Date: Wed, 23 Jan 2002 16:12:10 -0600
Reply-To: Stan Wilder <wilden1@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stan Wilder <wilden1@JUNO.COM>
Subject: Re: '80 Westfalia-- best way to drive over passes
Content-Type: text/plain; charset=us-ascii
You don't sound frustrated at all.
Everything you respond with is absolutely correct.
I think its just down to deciding if 5800 rpm is the redline on the
TypeIV engine.
I've never turned any VW aircooled engine over about 4400 RPM so I can't
even say it would spin that fast.
I'm turning about 3400 rpm at 70 mph running 185x14 tires and a standard
4 speed gearbox.
My Super Sun Tach II and my Snap on Tach show matching rpms up to about
3200 rpm (fast as I've ever reved the unloaded engine).
Stan Wilder
83 Air Cooled Westfalia
On Wed, 23 Jan 2002 13:16:05 -0800 harald_nancy
<harald_nancy@EMAIL.MSN.COM> writes:
> I find this thread has become very frustrating.
> Perhaps someone's tachometer needs to be recalibrated.
> I had a '81 vanagon westy back when it was a pretty new car,
> and drove it for many years.
> I towed a 2,500 lb sailboat with it, even across the Siskiyous,
> and the vanagon never gave me problems for 160,000 miles.
> As mentioned before, the most important thing about
> driving the aircooled vanagon is to keep the rpm up,
> so the cooling fan is at its most efficient.
> That means shifting down going uphills into 3rd, and sometimes
> 2nd, so the engine can rev at its most optimum.
> Lugging the motor can be more damaging than revving it.
> For the 2.0 liter air cooled vanagon, that means keeping
> the rpm around 3400 to 3800. That's the truth.
> If you don't believe it, check your VW specs.
> That means if you climb a hill in 3rd gear, at about 45 mph,
> your engine will rev somewhere around 3500 to 3800 rpm,
> which is good. That's the way VW designed it.
> Specs from original VW '80 brochure:
> HP 67 at 4200 rpm. (revving any faster will get you into a black
> hole)
> Top speed 75 mph (that would be about 4200 rpm)
> Max Torque 101 ft. lbs at 3000 rpm (above 4000 rpm, the torque
> just disappears).
>
> Btw, there are many different Type 4. There was the 1700 bus,
> which behaved quite differently than the 2.0 liter Type 4.
> Also the Porsche 914 Type 4 engine is built to rev higher than
> the Vanagon Type 4.
> Harald
> '90 westy
>
> ----- Original Message -----
> From: "G. Matthew Bulley" <gmbulley@BULLEY-HEWLETT.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Wednesday, January 23, 2002 4:26 AM
> Subject: Re: '80 Westfalia-- best way to drive over passes
>
>
> > I'm left more confused about Stan thinks than when I started. Was
> he
> > confirming or refuting my thoughts? Not sure.
> >
> > First off, I was talking about all Type 4 motors, 1968-1983.5,
> > particularly when in use in the Vanagon 1980-1983.5. Second,
> redline on
> > the type 4 is 5600, not 5000. I've routinely driven at or near
> 5,000 for
> > hours on end (on cross-country jaunts) with no issues or problems.
> This
> > is Type 4 vehicle #8 for me, and only one motor failure (at 135k
> due to
> > low compression)
> >
> > This whole notion that the "ENGINE ACCUMULATES HEAT OVER TIME" is
> nuts.
> > If it were true that THE ENGINE ACCUMULATES HEAT OVER TIME in some
> sort
> > of linear progression, every long trip would end in a meltdown.
> >
> > In actuality, once your motor reaches operating temperature, the
> engine
> > is constantly shedding heat. With its deep fins, alloy
> construction,
> > oversized fan, and huge oil cooler it has a finite capacity for
> shedding
> > heat, however, that capacity exceeds common usage by a wide
> margin.
> >
> > Since the only two moving parts of the cooling system (oil pump
> and
> > cooling fan, except the thermostat) are crank driven, cooling
> capacity
> > increases as crank speed increases, in relatively direct
> proportion. At
> > a certain point, (somewhere around 4800) you reach the point of
> > diminishing returns, no additional cooling air forced through the
> system
> > will shed any additional heat due to laminar flow and molecular
> > shielding constraints [ a thin layer of immobile air molecules
> forms
> > adjacent to the metal cooling surfaces preventing additional heat
> > shedding even with additional air flow].
> >
> > Even on the hottest summer days, I have crossed the southern USA
> with 5
> > people and a full load in a van and had no problems, we simply
> didn't
> > try to go 70 mph, or climb hills in 4th. We stayed below 5k, and
> just
> > plugged along.
> >
> > It is only when the driver places an exceptional load on the
> engine
> > (full throttle under heavy load), while keeping the cooling system
> in a
> > sub-optimum range (i.e. 3,000-4,000 rpm) that heat builds up. The
> crank
> > speed is insufficient to push enough air across the cooling
> surfaces to
> > displace the heat; only then does "engine heat accumulate over
> time".
> >
> > No-one proposed going 70mph in 3rd, as Stan suggests. What I said
> was
> > reduce your speed to 45 and relax in 3rd at 45mph for the climb
> (which
> > Stan also say he has done??). Again, this puts the cooling system
> at
> > peak capacity, while at the same time reducing the load on the
> > crankshaft.
> >
> > From historic, walkable Mount Olive, NC,
> >
> > G. Matthew Bulley
> > Bulley-Hewlett
> > Corporate Communications
> > Business: www.bulley-hewlett.com
> > Alliance: www.ntara.com
> > Home: www.MountOliveNC.info
> >
>
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