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PostPosted: Tue Dec 14, 2010 5:07 pm 
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If you look at the miata suspension arms you'll see that Mazda does it this way as well.
As far as the location of the steering rack, it should really be determined by numbers and not by space availability.
Plug your numbers into the wishbone software and see where the rack could be placed to make your front suspension work right.

Moti

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PostPosted: Tue Dec 14, 2010 5:55 pm 
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Yes. I didn't mean to imply that I was determining the rack location or length by the space available. I realize the rack and length is determined by the arm positions and angles.According to Wishbone, My IC is at 90.2 inches. I think my steering pivots are going to be a little over an inch above my lower arm inner pivot and slightly outside the line from inner upper pivot to inner pivot. It's my understanding that the steering pivot should be moved outward the same amount that the outer tie rod pivot is outside the upper ball-lower ball line as in this diagram.


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steering rack location.jpg
steering rack location.jpg [ 215.19 KiB | Viewed 1055 times ]
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PostPosted: Fri Dec 17, 2010 7:04 pm 
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Got my FU tubes and diagonal braces welded in the frame.Whew. They were not easy to position. Also, got the braces that run from the top of the FU tubes to the front bulkheat.


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PostPosted: Fri Dec 17, 2010 7:06 pm 
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Last couple of days, I've been working with the Wishbone program, trying to determine my rack length. Getting close, but still not ready to actually cut the rack just yet. Hopefully soon.


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PostPosted: Sat Dec 18, 2010 2:40 am 
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The pivot of the ball joint on the steering arm cannot be changed.
I found that the best way to locate the inner steering pivot was to draw a straight line between the upper and lower pivots.
YMMV.

Moti

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PostPosted: Sat Dec 18, 2010 10:02 am 
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Blackbird wrote:
The pivot of the ball joint on the steering arm cannot be changed.
I found that the best way to locate the inner steering pivot was to draw a straight line between the upper and lower pivots.
YMMV.

Moti

Yes, I know. The Miata steering arm lies outside the line drawn between the upper ball and lower ball(maybe and inch). It's my understanding that in this case the inner pivot needs to move outward that amount.So, I would draw a line between the upper and lower pivots and then move the rack pivot outward about an inch. Is this correct?


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PostPosted: Sun Dec 19, 2010 9:06 pm 
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Well, I've been playing with the control arms. Decided to put them on the car to see how they look. The upper arms are just quick mockups to get and idea.
Attachment:
front wishbones.jpg
front wishbones.jpg [ 500.93 KiB | Viewed 913 times ]
Here's a closer view. The upper arms are similar to Jack's. I'll probably use his for the real thing once I get a little farther along.I also put the steering rack on the frame and connected the tie rods. Guess what? The wheels really turn.
Attachment:
wishbone closeup.jpg
wishbone closeup.jpg [ 447.59 KiB | Viewed 913 times ]


Last edited by photoman on Sun Mar 13, 2011 12:28 pm, edited 1 time in total.

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PostPosted: Sun Dec 19, 2010 9:27 pm 
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Now that I've got the car actually on it's own wheels, I think I'll install the engine. I don't call it a motor. Goes back to when I was young. It was considered un-cool to call an engine a "motor'. Of course, I guess it really is a motor. There's Ford Motor Company, General Motors, etc. and of course, I do call the mounts,"motor mounts". Go figure.
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engine-1.jpg
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engine-2.jpg
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The door in the background is the door thru which the car will have to go to get out of the basement. How will I do that? I've got plenty of time to figure it out.
Attachment:
engine-3.jpg
engine-3.jpg [ 479 KiB | Viewed 909 times ]
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engine-4.jpg
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engine-5.jpg
engine-5.jpg [ 513.5 KiB | Viewed 909 times ]
Of course, installing the engine in this car is pretty easy. Just hoist it up and drop the transmission down, pulling down on the shifter to go under the upper tubes. It won't be so easy once all the other parts get installed.


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PostPosted: Mon Dec 20, 2010 11:42 am 
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i'm with you, it's an engine. to function as designed it takes 2 substances and harnesses useable power from their interaction, a motor does a conversion of one type of power to another (eg electric). .. do they even still teach that anymore??

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PostPosted: Mon Dec 20, 2010 12:06 pm 
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oldejack wrote:
i'm with you, it's an engine. to function as designed it takes 2 substances and harnesses useable power from their interaction, a motor does a conversion of one type of power to another (eg electric)


Yep, I learned the same semantics. However, that rule leaves me at a loss as to why those things are called a motorcycle or a motorboat... And then there's "Motor City", Detroit, not "Engine City"... I mean, would we have bought all those records if it had been called "Engtown" music??? 8)

I'm so confused. Jack, is it time for our medication again??? :D

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PostPosted: Mon Dec 20, 2010 12:33 pm 
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photoman wrote:
Well, I've been playing with the control arms. Decided to put them on the car to see how the look. The upper arms are just quick mockup to get and idea.
Attachment:
front wishbones.jpg
Here's a closer view. The upper arms are similar to Jack's. I'll probably use his for the real thing once I get a little farther along.I also put the steering rack on the frame and connected the tie rods. Guess what? The wheels really turn.
Attachment:
wishbone closeup.jpg

That looks like intereference to me, with a little bit of suspension travel the tie rod probably gets a little too friendly with the lower arm.
Do you have your numbers plugged into wishbone?

BTW, taking those 3 bolts that hold the shifter out will make your life easier when pulling the engine (motor? trans?) in and out of the car.

Moti

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PostPosted: Mon Dec 20, 2010 1:52 pm 
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Blackbird wrote:
photoman wrote:
Well, I've been playing with the control arms. Decided to put them on the car to see how the look. The upper arms are just quick mockup to get and idea.
Attachment:
front wishbones.jpg
Here's a closer view. The upper arms are similar to Jack's. I'll probably use his for the real thing once I get a little farther along.I also put the steering rack on the frame and connected the tie rods. Guess what? The wheels really turn.
Attachment:
wishbone closeup.jpg

That looks like intereference to me, with a little bit of suspension travel the tie rod probably gets a little too friendly with the lower arm.
Do you have your numbers plugged into wishbone?

BTW, taking those 3 bolts that hold the shifter out will make your life easier when pulling the engine (motor? trans?) in and out of the car.

Moti

Yes, that is interference, but it's not friendly since they're fighting for space..This is not the tie rod -rack combination I will be using. I just put the rack in place temporarily, just playing around. My rack will be shortened a good deal, and the pivot will be raised somewhat, however there may still be interference with the "real" rack position. If that occurs, I have another A-arm design which puts the ball joint on top of the plate, thereby lowering the angle of the arm.(not the angle from ball to pickup point) I appreciate you checking in and keeping an eye on me. I'm sure I'll make plenty of mistakes. Also, the shock mount isn't the real thing either. Just getting an idea of angle and clearence with the upper arm. How do you like my new aerodynamic shocks? They're cheap and available. Had PVC ones at first but when I decided to put the engine in, I wasn't sure about the extra weight, so I went with the galvanized ones.


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PostPosted: Mon Dec 20, 2010 1:55 pm 
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GonzoRacer wrote:
oldejack wrote:
i'm with you, it's an engine. to function as designed it takes 2 substances and harnesses useable power from their interaction, a motor does a conversion of one type of power to another (eg electric)


Yep, I learned the same semantics. However, that rule leaves me at a loss as to why those things are called a motorcycle or a motorboat... And then there's "Motor City", Detroit, not "Engine City"... I mean, would we have bought all those records if it had been called "Engtown" music??? 8)

I'm so confused. Jack, is it time for our medication again??? :D

I think it's time for a whisky, or is it whiskey?
English sure is strange.


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PostPosted: Mon Dec 20, 2010 2:05 pm 
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Blackbird wrote:
photoman wrote:
Well, I've been playing with the control arms. Decided to put them on the car to see how the look. The upper arms are just quick mockup to get and idea.
Attachment:
The attachment front wishbones.jpg is no longer available
Here's a closer view. The upper arms are similar to Jack's. I'll probably use his for the real thing once I get a little farther along.I also put the steering rack on the frame and connected the tie rods. Guess what? The wheels really turn.
Attachment:
The attachment wishbone closeup.jpg is no longer available

That looks like intereference to me, with a little bit of suspension travel the tie rod probably gets a little too friendly with the lower arm.
Do you have your numbers plugged into wishbone?

BTW, taking those 3 bolts that hold the shifter out will make your life easier when pulling the engine (motor? trans?) in and out of the car.

Moti

Here are my latest numbers in Wishbone.
Attachment:
Latest wishbone numbers.jpg
Latest wishbone numbers.jpg [ 343.37 KiB | Viewed 857 times ]

Not ready to cut the rack just yet. Still trying different numbers.


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PostPosted: Mon Dec 20, 2010 3:27 pm 
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Quote:
Photoman wrote: Yes, I know. The Miata steering arm lies outside the line drawn between the upper ball and lower ball(maybe and inch). It's my understanding that in this case the inner pivot needs to move outward that amount.So, I would draw a line between the upper and lower pivots and then move the rack pivot outward about an inch. Is this correct?


Rod-
When you shorten the rack you should not have an interference problem. It's my understanding that the pivot point at the rack end/ tie rod connection lies proportionally between the lower and upper A arm inner pivot points. It's described in Tanner's book about bump steer. Attached is the simple sketch as shown in his book. Ratio A/B must equal C/D. If this is met than the tie rod travels the same as the lower A arm.

Thanks for the quick response about the upper A arm angle and other questions.
Roy


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Bump Steer.jpg
Bump Steer.jpg [ 11.92 KiB | Viewed 844 times ]
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