Thoughts on de-powering the rack?
07-21-2011, 03:23 PM
#41
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Two styles of rack in the pic. One has the later two-piece casting, the other is wearing a one piece bathing suit. See how much cleaner de-nippling (ouch) and hydraulic port filling looks?
https://www.miataturbo.net/attachmen...1&d=1311276137
https://www.miataturbo.net/attachmen...1&d=1311276137
Last edited by sjmarcy; 07-21-2011 at 04:04 PM.
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07-21-2011, 06:22 PM
#44
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Define "over-loaded". Actually, don't. If you're so dense that you think I added 100lb/ft instead of something reasonable then you're beyond hope. This also reduced the slop.
Fab up a steering damper for me, for free.
I added a little pre-load because I like the way Porsches steer more than BMW feel. Maybe you can ask Porsche about their suspension problems.
Fab up a steering damper for me, for free.
I added a little pre-load because I like the way Porsches steer more than BMW feel. Maybe you can ask Porsche about their suspension problems.
Well, I don't give a rat's *** how you set up your steering rack, but I'm pretty sure your bodge isn't how Porsche get's their superior feel; I suspect they probably do it with tight tolerances and excellent design. But like I said earlier, if it works for you.
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07-21-2011, 08:39 PM
#45
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Wow. Kinda sensitive today, aren't you, hustler.
Well, I don't give a rat's *** how you set up your steering rack, but I'm pretty sure your bodge isn't how Porsche get's their superior feel; I suspect they probably do it with tight tolerances and excellent design. But like I said earlier, if it works for you.
Well, I don't give a rat's *** how you set up your steering rack, but I'm pretty sure your bodge isn't how Porsche get's their superior feel; I suspect they probably do it with tight tolerances and excellent design. But like I said earlier, if it works for you.
For Trey I'd want to know more about the white knuckle experience. More details. What is going on at what times, what types of turns and what else is going on at the same time. This may help come up with some ideas if there are any left you haven't yet tried.
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07-21-2011, 08:55 PM
#46
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My view on converting racks from power to manual is that only ONE rack/pinion seal is necessary. This is the one that lives at the steering input spline end of the pinion shaft. All of the other sealing is taken care of by your accordion boots which need to be in good condition.
So I remove the cylindrical spool valve with it's four o-rings. The other seals in the aluminum casting. The seal at the center of the rack that everyone removes. The one inside the cylindrical insert support that gets steel-ring retained into the passenger side end of the black rack housing tube. And the one that lives in the housing near where the black steel housing connects to the aluminum casting. Any other seals that do not touch the rack or pinion can stay. They have no effect on the steering. For instance, there is an o-ring on the outside of the cylindrical insert that can stay, not that it will do much of anything.
When you depower a rack like this, you can operate it with two fingers on the input shaft on an uninstalled rack. Unless you are a he-man like Trey, in which case you can just Chuck Norris think about it and it will move.
Here are most of the seals and crap I pulled on a recent conversion. There may be a few more. Again the idea is to wind up with one seal touching the moving bits, the steering input seal.
https://www.miataturbo.net/attachmen...1&d=1311296064
So I remove the cylindrical spool valve with it's four o-rings. The other seals in the aluminum casting. The seal at the center of the rack that everyone removes. The one inside the cylindrical insert support that gets steel-ring retained into the passenger side end of the black rack housing tube. And the one that lives in the housing near where the black steel housing connects to the aluminum casting. Any other seals that do not touch the rack or pinion can stay. They have no effect on the steering. For instance, there is an o-ring on the outside of the cylindrical insert that can stay, not that it will do much of anything.
When you depower a rack like this, you can operate it with two fingers on the input shaft on an uninstalled rack. Unless you are a he-man like Trey, in which case you can just Chuck Norris think about it and it will move.
Here are most of the seals and crap I pulled on a recent conversion. There may be a few more. Again the idea is to wind up with one seal touching the moving bits, the steering input seal.
https://www.miataturbo.net/attachmen...1&d=1311296064
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07-21-2011, 10:39 PM
#47
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I used to remove the seals at either end of the rack too, and greased the end of the rack where it goes through the big aluminum carrier, but I've since changed my mind about that.
I now leave in the seals in the aluminum carrier, and the other seal that keeps the hydraulic fluid within the rack cylinder just before the toothed section. The reason is that I now use hydraulic fluid (HF) to lubricate the carrier instead of grease because there's less friction that way. The shaft through the aluminum carrier is already designed to be lubed by HF, and with HF being roughly the viscosity of water, there's no significant friction at the seals using HF. After doing four racks I really can't tell the difference in friction between the ones with grease and no seals, and the ones with seals and HF, but I can feel the difference sliding the shaft through the aluminum carrier.
By far the greatest source of friction is at the pre-load at the lash adjuster. The factory has a specification for setting the adjuster, the intent of which is to maximize gear tooth contact while minimizing lash, friction, and wear - but you can do better (or worse) by feel.
I now leave in the seals in the aluminum carrier, and the other seal that keeps the hydraulic fluid within the rack cylinder just before the toothed section. The reason is that I now use hydraulic fluid (HF) to lubricate the carrier instead of grease because there's less friction that way. The shaft through the aluminum carrier is already designed to be lubed by HF, and with HF being roughly the viscosity of water, there's no significant friction at the seals using HF. After doing four racks I really can't tell the difference in friction between the ones with grease and no seals, and the ones with seals and HF, but I can feel the difference sliding the shaft through the aluminum carrier.
By far the greatest source of friction is at the pre-load at the lash adjuster. The factory has a specification for setting the adjuster, the intent of which is to maximize gear tooth contact while minimizing lash, friction, and wear - but you can do better (or worse) by feel.
Last edited by Thucydides; 07-21-2011 at 10:58 PM.
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07-21-2011, 10:51 PM
#48
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I used to remove the seals at either end of the rack too, and greased the end of the rack where it goes through the big aluminum carrier, but I've since changed my mind about that.
I now leave in the seals in the aluminum carrier, and the other seal that keeps the hydraulic fluid within the rack cylinder just before the toothed section. The reason is that I now use hydraulic fluid (HF) to lubricate the carrier instead of grease because there's less friction that way. The shaft through the aluminum carrier is already designed to be lubed by HF, and with HF being roughly the viscosity of water, there's no significant friction at the seals using HF. After doing four racks I really can't tell the difference in friction between the ones with grease and no seals, and the ones with seals and HF, but I can feel the difference sliding the shaft through the aluminum carrier.
By far the greatest source of friction is at the pre-load at the lash adjuster, which I'm from now on going to call the Porsche Feel Duplicator (PFD); this should not to be confused with the more common use of the acronym, "Pretty ******* Dumb". The factory has a specification for setting the PFD, the intent of which is to maximize gear tooth contact while minimizing lash, friction, and wear - but you can do better (or worse) by feel.
I now leave in the seals in the aluminum carrier, and the other seal that keeps the hydraulic fluid within the rack cylinder just before the toothed section. The reason is that I now use hydraulic fluid (HF) to lubricate the carrier instead of grease because there's less friction that way. The shaft through the aluminum carrier is already designed to be lubed by HF, and with HF being roughly the viscosity of water, there's no significant friction at the seals using HF. After doing four racks I really can't tell the difference in friction between the ones with grease and no seals, and the ones with seals and HF, but I can feel the difference sliding the shaft through the aluminum carrier.
By far the greatest source of friction is at the pre-load at the lash adjuster, which I'm from now on going to call the Porsche Feel Duplicator (PFD); this should not to be confused with the more common use of the acronym, "Pretty ******* Dumb". The factory has a specification for setting the PFD, the intent of which is to maximize gear tooth contact while minimizing lash, friction, and wear - but you can do better (or worse) by feel.
For seals you decide to leave in place, there is also another option. Most tend to use a circular spring to pull the seal lip closer to the item being sealed. You can remove that and still achieve a good seal, but you'll have to check that it is working properly. If I have the time, when I redo a rack I like to mirror polish the OD. That can't hurt and the seals may like it too.
In the end do what seems right to you, there are many good solutions here.
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07-21-2011, 11:07 PM
#50
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That's interesting. I don't recall any grease on any of the racks I've disassembled. I guess the carrier locating bore get's lubed by whatever wisp of HF get's carried on the rack past the seal in normal operation? In any case, a bit of high quality grease sure couldn't hurt there.
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07-21-2011, 11:39 PM
#51
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I'm pretty strong and I've been specifically working on strengthening my rotators and it's made a difference. A year ago I was moving my hands around the wheel to make it easier, today I'm "up to snuff" and can leave my hands on the wheel and turn the steering wheel 180* without pain and with enough strength to not saw back and forth over the bumps.
I should also note that I did this mod after a huge kayaking trip where I floated 45-miles in 3 days on class-4 rapids, so that may have affected my initial feelings on the rack.
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07-22-2011, 08:05 AM
#53
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07-22-2011, 10:26 AM
#54
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The added resistence makes it easier to hold steering angle, lessening the sawing-action over bumps. When it was really loose with the 45in/lb w/ "45*back" it felt like I could race the car with two fingers on the wheel, making me exacerbate minor surface change based corrections. I was going over bumps and surface changes and it really felt like the wheel was getting jerked out of my hand. So I made a little protractor on the jam nut and cut that 45* in half and it magically changed the feel of the rack. The wheel feels heavier at speed and jerks less. I can still push the rack in and out by hand, but it feels better on the track.
I'm pretty strong and I've been specifically working on strengthening my rotators and it's made a difference. A year ago I was moving my hands around the wheel to make it easier, today I'm "up to snuff" and can leave my hands on the wheel and turn the steering wheel 180* without pain and with enough strength to not saw back and forth over the bumps.
I should also note that I did this mod after a huge kayaking trip where I floated 45-miles in 3 days on class-4 rapids, so that may have affected my initial feelings on the rack.
I'm pretty strong and I've been specifically working on strengthening my rotators and it's made a difference. A year ago I was moving my hands around the wheel to make it easier, today I'm "up to snuff" and can leave my hands on the wheel and turn the steering wheel 180* without pain and with enough strength to not saw back and forth over the bumps.
I should also note that I did this mod after a huge kayaking trip where I floated 45-miles in 3 days on class-4 rapids, so that may have affected my initial feelings on the rack.
https://www.miataturbo.net/attachmen...1&d=1311344651
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07-22-2011, 07:25 PM
#57
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It's really not difficult. In addition to the flyinmiata write up, I also read the miatabusa site. I welded my own pinion making three tack welds each at 120 degrees around the perimeter then filled in between them 1 at a time, allowing it to cool between. I also cut off the line fittings on the rack body and welded them closed. I removed the recommended seals in the write-ups. I also replaced the boots. Got em at car quest for around $15 for the pair. The improvement is worth it.
I also installed the 93LE/R package endlinks to help with bump steer. I may end up shimming the rack up a little in the future to help even more.
I keep reading about the dropped spindle and re-designed uprights. What is changed and how is it an improvement?
I also installed the 93LE/R package endlinks to help with bump steer. I may end up shimming the rack up a little in the future to help even more.
I keep reading about the dropped spindle and re-designed uprights. What is changed and how is it an improvement?
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