[urq] 20VT 3B Power Steering

[Scott Justusson]

 Hmmm...  Several years ago, I looked at putting one of these cruise control pumps on my vacuum diffs for my 83 urq to help with high altitude ck valve freezing+sustained boost of the Steamboat Ice track conditions at 7200ft.  In Chicago I measured a whopping 17inHg (altitude 660ft) as max for the 3 CC pumps I tested.  In addition, they took quite a while to fill a couple vacuum resevoirs of less than 1qt total.  At 660ft a 20vt engine can generate about 15inHg at idle, and just under 30inHg under compression braking, so I went the route of larger and better ck valves and more resevoir capacity.

If you look at the cam driven vacuum pump on a 10v N/A car from Audi (mid 80's B chassis cars), you can see that the fitting ID is something around 3/8in so the 'refill' time to normal vacuum is almost instantaneous.  That bitty line from the CC unit will likely run continuous duty and still come up short without a couple extra reservoirs in the system.  Again, if 'reserve capacity' is a concern, just add the reservoirs and an additional large ck valve downstream of the IM.  On my 4ktq, I use 3/8 line to feed from the back of the 3B intake manifold to the stock 4kq booster ck valve.  I run the stock 4k master with G60 fronts A4 Rears.

The best thing about the vacuum setup in the turbo cars, is deleting that primitive bomb arrangement Audi delivered on the urq from the factory.  You don't see that hydraulic setup on Audi turbo cars after the urs cars....  For good reason IMO.

Cheers and my .02

Scott J
2 x 20vt with vacuum assist

 

 

-----Original Message-----
From: Louis-Alain Richard <laraa at sympatico.ca>
To: 'Patrick Carlier' <p.carlier at pandora.be>; 'Jee Yoo' <guards4s at gmail.com>; urq <urq at audifans.com>
Sent: Tue, Jun 19, 2012 4:42 pm
Subject: Re: [urq] 20VT 3B Power Steering


Easier than this, Renault diesels from the beginning of the 2000's have a pump 
that we all know too well. 

It's exactly the same Bosch unit that powers the cruise control on turbo cars... 
older or newer. 

Standalone 12V unit, with a check valve and rubber mounting for quietness of 
operation.

4B0 907 325: http://www.ebay.com/itm/1999-VW-PASSAT-CRUISE-CONTROL-VACUUM-PUMP-4B0907325-/160700434278#ht_2174wt_1163

I guess these are a dime a dozen in a scrapyard.

Louis-Alain

 

-----Message d'origine-----
If you do insist on having a vacuum assisted brake, then get one of those vacuum 
pumps from a diesel engine to power it. Some
diesels, Ford Transit fyi, have a vacuum pump on the alternator. Easy and 
effective.

Pat