Date: Sat, 28 Jul 2007 08:52:15 -0700
Reply-To: Mark Drillock <drillock@EARTHLINK.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Drillock <drillock@EARTHLINK.NET>
Subject: Re: Power output of actual vans? (long)
In-Reply-To: <001301c7d128$bbff0d60$a3b2d8d1@dhanson>
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The problem with simplistic numbers like peak horsepower is that they
are just that, simplistic. The power band requirements of our 4 speed
manual trannys make the peaks much less important than the shape of the
power curves. Since we spend most time in the 3000-4000 rpm range, how
much power is available at 7000 rpm does not really matter very much for
most driving. Modifications that raise the advertised "peak hp" may even
REDUCE the power available during typical driving. What matters most
is how well the power band matches up with the gearing available in our
Vanagons. The peak numbers game is just that, a game, at least when it
comes to pushing a loaded Westy on a thousand mile trip.
Mark
Don Hanson wrote:
> Has anyone actually documented the output of the various engine combos in
> vans? I ask this with a LOT of experience with boasting car owners,
> optimistic aftermarket parts vendors, erroneous factory HP figures, etc.
> While involved in racing with the Porsche brand, HP was an often exaggerated
> and misrepresented figure, sometimes stated as 'at the crank' sometimes "at
> the wheels" and with all kinds of different 'correction factors' inserted
> before the bottom line. The same motor in the same chassis would produce
> varied numbers on different brand dynos, also.
> So, when we hear figures for all these motor/combos, what, exactly are we
> hearing? Where do the numbers come from? If someone simply quotes what the
> factory said the power figures were, for a particular type motor, brand
> new, it may not have much relation to 'that motor' in the van..
> ..............
> So when someone says.."Ha, the X-type conversion motor has 150hp (or
> whatever), while the WBX is only 90 or some such, it'd be interesting to
> hear where those numbers are coming from.
> ................. There are dyno shops around in
> most larger metropolitan areas where you can get onto the roller for a half
> hour and get actual data for a nominal fee.
> I'd love to see the curves for the various types of conversion motors, to
> actually compare It's too easy to just 'say'.stuff about how a particular
> motor works..but the figures would be less subjective, if we had some.
> Don Hanson
>
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