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It looks like that couple of weeks turned into a couple of months. I finally took some time today to tear my wife's TRV down today to see if I can mount the PS unit in. I removed the front rack, all of the plastic, the radiator, the fuel tank and the pod and handlebars to open it up where I could see if it will fit. The first picture shows it stripped down. The second shows the cavity inside the frame from the right side. There is a pretty good size cavity in there. Then I set the steering unit in there to see if it looked like it would fit (nest picture). It should be plenty of room. So I pulled the steering shaft our to see if there is room to put the steering unit in the middle of it (next picture). I think it should work. So the next step is to figure out how to mount the steering unit in the shaft. I went back and disassembled the rest of the steering column from the Cobalt to get the shaft out of it with the spline that will fit the shaft on the steering unit. The last picture is of that shaft.

I want to put the ps unit in the shaft without having to weld it in if possible. I will use the spline from the Cobalt in the top and weld that to the top part of the TRV column. The bottom shaft of the ps unit actually fits snug in the TRV shaft. So I think I can bolt that together with a couple of grade 5 bolts through both shafts at 90 deg. from each other. I cut the top part of the Cobalt steering column shaft off where it tapers down and I will have my son who is a machinist make me a bushing that will fit the o.d. of the TRV shaft and the inside of the large portion of the Cobalt shaft. That should keep all of the new assembly all concentric so the shaft will turn smoothly. I will weld all of that up and then slide the spline down over the top shaft of the ps unit and clamp it in place. I had to cut the top short section of spline off of the long shaft on the ps unit in order to keep itshort enough to maintain the TRV shaft length. That will give me a small amount of adjustment to get the length of the TRV shaft back exactly where it needs to be. If all of that goes as planned then I should be able to put the shaft and ps unit back in the machine and see what will be needed to mount the body of the ps unit solidly to the frame. I don't think that will be too bad. Then all that should be left is to put power to it and see if it works. I hope the controller from the Cobalt will work adequately. I don't expect it to be as great as they say the new Arctic Cat unit is. But if it works even reasonably well it think it will be a success. I guess time will tell. I will post more as I get time to proceed with the project. Wish me well!
 

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Looks like a pretty straight forward fab job.... a bracket/ hanger and maybe a bushing...
 

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This is AWESOME!!! I'm absolutely loving this build up!!! Can't wait to so more :D

I think I can visualize what you have going on here. I have an idea though. Hopefully it's not to late. I'm not saying it's a good one though. What about welding a sprocket or gear onto both the PS shaft and the steering shaft. The you can connect the PS and Steering shafts either through gearing (which could help the PS unit) or with a good strong chain (like a timing chain). I'm sure there are good and bad to both the gear and chain ideas but it gives a little more for you to work with being as the area to build is so tight. Plus it might make the adapting easier.

Still pumped to see how yours turns out!!!!
 

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I have the ps unit sitting in the machine right now and am working on the bracket the will secure it to the frame so it won't rotate. Hopefully I can finish the clamps tonight. I have run into a couple of hiccups along the way. But I think I'm about ready to paint everything, take pictures and permanently mount it into the chassis. I was disappointed to find out that I can't just power up the controller and have it work. It evidently is going to require a trigger signal of some kind to make it work. I haven't had much time to start working on that part yet. So far I have been able to obtain a wiring schematic from the GM service manual. But I still need more. I'll work on that after I get it mounted. In the mean time I will mount it in the machine and we can ride it with manual steering. The ps unit has almost no resistance to turning the handlebars without power to the motor. While it was apart I ordered a set of Sanny's bushings and did the mod to the front suspension. That should help as well.

In order to get my wife back on the trails we decided to go ahead and get her a new TRV 550 S GT and we will keep the '05 for our family to ride. We picked it up last week and hope to get her out for the maiden voyage Friday evening. I'll post some pics if we make it out.

I will still keep fussing with the ps conversion. I'd like to see if it can be made to work and I have always had a hard time admitting defeat on a project like this. There has to be a way. I just have to learn enough to figure it out.
 

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Stick with it! Your doing more than any of us :) I think if you can iron this out, alot more people will be following your conversion to develop there own.
 

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Just wondering how the tinkering is coming? I've been shopping around for my own PS unit at the wrecking yards. My local dealer has been tracking this build now too! Too Fun:)
 

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Well! There's good news and bad news. The good news is that the ps unit will fit in the chassis. I did finish up the brackets, installed everything and hooked up the power to the control unit. But the bad news is that it still didn't work. I fugured we would just ride it with the ps unit in place until I can get the controls figured out. But when I took it out for a ride there is a dead spot in the steering that leaves several degrees of slop in the steering. I couldn't notice it without the resistance of the tires against the output side. Just sitting the handlebars rotate several degrees back and forth without any movement in the wheels. The movement is in the power steering unit. So we can't use the machine with the ps unit in place. I ordered a new steering column which I hope to put in this weekend so we can use the atv. I am keeping everything as is with the work I've done so I can re-install it if I can get the controls to work right. My initial enquiries have me beleiving that GM is not very inclined to share information about how this system works. I will continue tinkering as I can. So at this point we are going to enjoy the summer riding and I'll continue to look for a solution to the controls as I have some time. If anyone has any information about these systems that might be helpful or knows someone who does I would appreciate any input that would help solve the controls issue. There has to be a solution out there some where if I can just find it. But right now my attention has been diverted by good riding weather. If I make any progress, I will post it.
 

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I'm an engineer that works with controls systems (i wouldn't call myself a CS engineer though). If you post up the info you have or PM it to me i'll take a look. There are a lot of other smart guys and engineers on here too that can probably help.
 

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Dumb question, do you have three wires hooked up to that unit??? One is constant power, one is a ignition switched power and the third is a ground. Thats what the diagram for my 05 Cobalt shows anyway. The other problem I am seeing is that the power wire for constant battery power is protected by a 60 amp fuse on the cobalt, may draw to much power. Another thing my diagram is showing is a 4 wire connection with the vehicle data link connector, I also believe the electric ps units require a vehicle speed input and perhaps others, that may be what the dlc connection is for, missing these inputs could make the unit dead and useless.

More research has shown me that two of those 4 wires goes to the Body Control Module the other two to the DLC, I have a feeling the BCM is giving the ps unit vital info to work.

Actually this may help, please read.

Power Steering System Description and Operation
The electric power steering (EPS) system reduces the amount of effort needed to steer the vehicle. The system uses the body control module (BCM), power steering control module (PSCM), torque sensor, discrete battery voltage supply circuit, EPS motor, serial data bus, and the instrument panel cluster (IPC) message center to perform the system functions. The PSCM, torque sensor, not the EPS motor are serviced separately from each other or from the steering column. Any EPS components diagnosed to be malfunctioning requires replacement of the steering column assembly, also known as the EPS assembly.

Torque Sensor
The PSCM uses a torque sensor as it's main input for determining the amount of steering assist. The steering column has an input shaft, from the steering wheel to the torque sensor, and an output shaft, from the torque sensor to the steering shaft coupler. The input and output shafts are separated by a torsion bar, where the torque sensor is located. The sensor consists of a compensation coil, detecting coil and 3 detecting rings. These detecting rings have toothed edges that face each other. Detecting ring 1 is fixed to the output shaft, detecting rings 2 and 3 are fixed top the input shaft. The detecting coil is positioned around the toothed edges of detecting rings 1 and 2. As torque is applied to the steering column shaft the alignment of the teeth between detecting rings 1 and 2 changes, which causes the detecting coil signal voltage to change. The PSCM recognizes this change in signal voltage as steering column shaft torque. The compensation coil is used to compensate for changes in electrical circuit impedance due to circuit temperature changes from the electrical current and voltage levels as well as ambient temperatures for accurate torque detection.

EPS Motor
The EPS motor is a 12 volt brushed DC reversible motor with a 58 amp rating. The motor assists steering through a worm shaft and reduction gear located in the steering column housing.

Power Steering Control Module (PSCM)
The PSCM uses a combination of torque sensor inputs, vehicle speed, calculated system temperature and the steering calibration to determine the amount of steering assist. When the steering wheel is turned, the PSCM uses signal voltage from the torque sensor to detect the amount of torque being applied to the steering column shaft and the amount of current to command to the EPS motor. The PSCM receives serial data from the engine control module (ECM) to determine vehicle speed. At low speeds more assist is provided for easy turning during parking maneuvers. At high speeds, less assist is provided for improved road feel and directional stability. The PSCM nor the EPS motor are designed to handle 58 amps continuously. The PSCM will go into overload protection mode to avoid system thermal damage. In this mode the PSCM will limit the amount of current commanded to the EPS motor which reduces steering assist levels. The PSCM also chooses which steering calibration to use when the ignition is turned ON, based on the production map number stored in the BCM. The PSCM contains all 8 of the steering calibrations which are different in relation to the vehicles RPO's. The PSCM has the ability to detect malfunctions within the EPS system. Any malfunction detected will cause the IPC message center to display PWR STR (or Power Steering) warning message.
 

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yikes. nice job boaty. Sounds like this project is not feasible. Far too much input required, however it is possible that you could fool the signal to the PSCM with a constant volatge. It's now looking for variable analog proportional values for the variable settings. it's also possible that you could bypass that PSCM but that would involve creating you own control system. The picutres you posted show the PCSM integral to the EPS so i think it's impractical.
 

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Fooling may not work, those cars use a sophisticated communication system for the modules to "talk" with one another. The speed signal is inputted into the pcm, it then tells the bcm which tells the pscm. By then it may be more than just a AC voltage the speed sensor produces.
 

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I believe it could be fooled with a constant voltage (if you could find the voltage range) however I think the problem will then be finding a happy medium for steering assist as too much could be dangerous. Actually IMO this project although a great idea will have to chock up to FAIL as I would not be comfortable at this point putting my wife on a machine that could loose all steering ability at any point, because if it has play with the unit dead then it sounds to me that it is not equipped with any type of failsafe to where you could still steer in the event of unit failure. Chock this up to learning experience and scrap it is my vote!!
 

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UK EPS swap

Fooling may not work, those cars use a sophisticated communication system for the modules to "talk" with one another. The speed signal is inputted into the pcm, it then tells the bcm which tells the pscm. By then it may be more than just a AC voltage the speed sensor produces.

EPS swaps are common in the UK. There are aftermarket control moduals available for a reasonable price. At present I havent found a similar one that will work on a North American System
 

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What are small machines like golf carts and cushman's using? Maybe even an electronic forklift?
 

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Wish I still had my old Ford Ranger. It had manual steering and it was a very small steering box. Would be interesting to get out the tape measure.
 

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A small rack and pinion might work pretty good, but I'd wonder about the ratio being useable for a quad.

When I was looking for other PS units, I saw someone cut down a geo rack for use in a go kart.
 

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I Just ordered a Vauxhall Corsa EPS unit ans a control box for it from the Uk. The EPS unit is used and the control is aftermarket unit with a knob that cn be used to adjust the sensitivity..

The whole thing including shipping cost just over $300 much cheaper than the $1200.00 for an after market one.
 

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I have a cobalt EPS unit and have been interested in a swap with it as well. In the car it uses serial data inputs from the BCM and ECU to reduce the power assist at high speeds. I'm not sure if it will work without these inputs. It has however a defalt/limp mode that make kick in and be adequate for our application, without these signals.
 

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Interesting info guys. - I was looking at a '12 1000LTE at bass-pro recently and the frame on it with the power steering module was no different than the frame on my '09 1k TRV.
 

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I have a cobalt EPS unit and have been interested in a swap with it as well. In the car it uses serial data inputs from the BCM and ECU to reduce the power assist at high speeds. I'm not sure if it will work without these inputs. It has however a defalt/limp mode that make kick in and be adequate for our application, without these signals.
I used a 08 Nissan versa and used the orange wire to turn on the power box
 

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