Date: Fri, 4 May 2007 11:20:01 -0400
Reply-To: Christopher Gronski <gronski@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Christopher Gronski <gronski@GMAIL.COM>
Subject: Re: An upgrade for a more efficent A/C system?
In-Reply-To: <325305.128.qm@web62413.mail.re1.yahoo.com>
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Here's a prior post of mine regarding Vanagon AC systems...
From: Christopher Gronski <gronski@gmail.com>
Date: Jul 12, 2005 7:44 AM
Subject: Re: Bottom line on A/C ?
To: Vince Jahn <vljahn@sbcglobal.net>
Cc: vanagon@gerry.vanagon.com
I spent a bit of time investigating this.
VW changed the AC in our vans around 1986 or 1987. From what I can
tell '86 2WD do not have the change, but '86 syncros have a partial
upgrade (fan, condesnor, compressor), '87 and newer had even more
(this coincided with the switch to the grey interior).
In terms of the condensor, with the '86 syncro they moved from
255272413A that has two sections of fins (with none behind the
separation of lower and upper grilles) to 253260403 that basically
covers the whole rad.
Compressors were upgraded around '86 as well some got the SD510 and
some the SD709. Both were an improvement over the SD508. The first
number refers to pistons, the second to total displacement. In this
case the SD510 is about 11% more powerful than the SD709 but the SD709
is aparently much quieter and saps less power (and it is13% more
powerful than the SD508).
Both are available from Busdepot. I had the more powerful SD510 in my
syncro but its dead now and in the interest of future availability
(Sanden is no longer producing the SD510 - pity it is 25% more
powerful than the SD508 of earlier vans) I will be replacing it with
an SD709. The procedure is detailed in Bentley 87.16 and requires two
specialized refrigerant lines: 253260708E and 253260716A and two each
of these o-rings: 803260749B & 431260749.
Also around '86 fans were also upgraded from 251959455G to the more
powerful 251959455M.
The '87 and up grey interior vans got the extended AC ducting off the
rear AC as well as a larger evaporator and more powerful evaporator
fans.
So, it is possible that the other vanaagon owners who are reporting
50F at the vents have newer vans with the VW AC upgrades noted above.
I was lucky enough to already have the upgraded condensor and fan. I
am changing out the compressor and plumbing in a BEHR aftermarket AC
unit that has a second evaporator and fans up front. I am hoping to
catch a cold this summer...
Chris
On 5/3/07, roger sisler <rogersisler2000@yahoo.com> wrote:
> Hello,
>
> Vanagon A/C systems need all the help they can get.With either R12 or 134a ,they are marginal. I think the main problems are high heat load inside the vehicle, and small condenser. A second condenser seems to help this situation greatly.That is expensive and difficult to do. Some have done it with very good results..
>
> It is like driving in the rain in summer.The A/C seems to work much better then. Mine always does.The reason is that the liquid rain conducts heat from the vaporized refrigerant (inside the condenser) much more efficiently. More liquid refrigerant is avaliable for the evaperator, to pick up heat from the interior of the Vanagon. Cooling occurs with the evaperation of refrigerant.Thats why they call it the evaperator.
>
> Here is a second way that the condenser situation may be improved upon.The Vanagon has a two speed radiator fan. Seldom is the high speed ever used. Only comes on in very hot weather.Sometimes it never ever comes on..
>
> If this fan was to be switched seperately from how it is, now ,perhaps the fan could be used to run on high when the A/C is first switch on, or at will. The larger flow of air across the condenser fins is a dramatic way to reduce system pressures, and increase liquid refrigerant
>
> . Infact the late Vanagon (86-91) has such a high pressure switch to close at 210psi.When this happens,the fan runs on high speed.Why not add a switch on the dash to close this switch at will? Two wires would need to be added at the high pressure switch(easy to do), and be connected to the dash switch.This would bypass the switch when one wanted additional cooling.The existing high pressure switch would still work as installed by VW..
>
> The high speed is very noisy, but when it is 100 degrees outside, maybe this noise is not so bad.I hear of 134a systems not working as well as with r-12. Maybe this fix would help this margin.
>
> In the early WBX. there is no high pressure switch. However,the radiator fan is a two speed fan.Maybe it could be wired directly,to come on high speed by a dash switch? More air across the condenser = better cooling inside. This is easily seen on the highway..Sometimes people say their A/C works better on the highway. Not so in the city driving.This would add some extra cooling at will, on very hot days.
>
> Dont know if this would cause any other problems.Just a thought..
>
>
>
>
> ---------------------------------
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>
