E28 steering rack

[Silver Fox 43]

You're right Heath, just lost in translation. I don't know of any BMW racks which are quicker than this?

[DRTDVL 0]

ahh right i get where i lost you - inners...

sorry should have said internals of the rack...

[CamB 48]

A much more important factor is matching the **travel** of the rack - no point in having 2.5/3.25/whatever turns if it can't turn your wheels from (the old) full lock to full lock and you have the turning circle of a truck. For instance (and I can't remember the details), one of the Z3 racks is the same ratio as the E36 rack, but fewer turns lock to lock ---> it just gives less total steering angle.

When swapping racks, the key is to ensure the tie rod attachment point (I think its called the kingpin) is the same on the donor car and your car. If its further from the strut, you get less steering angle per turn of the wheel (and vice versa).

Actually, key points as I understand them are:

- rack should have tie rod ends attach to it at same distance as the box's tie rod ends attached to the pitman arms (avoid changing ackerman angle and, I think, bump steer)

- rack should be mounted at the right height to ensure there is no change in the relationship of the lower arms and steering arms, to avoid bump steer.

- rack should have same travel, or you will need to change the point at which the tie rods attach to the struts to match the donor vehicle, to ensure you get enough steering angle

Note: - I actually don't know that much about suspension geometry, so anyone feel free to correct me.

Edited November 27, 2009 by CamB

[Silver Fox 43]

Just checked Cam and it seems the box has 160mm of travel, the new rack has 150mm of travel, so pretty close, and still hoping it will work out. All the other points you raise are Ok I think at this stage. Will find out for sure soon, some of the things like tie rod angle I can still alter as I fit it up.

[CamB 48]

Sounds like its in the ballpark, and you have a little bit to lose (as far as ratio goes), and I am sure you'll have enough steering angle for a race car (just don't go drifting, ok :D)

[Silver Fox 43]

Oh no, it don't work, a whole days work down the gurgle because I believed Marty and Brent.

The E39 rack must push on the front of the wheel, cause it turns me the wrong way.

Back to the drawing board, and that Nissan's looking good again.

[kerry 10]

oh no alright lol, go the japa rack i guess

[gmccormack 0]

Why limit yourself to Nissan racks??, just about all front wheel drives use racks that steer from behind the king pins.

[Silver Fox 43]

I believe a lot of them mount on the firewall tho?

[gmccormack 0]

I believe a lot of them mount on the firewall tho?

Some might, mine doesn't. There must be thousands of variations to choose from

[DRTDVL 0]

the pug ones mount to the sub frame...

i'll check on the evo and mirage cyborg ones for you, i know those you can get in 2.2, 2.6, and 2.8 lock to lock

[Silver Fox 43]

Mmmm, VR and VS holdens as well it seems.

[topcat 11]

Oh no, it don't work, a whole days work down the gurgle because I believed Marty and Brent.

The E39 rack must push on the front of the wheel, cause it turns me the wrong way.

Back to the drawing board, and that Nissan's looking good again.

http://www.mye28.com/viewtopic.php?t=57271...9+steering+rack

[DRTDVL 0]

David,

You got me thinking over the weekend about a few things:

1) It's going to be rather hard to find a direct swap out rack, unless you just happen to luck out.

2) Can you replace the internals of the rack with that from anouther brand/model, leaving you to use the factory mountings for the main body housing?

3) Do you have a spare rack you could pull apart and take to a gear cutters and get them to make you a new rack/pinion gear set (then make a bunch and sell them to the other BMW boys) - I was looking at getting some torsion bars done in nz - i was going to get the spring steel from Snell Springs and then take the cut bars to someone like Gearcutting Services then hardened by someone else - from my costings it was going to work out about 400 less than importing them from the uk...

The Evo 6 RS has a 2.2 lock to lock, the Mirage Cyborgs have a 2.6 lock to lock. I'm asking the mivec boys if they have a spare rack i can use to dummy up with for the pug, if i get it i can see about popping over to look at if it will fit yours....

[Silver Fox 43]

Hi Heath, the measurements for mine are,

o/all length 1180mm, outer ball joint to outer ball joint,

length of rack body, 560mm, rack end to rack end,

rack throw from full lock to full lock, 150mm.

As I see it, if you look at the critical factors, the rack throw from side to side of 150mm is the main factor. I can't see how any of the other things are as important, so long as you can get the rest of the setup geometry right as far as positioning the rack goes.

As for getting things machined, it won't help with this body as the pinion comes in under the rack, therefore when you turn right, the rack will always come out the right side, and vice versa, if the pinion enters above the rack, when you turn right the rack will go left, which is what I want.

Going to go see a wrecker on wednesday to try a few combinations, will take my tie rod ends and see what I can come up with.

Edited November 29, 2009 by Silver Fox

[Silver Fox 43]

http://www.mye28.com/viewtopic.php?t=57271...9+steering+rack

Unless I'm going mad, and that's not beyond the realms of possibility, if you look at the first pic in his post Marty, turn the pinion to the right, and, as it's under the rack it will push the rack out the right side, and turn his wheels to the left. Not the direction you want to go, is it? Please tell me I'm wrong.

Edited November 29, 2009 by Silver Fox

[DRTDVL 0]

left hand driver....

[CamB 48]

No it doesn't matter - David's right. For a rear mounted rack the pinion goes on top of the rack. For a front mounted one it goes under.

[Silver Fox 43]

Thanks Cam, I'm not going mad am I.

I wonder if someone should tell him before he mounts it all up?

Edited November 29, 2009 by Silver Fox

[*Glenn* 854]

Just a thought Dave... try getting a L/H rack and fit it upside down with the head unit on the drivers side... could that work ??

Edited April 25, 2011 by *Glenn*

[Silver Fox 43]

Yes it would Glenn, shipping from the states is the killer there, will see what I can find here first.

[DRTDVL 0]

As for getting things machined, it won't help with this body as the pinion comes in under the rack, therefore when you turn right, the rack will always come out the right side, and vice versa, if the pinion enters above the rack, when you turn right the rack will go left, which is what I want.

Got a body that does fit in the orientation that you want but too slow? Could get the rack and pinion made for that body...

I'm just thinking that it's a lot of effort to hunt and remove racks test fit, modify, re-gig, etc... when it could be much simpler and cheaper to get it made...

If i remember correctly the 32 / 28 spline count ends (offset #'d ends) for the torsion bars where going to cost me under $60...

[Silver Fox 43]

I've found a wrecker with a wall stacked with racks in neat rows, ideal for me to look at and try to get it sussed I think.

[BM WORLD 1283]

are you sure that bmw rack you brought is from a e39 ???

looks like a e36 or e46 one

[Silver Fox 43]

Better be, came from JG BMW in Hastings. Will be checking tho, part numbers don't match to anything I can find.Looks like the RHD version of the one in Marty's link.

Edited November 30, 2009 by Silver Fox