Mustang II steering feel

[neongreen]

I searched a bit and didn't find anything addressing this topic specifically, so here goes.

I have a TCI Mustang II suspension in my Falcon. I haven't had a chance to really rail on it, I'm still sorting things out. However, my initial impressions are that the steering is touchy and overboosted. This hasn't been aligned properly and that may be part of my issue, but bear with me. Initially I had the caster settings all wrong. I don't think it was negative, but definitely closer to neutral, and it was very twitchy. I realized I had it set up wrong, so I adjusted the caster as positive as is possible with this suspension system. It helped a ton, but I still feel that the steering is overboosted.

I know that this can be an issue when GM pumps are mated with Mustang II racks, and it's common to use this valve to remedy the problem. http://www.speedwaymotors.com/Mustang-II-Power-Steering-Flow-Valve-for-GM-Pump-2-GPM,5852.html That would be all fine and good if I were using a GM pump, but I am using a Ford PS pump with the Ford rack but I don't really like the steering feel. Could this just be too much toe out? Not enough caster? Do I need a UCA with more caster built in? Is there a way to reduce the output of a late 80s Ford PS pump?

[Muttley]

if its touchy at speed, I would lean more to it being over pressurized for the rack although its surprising that a ford pump would be too much for a ford rack. when I changed to a tubular front clip in my c10 and added a rack, I used a shimmed valve similar to the one you posted since I was on the fence about going hydroboost and didn't want money invested to something I would need to change, although I have heard varying reviews from it doesn't help at all, to fixed all of the issues.
Heidts makes a relatively inexpensive adjustable valve block to limit the line pressure going from the pump to the rack that could be worth a shot and I may have to consider if I ever get the truck on the road.
http://www.summitracing.com/parts/hdt-ps-101

[dontlifttoshift]

Don't shim the valve. You are adjusting pressure when you need to adjust volume. A pump produces fluid flow (volume) that is what does the work. Pressure is created when there is a resistance to flow.....like holding your thumb over the garden hose, then it builds pressure.

I have used the heidts valve before and it also doesn't work. All the valve does is bleed pressure off into the return line. By the time you bleed enough pressure off for decent feel at speed you have given up most of the power assist at low speed.

What is your alignment set at? Caster/camber/toe

Links to other forums may be no bueno but there is some very good information in here. http://www.corner-carvers.com/forums/showthread.php?t=14991

[pro67coupe]

It may be over boosted, but I wouldn't try to diagnose around the obvious. If it hasn't been aligned yet, then align it and then go from there.

[dontlifttoshift]

Yeah, I glossed over that part of the post....start with an alignment.

[neongreen]

Thanks guys. Once I get to that point I'll check back with you.

[Protour_Pinto]

Pull the belt off and see how it feels.

[neongreen]

http://www.mustangandfords.com/how-to/drivetrain/m5lp-1207-power-steering-steered-straight/

Well after reading this, I'm thinking that my issue is that the torsion bar which controls the flow valve in my rack is probably pretty small, resulting in an overboosted feel. The good news is that I can replace the steering rack with an SN95 rack with only minor modifications. The other benefit is that the SN95 rack uses helical cut gears where the MII uses straight cut gears. The helical gears are supposed to have less lash, for a tighter, more precise feel.

[Sales-TCI-Eng]

Something else to consider. Our standard rack is 2.5 turns lock to lock but we offer 3 turn racks as an alternative. We can exchange it if you like. Personally, I think the 2.5 turn rack needs 5+ degrees of caster to finally be slow enough for my comfort, and that's with 2 gallons per minute of flow and a bunch of tire on the steering axle(275+).

-J

[another69]

I was told that the DSE rack was based on a Mustang rack. Is it Mustang II? Or is it the later SN95? Was there something in between?

[Sales-TCI-Eng]

I was told that the DSE rack was based on a Mustang rack. Is it Mustang II? Or is it the later SN95? Was there something in between?

We use the Fox body racks in our kits, not sure but I believe DSE's are custom. The SN95 rack have a stiffer torsion valve which makes them have less 'feel' when on center.

-J