-liter
> ->>engine... and
> ->>=>flies directly in the face of any complaints of the 16V being
> ->a dog down
> ->>low.   And further, this particular motor puts down about the same torque
> ->>=>at 2000rpm that the 1.8 16V does at its peak -- just under 100 to the
> ->>wheels -- which is, as we know, more torque than any VW 8V motor
> ->>=>(including the ABA) did from the factory.  So there's
> ->monumental high-rpm
> ->>power (VR6 territory) with low rev torque besting all other VW
> ->4-cylinders.
> ->>=>You just can't do that in an 8V VW motor.
> ->>=>
> ->>=>http://neubayern.net/mailman/listinfo/scirocco-l
> 
> 
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