Date: Wed, 12 Apr 2000 16:11:25 -0700
Reply-To: "Buettner, Peter" <PGB@DOLBY.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Buettner, Peter" <PGB@DOLBY.COM>
Subject: air suspension tests on Syncro and 2WD
Content-Type: multipart/alternative;
For a while now I've been sitting on the air suspension kit that I got from
Air Lift (http://airliftcompany.com). For the Hollister Syncro meeting I
finally made the time to pull them out of the box and install them. Since
my Syncro is currently on the road (without me!!! who would have thought) I
installed them in Steve Schwenks Syncro Westy first. Steve has the Bilstein
shocks and stock springs installed.
The air suspension looks like two red rubber cylinders with metal hose
connectors on the top. Kind of like a rubber beach ball. It was easy to
install. I lifted the rear of Steve's van so that the springs expanded all
the way. Then the two cylinders were pushed into the inside of the spring
by deflating them and inserting them between two adjacent coils. I
connected a short piece of hose and a tire valve (all part of the kit) to
each cylinder. Using cable ties, I attached the valves to the brake lines
that run along the top of the trailing arms. This all could be done without
taking the wheels off. Now the system was easily inflated with a standard
tire pump (I used a bicycle pump). Because the volume of the suspension is
so small it took only 5-6 strokes to bring it up to the max. rated pressure
of 25 PSI. I set the pressure to a conservative 20 PSI and Steve drove his
Syncro to Hollister like that.
Now the air suspension pretty much fills out the whole space inside the
spring from side to side and from the bottom of the trailing arm to the
rubber stop on top. Fully inflated the rubber stop just touches the air
suspension. As the suspension contracts the rubber stop is pressed into
this air ball. This is similar to having a spring with a progressive spring
rate. The more the rubber stop presses into the air ball the more pressure
inside the ball builds up. The increase in air pressure inside the ball is
proportional to the increase in force that is pushing against the rubbers
stop. By changing the initial pressure with a tire pump the "air spring
rate" is changed. Increasing the pressure makes the air suspension stiffer
(higher spring rate), decreasing it makes the air suspension softer (lower
spring rate).
Initially I was concerned that the rubber stop might puncture the air
suspension. I called Air Lift and talked to one of their engineers. He
insured me that this is what these things are designed for and it should be
save.
In Hollister Steve was quite impressed with the air suspension. His van was
about 2/3 loaded on his way to Hollister. He thought the air suspension was
an improvement over his stock setup. Steve also tested the air suspension
on the trails with his twins sitting in the back. The pressure was left at
20 PSI. More positive remarks.
Next the air suspension went into Mark Drillock's Syncro Westy together with
the new Betts springs. Mark has also the Bilstein shocks installed. In
Mark's Syncro we tested the air suspension at different pressures: 25 PSI
(max. rated pressure), 15 PSI and 0 PSI. At 25 PSI the rear became very
stiff. I was almost thrown out of the rear seat at big bumps. At 15 PSI
the rear was perfect. It now had the right damping. The traction of the
rear axle was much improved. At 0 PSI the air balls didn't seem to have any
effect on the suspension as expected.
Everybody was quite impressed with the way the air suspension changed the
behavior of the rear axle depending on the initial air pressure. By simply
changing the air pressure the air suspension can be easily adapted for
different load and road conditions. Low pressure for an empty van, high
pressure for a fully loaded van. Low pressure for highway driving, high
pressure for off-road driving.
We also tried the air suspension on Craig Drillock's (Mark's brother) 1982
Vanagon Westy with 1.9l turbo diesel engine. At 25 PSI the we were able to
lift the rear by 1/2". Guess that's great news for all you 2WDs with
sagging rear springs (the Syncro was not raised because of the higher
springs). Handling and traction of the 2WD was greatly improved with the
air suspension in place. We did a couple of turns on the dirt track and it
was amazing to see the difference between the front (without air suspension)
the rear (with air suspension). While the front felt rather unstable and
was breaking out left and right the rear seemed to be on tracks. Completely
stable.
Everybody that got to test the air suspension wanted to get one. So I'm
trying to put a group purchase together. There are also two compressor kits
available for the air suspension. Theses kits consist of a compressor, one
or tow pressure gauges and control buttons, and all necessary hoses and
connectors. These items can be installed in the van. With the gauge(s) and
controls mounted on the dash board the air suspension can be controlled
while driving. With the dual-gauge kit the two air balls can be controlled
independently. I think that could be very useful for 2WD Westies. This way
the weight of the water tank or other off-center weight could be easily
equalized. Here are some prices for the Air Lift suspension that I got from
the internet:
Air suspension for Vanagon $70
Compressor kit with single gauge $110
Compressor kit with dual gauge $159
I hope to get these prices further down if we get enough people together.
Please send me a p-mail if your interested. Please indicate which item(s)
your interested in. A similar kit is available from Firestone. I don't
have personal experience with the Firestone kit nor have I heard from
anybody who does.
Cheers,
Peter
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