The mathematics of the 8Vvs16V problem

[mr.utility at highstream.net (mr.utility@highstream.net)]

A very well thought-out comparision of both engines in the real world...  I 
thank you for the illustration....

David              fahrvegnugen

Quoting Jason <jason@scirocco.org>:

> 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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