Power Steering Rack

[frankeeski]

So talk to me about fox body power steering racks. There seems to be 3 choices in regards to the lock to lock, 3 turns, 2.5 turns and 2.25 turns. I currently have a Flaming River manual rack with an 18:1 ratio. I believe this would be the same as a 3 turns lock to lock but I will confirm this week when I pull down the car off of the lift. I went with the high ratio on the manual rack to make parking a bit easier. I'm thinking that the 2.5 is what I may want to go with but looking for opinions from those of you with power steering. I already have rack extenders, the rack adapter and a Height valve to regulate the pressure. What do you think?

[edwardb]

I can't cite actual driving experience, only what I've read studying this topic for my Mk4 build. Most say it depends on how the car will be driven. For street only use, many recommend the 3 turn. Although faster can be used, it may not be quite as comfortable for some. For auto-x, most recommend a faster ratio, like the 2.5 or even 2.25. I'm 100% street use, and went with a 3 turn Unisteer from Breeze in my Mk4 build. Rack extenders are installed. I'm using the electric pump setup from Freddies, which is adjustable. Let you know in a year or two how I like it.

[Jeff Kleiner]

Hey Frank,
Lots of personal preference and the car's intended use come into play here.

I built my own Mk3 with a 2.25 rack and Heidt's valve knowing that it would see a lot of autocross and track time. On the street I back the assist down a bit but go to full boost on the track. The car drives and behaves the same either way I just prefer a little more resistance at the wheel unless I'm really hustling it on the track where the additional cornering forces increase the effort. The car is cat quick in it's responses with this configuration which is just what I wanted although I know there have been some builders who used the fast ratio racks and felt they were TOO quick. By the way, rumor has it that the 2.25 and 2.5 racks are actually the same ratio but use different travel limiters although I've never checked the two side by side to confirm or disprove that.

Conversely I built a Mk4 with a 3.0 rack running full boost for a customer who uses it strictly as a cruiser. The steering is very light but not floaty, I think to a large extent due to the increased caster that PS allows. He loves it that way. The two cars drive quite differently. The 3.0 rack car compared to mine is still responsive but somewhat more "relaxed" if that makes sense.

FWIW, I'm building another one right now which the owner will use primarily as a street car but will see an occassional auto-x or track day. I get the idea that this is much the same way you use your car Frank. Given his priorities I recommended and installed a 3.0 rack. Depending on how he likes the feel after driving it we might trim back the relief valve spring to reduce the assist or install a Heidt's so that he can vary it at will.

In a nutshell my recommendation is:
---If your priorities are for track duty go with the 2.5 or 2.25 rack
---If your priorities are for street use run with the 3.0 rack

Good luck!

Jeff

[skullandbones]

Hi Frank,

I have a 92 GT PS rack. I have done some go kart runs. The ratio is supposed to be 15:1 for that model. It says Quick Ratio on the specs. I find it to be "wickedly" quick. There is a sharp negative curve that I take that really accentuates that point. No hand over hand steering is necessary. I have small tires on the front at this time but when I go with 8 inch rubber on the new wheels, I'm sure that may change the feel some. I also have a quick release so I can change to a smaller diameter steering wheel if needed for autocross. Haven't personally used a small wheel but some swear by it. Good luck, WEK.

[emac]

I went from the FFR manual rack to a 3 turn LTL AGR rack. I am running a 1000psi pump with 2.5 gpm flow. I havent used it a lot, and I have little to compare it to, but I am very happy with how it drives on the street. It is quick but predictable. I really like the car with PS. Personally, I dont think I would enjoy anything faster for street use.

[Mr. Barry]

Strongly recommend the 3:1 rack....Plenty of response, unless you are a full-time auto-xer....When set up with max caster, car will run straight, and steer easy....I did go from the FR 18:1 manual rack, and would never go back.
Edward

[CraigS]

Have done this twice so here is my experience. My MkI came w/ depowered 2.25 rack which I powered up. Was great autocrosser but to quick on the street for me. So went to the 3.0 rack. Got my mkII w/ a 3.0 manual rack and quickly installed a 3.0 power rack. Have autocrossed it that way since 08 and about twice a year wished I had a 2.5 but never changed it. Last summer had three events in a row where the 3.0 was a handicap so installed a 2.5. This is the way to go for autocross for me no question. I am living w/ it on the street and have gotten used to the fact that I need to acclimate to it each drive. I have 8deg positive caster and run the assist just a tad stiffer than my Tacoma. BTW, I prefer cutting the pressure spring to using the heidts valve. I ad one in the MkII but getting the assist stiff enough seemed to leave me w/ occasional reduced assist in the parking lot. So I opened it up all the way and started cutting the spring. that worked better so the mkII doesn't have a valve.

[frankeeski]

I kind of knew this thread was going to get proponents both ways. And I do appreciate each of your experiences with the racks that you have. At this point I am leaning towards the 2.5 lock to lock rack. I talked with D. Ziol this afternoon and asked him about his setup. He is running Hydroboost and PS with no pressure reduction. His experience is the same as some of you, the 2.5 is quick but manageable. What my experience has been on our yearly week long cruises with the Wine Country Cobra Club is that on tight switchbacks I am having to hand over hand the wheel. This can end up being a bit hairy depending on the speed at which we may be traveling. I am still going to talk to Karen Salvaggio, Ricky "Bobby" Anderson and Tom Coon, each of whom have street legal spec FFR's. I believe their insight on how an actual "race car" which is driven on the street will be very helpful. To date, I have not had the car on the track, primarily because the stock donor motor has 239K miles on it and I don't want to push my luck and be left with a car I can't simply jump in and drive at a moments notice. Blown up motor is not fun. Anyhow, that issue will soon be remedied. The power steering will also be installed at the same time.

[tcoon]

When I first bought my challenge car, it had the 18:1 rack. With highly boosted power steering I found it unmanageable on the track. I found it particularly hard to manage the combination of hard manual brakes and extremely light twitchy steering. It was wicked darty, and I spun out MANY times. We called it "Mr Toad's Wild Ride". It had previously been raced by an auto crosser, and he liked it that way. I switched to the 2.5:1 rack with a heidt valve, and find that combination very drivable. This is what I put in my new competition coupe as well. It offers the combination of quick steering and adjustable effort without being overly twitchy, important on longer runs and enduro driving.

[frankeeski]

Thanks Tom, I didn't even have a chance to pick up the phone and call you and here you answer my question. I'm thinking that I'll be hearing something very similar from both Karen and Rick. Thank you for your insight.

[vnmsss]

In my new Coupe, I'm running the 2.5 rack and instead of a Hedit's, cut the spring on the PS........Road course and drag raced it over the last two days, and in terms of the PS, found it still a bit over-responsive, but not unmanageable. Settings: 1/16" toe out, -2 camber front, and +7.5 caster....Turns in great, and tracks straight and true.....Going to cut 1 more round out and stretch the spring today to add some feedback....Should do the trick. :)

Karen

[frankeeski]

Sounds Good Karen. I already have the valve so I'll be using that. 2 down and one to go, where is Ricky Bobby?

[FFRSpec72]

In my new Coupe, I'm running the 2.5 rack and instead of a Hedit's, cut the spring on the PS........Road course and drag raced it over the last two days, and in terms of the PS, found it still a bit over-responsive, but not unmanageable. Settings: 1/16" toe out, -2 camber front, and +7.5 caster...Turns in great, and tracks straight and true.....Going to cut 1 more round out and stretch the spring today to add some feedback....Should do the trick. :)

Karen

I assume that is +7.5 caster

Yes...:)....Thanks Tony!

[tcoon]

Hey Frank just a note on the Heidt's valve...I bought the Heidt AN fitting set and stainless hoses from Summit and it made the job a snap. Otherwise a pain to try and find all the proper size fittings, etc. Only took about an hour to set up the whole thing and voila! No leaks!

[CraigS]

If you happen to cut the pressure spring a little too short, you can shim it w/ small washers. Don't ask me how I know. This could almost be a recommended procedure since you can make small changes easily and have a real way to watch the results. Easier to count washers than try to figure out that spring coil count or length.

[CHOTIS BILL]

Karen,

I understand the cutting of the PS prssuer relief spring to lower the pressure but why stretch it? Or are you stretching some other spring?

Thanks,

Bill Lomenick

[frankeeski]

Hey Frank just a note on the Heidt's valve...I bought the Heidt AN fitting set and stainless hoses from Summit and it made the job a snap. Otherwise a pain to try and find all the proper size fittings, etc. Only took about an hour to set up the whole thing and voila! No leaks!

I have the hose situation pretty well taken care of, I have a secret weapon for that. The biggest issue I can see right now is that I have 2 brake lines running to the ABS pump that may give me a bit of a challenge when I go to tie in the PS lines to the rack.

[vnmsss]

Bill.......Same spring....Cutting the spring a certain number of coils/rounds and then stretching it a bit is a way of fine-tuning the adjustment.

Karen

[CHOTIS BILL]

Karen,

Thanks for the clarification. CraigS has a good idea for easy fine tuning and it would be easy to return to a previous setting.

Thanks,

Bill Lomenick

[frankeeski]

Ordered the rack and power steering pump today. Should be picking them up tomorrow. Have an order from McMaster Carr coming in tomorrow as well.

[JJ'snakepit]

Sounds like you are about ready to drop that engine and power steering in? Pretty soon now eh? or are you going to wait until after HB.... JJ