S2k rack on NA1

[comptonassdaniel]

Progress is progress! Looks like it fits, at least.

 

[17sd]

Thank you for sharing the conversion process.
It would benefit a lot of people.

 

[nsxmugen]

Waiting on aluminum sheets to get here as the mount is almost done. Needs some final adjustments but I should get it right in the next attempt want to get in to wiring this thing already but can’t start before it’s bolted on.

Final mount should look very similar to this but in aluminum and have more support on bottom.

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[RYU]

exciting!

 

[comptonassdaniel]

Whoa! You’re getting there!

 

[nsxmugen]

Small update. The rod that connects to steering column is too long. I could mod the steering column to make it work but I don’t want to mod the car to fit the part. I rather mod the part to fit in the car so if I want to revert to stock I can.

The rod is made out of two parts the inner that steers and the outer that controls torq sensor. Both parts are staked at the end and move together.

Torq sensor removed. This needs to be shorted over an inch.

Here is the outer already cut to length and ready to tig weld

Here is the outer already welded that will slide on the inner that is on top. I just need to make a drill hole through it and stake it so it will become one part again. Good thing is that the inner does not need to be welded. It’s made out of hardener steel and would need to be anneal even to make a hole in it. The outer is mild steel and forms easily.

In spare time I just installed steering wheel from EU civic with airbag from rsx.

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[bj91nsx]

Cool project! I also have steering wheel I want to install. It's a U.S. spec RSX steering wheel. Not to thread jack but Question, what will I need to install it? I remember someone saying a hub perhaps? Thx

 

[nsxmugen]

Cool project! I also have steering wheel I want to install. It's a U.S. spec RSX steering wheel. Not to thread jack but Question, what will I need to install it? I remember someone saying a hub perhaps? Thx

Yea, I like the RSX steering wheel the most. I just wanted red stitching and with out cruse control buttons to make it look sleek. In found that sport civic in EU had that and found one for very cheep. Initially I was looking at S2000 steering wheel, but I did not like the cruise control and I would still need to get rsx airbag because I did not like to have honda logo on it. Yes, there is member on prime that makes adapter here is I think his thread. Link I think he still makes them but contact to be sure, but if you use nrg quick release you can just bolt on the steering wheel to the quick release. Two adjustments that are needed are that to center the wheel it needs small ring unless someone has good eye to center it and the column nut needs to be cut a little on steering wheel for the quick release to be flush. After that couple of pre drilled holes in steering wheel align, I just drill couple more to hold the quick release in place.

Here are few pics

 

[nsxmugen]

Another update, it’s now cut out of aluminum and fit is better then I expected. After 9 prototypes and removing and installing it back at list 30 times. Lol. It’s welded now too. I’m still learning to tig weld so my welding is not as clean as pro welders but it will hold. The next couple of weeks will be working on electronics.

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[hkz286]

This is so badass. Are you going to produce the mounting kits for sale?

If not would you be willing to sell your design so I can make a kit for my own car?

 

[stuntman]

Very interested in the results.

How did you reverse the steering rack? The S2000 has the rack mounted in front of the wheel centerline, while the NSX is behind. So mounting an S2K rack in the stock NSX location would make the tires turn in the opposite direction of the steering wheel.

Are you eventually going to incorporate rubber isolators in the mount? Without them, a lot of NVH can be transmitted into the steering wheel.

I don't have an NSX infront of me. Does the NSX rack bolt directly to the subframe? What are your thoughts in terms of your mounting plate flexing when the s2k rack is mounted in the middle of that flat plate?

 

[nsxmugen]

This is so badass. Are you going to produce the mounting kits for sale?

If not would you be willing to sell your design so I can make a kit for my own car?

For now this is home project, I don't know how safe this is and would be little hesitant of offering this unless is well tested. Yea I would consider selling the design but again for not too early to say. At the end this might not work and I'll revert back to OEM. Thanks

 

[nsxmugen]

Very interested in the results.

How did you reverse the steering rack? The S2000 has the rack mounted in front of the wheel centerline, while the NSX is behind. So mounting an S2K rack in the stock NSX location would make the tires turn in the opposite direction of the steering wheel.

Are you eventually going to incorporate rubber isolators in the mount? Without them, a lot of NVH can be transmitted into the steering wheel.

I don't have an NSX infront of me. Does the NSX rack bolt directly to the subframe? What are your thoughts in terms of your mounting plate flexing when the s2k rack is mounted in the middle of that flat plate?

Oh, there is that.. reverse steering rack! It's embarrassing but to be honest I totally oversee that. I know it is in front on the wheel on S2000 but I got focused on the mount and it slipped my mind. Thanks !! now I need to go back to drawing board lol. The solution right now looks pretty simple just to get JDM rack. RHD rack once turned over it will be turning int he right direction. Let me know if I'm thinking it correctly now. Otherwise it would need some sort of helical gears to reverse the rotation.

Yes, it will have urethane bushing with 80 hardness to adsorb any vibrations

It bots on to the subframe and the thought of twisting was on my mind since day one. There are a lot of forces to play in there and the rack either coming of mounts or bending was not an option. I'm using .75" on mounts and .25" on the back. It bolts on to multiple spots passing the load. The battery brackets that goes under it provides additional support, it sits directly under rack and I made it bolt on to it as OEM does. This gives support in the middle.

thx

 

[docjohn]

haha thanks to Billie for saving your life during your first shakedown drive

 

[RYU]

good catch on that one also good idea on the JDM rack!

 

[stuntman]

Oh, there is that.. reverse steering rack! It's embarrassing but to be honest I totally oversee that. I know it is in front on the wheel on S2000 but I got focused on the mount and it slipped my mind. Thanks !! now I need to go back to drawing board lol. The solution right now looks pretty simple just to get JDM rack. RHD rack once turned over it will be turning int he right direction. Let me know if I'm thinking it correctly now. Otherwise it would need some sort of helical gears to reverse the rotation.

Yes, it will have urethane bushing with 80 hardness to adsorb any vibrations

It bots on to the subframe and the thought of twisting was on my mind since day one. There are a lot of forces to play in there and the rack either coming of mounts or bending was not an option. I'm using .75" on mounts and .25" on the back. It bolts on to multiple spots passing the load. The battery brackets that goes under it provides additional support, it sits directly under rack and I made it bolt on to it as OEM does. This gives support in the middle.

thx

No worries. Easy oversight since most cars don't have rear steer racks like the nsx.

Are there no Variable-ratio JDM racks? I'd rather pick the slower 14.9:1 rack than the faster one. Hopefully JDM wiring and ecus are compatible and the RHD rack does not have clearance issues when flipped 180*. -that should work.

As far as twisting goes, if you put a 90-degree bend at the top and bottom of the vertical plate, making it a "C-channel", it will greatly increase the stiffness. Just watch the tolerances to the battery tray which could cause vibrations and noise.

Glad to hear about the 80-durometer urethane. Make it thick!

Keep us posted!

 

[nsxmugen]

I reach out to couple of vendors that import JDM parts. I'm determined to get his working one way or another but it's a setback for sure, thanks again for the info. Right now I'm looking to get the JDM rack in non variable ratio because the variable ratio has large additional motor with gears that will never fit for nsx. As plan B, I have my eyes on 2005-2007 honda Accord hybrid rack. (accord hybrid got eps, standard did not for hose years) It almost looks identical to s2000, and looking at it I see less fab work, it sits closer to driver too. The specs on accord hybrid are 3.17 lock-to-lock with 16.25 steering ratio. I just ordered shop manual to see if it's canbus, if it is, it will add complexity on electronic side. If not I might get the accord one instead. I like how s2000 does not need steering angle sensor..

Will update once I get any ware with it

 

[comptonassdaniel]

Good things to know; hopefully it works out whichever way you go.

 

[nsxmugen]

I was able to find JDM s2000 rack and it's shipped already, should have it here next week. But this situation made me do more research and after I got my accord hybrid service manual, its clear it's the same electronics with just slower response, more similar to oem nsx feel but with assistance and it's behind the wheel so it will not need to be rotated and it runs kline not canbus easier to get the electronic part to work. I have my JDM rack shipped but this accord hybrid is very good alternative. It even looks very similar, and it lays flat most likely no need to cut the oem mount just create adapter bracket. If I had larger budget I would get both to work, see what feels better hehe. It sounds like for faster response s2000 rack from normal accord rack. At the end of this I'll know all about honda racks, lol.

S2000 Jdm rack

Accord hybrid

 

[RYU]

This is great. Thanks for sharing.

When you say the Accord rack is slower your saying the ratio is slower right? If that's the case, why not just swap with the OEM NSX EPS rack? Is the Accord rack still faster than the OEM NSX EPS rack?

 

[stuntman]

This is great. Thanks for sharing.

When you say the Accord rack is slower your saying the ratio is slower right? If that's the case, why not just swap with the OEM NSX EPS rack? Is the Accord rack still faster than the OEM NSX EPS rack?

I think he's saying the Accord rack is slower than the S2000 (which may be too quick for the NSX chassis, but i'd be eager to try it). I think he said earlier that the OEM NSX EPS rack is very expensive while the S2K (and I imagine the Accord) racks are much cheaper.

What's the ratio of the Accord rack?

I'd really like to figure out how to adjust the inputs to the rack to vary the assist. I'm going to have Motec that I can program an output to adjust it based off of vehicle speed, or an adjustment knob inside the car.

 

[RYU]

Gotcha, I'd be curious on the ratio of the Accord also. I also think the s2k is a bit too fast for my liking but all things considered it would be a great option.

I have everything ready to swap the OEM EPS NSX rack into my 91 and I think I've figured out all the wiring conceptually. I'm just waiting on pigtails. The NSX EPS only provides assist up to 18mph. This can be adjusted easily by modifying the VSS signal going into the rack but what I don't know is if it's a variable electronic assist... Meaning as you get closer to 18mph does it assist less...I think it's more an on/off switch if I was to guess.

I think he's saying the Accord rack is slower than the S2000 (which may be too quick for the NSX chassis, but i'd be eager to try it). I think he said earlier that the OEM NSX EPS rack is very expensive while the S2K (and I imagine the Accord) racks are much cheaper.

What's the ratio of the Accord rack?

I'd really like to figure out how to adjust the inputs to the rack to vary the assist. I'm going to have Motec that I can program an output to adjust it based off of vehicle speed, or an adjustment knob inside the car.

 

[stuntman]

I did not know that. So the EPS rack is the same ratio as manual, but only adds assist below 18mph? That sounds excellent to me. The only thing I would add to that is a feature that adds assist in yaw, when catching an oversteer moment.

I agree the S2K rack might be too fast, but worth the $ to try it out. It may work pretty well with assist, and with a longer wheelbase in the NSX, it might not be bad at all.

 

[nsxmugen]

My JDM rack got here and it looks like I'll need to modify the mount just a little bit, might not have to re-do the whole thing. I'm not sure if s2000 or accord disengages at higher speeds but when will get it installed I want to measure the current flow to esp motor to see when it happens. Yea it would be nice to set different modes, I'm sure if someone knows circuit boards they can figure out but that is beyond me.

This is what I was able to find about nsx and accord hybrid esp. Will see how my JDM s2000 rack works in practice, and will share my findings for sure.
• 3.17 lock-to-lock with 16.25 ratio, accord hybrid ESP
• 3.07 lock-to-lock with 18.6 ratio, nsx ESP

On the left is the picture of the JDM s2000 rack, and the one of the right is my old US. I still need to swap the shaft from one on to the other, oem is bit too long, this is where accord one is much shorter and might not need to be cut but don't know that for sure.

 

[stuntman]

Thanks for the update. It would be good to also measure the horizontal throw of the stock, s2k, and Accord racks. If the throw is longer than stock, you may need to put a steering rack limiter spacer in to prevent turning the tires too far.

Where are you located? I'd really like to try the s2k rack and or the Accord. The Accord ratio might be a little better but it's all a guess at this moment. The s2k ratio could be better... Need to test it!