Does anyone understand how the RPM sensitive power steering system in the FD functions? I understand that the power assist is decreased as RPMs increase. I also know this is controlled by a single wire from the ECU to the power steering pump. I am assuming the ECU sends a small amount of current to the pump which somehow controls fluid flow through the pump. Can anyone confirm this or have any info that can help me understand this process?

Thanks
Josh

 

I can confirm that you don't need it.

 

I realize it's not needed. I've been without it for quite a few years (haltech E6K). However, I'm trying to understand how it works.

 

Peter,

Josh and I were just at Mid Ohio. I installed the bypass loop and removed the pump (yes, Maval gear mod would have been better). I love the feel of the car w/o the pump, but it was too much work to quickly maneuver the car at Mid Ohio. My current setup would be fantastic at VIR or WGI, but not for the tight turns at Mid Ohio. So, I'm looking for a better compromise---hence Josh's question.

thx,

Ramon

 

One of the changes made to the '99's in Japan was a restrictor valve that was put in the power steering to give it more "feel." I've always felt the steering in my U.S. version was a bit overboosted. I'm surprised that none of the aftermarket vendors has sold this part or some type of conversion kit. (At least to my knowledge they haven't.) It would seem a reasonable compromise to removing the power assist.

 

I was under the impression that the stock steering pump has some kind of variable orifice that controls the amount of "boost" to the pump. All I would have to do is find a way to close the orifice until the feel was improved. To do this I would have to better understand how the stock variable steering pump operates. Installing a restrictor is another way of going about it and could even prove to be more reliable.

 

The wire from the P/S pump is a pressure sensor that feeds the electrical load control system. It's purpose is to casue the idle speed to increase slightly in response to turning the steering wheel (at idle).

Whatever the RPM sensing is, its not that wire.

 

Thanks FDjunkie. I did not know that. So the RPM sensitive steering is entirely internal and mechanical. I will have to investigate what is involved in using some sort of restrictor to help decrease some of the power assist.

 

Ramon,
Mid-Ohio any twistier than Summit Point? (I realize it's longer). Admittedly, i've only used this setup around town, and at WGI, Summitt, and VIR (North and full).

 

Peter,
If you are talking about the "main course" at Summit, it's not even close in terms of a comparison. Mid Ohio has many semi tight consecutive turns and two 180 degrees turns. It would be interesting to see what your thoughts would be on the new Shenandoah course. PLease note that I run 17x10s with r-compounds in front. Again I think my setup would be fantastic at VIR full/North and WGI.

I also share my car with my wife at the track so there are other reasons why I need put P/S back in. She couldn't use my car at Mid Ohio at all.

R

 

Interesting.

I'm going to miss the MDA at the shenandoah, i'll be at WGI... But i'd be surprised if the maval setup is hard to use at anything but an autox. I really don't even notice it anymore, and i'm running 275/40 R's too. Fritz is supposed to be putting on on the bee, so we'll see what he thinks.

 

Keep me posted on what Fritz says. However, he basically only runs Summit or VIR. You are talking about WGI with Tracquest on Halloween, right? I'm targeting this event as well.

 

I found what looks like a pretty good solution. A power steering adjustable valve from Heidts (http://www.heidts.com/heip27.htm). This seems to be a little better than just installing a restrictor valve in the power steering line since it controls power steering fluid through the line and sends the bleed off fluid back to the resevoir.