the ol' rack and pinion discussion

[lelio]

i know this has been talked about but im attempting my own conversion and was interested in some info, hopefully from NickVyse, you did the e21 rack right?

what was the dimension between the inside of the tierods and what was the amount of travel (in distance, not turns) from lock to lock?

I measured the stock 2002 stearing set up as ~16 inches (40cm) between the inner tie rods and ~8 inches (20cm) full travel . This was with the box and arms already out so i could have completely screwed up, please let me know if anyone knows better dimensions.

Im not too educated on how changing the pivote points would effect things, it seems like you could have problems where bumps would make the tire steer if you put it too far off, or maybe change how well the steering "finds" straight if you get my meaning.

what im getting to is, did the e21 rack pivot in about the same place? and if not did you notice any symptoms similar to the ones mentioned above?

I realize you had the turning radius problem because of the longer arms on our cars. Shortening the steering arm is something i can play with. how is your's coming along lately?

pretty much shortening the steering arms looks like a neccesity, even if you could find the perfect rack and pinion set up with 16 inches between the tie rods and 8 inches travel that would put your steering column only 4 inches out from centerline of the car , and were only a few inches out from the firewall. i guess that's not impossible, but it would require some pretty tight steering column joints.

[NickVyse]

Morning,

I've not fitted my shortened steering arms yet after deciding that I need to move the position of my e21 rack further forward by the same amount as I've shortened the arms.

As it's set up now (standard arms, end of rack mounted in line with them at dead centre) I don't experience any of the problems you note.

Self centering is just about right (and I think it's more a factor of caster than anything else), an no weird feed back. In fact, very little feedback due to the slower turning ratio.

I'm having fun with the m2 on the road at the moment and have my new 1600-2 in bits, so that's taking all my spanner time. I'll post results as and when they happen later in the year.

Good luck.

BTW I saw your post about the nissan rack - someone has fitted a similar rack from an e30 that mounts ahead of the wheels. Swap the steering arms left to right and there you go - although the next problem is probably the roll bar, which you could put behind the front axle (Schnitzer did), but you're into the realms of why fecking bother!

[TJW]

I cannot give you any info on the dimensions because I didn't bother, I just took the e21 rack,centered it, bolted it to a plate welded to the crossmember, centered the wheels cut approx. 10mm of thread off the track rod ends to fit and there you go, actually there was a bit more than that but it wasn't difficult.

This is a RH drive so in order to fit a good exhaust you have to fit a rack.

The downside is the steering is very light as I have not cut the steering arms thus they become big levers and of course more turns lock to lock.

It maybe worth looking at a 70's 5 series as the arms have a similar fitting on the strut and maybe shorter but I have not checked that.

Bump steer has not been an issue, although I have not measured it I have driven this (race) car across the rumble strips a few times and not noticed it, even so there are a number of things you can do to eliminate bump steer.

A few pics.

[robspeed]

I cannot give you any info on the dimensions because I didn't bother, I just took the e21 rack,centered it, bolted it to a plate welded to the crossmember, centered the wheels cut approx. 10mm of thread off the track rod ends to fit and there you go, actually there was a bit more than that but it wasn't difficult.

This is a RH drive so in order to fit a good exhaust you have to fit a rack.

The downside is the steering is very light as I have not cut the steering arms thus they become big levers and of course more turns lock to lock.

It maybe worth looking at a 70's 5 series as the arms have a similar fitting on the strut and maybe shorter but I have not checked that.

Bump steer has not been an issue, although I have not measured it I have driven this (race) car across the rumble strips a few times and not noticed it, even so there are a number of things you can do to eliminate bump steer.

A few pics.

NICE... i will move this over to the FAQ CONSTRUCTION ZONE board ... if there is no other input here... can you show what you did with the U-joints more closer-upper/detail?? EDIT: err, tell us how you did that.. parts source etc

[TJW]

The steering u/j's were purchased here (good service and recommended)

http://www.borgeson.com/ you can see quite a few angles.

I can only find one closer photo of the u/j's, but fitting was a case of trying and if it works then it must be right then clamping and welding.

[Guest Anonymous]

has anyone made the equivalent measurements on a 320 i?

If so what did they measure? Is this information available on the E21 forum?

[robspeed]

has anyone made the equivalent measurements on a 320 i?

If so what did they measure? Is this information available on the E21 forum?

uhh, e21s are already rack-n-pinion'd!! no conversion needed (unless you meant to RHD???)

[Guest Anonymous]

Sorry Rob, I should have been more clear. I was asking if anyone had measured the dimensions of the front suspension and steering linkages for an E21. IIRC, the steering rack bolted to the rear of the front cross member, and the tie rod ends extended out (I have a complete rack and pinon set waiting to install).

But at what angle do the tie rod and steering rods sit at dead center?, how long are the steering rods on a E21?; what are the respective tie rod and wheel angles at maximum lock?

This type of information is needed to reverse engineer it and come close to a factory setup and have the type of steering worthy of a Bimmer.

My apologies for not being clearer the first time around.

[robspeed]

Sorry Rob, I should have been more clear. I was asking if anyone had measured the dimensions of the front suspension and steering linkages for an E21. IIRC, the steering rack bolted to the rear of the front cross member, and the tie rod ends extended out (I have a complete rack and pinon set waiting to install).

But at what angle do the tie rod and steering rods sit at dead center?, how long are the steering rods on a E21?; what are the respective tie rod and wheel angles at maximum lock?

This type of information is needed to reverse engineer it and come close to a factory setup and have the type of steering worthy of a Bimmer.

My apologies for not being clearer the first time around.

ahhhh sorry for being so dense!!

[DawieM3]

See pic`s below,

Rack is a E30 M3 LHD rack mounted in a RHD.

[NickVyse]

See pic`s below,

Rack is a E30 M3 LHD rack mounted in a RHD.

Interesting idea, but what made you want power? Is it a race car with huge rubber?

[DawieM3]

Hello Nick,

E30 M3 is a quick rack and just happend to have one spare lying around the garage from my track car.

May not use the power side of it, as still undecided if it will be for track or a road / track car.

Engine went in today, just simply slid in.