BT Tech Stiffening plate

<div class='quotetop'>QUOTE(The Annoying One @ Mar 25 2007, 10:24 AM) [snapback]411908[/snapback]</div>

PriusChat > Toyota Prius Forums > Prius Modifications > BT Tech Stiffening plate

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Inflected Form(s): plural forums also fo·ra /-&/
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By definition, discussion of ideas is what one does in a forum.

 

<div class='quotetop'>QUOTE(John in LB @ Mar 25 2007, 02:12 PM) [snapback]411899[/snapback]</div>

It wont rust, but it will corrode, especially in the presense of salt. Aluminum does not resist salt corrosion at all. The center of the front upper edge of my plate has actually worn through the hard anodization, and shows salt corrosion. And this is after one Chicago winter. Let alone the bimetallic corroision issues if the plate is not finished with a nonconducting surface finish. I do not see any bimetallic corroision on my plate.

As far as the overlap of the rail bump, without testing it, can you say that is not part of the improvement the plate provides?

Yes, if its stiffer, the bolts may pull through either the bottom of the counter bore of the plate, or the steel rail. Most likely the bottom of the counter bore.

I agree on the functionality. But that does not mean it does not need to be as simple as people tend to assume.

 

[attachmentid=7095]<div class='quotetop'>QUOTE(donee @ Mar 25 2007, 12:46 PM) [snapback]411986[/snapback]</div>

In order to achieve the torsional capacity of the plate, you will have to maintain the moment arm and overlap the rail bump - so, we have to machine out that portion (versus just cutting it out)... oh well - more money...

Rust in Chicago... hm... here is an excerpt from corrosion-doctors.org, titled: Corrosion of Aluminum Alloys:

The corrosion resistance of aluminum is dependent upon a protective oxide film. This film is stable in aqueous media when the pH is between about 4.0 and 8.5. The oxide film is naturally self-renewing and accidental abrasion or other mechanical damage of the surface film is rapidly repaired. The conditions that promote corrosion of aluminum and its alloys, therefore, must be those that continuously abrade the film mechanically or promote conditions that locally degrade the protective oxide film and minimize the availability of oxygen to rebuild it.

In terms of galvanic action, Aluminum and Carbon Steel are next to each other in galvanic ranking - so we would expect negligible interaction - I would refer you to Clarke, Lincoln, and Sterrett, Proc. API, 1935.

Although I won't swear by it, my conclusion is that the aluminum may pit in Chicago, but it won't just rust away like carbon steel. Besides, from what you say, the leading edge of your plate is no longer anodized and therefore is no longer protected - so the protection is short lived at best. So, I would take a chance that the plate will outlast the car - especially in California...

No question about it - I would fully expect that the bolts would tear through the aluminum plate before destroying the threads on the car body.

I don't have the BT Torsion Plate on my car (that's really what it is... ) but I do have a scientific test you could conduct and report back on its effectiveness. We would measure how much the car deflects with or without the plate. The difference would represent the added stiffness the plate provides.

Here is the test procedure that I propose:

Remove the BT or factory plate, for the no torsion plate test:

1 - Jack up the front left wheel (per instructions by Toyota). Continue lifting until the rear left wheel comes off the ground a small, but measurable amount - say 1". Now measure the height that the front wheel is off of the ground (let's call that 8" from the bottom of the tire to the ground for the purpose of discussion).

2- Raise and lower the car a couple of times until the answer is repeatable. (First couple of times off the ground may have a different answer until all the suspension parts of the car settle down).

Now, install the BT torsion plate, jack the car back up to the 8" reference point and measure the distance the rear wheel is off the ground. If the BT plate is perfect, making the car a perfectly rigid box, the answer should be 8". If the BT plate does nothing for the car - the answer should be 1". I would expect an answer somewhere in between (probably closer to 1" than 8" ~ let's say 3")

I would jack it up and down a couple of times to make sure the answer is repeatable.

Finally, I would repeat the whole thing again with the factory plate installed. The difference in all three measurements would indicate the effectiveness of each of the two plates in real life driving.

Please note: You have to jack the front wheel up and not the rear wheel because that's where most of the weight is - don't try it the other way.

I would be willing to do the test and report back if someone lends me a BT plate. As an alternative - you guys can do it and report back - It would be very interesting to see what difference the plate has on torsional stiffness of the car body.

By the way, I am attaching a picture showing you how a Porsche would behave in such a test (engine/weight is in back). Notice how stiff the body is! The front wheel is almost at the same height as the rear wheel - and that's for a convertible, where you do not have the benefit of a steel top. (Oh well, that's what $90K gets you... )

 

<div class='quotetop'>QUOTE(John in LB @ Mar 26 2007, 07:36 AM) [snapback]412257[/snapback]</div>

Being there, done that: http://priuschat.com/index.php?s=&show...st&p=354458

search [surch]
v (past and past participle searched, present participle search·ing, 3rd person present singular search·es)
1. vti examine something thoroughly: to look into, over, or through something carefully in order to find somebody or something

 

<div class='quotetop'>QUOTE(The Annoying One @ Mar 26 2007, 08:14 AM) [snapback]412315[/snapback]</div>

Thanks for pointing that link out. Unfortunately there are no results from it. So, we are no better off now than then.

PS: your smart nice person attitude is really not necessary.

 

There's already been a discussion (make that several) on the effectiveness of the plate. We could go through the same circles again and get nowhere, or you could just take a chance and buy the plate. Really... it isn't that expensive. Starbucks addicts can buy enough coffee equivalent to the cost of a BT plate in a month.

If you feel you're being taken. Go try and manufacture your own. All this discussion is just more time that you get to deal with the stock plate. $160 for significant handling improvement is a lot better than taking the big step to the TRD shocks and springs for $980.

 

<div class='quotetop'>QUOTE(Presto @ Mar 26 2007, 05:37 PM) [snapback]412563[/snapback]</div>

I don't believe the hype. Toyota engineers are a lot smarter than the BT Tech people would make you think they are. There are reasons that the stock plate is like it is, putting a stiffer plate in there will transfer loads to other parts of the chassis which could in time do damage to the car. If you want a sporty car, don't buy the Prius, get the Honda Civic Hybrid. I for one won't waste $170 plus shipping on a plate for my car. There has never been any data published that proves the plate improves handling either, it's all word of mouth. The power of suggestion is pretty strong, and if people say "Hey wow the car handles better" other people are liable to believe it even if they don't notice anything.

If there is published scientific data available on this, please post it here.

Dave

 

This is well past the point of hype. Are we to think that everyone who feels a difference (almost every purchaser of the plate) is getting the placebo affect?

Toyota's engineers are masterfully skilled, I'm sure. The only problem is that they have to work with the bean counters too, and they like to shave costs wherever possible. The plate is just one of the many areas that could've got something better, but didn't due to costs.

I invite you to come up to Vancouver, and I will be happy to slap a BT plate on your Prius to do some testing.

 

<div class='quotetop'>QUOTE(Presto @ Mar 26 2007, 04:36 PM) [snapback]412593[/snapback]</div>

Wow that's a generous offer. And Seattle isn't far from Vancouver. I say take him up on it and see for yourself it it's real or just hype.

 

Spring is here. I'll be pulling off the BT Plate, and finally, installing Tom's rear brace, and floor brace. BT Brace installation/removal should take about 5-10 min tops. I could even sell it to you, if you like.

 

<div class='quotetop'>QUOTE(John in LB @ Mar 26 2007, 06:36 AM) [snapback]412257[/snapback]</div>

I just got in from my garage where I did the test you suggest. I couldn't use the BT Plate because I don't have one so I made a suppliment to the OEM plate of a 1/8" solid steel plate. First I tried the torsion test with no plate. I got a deflection of 3 13/16" between the top of the front and the top of the rear fenders. Then I tried the torsion test with the OEM plate installed with the factory bolt torsion of 22 foot lbs. The defelection was identical. Then I did the torsion test with the enhanced OEM plate and a torsion on the four bolts of 25 foot pounds and the deflection was 4 1/4".

By the way, I tried the doors at the maximum flex and they worked fine.

That was a lot of work and it seemed to prove that the plate has little to do with the body flex of the car.

I drove the car for a while with no plate and I couldn't feel any difference. I will leave the enhanced OEM plate on for a while to see if I notice any difference.

 

I just installed the BT Tech plate on my new (1K miles) 2007. Just like in 2005, I could feel the difference turning out of the shop's parking lot.

I don't know what percentage of people who install the BT Tech plate feel it is ineffective, I know the vast majority feel it improves handling. This doesn't "scientifically" prove it, of course; we may all be deluded, unlike those who don't install it. A great number of Prius drivers think the Goodyear Integrity tires are just fine too; others replace them right away to feel safer as they drive.

There is no right answer. If you are happy with your Prius as you got it from the dealer, wonderful! If you have changed your tires and/or changed the plate tying the car together and you think it has improved driveability, wonderful!

But if you have the OEM stock car, don't p!ss on people who have made the manufactured vehicle their own. No one is forcing you to do anything. If you feel inadequate, that's your problem.

 

<div class='quotetop'>QUOTE(Allannde @ Mar 26 2007, 07:31 PM) [snapback]412687[/snapback]</div>

Thank you for conducting the test. I wish it had indicated some difference - too bad it does not. One question, did the steel plate you added have the width of the BT Plate? I am guessing, but say 7 or 8 inches? That's the critical part for controlling deflection (not just the space between the bolts).



I think we are all done with this topic...

 

<div class='quotetop'>QUOTE(Allannde @ Mar 26 2007, 08:31 PM) [snapback]412687[/snapback]</div>

Just to be clear, this only proved that the steel plate that you used had little do with the body flex. I thought there was a thread where someone had done this test, but I guess not.

 

<div class='quotetop'>QUOTE(Presto @ Mar 26 2007, 11:01 PM) [snapback]412778[/snapback]</div>

Presto: I would appreciate if you do the test... it will take about 1/2 hour and settle the whole damn thing.

 

<div class='quotetop'>QUOTE(Presto @ Mar 27 2007, 12:01 AM) [snapback]412778[/snapback]</div>

I would guess that a 1/8" flat soft steel plate would flex and twist a lot more than the machined 1/2" thick aluminum plate. But there's no convincing the ones who know better.

 

<div class='quotetop'>QUOTE(Bill Merchant @ Mar 26 2007, 10:15 PM) [snapback]412753[/snapback]</div>

Come on Bill... I do believe the BT Tech plate will make some difference in stiffening the body. But coming out of the parking lot? You are not driving a wet noodle... I have to believe that's the Placebo effect you are feeling

(probably in your pant pocket, somewhere around your wallet... )

 

<div class='quotetop'>QUOTE(John in LB @ Mar 26 2007, 10:45 PM) [snapback]412771[/snapback]</div>

Hi John

Thank you for describing a test which I could do in my garage!

First to Presto, if the plate has some effect on the body flex, there should have been some effect between no plate and the OEM plate. There was none.

Second, The width of the added plate was three inches just like the OEM plate. I don't know if it makes the OEM plate as strong or stronger than the BT plate but it surely makes the OEM plate stronger. Still, no change.

Third, from making the supplemental steel plate, it is clear to me that the BT plate and the OEM plate have built in slop on one side such that the torque on the bolts is critical to the stiffness provided rather than the plate unless there is an AWFUL lot of body flex. The plate could be TOTALLY rigid and the only effect would be the torque on the bolts. If this is just because there might be variance in the spaciing of the bolts, this means that the rigidity of the plate would only be in one direction for some and the other for others.

Finally, I hope that many others duplicate this test. The results should be good for all to see.

 

It is my opinion that the stock plate is garbage. Hell, I could even flex it a little myself if I try to twist it in my hands. Your argument for the BT plate being ineffective is still far from proven. The steel plate proves nothing as it doesn't even have the same dimensions as the BT, not the same material, nor are the bolts flush mounted in the installation.

My car isn't the best candidate to do the test since I've added most of the chassis and suspension pieces already. A nice, stock Prius would be the best one for the test.

 

<div class='quotetop'>QUOTE(Presto @ Mar 27 2007, 08:35 AM) [snapback]412964[/snapback]</div>

Please find a stock Prius and do the test but with a BT plate. My purpose is not to prove the BT plate is a bad thing. It is to find the truth.

It appears that what ever is bolted down there is simply bolted down there. The whole body flexes, not just the tunnel through which the exhaust pipe passes. That is why some cars have frames. It is possible that the tunnel makes the body more rigid than it would be without the tunnel. I have no idea why the factory installed what they call the "front floor panel brace". It is apparently strong enough to do the job for which it was designed.