Steering Rack swap?

[The Dark Side of Will]

Hello everyone. I spoke to EPAS and they are more than excited to work with us. We briefly discussed doing a custom kit that would go on the column but then they said we may be able to do a fully custom manual rack with electric power assist. I will update everyone when I speak to them again next week. Please let me know if either of these options seems interesting.

Be careful with that... there's VERY little room in the engine bay and around the rack to package the EPAS motor. That's why I was interested in their column mounted units.

[nando]

That doesn't actually reduce any force feedback.

I @$$ume that it's designed to transmit steering torque unassisted for long periods of time. I've never heard of one break.

No, but it reduces how responsive the steering is. Because when you turn the wheel, it doesn't immediately move the rack - the torsion bar has to twist first, up to whatever torque value it's designed for. I wasn't trying to say it would break..

Which is why, if you read that ZHP rack thread I posted above - some racks have better/more responsive feel than others, even if the ratio is identical. On the E90, the steering is really heavy, but that also gives it a lot of feel and responsiveness. The E30's steering in comparison is super light and mushy. I'm certain the design of the torsion bar on the E30 steering rack is the reason, and why it really doesn't work very well as a 'manual rack'.

[madman23]

Ok. So in speaking to the guys about the electric rack mod they said their rack cannot be customized to fit our spacing. We can go the rout of doing the electric swap which will allow you to change the steering feel and behing that put a steering quickener. Does hat sound like a good option to anyone?

[nando]

I did consider that too. A steering quickener would double the response (but also the effort). But honestly, I'm not interested much in electric steering. that sounds like a bunch of extra weight, complication, and taking up valuable space.

[The Dark Side of Will]

No, but it reduces how responsive the steering is.

The E30's steering in comparison is super light and mushy. I'm certain the design of the torsion bar on the E30 steering rack is the reason, and why it really doesn't work very well as a 'manual rack'.

Do you actually notice the torsion bar deflection *now*? or just poor force feedback?

Another part of the reason the iX steering feels mushy is that the suspension has essentially no caster. There's not good feedback from the front tires about when they start to slip. There are a lot of factors at play.

I did consider that too. A steering quickener would double the response (but also the effort). But honestly, I'm not interested much in electric steering. that sounds like a bunch of extra weight, complication, and taking up valuable space.

I'm pretty sure it takes up *LESS* space overall and weighs less overall, because if you're not running a hydroboost, you can ditch the power steering pump AND all the hoses associated with it.

The the effort change associated with the quickener depends on where it is relative to the spool valve or torque sensor. If the quickener is "downstream" of the spool valve or torque sensor, then there should be very little change in steering effort from adding one.

This is an advantage for the electric power steering, as divorcing the spool valve from the steering rack requires a lot of extra work.

With the Quaife rack, we wouldn't need steering quickeners either.

[nando]

To answer your question on feel - I am sure it makes a difference, because otherwise the ZHP 330i rack wouldn't feel different from the non-ZHP rack. They have the same ratios, travel, etc, the only difference is the torsion bar (which is thicker). The steering is noticeably heavier with more feedback.

Both electric *and* a quickener is not going to be less space. You gotta pack that somewhere.

I would be happy to remove the PS and all that complication though. Since I'm working on a swap, there's an extra cost associated with making all of that work too (I don't have a PS pump for this motor, and now I wouldn't have to buy one, fab hoses, buy a new reservoir, etc). I bet that all weighs easily 30lbs. Removing the reservoir would give me more space for a plenum too.

So perhaps the options of a manual rack and an electric booster would be enough to satisfy most people? I think I'd be perfectly fine with manual steering, personally, but I understand not everyone is (I think with how much weight I'm removing from the front, it will be fine). It's not like a steering quickener costs much less than a Quaife rack and pinion (you still need a bunch of couplers to make it work, fab a mount bracket, etc) - and the electric assist is already an investment on its own.

[The Dark Side of Will]

A Quaife is a "bolt in" affair... the quickener requires all the fab work you noted AND takes up extra room in the engine bay. That's what I find so attractive about the electric PS... it's all inside the firewall and does not take up any room in the engine bay.

[nando]

It also seems the quickeners are not well suited to street use - they need regular inspection/maintenance. They also put extra strain on your PS pump which will have to work 50-100% harder.

And they present a safety issue since you replace part of the column, which is collapsible in case of an accident, with a fixed part.

[Kershaw]

If it was around $500, $250 for the quaife rack and $250 for the electric assist I would be in.

[EyExR]

I'd be in, too. I'm willing to try anything out. I'm really disliking my steering right now.

[nando]

I haven't had a Friday off in like 2 months, unfortunately - so I haven't done anything with this yet. Hopefully that ends soon, 60 hour weeks is good for money but I have zero free time.

[EyExR]

Wow. And here I am hating a 35 hour work week... Let me tell ya - THIS guy (me) is cut out for retirement!! :)

Ok, Chris! I'll keep my eyes peeled...

[nando]

40 hours a week feels like part time. lol

but really, I'll dance as long as the music is playing.... I just hope this is an EP, and not a double album... ;)

[EyExR]

I'm at the point now where I think I just need to buy another rack. It's amazing to find places like rack doctor who charge around $250 and sites like ECS charge up to $1,200 for a re-manufactured rack. Why the drastic difference??? FCP has one for $342. Who do you trust?

I had purchased two manufactured racks from a somewhat unknown vendor and swear that both are bad. Steering wander that I've never been able to iron out by replacing EVERYTHING else. At my wits end.

[fresh_TD]

I'm at the point now where I think I just need buy another rack. It's amazing to find places like rack doctor who charge around $250 and sites like ECS charge up to $1,200 for a re-manufactured rack. Why the drastic difference??? FCP has one for $342. Who do you trust?



I had purchased two manufactured racks from a somewhat unknown vendor and swear that both are bad. Steering wander that I've never been able to iron out by replacing EVERYTHING else. At my wits end.

At least with rack doctor you get the $250 core charge back, once you ship your old rack back to them. At the end, it only cost $250 for a reman rack from them.

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