Twitchy power steering

[gofastoldguy]

My power steering is overly sensitive to me. If I move it 1" I will change lanes! Is there an adjustment to the rack that will help make it less sensitive? Is there an add-on control valve that will reduce the problem? Thanks

[Jeff Kleiner]

I think often times people try to run manual steering alignment settings with power and wind up with the same complaint as you so I'd tackle the alignment first. With a power steering car you can (and should) get more agressive with caster which, in addition to other good things, will make the car want to track straighter, promote self centering and increase the resistance to turning. Basically it stabilizes the car greatly. You can probably easily get to 8 degrees positive. When you do though you will need longer adjusting sleeves for the forward links in the upper control arms. Read this:
http://www.ffcars.com/forums/showthread.php?t=244160
Along with caster be SURE that it is set for 1/16"-1/8" TOE IN. Toe out will make the car darty and it will not want to self center.

Once you are certain that the alignment is sorted out if you still feel that it is more sensitive than you like determine which rack you have. It could be 2.25 (fastest), 2.5 or 3 (slowest) turns lock to lock. I have a quick 2.25 ratio in mine but do a lot of autocross and track days so it's perfect for me. Some builders who only use the cars on the street prefer the 3.0. If you have the fast ratio it might simply be something that you won't ever be comfortable with and a rack change might be in order. I built a Mk4 for a customer using the 3 turn rack and he feels that it is perfect even with full assist---responsive but not overly sensitive.

No matter what rack you have the amount of assist can be changed by a couple of different methods. In my own car I incorporated a Heidts valve so that I can adjust the amount of assist depending on which I happen to be doing; full boost for auto-x, reduced on the street and usually somewhere in between on a road course.

http://www.heidts.com/steering_kits_components.html Go down the page to "adjustable power steering valve".

If you simply want to reduce the assist and not vary it once you get a level that you are comfortable with you can cut down the pressure relief spring in the pump. Generally about 1/8" cut from the more tightly coiled end is a good starting point.

I know I dumped a lot of info on you there...feel free to shoot me a PM if you like and good luck!

Jeff

[Marty Prario]

Mine felt the same way. Try the alignment 1st like Jeff said, it fixed my steering problems.

[Brian Z]

Jeff is right. It sounds like you need more caster. That will make the wheel want to return to center. If there is not enough caster the tires will follow the ruts in the road.

We recommend 3 degrees of caster for a manual steering rack and somewhere between 6 and 9 degrees for a power steering set up.

Also make sure you have 1/16" to 1/8" of toe in.

Best regards,

[ehansen007]

Try letting off the gas and then steering.

No fun is it!??! Haha

[gofastoldguy]

Did some alignment the other day and bumped the caster up to 5*. Couldn't go higher because I ran out of adjustment with the FFR sleeves (too short). Will pick up some 5" ones from Summit and that should get me closer to 6-8*. Thanks for all the suggestions guys. The car handles 100% better with 5*.

[Jeff Kleiner]

Good! It will be even better with 8. Again, be sure that it is toed IN, not out.

Jeff

[E-Ticket Ride]

Did some alignment the other day and bumped the caster up to 5*. Couldn't go higher because I ran out of adjustment with the FFR sleeves (too short). Will pick up some 5" ones from Summit and that should get me closer to 6-8*. Thanks for all the suggestions guys. The car handles 100% better with 5*.

I am just assembling my IFS. Do I need to replace both sleeves on the UCA, or is just the front replacement sufficient to achieve 6-8 degrees?
I am going with the Autozone 2.5:1 powered rack, and the FFR spindles.
TIA
CL

Never mind my question regarding one or both - finally got a chance to dig through the older thread and see that only the front 2 required.
Mine now ordered from Summit, and due in next week. I am out this weekend, so that works well!
CL

[crash]

If yo still have issues, or if your particular application will not allow large amounts of caster, then www.myraceshop.com offers this product:

http://www.myraceshop.com/Power_Stee...ontroller.html

It is a controller to make you power steering system speed sensitive, just like all modern cars have. It also incorporates a feature to make the power steering cockpit adjustable with the turn of a knob.

At this point a very basic controller is all that is offered, but the complete polished setup is very close to completion and will be listed on the same webpage in the next few weeks or so.