89-05 ELECTRIC Steering Rack, Adjustable!!!
 

For sale on eBay for $1050. On sale through MT for $975. Message me for more info.

Complete Column Based Electric Power Steering (EPS) Conversion Kit for all 1990-2005 Mazda Miata. This system's assist amount is fully adjustable on the fly to the driver's taste via a Knob that can be mounted anywhere you prefer. This is Full DIY plug and play kit. Installation is very simple and should average around 3 hours. Please email any installation questions and will gladly send you some basic install instructions. Allows you to have the best of both worlds by removing the bulky and power using OEM Power Steering Set Up from your Miata and having an even better feel for your vehicle by being able to dial in the amount of assist you desire. Cleans up the engine bay nicely, saves some weight (About 5 LBS and Provides Slightly Better Weight Distribution As well) and some power and works better than OEM Power Steering! Wonderful Solution for Miatas with Big or Custom Turbo Set Ups or that have had engine swaps like LS Miata, K Miata, V8 Roadsters, Monster Miata and etc... Great for Autocross, Drifting, Time Attack, Road Course etc... Mounted under that dash and grafted to the factory steering column allowing an OEM fit and OEM Function (OEM Turn Signals, OEM Ignition Switch and Key, OEM Steering Column Lock, OEM Steering Wheel and Airbags etc... will all be able to be retained. Any OEM Miata Steering Rack will work with this Conversion Kit. This system will even work with the OEM Power Steering System Still Installed on your Miata and Just the Power Steering Belt Removed. We also offer a Professional Power Steering Rack Depower service as well for those that do not want to undertake that themselves. There is a $199 Steering Column Core Fee that will be billed separately before your Miata EPS Conversion Kit is Shipped. Once we received your Core Steering Column that is found to be in Good Re-usable condition you will receive the Steering Column Core Fee Back in Full. You may also elect to send in a Good Re-usable condition Steering Column core before we ship to avoid the core charge all together. We only need the bare steering column with no ignition switch on it or anything else attached to it. Easiest way to remove the ignition switch from the column is by cutting a slot in the top of the steering column bolts with a die grinder or Dremel so that they can be removed with a flat head screw driver. https://cimg3.ibsrv.net/gimg/www.mia...c674802f06.jpg
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So this will work with all PS components removed but an untouched rack? Meaning I ditched all PS components but haven't taken the rack apart to cut the seal and weld the pinion. How gradual is the adjustment? Can you add a very minimal amount to ease up on a typical depowered feel while keeping it still much like a depowered rack?

^ This is a good question. I'm not a potential customer, but for those who are, what are the expectations for the rack? Unmodified PS rack, welded PS rack, OEM manual rack? If PS rack, recommendations as to seal-cut vs. looped lines vs. something I haven't thought of?

(As an aside, this is really fucking awesome.)

Yes, since you can test how you like a de-powered Miata by simply removing the belt. It has more resistance than a proper depower, therefore you'd have a higher setting on this electrical rack for the same level of assist vs. a de-powered rack.

One last question. By dialing the adjustment knob fully "down" will the assist be off or slightly engaged? If not off, by killing power to the controller will the steering be as it would prior to installation or will there be drag on the column from the motor? If it's what I hope this is great! Just not for my wallet.

Sorry for the delay. When the rack is off, it's off. When it's fully on, it's true one-finger driving. Obviously if you don't do a proper rack de-power then the electronic unit will be fighting against the inner seal, so a proper de-power is recommended.

This is an OEM unit that's modified by a company that specializes in steering assemblies. It's not a garage job.

How's the road feedback with this rack?

Having driven alot of newer cars with electric steering, they're almost all numb. The only rack that gave some feedback was the Toyota GT-86/Subaru BRZ/Scion FR-S implementation...

I'm guessing that it's variable due to the adjustment.

This is an amazing product! I hope to own one once my cars k swapped.

I'd imagine the "weight" of the steering would be variable based on the adjustment, but the actual feeling transmitted from the road? Not so much

I'm talking about being able to feel a camber change, being able to feel the front start to push just before the car actually understeers, feeling the level of grip on the road, feeling the grain of the road, feeling the steering weight up as you lean on the car in a corner. Basically everything that (for example) BMW have neutered from every post 2012 car with their EPAS implementation.

Exactly. You get to decide how much feedback you want. Technically you can turn it way up in the parking lot and then turn it down on the track. This really is the answer.

These racks are used extensively in the off-road industry--all the "truggies" and unlimited trucks use them as the packaging is far easier than running hydraulic lines from the mid or back of a race car.

And this is why being able to run it through CANBUS and have it automated based on VSS slash what have you would be so freaking cool. It would be a full manual rack at speed should you want it to be and then the assist can come on and off based on your speed and what you require.

Since the unit appears to already be setup to take an analog input, I'd imagine that it should be possible to control it with a programmable 0-5v output from the ECU.

I can't help but feel you guys are both conflating

feedback - the feel transmitted from the road surface and suspension movement/position through the wheel to the drivers hands

and

weight/steering effort - the amount of physical effort required to turn the wheel.

The Miata has great steering feel, just as my RX-7 did, both are HPAS. Most modern EPAS systems are as numb as my face after a root canal.

That's my query. Is this rack numb like modern EPAS?

I think you intuitively know the answer. When it's off, it's 100% responsive. That means all the good and all the BAD of being "responsive". You get to dial in how much help the rack will give with the rheostat. Yes, it's probably possible to create a program to tie the power variable to the speed of the car, but then again you've got a rheostat right there. That's the big difference as far as I'm concerned.

I think you'll find that you can dial it in so it feels better than factory. My personal opinion.

Yes, this unit will work with all PS components removed but an untouched rack and even untouched complete OEM Power Steering System with the exception of the Belt. We are currently testing this unit on a daily driven NB Street Car and all we did was remove the power steering belt. Since the EPS Unit is having to fight the hydraulic fluid we have to turn the knob to approximately the half way point between off and full assist to get similar amount of assist as the OEM Power steering. In our opinion the Road Feel is Better than OEM! We are also running this same EPS System on our Optima Ultimate Street Car Challenge Miata. On that car we had the Original OEM Power Steering rack professionally depowered including welding of the pinon shaft. For Motorsports and Competition Application professionally depowering the OEM Power Steering Rack is the way to go in our opinion. With a properly depowered OEM Power Steering rack Even with big fat sticky tires the EPS control is dialed way down (Probably Around 25ish% Max) and the wheel is very easy to turn and the road feel and feedback is even better than OEM in our opinion. There is a way to have the unit vary in assistance based on speed automatically. Those of you that are interested in trying out that option please let Cord know so something can be put together for you.

If you turn the adjustment knob all the way counter clockwise it will turn the EPS Unit completely off and it will be exactly like having no Power Steering At all.

In our opinion its better than OEM Power Steering. Most modern day EPS Cars have an Electric Steering Rack. This system retains a mechanical steering rack and adds assist through the column instead of at the rack like many modern EPS Systems on many modern vehicles. Because of this system being a column based steering assistance, the Road feel is amazing in our opinion.

The BMWs and Most Modern EPS Vehicles are assisted at the Steering Rack.


Because this Miata EPS's assistance is at the Column this system has great Road Feel and Feedback in our opinion.

Ok that's an interesting comparison. Thanks for the clarification!

This probably explains why out of all the modern cars I've driven with an electric assist, the ToySciBaru GTBRFR86SZ felt the best because they too have the assist on the column rather than at the rack.

@ewsmotors, is there a way to output the steering angle and dc motor duty through CAN bus to log and do idle-up correction?

Looks like a Saturn/GM column modified to a Miata one with the PSCM attached. If that is the case I know the GM modules use information sent through a low speed network for it to know vehicle speed in order to control the assist amount.

Not sure of how MS uses CAN communication but if it is either a 0-2.5 volt pull up or down then maybe it could talk to a MS ECU.

Now I want one. I really like the idea of being able to have depowered and assisted steering in the same car. Being able to add assist when driving around in parking lots, or when my mom wants to drive my car or if I'm trying to drink a beer(jk) is very appealing. Is the rheostat something that is readily available? Just curious because I work with voltage adjust rheostats and they often go bad, but different environment for sure.

This is seriously cool. Not that I can afford it, but I would buy if I could.

For those concerned about "feel", there is nothing inherent to EPS that reduces feel beyond multiplying an input torque signal. EPS replaces the torsion arm in the PS valve body with a strain gauge, which is an opportunity to improve stiffness of the assembly for a given input torque (note this opportunity is best taken advantage of with the motor co-located with the rack). Lag, filtering, and damping may exist depending on the electronics used or calibration, for better or worse. S2K/RX8 have excellent steering and some of the first generation EPS racks. On the other hand, BMW reduced the effective outboard geometric arm between the contact patch and steering axis on the F30, which, so BMW says after increasing it in the G20, is why the steering feel was so bad on the F30 (I suspect the variable rack didn't help). I wonder if their decision was to reduce power requirements (and improve efficiency) from the electric motor.

This is a great offering, HPS is annoying to package and requires dealing with a (very) flammable fluid in the engine bay.

Ref:
https://jalopnik.com/the-engineering...ing-1830257906
https://garrett-engineers.com/cases-...o-fluids-burn/

I too am wondering about information than can be sent to the ECU for idle control and speed sensitivity (however a bit weary to trust the ECU to do this safely).

Three questions:

1. Does the system retain the OEM computer from the booster (and corresponding safety features)?
2. I think I can see the upper oiled sliders in one of the pictures - are the Mazda OEM collapsing stages maintained?
3. What happens to the ignition switch/lockout?

Thanks,
Chris

https://www.facebook.com/GuarinoWatsonRacing/

For this price tilt steering adjustment would be a clutch deal...

Otherwise I'm pretty "Meh".

On our car we adjusted the steering column Tilt/Height with 2 Slightly Longer Bolts and Some Aluminum 3/8 ID - 3/4 OD Spacers from McMaster-Carr (https://www.mcmaster.com/catalog/125/3376) to get it to where it feels best and we found we just leave it there.

5mm spacers on my column with lotus seats on flipside brackets and I'm 5'9. Feels almost perfect, might try the 10mm I have.

Oddly enough, normal-sized people have differing opinions.


(Just gigvng you shit, dude. I know I'm a freak of nature. :giggle:)

Hey man, average height is 5'7 :p

Has there been any follow up on this where someone has installed it and configured it to work with MegaSquirt to do variable assist based on VSS? Or to idle-up when steering assist is engaged? This is an appealing item for one of my cars, but I would ideally want to be able to dial it in for control by the MS3.

I'm going to be putting one together for my kart. At some point I may be able to put together a DIY kit for those adverse to the big ticket price tag these currently demand.

Electric Power Steering
 

FYI, I bought/installed one of these units in our endurance race car and this past weekend was our first outing with it at Hallet. Out of our 4 drivers, all liked it except one guy and he would turn it off during his stint. Its notable that the driver that didn't use it was also driving another miata at the event with manual steering. His comment was he would over correct if the car got loose with the power steering turned on.
Overall, very happy with the electric power steering! I was concerned about amp draw being too high but it was not an issue. We ran the adjustment at the minimum setting and the three drivers that used it were very happy!

Has anyone tried this and driven at say 130mph over an uneven road with cambers?

OEM EPS systems have a VSS based damping map to make up for the inherent lack of natural damping that you get in an HPAS system from having to push a viscous fluid around.

I'm very interested to see how this can work without VSS to both be stable at high speed and not over filtered and over damped at low speed.

Any updates on this in the last 5 months?

This is a for sale post. That being said, I have one I made at home using similar components (same major components), and it works great. Stable and predictable up to 160mph

what parts did you use?
i'm looking at doing this myself.