19

The rest of the steering still has to be modified. The steering slider had an issue with rotating in the bearings causing play. We are going to have to find anti-rotation ball spline linear bearings. Such parts exsist for applications like Helicopter controls and precision machine tools. 
 

Brian had to build a sturdy support structure for the front splitter/belly pan.  Since this can generate over 1000 lbs of downforce, it has to be quite strong and stiff. 

The old structure was made out of aluminum tubing and it instantly collapsed when aero load was developed. The new structure is made out of strong and stiff chromoly tubing and attaches to the engine cradle/cross member. 

 

Since the BNR32 frame rails were originally designed in an era before stringent crash requirements and before engineers were really cognizant of how important chassis stiffness is for suspension functionality, they are quite weak.

This makes the BNR32 a flexy flyer. It was also causing vexing problems like severe flex when the load of the steering box was applied to it. Since time attack rules precludes loping off the front of the car and making it a tube frame, reinforcing the unibody would have to do.

Brian built these nifty chromoly braces to triangulate the frame rails to the solidly mounted transmission and subframe/engine cradle. Now the chassis will be much stiffer in this area, the engine and trans can be effectively structurally coupled to the chassis in more places, and the aero load is spread out over a wider area. 

 

Here is a closer look at the steering shaft that was causing problems with flexing the frame rail. 

With the steering box now partially mounted to the cage and the frame rail being reinforced, things are a lot better.

 

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Comments
stylngle2003
stylngle2003link
Tuesday, March 20, 2018 10:11 AM
hooray for updates! Thanks for keeping us junkies going, Mike!
Dan DeRosia
Dan DeRosialink
Tuesday, March 20, 2018 10:36 AM
It lives!
SM_Clay72
SM_Clay72link
Tuesday, March 20, 2018 2:47 PM
Best of luck!

I need to dig back and find the article that explains why a normal rack was not used. Surely a custom rack would have paid for itself many times by now. Linkage difficulties and all.
8695Beaters
8695Beaterslink
Tuesday, March 20, 2018 3:51 PM
@SM_Clay72: They used the steering system they did because a normal rack would run right through the middle of the engine. The recirculating ball rack and slider gave them good steering geometry without having to lift the engine for clearance.

Really glad to see this car is going back together. Was definitely an inspiration during my college/FSAE years.
theneil
theneillink
Tuesday, March 20, 2018 9:21 PM
Very good, does this mean the miatabusa will get an update as well?
ViCore
ViCorelink
Wednesday, March 21, 2018 7:19 AM
Glad to see this car again getting some love. Where do we see this being campaigned in the future?
jeffreyball610
jeffreyball610link
Wednesday, March 21, 2018 10:48 AM
FINALLY!!! I've been thinking about this car for a while and wondering what happened to it. Glad to see it's back on track. I doubt you have a timetable for when it might be ready, but it would be great if you did so we could look forward to seeing it at an event or show. WTAC 2018? SEMA 2018?
RedX
RedXlink
Wednesday, March 21, 2018 11:47 AM
Great news. It takes a lot of dedication to keep troublesome projects going.
warmmilk
warmmilklink
Wednesday, March 21, 2018 11:36 PM
Is this car gonna get infinity wings?
warmmilk
warmmilklink
Wednesday, March 21, 2018 11:45 PM
And will the turbo still be in the passenger compartment?
Rockwood
Rockwoodlink
Thursday, March 22, 2018 1:05 PM
When using U-joints like that for steering, it is very important to clock them like Brian did. Ask me how I know... :(
SM_Clay72
SM_Clay72link
Friday, March 23, 2018 10:16 AM
@8695Beaters just going from these pics it looks like a rack could in the same location as their slider, especially with such set back driving position.

Pictures and actually being there to look at it are very different things of course. I love the thinking around corners that went into the system.
Mr. T
Mr. Tlink
Friday, March 23, 2018 10:59 AM
FINALLY!!!!!!!!!!!!
Maxzillian
Maxzillianlink
Tuesday, March 27, 2018 10:17 AM
Concerning steering:

Another option over anti-rotation linear bearings is to install an anti-rotation link to the "rack". IE, if you can find a chassis location in front of or behind the rack to secure a link that runs longitudinal with the car and attaches to the same location your steering link attaches to on the rack.

As long as this anti-rotation link is kept long enough, rotation in the rack should be kept to a minimum, but the key is that the behavior will be symmetrical and consistent. However, it may eat some ground clearance.
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