Date: Wed, 8 Oct 2008 12:56:30 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Magical cast iron suspension?
Content-Type: text/plain; format=flowed; charset="utf-8"; reply-type=original
For sure, the later vanagons with the cast iron lower control arms in front
seem quieter, and their handling is 'less lively, less tossable' than the 82
to 84 vanagons ( I don't talk abut the air-cooled ones much .........so just
starting with 82 diesel vanagon, to 84 waterboxer ) .
I've pondered why this is. I have not compared alignment specs between the
two, but I'd start there.
about this 'flywheel affect'.
Ya' all know what Unstrung Weight is, right ?
that's the weight of tires, wheels, brakes, and suspension parts that are
not help up by the springs. The body is all sprung weight. The
wheels/.brakes, tires etc are 'Unspring weight' ..........and in the case of
the lower control arms ..........one end is supported by the springs - the
body end, and the other is part of the Unsprung weight."
Unsprung wieght is a Bad Thing. It's the mass that the springs and shocks
have to keep in contact with the road. The higher the unsprung wieght, the
harder it is for the spriungs and shocks to do that.
Consider a solid rear axle on a car - massive unsprung weight ..........the
entire rear end plus brakes, wheels, ties..........might be say .........400
lbs on my 88 740 Turbo volvo sedan.
Reducing that weight improves handling, particurily where the road is not
billieard table smooth.
That's how you get to indpendent rear suspension. ( Vaagons have this of
course ) The differential is now part of the sprung weight, and Unsprung
Weight is reduced by a 100 lbs right there.
Same for inboard rear brakes - ala Jaguar ..........the brakes don't move up
and down with the rear wheels.........that wieght, another 120 lbs perhaps,
is no part of the sprung wieght. ( 'unsprung' .........that word, I would
bet is a British term originally , btw..........Britain is the home of demon
handling cars traditionally...........Lotus and all that, and many of the
world's single seat race cars are made there, or sure were through the 90's
at least )
so.........adding unsprung weight to the front suspension .........you'd
think would not have a damping affect , but would be detrimental to good
handling and ride.
I think .......no.............. suspect.......
that the cast iron lower arms are pretty rigid, and the stamped ones flex
some.
I also wonder if the alignment specs are the same for both versions of 2WD
vanagon.
as aside story about alignment............I'm restoring this 83 Westy
.........really nice looking one in Terracotta Southwest Red .( for sale )
........I went through the whole front end.
I adjust camber and toe.........and have a way to see if the castor stays
the same after taking the whole front end apart.
I had it pretty close, and she's driving fine. ..............and then went
in to replace a steering rack boot on the left side that was shot.
From my previous measurements of toe, I knew to add just a touch of toe-in.
It had been running at zero toe, or maybe 1/16th inch toe out.
Amazingly.........adding the tiniest bit of toe-in..........made it drive on
the highway another 5 % smoother. That was fun and rewarding .
Scott
www.turbovans.com
----- Original Message -----
From: "Chris S" <szpejankowski@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, October 08, 2008 5:56 AM
Subject: Magical cast iron suspension?
> http://cgi.ebay.com/ebaymotors/VANAGON-CAST-IRON-FRONT-SUSPENSION_W0QQcmdZViewItemQQcategoryZ6755QQihZ016QQitemZ260133939554QQtcZphoto
>
> Item #260133939554
>
> "The ride difference between the sheet metal lower control arm
> suspensions,
> and this one, is comparable to the *difference between a truck and a
> Cadalliac*. If you have been wondering why your Vanagon just dosent ride
> as
> nicely as that other Vanagon you once rode in, this is probably the
> reason.
> The cast iron lower control arm *acts as a flywheel*. It absorbs the
> energy
> caused by bumps in the road.* Stores it and keeps it from being
> transmitted
> to you.* Arrive at the camp ground fresher with this suspension. "
>
> Could someone explain to how suspension can "act as a flywheel" and what
> laws of physics it invents or overcomes by "storing energy" indefinitely?
> Curious minds want to know!
>
> --
> Chris S.
> Disclaimer: "Death and serious injury may occur"
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