2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Manual steering VS. de powered 15.2:1

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Old 06-21-08 | 08:13 PM
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Manual steering VS. de powered 15.2:1

Hey, i'm currently desmantling most of my first FC3S besides the engine, and some of the suspension, and wondering about what to do with steering. I have a manual rack, but heard the feel of the de-powered rack is better, but also that 15.2:1 is not recommended to the 17:1, why is that? I need to remove the pump, and the rest of the AC stuff, which is better for getting a greater steering angle too, for corrections if my driving doesn't go as planned, i've read you can shim the tierods out. Well thank for the advice, i want good road feel, and something to go with my quick responding suspension. Its my daily driver, but it'll pretty much be a time attack car.
Old 06-22-08 | 04:56 AM
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15:1 rack all the way. The feel of a de powered rack is not as good as a true manual rack (maybe if you weld the piston?). However a de-powered 15:1 rack will be harder to steer at -3mph than the 17:1.
Old 06-22-08 | 11:31 AM
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Done this mod with the 15:1 rack and it is awesome the feel is much better than the power steering and the effort is no different unless you are going 5 mph, plus you'll get used to it after a few days. Look up a write up on it though, the important thing is that you weld the pinion shaft to the upper part of the shaft otherwise you will get some degree of twist before the wheels start to steer. I had modified the rack except for that part of the mod and when I finally took it out and welded it it was a night and day difference, it felt like before the steering wheel had somewhat of spring to it.
Old 06-22-08 | 12:31 PM
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I've driven both (depowered and manual), and the manual rack is noticeably better.
Old 06-23-08 | 12:49 AM
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ok?

i have an 1988 gxl with a power steering leak that is vary bad. i may need new parts. i have no money. my question is, should i fix it or should i take what i can out and have no power steering? i miss the power steering in my old 88 se it was an experience in itself how you had a lot of assist at low speeds and not much at high. but what am i missing here? is it better some how to not have it at all? or is it worth saving up and getting it fixed? what would you do?
Old 06-23-08 | 01:57 AM
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So your leak is so bad there is no assist at all? I would find the leak, its either the lines or the cap itself. Get some gasket sealer or vacuum caps or whatever you need and ghetto rig something. Don't have much to lose here. Taking it out is a performance mod (at the cost of no assist) that gives better tire and steering feedback during hard driving. You could bleed the fluid, remove the pump and loop the lines and that would make it a little easier to steer (nowhere near with the PS working) at no cost.
Old 06-23-08 | 02:02 AM
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hm, well i'm for welding the power steering rack, but since arghx mentioned the manual rack being better, anyone second that? what was better about it because i'd rather install that and save weight, than weld the power one. i was gonna ask about the manual rack ratio but i'll search.
Old 06-23-08 | 02:05 AM
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I don't think you'd like the 20:1 ratio that the manual racks have. I vote for 15:1 depowered for performance and 17:1 de powered for a compromise of both.
Old 06-23-08 | 04:32 AM
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Mines a disabled 15:1, and like previously stated, it's only rough on you below 5 mph or if you have no muscles in your arms. Been driving it for a few years like that and no issues. Need to get around to "depowering" it via that writeup in the archive. I did drive a vert with p/s a few months back and in comparison you only really notice the difference in a parking lot or backing into a small space or parallel parking. You get used to it after a while.

Although, the road feel is greatly improved.
Old 06-23-08 | 06:20 AM
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Originally Posted by KhanArtisT
I don't think you'd like the 20:1 ratio that the manual racks have. I vote for 15:1 depowered for performance and 17:1 de powered for a compromise of both.
cool thanks, i've skimmed though the write up, i'll probably go that route, i have to remove it either way.
Old 06-24-08 | 09:54 PM
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http://forum.teamfc3s.org/showthread.php?t=54847

I only ever not reccomended the 15.2:1 simply because I'd never tried it so I couldn't speak to the effort required. I've now got one and I did the pinion welding as in the above link and it does make a noticable, very good difference. I can't see that the feel of the manual and power racks will be any different when you do that extra step (well other than the slight effort and speed differences).

Of all the steering my car's had, I like the current 15.2:1 welded rack the best.
Old 06-24-08 | 11:30 PM
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my depowered 15:1 works great and isnt hard to turn unless you are complete wimp.
Old 06-25-08 | 12:55 PM
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Which cars came with which racks?

I didn't see it in the FAQ.
Old 06-25-08 | 09:25 PM
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More or less, S5 NA's had the 17.4:1 rack, all S4's and all TII's had the 15.2:1 rack, and then there's the cars with the manual racks which are ~20:1.

If it's got 3 hoses between the rack and the pump, its the faster one, if it's got 2, its the slower one, if it's got none then it's the manual one.
Old 12-26-08 | 08:05 AM
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FC Steering Rack Ratios

Originally Posted by Black91n/a
More or less, S5 NA's had the 17.4:1 rack, all S4's and all TII's had the 15.2:1 rack, and then there's the cars with the manual racks which are ~20:1.

If it's got 3 hoses between the rack and the pump, its the faster one, if it's got 2, its the slower one, if it's got none then it's the manual one.
Sorry to bump an old thread, but it's better than starting a new one.

I just want to clarify:

15.2 : 1 - Faster - Three Hose
17.4 : 1 - Slower - Two hose

Now where will these hoses go? Is a diagram available?

There'll be a high pressure output from the pump to the valve assembly/quill. Then there'll be hoses from the valve assembly/quill to the rack, then from the rack to the return.

So far as I can see, there'll always be only two hoses to/from the pump: Pressure output and return.

I don't have an FC, I just have the rack and front subframe with control arms. I know it's an S4 because of the removable ball joints. I believe it was from a GXL originally.
Old 12-26-08 | 08:53 AM
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whats the rack ratio on the FD ?
Old 12-30-08 | 01:02 AM
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Yes, 15.2:1 is faster steering (more wheel movement per rotation of the steering wheel). The three hoses are from the pump to the rack, I'm not really sure what they're all for, probably two different pressures of feed or something.

The FD rack is 15.2:1 as well. For all I know it's the same thing.
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