Re: Speed Application

[Khan Klatt <kmk@pacificrim.net>]

I don't see why you would say "Not true."

First of all, a GTI and a GLX have *DIFFERENT* gearing.

So, the 144mph, was that in the GLX, or in the GTI-- it *will* be different.

Second of all, I have no factual or experiential basis for this
"efficiency" rating, but a rating _of_this_sort_ may explain why the top
speed by the calculation is so far off. I think you'll agree that 179 MPH
is *NOT* realizable by our GLX's with the current gearings.

As a result, my "adjustment factor" was an attempt to adjust the
theoretical top speed with a "realistic" top speed, and the factor I "came
up" (pulled out of my ass) was .75 in fifth gear. I didn't imply that this
was ABSOLUTELY TRUE, so why are you discounting it off-hand?

All I said was, there should be an adjustment factor that takes into
consideration real world conditions such as wind resistance. So if the
factor is not .75 in fifth gear, maybe it's .81 (.81 * 178 = 144)... the
details of the "factor" are not as important as the general idea of an
adjustment.

And, again, the gearing on a GTI and a GLX are definitely different, and
will produce different top speeds.

-Khan

P.S. The speedo reading at 150 was probably not very accurate, as many
readers have pointed out that the speedo consistently shows several miles
faster than you are really truly going. It's about 3 mph around 40, and
about five mph around 60-75, and could be as much as 6 mph around 144.

At 6:44 PM -0400 10/15/98, Greg Coe wrote:
>Not true.  I ran my car to 6100 rpm in fifth gear.  With the gearing that
>the GTI and GLX have, 6100 rpm in fifth equates to 144mph, according to Todd
>@ AWE.  BTW, the speedo was showing nearly 150 mph at that speed.
>
>Later,
>Greg
>-----Original Message-----
>From: Khan Klatt <kmk@pacificrim.net>
>To: jettaglx@igtc.com <jettaglx@igtc.com>
>Date: Thursday, October 15, 1998 6:38 PM
>Subject: Re: Speed Application
>
>
>>At 4:43 PM -0400 10/15/98, VWDrvrsWtd@aol.com wrote:
>>>In a message dated 10/15/98 2:26:40 PM Central Daylight Time,
>>>piecuch@hsd.utc.com writes:
>>>
>>>> So, let me get this straight....
>>>>  Let's sample Top speed.
>>>>  205/50 R15 at 6500RPM in 5th gear on a Jetta GLX
>>>>
>>>>  TD = 23.08"  (Stays the same)
>>>>  MPH = (6500 * 23.08)/(0.84 * 1000)
>>>>  MPH = 178.6   WOW!!!!
>>>
>>>What, yours doesn't go that fast?  :)
>>
>>I'm sure mine would go that fast, if it were on a dyno. Add the wind
>>resistance (our cars are no formula-1 racers) and other factors (perhaps
>>road friction, etc.) and your road efficiency will be reduced.
>>
>>You could add a "efficiency" factor to this calculation, on a sliding
>scale.
>>
>>At first gear, multiply your speed ratings by 0.95, to get "real world"
>>numbers.
>>In second gear, multiply your speed calculation by 0.9 to get real world.
>>In third gear, multiply by .85 to get real world speed.
>>In fourth, multiply by .80,
>>and in fifth, by .75 to get real world speed.
>>
>>That would produce roughly 135 mph, at 6500 rpm in fifth gear, adjusted for
>>"real world efficiency" by my rough "adjustment" factor.
>>
>>-Khan
>>---------------------------------------------------------------------------
>-
>>
>>Khan Klatt <kklatt@nw.verio.net>
>Verio
>>Network Engineer                                    Bellingham Branch
>Office
>>Tel 800.591.2757 x 13                                    725 N. State
>Street
>>Fax 360.738.8315                                        Bellingham, WA
>98225
>>
>>---------------------------------------------------------------------------
>-

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Khan Klatt <kklatt@nw.verio.net>                                       Verio
Network Engineer                                    Bellingham Branch Office
Tel 800.591.2757 x 13                                    725 N. State Street
Fax 360.738.8315                                        Bellingham, WA 98225

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