Yes sir I actually do. I'll check for you tomorrow when I'm working on it
Sir? I had to look over my shoulder to see if my dad was standing behind me
I knew someone would have one handy... Asking because another member is trying to fit a Honda S2000 electric rack into a Fiero. Seems the S2K rack might be too long...
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10:02 PM
olejoedad Member
Posts: 18236 From: Clarendon Twp., MI Registered: May 2004
Ironically, I did measure a pre 88 just the other day for an odd reason. The threaded to threaded (not the housing) measure is 28.5 inches.
-Dave
quote
Originally posted by dobey:
The S2K rack shaft end-to-end without any of the tie rod hardware is 32 inches. Complete assembly from S2K with all tie rod hardware is 57 inches. How long is the Fiero rack shaft end-to-end? I think it's a fair bit shorter than that, no?
Hmmm, could you put shorter inner tie rod ends on the S2000 rack? Or possibly cut deeper threads on the S2000 inner rods?
Shorter tie rods will not work, you need the pivot-point to be in the same location. oving that picot point further out on the shaft will cause bump-steer...
Anyone with a rack out of the car, if you've got the tie rods and boots off, if you could turn the rack full tilt in both directions, and take pictures of both ends of the rack at full tilt in both directions, that would be very helpful. Thanks!
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07:54 PM
PFF
System Bot
IFLYR22 Member
Posts: 1775 From: Tucson, AZ. Registered: May 2007
Anyone with a rack out of the car, if you've got the tie rods and boots off, if you could turn the rack full tilt in both directions, and take pictures of both ends of the rack at full tilt in both directions, that would be very helpful. Thanks!
I have 2 pre 88 racks out of cars. One has inner and outer tie rods on it, the other has nothing on it. One has been on a shelf for about 8+ years (the one with nothing). The other is fresh out of a car. Define "full tilt in both directions". What are you looking for?
-Dave
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09:08 PM
slicknick Member
Posts: 385 From: Jacksonville, FL Registered: Feb 2010
Originally posted by IFLYR22: I have 2 pre 88 racks out of cars. One has inner and outer tie rods on it, the other has nothing on it. One has been on a shelf for about 8+ years (the one with nothing). The other is fresh out of a car. Define "full tilt in both directions". What are you looking for?
-Dave
If you turn the input shaft as much as you can for "left turn", where is the passenger end of the rack at, and the reverse for full "right turn" on the input shaft. Basically, how far into the housing, does the rack actually go.
An '88 rack is a hair under 51" tip to tip. That's to the end of the threaded section without the outer tie rod ends. That's what you wanted, right?
No. The length of the steering rack shaft/gear itself, without anything attached on the ends of it; no CV boots, no tie rods, no steering damper. Just the solid steel rod with teeth cut into it that goes inside the housing, only.
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10:07 PM
Blacksheep Member
Posts: 680 From: Oregon, United States Registered: Sep 2003
my steering rack is pretty messed up, the bearing near where the input shaft/pinon goes into the housing disintegrated and the rack is missing its bushing at the moment so my measurements are no where near exact but I put the shafts back in and turned it as far to each side as possible trying to keep everything near center (I did have the rear bearing on the input shaft to help). This is what I got
It looks like it goes into the rack about 1/2-3/4in. and sticks out about 5 3/4in. or so? The longer rod with the teeth is 28 1/2in. not including the little areas on the end with the threads (they are just over 1/2in.) The teeth on the longer shaft are about 7 1/2in.
This is a rack from an 88 formula. And again my measurements are not exact, but hopefully close enough to give you some kind of useful info.
Originally posted by Blacksheep: This is a rack from an 88 formula. And again my measurements are not exact, but hopefully close enough to give you some kind of useful info.
Thanks! Quite helpful. Hopefully I can pull the broken S2K rack apart today.
I have an 88 rack that was sitting behind my computer in pieces, I don't have the inner or outer tie rod ends here tho. I have
Is that 88 rack showing 32" end to end? Looks like your tape starts at the 3" mark. If it really is 32", then the S2k rack would be VERY close
quote
Originally posted by dobey: The S2K rack shaft end-to-end without any of the tie rod hardware is 32 inches. Complete assembly from S2K with all tie rod hardware is 57 inches. How long is the Fiero rack shaft end-to-end? I think it's a fair bit shorter than that, no?
[This message has been edited by ALJR (edited 06-22-2011).]
Originally posted by ALJR: Is that 88 rack showing 32" end to end? Looks like your tape starts at the 3" mark. If it really is 32", then the S2k rack would be VERY close
No, it's showing 28.5" (not counting the threaded portion on the ends). Which is the same as the 84-87 rack. Notice how the left end the tape measure starts around 3" and not 0.
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12:47 PM
nitroheadz28 Member
Posts: 4774 From: Brooklyn, NY Registered: Mar 2010
Originally posted by ALJR: I agree... But it is infinitely more difficult to shorten a rack then it would be to extend it...
I'm not sure that shortening the rack is really a requirement. I wish Blooze's thread had technical drawings of the front suspension, like he has for the rear suspension. Of course that's on an 88, and it might be slightly different on 84-87. But it would be very helpful for seeing how it could work. And I think a lot of people are incorrectly using the "bump steer" argument in a lot of these steering threads.
Originally posted by ALJR: I respectfully disagree...
What would you call the front tires toeing-in as the suspension travels up or down?
If both wheels rise together, it's bump steer. If one wheel rises and the other falls (one has increased toe in, and one increased toe out), it is roll steer. But blindly assuming that either of those will increase with a longer steering rack is incorrect. Sure, if you use the full stock length tie rods, it will cause toe out. But since we're already having to modify mounts and use different length tie rods, it is very possible to maintain correct suspension geometry, with a little bit of math and work. My real concern is turn radius. I don't want the wheels turning far enough to rub the wheel wells, and I don't want it not turning far enough to have at least the same radius as stock.
Sure, if you use the full stock length tie rods, it will cause toe out. But since we're already having to modify mounts and use different length tie rods, it is very possible to maintain correct suspension geometry,
Its not the length of tie rod that presents the problem, its the inner pivot joint. If that joint is in or out from center, its angle will not corrispond (or match) the angle of the control arm. This difference in angle translates to the tie rod pulling in (it not really moving) when the suspension travels up or down. So if you hit a bump or dip, the wheels will toe out a degree or two...
Originally posted by ALJR: Its not the length of tie rod that presents the problem, its the inner pivot joint. If that joint is in or out from center, its angle will not corrispond (or match) the angle of the control arm. This difference in angle translates to the tie rod pulling in (it not really moving) when the suspension travels up or down. So if you hit a bump or dip, the wheels will toe out a degree or two...
But you're assuming that the rack is mounted in the exact same location as stock. We're already moving the brackets to fit the new rack, and in doing so we can also drop the rack and correct the tie rod angles. There are all sorts of adjustments that can be made to have zero bump steer with a longer (or shorter) rack. It just happens that shorter racks are easier, simply because it's easier to add length with adapters. It's a rather simple engineering problem is all.
Originally posted by dobey: But you're assuming that the rack is mounted in the exact same location as stock. We're already moving the brackets to fit the new rack, and in doing so we can also drop the rack and correct the tie rod angles. There are all sorts of adjustments that can be made to have zero bump steer with a longer (or shorter) rack. It just happens that shorter racks are easier, simply because it's easier to add length with adapters. It's a rather simple engineering problem is all.
Ok, let me know how it works out for ya Dropping (or raising) the rack will not make up for an overall longer length steering rack; nor will using shorter tie rods. The issue is the inner pivot point (inner tie rod joint) on the rack in relation to the inner pivot point of the suspension arms. If these pivot points are not the same (and you do not change the outer tie rod location; make it further out from sock), then you will have a change in steering as the suspension travels up/down. Making it that much more important to mount the rack in the same location as stock...
If the outer tie rod mount is (just making up a number) 5" above the outer control arm joint. Then the inner tie rod joint must be mounted at the same height or distance from the inner suspension arm bushings. Have a difference between the two will cause changes in steering geometry as the suspension travels up/down...
[This message has been edited by ALJR (edited 06-24-2011).]
Originally posted by ALJR: Ok, let me know how it works out for ya Dropping (or raising) the rack will not make up for an overall longer length steering rack; nor will using shorter tie rods. The issue is the inner pivot point (inner tie rod joint) on the rack in relation to the inner pivot point of the suspension arms. If these pivot points are not the same (and you do not change the outer tie rod location; make it further out from sock), then you will have a change in steering as the suspension travels up/down. Making it that much more important to mount the rack in the same location as stock...
If the outer tie rod mount is (just making up a number) 5" above the outer control arm joint. Then the inner tie rod joint must be mounted at the same height or distance from the inner suspension arm bushings. Have a difference between the two will cause changes in steering geometry as the suspension travels up/down...
I will. And I can tell you it will work out great.
As long as everything is aligned correctly, it will be fine. A bit of observation and math can tell us exactly where to place everything in the car.
That article only proves what I have been saying... Your not going to be able to shim out the bumpt steer w/ an almost 2" longer pivot point. That means you would have to use a 2" shorter tie rod...
from the article: "In order to accomplish zero bump the tie rod must fall between an imaginary line that runs from the upper ball joint through the lower ball joint and an imaginary line that runs through the upper a-arm pivot and the lower control arm pivot. In addition, the centerline of the tie rod must intersect with the instant center created by the upper a-arm and the lower control arm (See diagram below)."
Originally posted by ALJR: That article only proves what I have been saying... Your not going to be able to shim out the bumpt steer w/ an almost 2" longer pivot point. That means you would have to use a 2" shorter tie rod...
Yes, different tie rods are going to be needed anyway. The way they attach to the S2K rack is not the same as how they attach to the Fiero rack. So there's no reason they can't also be shorter. Nobody ever said we'd use the stock Fiero ones (or even the stock S2K ones). Tie rod length is an easy problem to solve as well. None of these issues are actually hard problems. They are all things that have been solved again and again in other cars.
Lowering also changes bump steer, and nobody on here goes off on wild tangents about how you can't lower your car because the bump steer will be worse to deal with. And I'm pretty sure most of them don't move the rack and adjust the tie rods to fix the increase in bump steer when they lower their cars.
I'm past the bump steer issue (and was before it was brought up), and will be moving on to the hard problems, as soon as I can.
[This message has been edited by dobey (edited 06-24-2011).]
Yes, different tie rods are going to be needed anyway. The way they attach to the S2K rack is not the same as how they attach to the Fiero rack. So there's no reason they can't also be shorter. Nobody ever said we'd use the stock Fiero ones (or even the stock S2K ones). Tie rod length is an easy problem to solve as well. None of these issues are actually hard problems. They are all things that have been solved again and again in other cars.
Lowering also changes bump steer, and nobody on here goes off on wild tangents about how you can't lower your car because the bump steer will be worse to deal with. And I'm pretty sure most of them don't move the rack and adjust the tie rods to fix the increase in bump steer when they lower their cars.
I'm past the bump steer issue (and was before it was brought up), and will be moving on to the hard problems, as soon as I can.
Your taking what I am saying too personally I am on YOUR side in trying to make this work...
Originally posted by ALJR: Your taking what I am saying too personally I am on YOUR side in trying to make this work...
Am not taking it personally at all. Just tired of seeing people blindly pull out the bump steer argument on this forum, without any consideration for the math and mechanics involved in it. And once the length difference was determined, all your posts are "well i guess we can't do it because of the bump steer" now. And I'm just saying it's not a problem, and I'm tired of seeing people talk about bump steer, which is such a minor problem with changing steering racks.
It's all good though, because I WILL make it work.
Not to stir up a hornest's nest, but ALJR, have a closer look at the last drawing in the link that dobey posted. What dobey's saying is that a new steering rack, if longer or shorter than the original, can be installed at a different height in the car and still achieve zero bump steer. Since the imaginary line drawn between the two inner control arm pivot points is slanted outwards from vertical at the top, then a longer rack could be mounted higher up in the chassis to get the inner tie rod joint to intersect the lines on both sides of the car. A shorter rack would have to be lowered.
That's only half the problem though, and forgive me if I'm wrong, but I'm not entirely sure that dobey has considered this part: The new height of the inner tie rod ends will dictate the new height of the outer tie rod ends, ie where they must attach to the knuckle, and that is not as easily accounted for. Bear with me for a second... to avoid bump steer, the new outer tie rod ends would have to connect to the knuckle at the height determined by the intersection of two lines: a sloped vertical line drawn between the outer balljoints, and a sloped horizontal line drawn from the roll center, outwards through the inner tie rod joint, and extended until it intersects the first line. In every case, if you lower or raise the steering rack (ie inner tie rod location) from it's original position, it will result in the need to relocate the height of the hole in the knuckle where the outer tie rod connects to it. In most cases this will mean a new knuckle. If you can achieve this, then you would still have zero bump steer.
You have to bear in mind though that while having zero bump steer is ideal, many, many hot rods and modified cars out there have some bump steer. Until they started offering user selected rack lengths in the '90's, basically every hot rod out there used stock Mustang 2 suspension and steering components on a narrowed front end. The result was bump steer. How much depended on how much narrower you made the front end. I'm just saying that people adapt their driving style to suit the nature of their cars. All suspension systems are a compromise between several performance factors, so while a little bump steer may not be ideal, you can easily learn to live with it. Heck, I would imagine that most people here drove their Fiero's without any knowledge of rear bump steer for many years before reading their cars suffered from it. I certainly was one of them.
Originally posted by Bloozberry: Heck, I would imagine that most people here drove their Fiero's without any knowledge of rear bump steer for many years before reading their cars suffered from it. I certainly was one of them.
And anyone on here who has lowered their car with aftermarket springs, or cut springs, or with drop spindles, or who have done any number of other things to their car, don't realize that they've increased the bump steer in their cars, and haven't corrected for it in the suspension. Rather, they correct with their driving. And I am certain that an acceptable level of bump steer can be had with the slightly longer S2K rack, in a Fiero.
I had considered what you mentioned with the tie rod ends, but I don't think it's a problem worth worrying about right now. I will conquer it when I get to it.
Thanks Blooz, I understand what your saying and its "basically" what I was "trying" to say. But the way you described and presented it is much more clear My main point is I think its going to be hard to adjust or shim out the effects of bump steer when the rack is 2" longer; two inches is quite a bit. I could see making adjustments for 1/4 or 1/2"...
Dobey, I really do not care what others do to there cars or what effect a mod had on them. If I am going to do something to my car, I would like it to be an improvement. You can do what ever you like to yours. This is just a discussion here, tossing ideas around; but to say "I will conquer it when I get to it" may be costly...
Originally posted by ALJR: Dobey, I really do not care what others do to there cars or what effect a mod had on them. If I am going to do something to my car, I would like it to be an improvement. You can do what ever you like to yours. This is just a discussion here, tossing ideas around; but to say "I will conquer it when I get to it" may be costly...
Why? Worst case scenario, I go wide track, move everything out 1.5" on each side, and end up with a widebody. I'm probably not the best person to offer such advice to. I'm also doing an LS4 + F40 6 speed swap. Not exactly the drop it in and fire it up kind of swap. Nobody else has completed one yet. It's just fieroguru and myself doing them, and we are both crazy.
Or maybe I make a custom rack gear, or modify a Fiero one. There are lots of options to make it work. Ideally, I'd like to go the route of minimal custom parts, of course. I'm pretty sure this can be done with custom mounting brackets and shorter tie rods. We'll see though.
[This message has been edited by dobey (edited 06-24-2011).]
