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What's the fastest can ever take your Scirocco? - more numbers



Here are some more numbers:
Don's kid's finding:
<<http://www.perry-lake.k12.oh.us/phs/Classdept/ScienceDept/Physics/ClassTop
ics/friction/car_topspeed.html>>
F = (0025) x Cd x A x V^2
P = (.0027) x F x V

<<http://elf.sqush.net/car2.html>>
MKII Scirocco has an advertised Cd of 0.38
A = 18.3 square foot = 1.7001256 square meter = 1.7

<<http://www.performancetrends.com/PDFs/DRAMan4.pdf>>
page 33 "For a realistic Cd, add .03 to .05 to the advertised Cd."
Cd = 0.38 + 0.04


You mix both formulas (F and P):
P = (.0027) x ( (.0025) x Cd x A x V^2 ) x V

P = 0.00000675 x Cd x A x V^3

You plug in the numbers:
P = 0.00000675 x 0.42 x 18.3 x V^3

P = 0.00000675 * 7.686 * V^3

P = 0.0000518805 * V^3 where 0.0000518805 = ( 1 / 18275 )

P = V^3 / 18275

So for a speed of 124 MPH, you need:

P = 104.33 (Wheel HP)

Does it make sense?

Cheers.

Marc
'83 Scirocco
'97 A4

> -----Message d'origine-----
> De : Don Walter [mailto:dswalterwi@earthlink.net]
> Envoy? : lundi 8 mars 2004 17:33
> ? : Marc_Scirocco_Qu?bec; Dan Bubb; Patrick Bureau; 'Drew MacPherson';
> 'reptilis'
> Cc : 'scirocco'
> Objet : What's the fastest can ever take your Scirocco?
>
>
> I gave my 14 year old son the task of finding how to comute this
> and darned if he didn't find this for you:
>
> <http://www.perry-lake.k12.oh.us/phs/Classdept/ScienceDept/Physics
> /ClassTopics/friction/car_topspeed.html>
>
> It is an excellent web site on the topic.
>
> Don
>
>
> -----Original Message-----
> From: Marc_Scirocco_Qu?bec <marc_scirocco@sympatico.ca>
> Sent: Mar 7, 2004 9:09 AM
> To: Dan Bubb <jdbubb@ix.netcom.com>, Patrick Bureau <ats@longcoeur.com>,
> 	'Drew MacPherson' <drew@scirocco.cs.uoguelph.ca>,
> 	'reptilis' <reptileis@comcast.net>
> Cc: 'scirocco' <scirocco-l@scirocco.org>
> Subject: RE: what's the fastest you've ever taken your Scirocco?
>
> The specs for a MKII 8V are a cd of 0.38, and a frontal area of
> 18.3 square
> feet.
>
> Anybody knows the math to compute how much hp are needed to pull
> a Scirocco
> at, say 120 MPH?
>
> Cheers.
>
> Marc
> '83 Scirocco
> '97 A4
>
> > -----Message d'origine-----
> > De : scirocco-l-bounces@scirocco.org
> > [mailto:scirocco-l-bounces@scirocco.org]De la part de Dan Bubb
> > Envoy? : dimanche 7 mars 2004 11:56
> > ? : Patrick Bureau; 'Drew MacPherson'; 'reptilis'
> > Cc : 'scirocco'
> > Objet : Re: what's the fastest you've ever taken your Scirocco?
> >
> >
> > I thought you had a 4K gearbox??
> > That would have a 3.94 final drive and 6600 RPM would net 129MPH.
> >
> >
> > ----- Original Message -----
> > From: "Patrick Bureau" <ats@longcoeur.com>
> > To: "'Drew MacPherson'" <drew@scirocco.cs.uoguelph.ca>;
> > "'reptilis'" <reptileis@comcast.net>
> > Cc: "'scirocco'" <scirocco-l@scirocco.org>
> > Sent: Sunday, March 07, 2004 9:31 AM
> > Subject: RE: what's the fastest you've ever taken your Scirocco?
> >
> >
> > > Humm glad the system is back out,
> > >
> > > Tested my numbers...against the computer gear thing.
> > > Rememebr I recalled it sbeing 240KPH/150MPH @ 6600 RPM, well
> > seems that WAS
> > > a high guess.
> > >
> > > 205-50-15, 3.67 FD, .89 5th gear @ 6600 RPM = 138 MPH/223 KPH
> > > But at 7000 RPM I would be going 148MPH (my next goal)
> > >
> > > Do the digifiz is off by 10MPH over 130MPH... Ah who would of
> > guessed it!
> > >
> > > Note the same specs (205-50-15, 3.65FD, @ 6600RPM  but .75 5th
> > = 165 MPH..
> > > Hummm I do have that FN laying around on the 82.. MUAHAHAH
> > >
> > > ---
> > > ATS - Patrick Bureau -  Web site :
> > > http://ats.longcoeur.com]http://ats.longcoeur.com
> > > AIM: texasscirocco - Yahoo: atsgtx - ICQ: 32918816 - MSN:
> > atsgtx@hotmail.com
> > > See what I am selling today on eBay: http://tinyurl.com/22e5b
> > >
> > >
> > > -----Original Message-----
> > > From: scirocco-l-bounces@scirocco.org
> > > [mailto:scirocco-l-bounces@scirocco.org] On Behalf Of Drew MacPherson
> > > Sent: Sunday, March 07, 2004 7:36 AM
> > > To: reptilis
> > > Cc: scirocco
> > > Subject: Re: what's the fastest you've ever taken your Scirocco?
> > >
> > >
> > > Perhaps not a new speedo, but a new guesstimator is in order... :)
> > >
> > > FYI  A stock 4K is doing 108 mph on 175/70R13.  Even if you had
> > a 16" tire
> > > with a 25" rolling diameter you'd only be doing 119mph at 5700 rpm.  A
> > > 215/40R16 has a rolling diameter of about 23.6"
> > >
> > > Check out www.scirocco.org/gears for assistance in calculating
> > speeds with
> > > given gear ratios/tire sizes.
> > >
> > > Drew
> > >
> > >
> > > On Sat, 6 Mar 2004, reptilis wrote:
> > >
> > > > Since the mods, and pushing about 180 crank HP with a 4K tranny, 16"
> > > > wheels, and all new suspension and steering components:
> > > > Ive had the needle of the speedo buried so deeply that it
> took longer
> > > > for it to come back to the point of registering 85mph than
> it does to
> > > > come come down from 85MPH to zero. In 5th gear, the car was at about
> > > > 5700 rpm and still had power to continue acceleration.   I would
> > > > guesstimate that i was doing 150-160 easily.      On  a
> nice straight
> > > > stretch of I-5.
> > > >
> > > > I really need a new speedo.
> > > >
> > > >
> > > > _______________________________________________
> > > > Scirocco-l mailing list
> > > > Scirocco-l@scirocco.org
> > > > http://neubayern.net/mailman/listinfo/scirocco-l
> > > >
> > >
> > > --
> > > ============================================
> > > 84 Wolfsburg Edition TurboDiesel Scirocco
> > > http://scirocco.cs.uoguelph.ca/gtd
> > > 89 Audi 200 Turbo Quattro Avant
> > > 99 A3 Jetta TDI
> > > ============================================
> > >
> > >
> > > _______________________________________________
> > > Scirocco-l mailing list
> > > Scirocco-l@scirocco.org
> > > http://neubayern.net/mailman/listinfo/scirocco-l
> > >
> > >
> > >
> > >
> > > _______________________________________________
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> > > Scirocco-l@scirocco.org
> > > http://neubayern.net/mailman/listinfo/scirocco-l
> >
> >
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>
> Don Walter - Waukesha, WI
> 1984 1.8 8V Pewter Scirocco (sold years ago)
> 1986 2L 16V Toronado Red Scirocco (under repair)
> 1988 1.8 16V Toronado Red Scirocco (for sale)
> 1986 1.8 16V Black Scirocco (my new ride)
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