- BigBlackBeaSSt wrote:
- replacing pump, lines and steering box (with an AGR 12:1 box) Should I re-install variable assist or go directly into the pump with the line?
As Jim says, if it is working, then keep it. The control method is valid no matter how fast the box ratio or how stiff the torsion bar is. All it does is to back off on the pressure applied to the box at higher speeds and low steering angles.
The system is pretty reliable, any problems can usually be traced to the steering angle sensor. The contacts can become worn or dirty, and then may give spurious signals to the control unit. If the system should start to act up and you don't want to spend the $ to fix it, then just disconnect the electrical connection, it's cheaper than removing the valve and replacing the high pressure hose with the Caprice specific line. All that will happen is that in effect the system will apply full pressure at all times, as the Caprices already do. Should one find that the system is too numb to run in that mode all of the time, then there is a fix for that too.
An easy way to improve the road feel on any of our boxes is to shim the pressure relief valve in order to lower the line pressure to the box. The only caveat is that the low speed assist will drop off as the pressure is reduced, but as long as you don't go too low, then the increased effort trade off shouldn't be objectionable. GM had to provide some level of minimum assist which usually is quite a bit less than the enthusiast type person is willing to tolerate in exchange for better road feel.
You can do this with nothing more than some properly sized washers, but it is easier just to buy the kits that are already put there to do this. They are marketed towards the street rod guys that are running Mustang II style steering racks that require less pressure that the GM pumps are set up to produce.http://www.summitracing.com/parts/BRG-899001/http://www.summitracing.com/parts/MCH-P306/?rtype=1http://static.summitracing.com/global/images/instructions/mch-p306.pdf
Why more people don't do this I don't know. It's not like it is a big secret, but it doesn't get much ink when compared to all the threads over on the ISSF about replacing the box with a high end unit.
The road racers and autocrossers complain about boiling the fluid and melting the plastic parts begin by adding band aids like coolers and metal reservoirs, when the first place to start should be understand that the fluid power formula is HP = PSI x GPM / 1714. If we cut back on the unneeded pressure by say 30% - 40%, then the heat generation will be reduced correspondingly.
Reducing the pressure first at least approaches the problem with some understanding of what is happening and spending the least amount of coin first, rather than just pulling out the credit card and throwing money at the situation.