Author Topic: pst vs firmfeel fast ratio pitman arms...manual vs power steering dilemma...  (Read 6988 times)

Offline Mopar Mitch

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MPDLAWDOG -- Forget the manual steering unless you'll only be doing oval-track events, or some HPDE/HSAX with very minimal turning required.  Stay with the PS... add the longer Pitman arm ("Fast Ratio"), as well as the longer idler arm.... the longer idler arm was an over-sight by the factory to match the steering radius left/right... when they realized what they forgot, the production was ending... too, late to change... that's the factual side that is never exposed to the mystery (I had a discussion with Chrysler engineers many years ago about this matter, back in the late 70s).   The longer idler arm is, simply, the C-Body (ie: 70 Fury), idler arm... get them any where/any time... they are all the same... no such thing as "fast ratio idler arm".... but, the term has been increasingly grouped with the Fast Ratio pitman arm since its exposure late 70s into the 80s (fellow SCCA Solo II/autocross racer John Sandberg first exposed this matter of the longer required idler arm for his AAR race Cuda via the SIAC club newsletter (for AARs and T/As).. in the late 70s... he gets ALL the credit... not the business companies... FF, PST, etc etc).

The "Fast Ratio" pitman arms are unique... small spline needed for 72 and older ps boxes, large spline needed for 73 and newer ps boxes... plus the exclusive T/A ps box uses the large spline.  So, you could actually use any ps factory Mopar ps box and add the longer pitman arm... the factory T/A ps box has an internal stop so to prevent excessive turning radius and frame-rail scrubbing... the other ps boxes to NOT have that internal stop.... actually, that allows tighter turning radius (preferred for autocross), but will cause increased hitting of the frame rails, pending your rim offsets and tire diameters up front.

Make certain that you use ONLY the SAGINAW ps pump as ONLY it will keep up with fast l-r-l-r- maneuvers (ie: pylon slaloms), especially during higher rpms.   DO NOT USE the Federal ps pumps... avoid them like a plague!!!

Add a ps fluid cooler.

Use a smaller diameter steering wheel to further help with quick steering response.   (I use an 11.5" thick grasp, deep dish (~5") from Superior.   The "Tuff" wheels (~15" dia) are ok, but, the factory units are too slippery, as well as still too big, but better than the typical thin large diameter wheels.   At least, get the smaller 14" TUFF wheel (Flaming River?... the Grant is 15").

Also, increase your steering alignment with (1) Moog offset uca bushings, or, (2) take your pick of tubular-type uca units.    The Hotchkis design requires a different locating point... and that may not be legal in certain clubs/racing... check your chosen club/class rules!!!   The FF and others are all good for increased +caster, -camber.   Find a good alignment shop that will spend time and work with you!!!

My overall combo is awesome... pylon autocrossing... it whips through fast maneuvers with the best of the competition!    HSAX/HPDE/hwy cruising.... awesome!! NOT "twitchy" at all... alignment is critical, as well as toe settings.  For maximum pylon racing, a touch of toe-OUT (~1/4") is desired (trailer car/competition.. not daily street).. as it'll assist on quick l-r-l-r turns.   For street/hwy/HSAX/HPDE.... get ~0 toe, or preferred at ~toe-IN at ~1/16-1/8 maximum.

Next... get a good lateral supporting driver's seat (and harness) to get the feel of your steering.. become part of the car via the seat... try many seats to FIT your human body size.

The "Steering Quickeners" are not legal in many classes of racing... again, check your club/class rule books first before spending the $$... or else... you may regret it in the future.

Finally... your choice of suppliers is up to you.... Dick Ross at FF has been active with the Mopar customer base for many long years.... he gets high reviews for excellent service, etc.
« Last Edit: July 14, 2015 - 05:11:34 PM by Mopar Mitch »
Autocross/road racers go in deeper... and come out harder!

See  MOPAR ACTION MAGAZINE, AUGUST 2006 ISSUE for featured article and details on my autocross T/A.




Offline crash340

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Do what Mitch has said, :2thumbs: if its a streeter just use the offset UCA bushes, I Dont see the need to spend the money on aftermarket adjustable UCA'a unless you want the cool look that you only see from laying on your back. I still have the factory big thin wheel, on the interstate, I was worried it would be twitchy but its far from it, I love the fast ratio arms and FF ps box. One of my other cars I drive daily is a 2014 C Class Benz, I gotta tell you my Cuda out shines it on the interstate in many ways!
Greg

73 Cuda
Brisbane, Australia

Offline HP2

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I guess my question is as far as road feel and switching it over to non power steering...I had a 68 charger that was power steering and was not a fan..it felt way to "light." 

This is typical of stock mopar systems from this time period. You can do several things to fix this; )1 use a Firm Feel box, and/or 2)shim the steering pump valve to reduce the pressure put into the box, along with 3)maxing out caster which increases steering effort, or 4) swap it all out for a Borgeson unit.

I agree with Mitch above. I would stick with the power unit and use ways to firm up the system rather than go all manual. A manual box with wide tires and parking lot maneuvers in a car as large as a Challenger is a recipe for an uncomfortable driving experience.



I read this in an article about the Emax challenger...anybody done this????  It has powersteering at least in a few pics I have seen.....

"Here's a little trick about his retro pony car that Hotchkis doesn't mention publicly. He uses a Coleman Racing Products 1.5:1 steering gear that's located directly on the shaft to the steering wheel. When combined with the heim-jointed steering linkage, this item both quickens the response of the steering and transforms the precision of its action."

Steering quickeners do produce effective results but require modifications to the steering system that are beyond what most guys are willing to do. You have to cut and modify the steering column and shaft to mate with the quickener, then you have to mount the quickener box with adequate support to prevent it from deflecting. This is also the reason behind the heim joint system instead of the factory style slide coupler