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16v model year differences [GEARING]
30 km/h more from a FN? Perhaps with a turbocharged VR6.
There's a lot more to top speed than a gear ratio. Gear Ratio is important
-- but far, far more important engine torque characteristics and aerodynamics.
Putting a FF or FN in your stock 1.8 16V will not increase top speed my 30
km/h. You can't just assume that the engine will be able to redline in 5th
gear. The Scirocco's top speed (even with the very short stock gearing) is
limited by resistance, not redline.
Using the torque curve from a stock 1.8 16V and an AGB transmission, we can
calculate top speed at about 195 km/h. This would occur in 5th gear at
6100rpm.
The FN has a very different 5th gear... Using its ratios in our
calculations, we find that top speed will actually increase to 196 km/h --
a mathematically insignificant change. The big change, however, will be
that this speed occurs at 5070rpm - considerably less revs than the stock
gearing.
So as you can see, gearing does effect top speed, but not nearly as
dramatically as you presumed. What it did effect dramatically is
elasticity, or the car's ability to accelerate in 5th gear:
5th Gear Acceleration, (s)
30-50mph 50-70mph 80-120km/h
----------------------------------------------------------------------
AGB 8.76s 9.39s 11.81s
FN 12.03s 13.05s 14.58s
For any specific engine and vehicle combination, you will reach the ideal
top speed if you pick a gear where the top speed occurs at the horsepower
peak. For a stock 16V Scirocco, using the stock final drive of 3.67:1,
this would be a 5th gear ratio of about 0.83:1 and giving 201km/h at
5700rpm. The closest existing VW 5th gear to that would be using the
0.805, which would give a top speed of 199 km/h at 5500rpm.
For what it's worth, if you threw a VR6 in the Scirocco, you'd hit 220 km/h
as a top speed (at 5850rpm with a stock VR6 transmission).
Jason
At 10:12 PM 4/7/2003, Big Kid wrote:
>Top Speed? It's all in your gear box. 16v's came with a close ratio
>trannies. Mine had an AGB most other rocs came with taller geared boxes.
>like the FFor FN. I put an FN on my 1.8 16v and top speed increased by at
>least 30km/h.
>
>There is a link on the .org website as to what your tranny holds.
>----- Original Message -----
>From: "Scourge" <scourge@cogeco.ca>
>To: "Rocco list" <scirocco-l@scirocco.org>
>Sent: Monday, April 07, 2003 12:34 PM
>Subject: Re: 16v model year differences
>
>
> > In my stock 8v non-gti golf I could hit 112mph.....
> > And my rocc 8v 1.7 with 2" exhaust does 106mph.....
> >
> > -The George
> > ----- Original Message -----
> > From: "Adam J Garside" <adam.garside@uk.ibm.com>
> > To: <scirocco-l@scirocco.org>
> > Sent: Monday, April 07, 2003 10:48 AM
> > Subject: RE: 16v model year differences
> >
> >
> > >
> > > I've had 120mph on the clock on my 8v.
> > > Was just hitting the redline too.
> > >
> > > Felt a bit strange compared to the BMW, 146mph with 800rpm left !!
> > >
> > > MMmm 2.5litre straight 6 in a scirocco, sounds like a project! Get the
> > > shoehorn out!
> > >
> > > Adam,
> > > '92 Scala 1.8i
> > > '88 325i
> > > http://www.geocities.com/little_log
> > >
> > >
> > >
> > >
> > >
> > > "ATS - Patrick
> > > Bureau" To:
> > <scirocco-l@scirocco.org>
> > > <txrocco@sbcglobal cc:
> > > .net> Subject: RE: 16v model
> > year differences
> > > Sent by:
> > > scirocco-l-admin@s
> > > cirocco.org
> > >
> > >
> >
> > > 07/04/2003 15:23
> > >
> > >
> > >
> > >
> > >
> > > humm 123MPH top sped for a 16v... interesting.. The spedo on an 8v is
> > > 140MPH
> > > and I have run 117MPH on my 8v, one would think the 16v could get close
>to
> > > 140MPH no?
> > >
> > > ATS - Patrick Bureau - txrocco@sbcglobal.net
> > >
> > >
> > > =>-----Original Message-----
> > > =>From: scirocco-l-admin@scirocco.org
> > > =>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Jason
> > > =>
> > > =>RE: Other questions, no, the 16V cannot do 160 -- top speed is
> > generally
> > > =>accepted at 123mph.
> > >
> > >
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> > >
> > >
> > >
> > >
> > >
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