Rack and pinion - homemade Steeroids with GrandAm rack

Here you go Karsten,




I have a power rack Grand Am, new from junkyard, your rack being manual and shorter? makes it hard for me to comment on how it's rotated, all I can say is that the input coupling was hitting the frame, so I cut a crescent out of it with a hole saw....I have only TWO universals one at the column, one at the rack, and a DD shaft in between, it happens to have a rubber isolator in it, as this all came from various scrap cars...most of the parts are from a Lumina van, as I recall.....:crutches:
 

Attachments

  • Rack pix 001.JPG
    Rack pix 001.JPG
    685.3 KB · Views: 91
  • Rack pix 002.JPG
    Rack pix 002.JPG
    747.6 KB · Views: 87
MYBAD79 said:
Twin_Turbo said:
Something's dripping down there :D

Is the center bracket mounting pattern the same as on the power rack? Looks like it. I have a spare one from Speed Direct. Could come in handy sometime in the future if I convert to a manual rack setup.
Click to expand...

NO - the power rack is longer than the manual rack and easier to mount. I just finished the passenger side bracket and my rubber clamp mount (stock Pontiac GrandAm or GM Cavalier) is located 4" off the frame towards the center.
The power rack mounting point could be 3" closer to the passenger side frame rail....
The driver side is identical.

Let me know if you want a set of brackets :D
Click to expand...

I meant the center take off tie rod bracket
 
mrvette said:
Here you go Karsten,

I have a power rack Grand Am, new from junkyard, your rack being manual and shorter? makes it hard for me to comment on how it's rotated, all I can say is that the input coupling was hitting the frame, so I cut a crescent out of it with a hole saw....I have only TWO universals one at the column, one at the rack, and a DD shaft in between, it happens to have a rubber isolator in it, as this all came from various scrap cars...most of the parts are from a Lumina van, as I recall.....:crutches:
Click to expand...

Interessting that you used the GrandAm inner tie rod end location. your tie rods are about 7" longer than stock .... The 1" square tube that I use between the rod ends is 16.5" center hole to center hole, same as the C3 Corvette steering linkage. This way I am using stock C3 length tie rods.

We'll see how it turns out.... I figured if I duplicate the stock C3 inner tie rod end location the steering geometry is the same as stock....
 
MYBAD79 said:
mrvette said:
Here you go Karsten,

I have a power rack Grand Am, new from junkyard, your rack being manual and shorter? makes it hard for me to comment on how it's rotated, all I can say is that the input coupling was hitting the frame, so I cut a crescent out of it with a hole saw....I have only TWO universals one at the column, one at the rack, and a DD shaft in between, it happens to have a rubber isolator in it, as this all came from various scrap cars...most of the parts are from a Lumina van, as I recall.....:crutches:
Click to expand...

Interessting that you used the GrandAm inner tie rod end location. your tie rods are about 7" longer than stock .... The 1" square tube that I use between the rod ends is 16.5" center hole to center hole, same as the C3 Corvette steering linkage. This way I am using stock C3 length tie rods.

We'll see how it turns out.... I figured if I duplicate the stock C3 inner tie rod end location the steering geometry is the same as stock....
Click to expand...

I was told that stock steering geometry really needs longer tie rods to help with bump stear.....and so it seems my longer tie rods did help alot, even with them being 19" and 21" on the pass side....now here is the trick, I should have maybe made another block on the rack output, but how much and so forth I didn't know what to do, it's been working well for some dozen years now....that adapter block cost me 80 bux to have machined.... so reluctant to spend it again....it had to be cut/welded to move the tie rod ends up top of the block, instead of directly off the ends of the block, thank God for my welder buddy, who BTW, I took to the airport yesterday for a week's trip to Germany....and 30f weather....can't recall name of the town, but it's some 3 hours from Stuttgardt (sp?).....his fiance' is there for a month now, her father is deathly ill.....:sweat::(
 
Now I see what you did and why.... You moved the rack 1" off center towards the driver side, that way you cut a hole in the engine mount and got away with only 2 Ujoints. I'll position the rack the same way but I offset the tie rod attachment also- if your block was offset 1" towards the passenger side you could use two 20" rods instead of 19" and 21".

I think for now I'll just go with stock length rods, I want to drive it first before I make too many changes at once. It will be easy to replace the center square tube with a shorter one and use two longer tie rods ..... That can be done at any time and won't take much time at all....

Then I will have a true "apple to apple" comparison between stock length and longer tie rods and the effect on bump steer.
 
Ok, tack welded the passenger side in place, 4" off towards the driver side, should be very close to where I want it to be, driver side is not welded yet, just clamped in place for now ....

photo_zpsa63fdd34.jpg
 
THE ONLY reason I recall for mounting my rack toward the driver side was to allow clearance for the headers, and I had a old Vette set on there, I forget who from....sorry... at any rate a stock rams horn would work for sure, so would a L98 setup.....but I went with a cheap set from Schoenfeld, and they cleared the rack input just fine....so I was able to raise the input by tipping the rack forward on top, and notching the frame....

another reason I never went for a long arm on the rack output was to reduce various torque loadings on the rack traveler......too much twisting and shit from dynamics I didn't understand really well, I took the conservative route, and it's been fine.....but I"m not a racer....I drive quickly, but not balls out....

:surrender::eek:
 
If you try to center the rack you will clear the engine mount but then the angles are really bad and you need three U-joints like the steeroids kit......
 
MYBAD79 said:
If you try to center the rack you will clear the engine mount but then the angles are really bad and you need three U-joints like the steeroids kit......
Click to expand...

I STILL think that making my center mount about 4" to the right side, shortening the tie rod, and about a inch on the driver side....the tie rods would be equal length.....and up in the air, and keep the lateral/twist loading to a minimum.....but you know, it's been fine....

call it laziness if you will,.....BUT it works, kinda like the mounts, not much but really not much more is really necessary.....

:smash::surrender:
 
The off-center location of the rack is not a problem since you have to make a center link anyway. Moving the steering input connection to a convenient location simplifies the installation and make life a lot easier. Use an asymmetrical center link to put the pivot points of the linkage back in symmetry with the car center line. The wheels won't know the rack is offset.

Most posts on bump steer with experimental data show the tie rods need to be longer than stock. I installed the inner rod ends with the bolts horizontal for space reasons and to better shield the joints/seals with the safety washers. It's typically the outer tie rod ends that are adjusted down to do the final bump steer tuning so mount the rack as high as possible to minimize that efffect.

The 3/16 stock for the driver's mount should be plenty if you provide the proper load path. The force vectors are predominately along the axis of the rack. The driver side cast mounting flanges on the rack transmit those loads to the driver side bracket. The loads are in the plane of your gusset. The idea is to provide a load path from the rack to the frame. The mount must have a shear block to fit in the slot between the cast flanges and take the load off the mounting bolts. It would be best to attach the gusset(s) to the shear block.

Grampy
 
Grampy said:
The off-center location of the rack is not a problem since you have to make a center link anyway. Moving the steering input connection to a convenient location simplifies the installation and make life a lot easier. Use an asymmetrical center link to put the pivot points of the linkage back in symmetry with the car center line. The wheels won't know the rack is offset.

Most posts on bump steer with experimental data show the tie rods need to be longer than stock. I installed the inner rod ends with the bolts horizontal for space reasons and to better shield the joints/seals with the safety washers. It's typically the outer tie rod ends that are adjusted down to do the final bump steer tuning so mount the rack as high as possible to minimize that efffect.

The 3/16 stock for the driver's mount should be plenty if you provide the proper load path. The force vectors are predominately along the axis of the rack. The driver side cast mounting flanges on the rack transmit those loads to the driver side bracket. The loads are in the plane of your gusset. The idea is to provide a load path from the rack to the frame. The mount must have a shear block to fit in the slot between the cast flanges and take the load off the mounting bolts. It would be best to attach the gusset(s) to the shear block.

Grampy
Click to expand...

I read this a couple/few times and methinks you are describing my idea/concept/understanding of what to do on that driver side mount....I should have made the inner mount different, kept both tie rods at ~19" length, and at present elevation for the rods on the inside....but for a street driven car....it's fine, not worth the effort....



:smash:
 
Last edited:
Grampy said:
The wheels won't know the rack is offset.
Click to expand...

:thumbs: this is the best description I've heard/seen of what I tried to say...

I very likely end up using longer tie rods and bring the inner pivot point closer to the centerline but for now I want to be able to compare the rack with the stock steering ("apples to apples") ... so for now the tie rod length stays stock. Once I got a few miles on this setup I'll swap the center square tube with a shorter tube and longer tie rod tubes..... then I know what is changing what....
 
MYBAD79 said:
Grampy said:
The wheels won't know the rack is offset.
Click to expand...

:thumbs: this is the best description I've heard/seen of what I tried to say...

I very likely end up using longer tie rods and bring the inner pivot point closer to the centerline but for now I want to be able to compare the rack with the stock steering ("apples to apples") ... so for now the tie rod length stays stock. Once I got a few miles on this setup I'll swap the center square tube with a shorter tube and longer tie rod tubes..... then I know what is changing what....
Click to expand...

I had my car on jack stands, and so took another pair of stands and positioned the rack up where it was needed, and I was off a hair, so had to ding the oil pan up front a hair to clear the bellows, I bent the power/hydraulic lines down to the front a tad also....I cut the tie rod tubes, drilled holes in them got some 9/16th rod, welded through the holes then some tubing left over from a garage door was fine to make an outer sleeve, maybe a bit overkill, but they strong as shit....:smash:

Don't forget my comment about too much twist on the rack traveler due to too much torque from too long a center mount bar....I just being conservative on that comment, as I really dunno for sure....:twitch:
 
On another forum, one guy added a rail and linear bearing to help support the center link. He claimed it really helped stiffen things up.
 
rtj said:
On another forum, one guy added a rail and linear bearing to help support the center link. He claimed it really helped stiffen things up.
Click to expand...

I remember that one too,....sucker looked heavy though, as I recall....

AND didn't it use heim joints instead of stock tie rod ends???
 
mrvette said:
rtj said:
On another forum, one guy added a rail and linear bearing to help support the center link. He claimed it really helped stiffen things up.
Click to expand...

I remember that one too,....sucker looked heavy though, as I recall....

AND didn't it use heim joints instead of stock tie rod ends???
Click to expand...


Yes, speedway sells a heim joint with the tapered bolt, probably what he had too.

Linear bearings are light, if you go to big on the rail, that could get heavy.

I won't Likely be adding one.
 
MYBAD79 said:
rtj said:
Yes, speedway sells a heim joint with the tapered bolt, probably what he had too.
Click to expand...

Found that tapered bolt -AFCO #10270 ..... It says it's not for use with stock spindles, wonder why.....
Click to expand...

Legal cya?

I have them on both the Vette and Camaro. I think they come with the steeroids kit.
 
They sell another adapter bolt that is longer but only $9.99 each, it sure needs to be shortened, it's 5/8" threaded .... Made by AFCO, same brand as the other $26 bolt.....

I don't really see the advantage of using rod ends on the outer end of the tie rod, maybe it's more adjustable than the ball joint but since the inner tie rod end is adjustable I don't see the reason for using rod ends on the outer end....

The rod ends (heim joints) are more sensitive to dirt, another reason to use ball joints with dust boots. On the inner tie rod end I feel it's much easier to protect the heim joint from dirt....
 
You must log in or register to reply here.
Top