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A racers viewpoint of the CP Rack/Pinion kit

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Old 06-13-04, 09:49 AM
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A racers viewpoint of the CP Rack/Pinion kit

I finally got to drive a converted car this last weekend. It's amazing, I could tell an imediate difference about 10 degrees into turning the wheel. It's certainly a whole different feel. I did notice however it's not all it's cracked up to be.

Pros:
Awsome feel
Very tight
Great feedback

Cons:
Sluggish at the center
Slow or non existant centering effect
Terrible turning radius
Slow turning

So what's this all mean? Well, as a street driver, it means go buy the kit. It's certianly worth it for a dialy driver. Also, I'd put this on my track car as well, the feeling is just amazing.

I WOULD NOT put it on my autoX car, nor would I put it on any car I intended to try to drift. The turning is very slow, and the centering effect makes it a lot of effort to autoX on. You'll be much better off with a smaller wheel on the stock box. As for drift, big no-no. The turning radius means you'd better expect to spin if you get too far out, because you'll have no room to catch it. Also, the wheel will not center quick enough, making it virtually impossible to transition from one drift to another without spinning out.


All in all, it's a nice product that has it's place IMO, it's just not for all cars in all situations.
Old 06-13-04, 11:33 AM
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I agree with everything you said. Thanks for sharing your viewpoint
Old 06-13-04, 03:48 PM
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I wonder if you could improve the wheel centering effect if you deviated from the stock alignment settings. Perhaps the R&P demands an entirely different toe-in or toe-out setting. Just a thought.
Old 06-13-04, 05:07 PM
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Thanks for the feedback, I'm about to order one (for my streetcar) and knowing this before hand is nice. I'll be interested in seeing what I think of it, just have to wait I guess
Old 06-13-04, 05:17 PM
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Originally posted by inittab
I wonder if you could improve the wheel centering effect if you deviated from the stock alignment settings. Perhaps the R&P demands an entirely different toe-in or toe-out setting. Just a thought.
Would make absolutely no difference. What is good for R&P is good for recirculating ball.

Just think of recirculating ball as an R&P setup except instead of a pinion gear sliding the rack side to side, you have a gearbox that moves a lever that does the same thing.
Old 06-13-04, 07:42 PM
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peejay - why would the R&P be sluggish at center and not return to center quickly?
Old 06-13-04, 08:08 PM
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Did you do an alignment?

Did you change anything else at the same time?

Is the rack used or remanufactured? (If it's reman it is probably faulty, probably one out of every two racks/boxes I've ever done were screwed up internally)
Old 06-13-04, 09:01 PM
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So there's a possibility that the sluggishness and non-re-centering is actually an alignment or the rack's fault?

Well at least it's good to get another viewpoint from another person who has driven this conversion. Especially someone who has a better idea of what they're looking for.

And I'm wondering if the *slightly* smaller lock-to-lock of the GTI rack would have any effect on the "slow" steering.

But I'm guessing a brand new GTI rack would cost a bundle... Then again if I had enough money to do the conversion, I would probably save the extra money and do it properly... IF I could find a new rack that didn't cost more than the conversion itself.

Jon
Old 06-13-04, 09:39 PM
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It's possible. Heavy amounts of toe-in or toe-out can do some weird things.

So get yourself "in the ballpark", center the steering wheel and eyeball the tires front to back (use one eye so binocular vision doesn't mess you up!). The face of the front and rear tires should be even with each other. (A nicer way of doing this involves a couple coffee cans with a string tied around them about 4-5 inches up) Adjust the tie rods until they're close to even. Note that you MUST check with the car on the ground, and after rolling it back and forth several feet a couple times to make sure it's at normal ride height.

After that you can measure the front of the tire vs. the back and get it fairly close. Don't worry about toe in vs. toe out - this will not be exact so shoot for indicated zero toe. This will get you within 1/8" of zero, from my experiences of aligning at home and then taking the car into work and checking it on the alignment rack.

After you do all that, then you can start making objective and subjective analyses.

Lock to lock doesn't matter as much as rack *travel* - how many inches of travel vs. how many degrees of steering wheel travel. It is impossible to have a variable-ratio R&P, so it should be quicker off-center than the P/S box or about the same as a manual box.

I don't have the R&P setup. I simply don't believe in it.
Old 06-13-04, 11:27 PM
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I don't get what all the fuss about the 'vague' feeling that our steering boxes have. I've driven cars with a rack and cars with recirc ball/nut. No car that didn't cost a whole pile of money had the steering feel that my SA has. My box has ZERO play, I nudge the wheel ever so slightly and the car turns ever so slightly, it's very direct and precise. I don't have any wandering problems at speed and I don't find the steering effort to be too heavy. Sure, on center the steering doesn't feel as precise as a nice rack from a MR2 for example, and the lock to lock ratio isn't very good, but it seems that this RP conversion solves neither of those problems.

I think that some people blame bad steering on the box when they should ensure that all alignment settings are good and that all steering linkages are in proper spec.
Old 06-13-04, 11:56 PM
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That's how i felt - my '80 had a super excellent box too.

My '85 has a P/S box that is worn out - there's about 1/8" total play at the bottom of the sector shaft, and since the shaft rides directly on the iron case, there's nothing that can really be done to adjust it or quickly fix it.

The play is only really noticeable when grippy low-profile tires are installed. With standard tires on it, it's just fine, better than many cars from the 60's-70's anyway.
Old 06-14-04, 06:56 AM
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To be honest I can't say a whole lot of bad things about the box on my 83 S, on the backroads its nice and responsive, and even with the smaller momo wheel and sticky 205/60/13 tires the effort is just what I want. The slop is very noticable at 65mph and above however, it wanders all over the highway. I'm leaving that car stock and am putting the R/P kit in my 83 GS (that box is wasted) I'll be interested to see what I like better...
Old 06-14-04, 01:26 PM
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The alignment on the car I drove was nearly identicle to mine. Zero Toe, 3.5 degrees of caster, and -1 degree of camber. There's no reason with those settings that there should be any problem with wheel centering. The only thing I can think of is that possibly the way the rack is possitioned caused some diminished effects, but I noticed zero bump steer. This is purly speculation, I have no idea why the car didn't center like it should, or I'd offer suggestions to fix it. I was very surprised with the feel of the unit, I would have expected quicker steering, which is the reason I started this thread in the first place. Being a racer, I have yet to see anyone quantify their experience in a way that mattered to me. I figure at least now, fellow racers will have an opinion of experience to draw from.
Old 06-14-04, 05:39 PM
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Is the steering slower than the stock unit? If so I don't know why anyone would buy it.
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