Custom mid-chassis "stiffening box beam" vs "plate" for Prius "v"

Not quite yet - probably next weekend (at my ~2000mi oil change). I'll report back once I get it on!
Andy

Yep! Got mine in yesterday. PC member Chazz8 came over yesterday (Thanks Chazz!) and we worked on an oil change and installing this beam.

Here's the factory brace:


Working on the new one - used the factory bolts. I SHOULD have put a little bit of anti-seize on the bolts before re-installing them, but I forgot.




I had to file the inside of each hole just a little bit to get it to fit. I might have been able to force the bolts without filing, but that seemed like a bad idea. Maybe my v is a hair wider than Mike500's, or maybe its position on jack stands stretched it a bit - who knows. Either way, about one minute of filing on each hole, or about 0.5mm of material removed on each, allowed a perfect fit. After filing, each bolt was just touching the inside of the hole on the brace, but they lined up well and went in without having to be forced. FWIW, I appreciate the snug fit - I'd rather have to file to get a customized fit than use a product that was drilled oversize to allow slop (and therefore, potentially, allow more flex). A pic of the filing process:




And then, with the dutiful assistance of helper-dog...



...the beam was installed.



I was worried that the box design would prevent a standard socket from fitting over the hex screw head, but there no problems at all.



Looks great, and I look forward to giving it a thorough driving test. Thanks Irv!
Andy

Great picture, Andy.

I especially like the one with the dog. I hope the newer mode; will not need to be filed, but I still like the tighter fit than the ones sold by Cusco and the old BT plate with the slots.

From my experience with metalurgy, I know that the multiple welds weaken the heat traetment on the 6061-T6 aluminum. While the 1-1/2. instead of 1/2 inch "hang down" is fine for the "v," the 1 inch "hang down" will be better for the Gen III. I know that the Tanabe Sustec TUB153F "hangs down" at least an inch.

I ordered one from Amazon.com. for $98 delivered.

http://www.amazon.com/gp/product/B004QNYM4M/ref=oh_details_o01_s00_i00

I'm almost sure that it will fit the 2012 'v."

Interesting - is that an alternative to your box beam brace, or is it something you can add in addition? Where does it mount?
Thanks,
Andy

Andy,

That brace mounts to the front of the mid brace.

Check out this link;

http://priuschat.com/forums/gen-iii...hassis-brace-trd-rear-sway-bar-installed.html

Andy,

I installed it this morning. It was absolutely easy. Here's my new post for all "v" owners.

http://priuschat.com/forums/prius-v...chassis-bar-fits-perfectly-v.html#post1544262

Installed the M500BB box brace this morning, minor enlarging of a couple holes was required...no big deal. In combination with the 2 point front brace the wet noodle handling characteristics are pretty much gone, the OEM brace may as well not even be there, very flimsy. If Mike...aka Irv makes anymore I'd grab one up for sure.

Can I get one too please?

I've been Prius v Accessory Junkie | PriusChat

All of the "box beam" braces have een sold, except for one "high end" super lightweight "sectioned" one that weighs the same as the standard flexible OEM one. It weighs 1 pound 4 ounces, but is is still as stiff as the full box beam.

Here's a link to the one brace left;

For Sale - Custom "Tricked Out" Lightweight Prius"v" or gen III "box beam" mid-chassis brace | PriusChat

I have uploaded photos of the brace, along with photos of the OEM brace, and a similar brace installed on my Prius"v."

The designed and a sample has been sent to a manufacturer for testing and to make for sale. They have said that it would be fancied up and be sold for about $160.

Hope this helps,

Mike500

Wow - congratulations? I hope you'll at least get some recognition for this, if not royalties, or a cut of the profits, or whatever. Good work!
Andy
(Happy to "get in on the ground floor" - and thanks for sharing your prototypes here!)

Thanks Andy,

I'm not really in for a big profit. Basically, I've offerd it to them for a nominal charge that would have covered the time I spent. I enjoyed developing it and enjoyed sharing the design with all of us, here.

I have not given anyone "exclusive" rights to the design, so anyone could make them. It would be nice if the Priuschat Shop would offer it. I would glady turn over the design to them for "FREE."

Very cool! You seem very skilled and knowledgeable. Now they just need to add all your other "products" too and sell a Mike500 special Prius package.

Andy,

I finally figured "why" and for what reason, Toyota desined the stiffer brace that you had installed on your car.

I'm sure that Toyota explored the BT Tech plate and most other aftermarket stiffening plates that have been avilable.

Toyota wanted to stiffen the space between the rails of the exhaust tunnel, while still allowing flexibility to allow the bar to "twist."

The rod in the middle is "in effect" a torsion bar. Think of the car as having bbemn divided down the middle center line like a pair of scissors. The bar is actually a torsion spring that allows the rails to move independently like the pair of scissors. The middle of the bar twists to resist the movement and returns to its original position when the car is on level ground.

The bar is designed so that the bending stiffness is heavier than the "torsional stiffness." The wider BT Tech plate and all of the clones are made wider and have likely got it wrong.

My design, like Toyota's has very high bending resistance but much less torsional resistance, since it's like a long cardboard tube that is open on both ends. This is how the Wright Brothers came up with the stiff wing and the less stiffer "wing warping" control concept. As I recall, the outer sleeve of the outer box that held bicycle inner tubes had a carboard sleeve that was open on both ends. One of the Wrights held the ond of the tubes and felt how hard the tube was to bend, but how much liss it was to twist.

Irv, I think Jaguar (2012 XF) is stealing your design:

http://blogs.insideline.com/roadtests/assets/xf_under_4.jpg

Thanks for your finding. Theirs appear to be a "composite," like Toyotas.

The most important thing is that it supports my finding that the cross brace needs to "twist" and that a plate with high torque resistance like the BT Plate, the G7 and the one sold by JuicedHybrid.com might eventually cause "metal fatigue" cracking of the underchassis rails at the mounting bolts.

This post in the Gen II forum explains how the "plates" might cause long term damage;

How some aftermarket chassis stiffing braces or plates might eventually damage your car... | PriusChat

The sad thing is that the Gen II "chasis stiffenting plate" owners have basically ignored my warning.