BT Tech Stiffening plate

<div class='quotetop'>QUOTE(Tyrin @ Mar 28 2007, 03:58 PM) [snapback]413790[/snapback]</div>

Oh no...you must be mistaken...... How do you know the stock plate really works?.. have you driven with it off yet?.. how do you know its not just a placebo effect to have it?



And when you car flexes up and down because the stock plate if flimsy, how do you know you are not really flexing up and down with it?



How do you even know the prius drives good at all?.. what are you comparing it too.. your "other" car?.... how do you know your not just all psyched up driving your new hybrid?



BTW.. I'm not implying these are your feelings.. just using your post as a spring board.



My point is.. when it comes down to it.... what do you or "we" really know, verses what you think you know?.. have you scientifically proven your prius drives better than your other car?... if not, then how do you know your not just imagining it?....



Doesn't it sound like I"m insulting your intelligence as if you have none to even be able to tell how you think your car drives?



Even so, when people get out here and try to "prove" the plate is no good and they don't even own one yet, it totally insults the intelligence of everyone that does and only makes themselves look like the fool.



We have the same problem when people won't believe in an invisible God that others "know" exist.

There are many things in life that are not tangible enough to prove without tremendous expense and even then its subjective.



Its quite funny, this is such a big deal.... we have allot of cheapskates that squeak so loud they annoy everyone around them.



Most people who only trust facts and numbers, miss out on most of the true riches in life that can't be measured with machines and pencils.



My other point is..... if so many people like it.... then buy it... you will too!



And if you don't.... you can make history!... either way your a winner!

 

<div class='quotetop'>QUOTE(windstrings @ Mar 28 2007, 06:35 PM) [snapback]413815[/snapback]</div>

Indeed, things are only as we "percieve them to be"... Hence, some choose to alter their perception...... and, no offense, but reading your post, I think you need to SHARE !!!!! :lol: :lol: :lol:

 

Hi Allande,

Well, as a person who is daily involved in measurements, I do not think much of your nail in a board and vernier caliper .

Still think you need to get some real dial indicators and watch the needles wiggle as static load is applied and removed. Those disk brake dial indicators with the adjustable stalk might work.

John in LB has a good point. It might be vertical twist. Diagonal dial indicators are sensative to bolt hole locations moving forward and back in the same plane (crabing - the two dimensions change with respect to each other), or up and down without twist (both crossed dimensions get larger) and horizontal twist (both measurments get smaller or larger). If there was a vertical twist the dial indicators would have little change in reading. Think about a device that is four metal rods with ballend joints on the ends of the two long rods. The two long rods cross, but are free to slide past each other. One can easily hold one short rod and twist the other short rod, and the two long rods are the same length.

Its the twist that the stock plate readily does, and the BT Plate does not. The BT Tech plate is probably not as good at holding the ends at the same distance, due to the slotted holes. Although torqueing down the bolts, digs into the aluminum, providing a step that the washer and bolt would have to sheer away to move.

 

<div class='quotetop'>QUOTE(windstrings @ Mar 28 2007, 05:35 PM) [snapback]413815[/snapback]</div>

Thank you for missing my point entirely. Do I know the stock plate works? Well enough to do what? Drive? Do I care whether it "actually" handles better than my last car? No. All I said was that I was happy with the way the Prius handles, and if you aren't, then go try the plate...Why the hell would I buy it if I was already happy? I'm not the one squeaking to try to change someone's opinion.

 

<div class='quotetop'>QUOTE(Tyrin @ Mar 28 2007, 08:29 PM) [snapback]413890[/snapback]</div>

OH common tyrin.. I already said I didn't think that was your thoughts.... I just used your post as a springboard to bring up other points.. they are not directed at you... so don't take offense unless the shoe fits.....



I"m just trying to point out that it takes more "faith" to not believe something than it does to believe... when the evidence for believing is so obvious among so many people.....



I guess what some folks put thier stock in is not what others do.... my myself and I... don't put much stock in numbers, charts and "proof" on paper... I'm old enough to know that the more complicated and the more bulletproof the "proof" the easier it is for the majician to decieve.



Aren't you tired of the car and truck commercials and ads from A to Z on how thier product is best based on an "independent study".. do you really believe those studies?.. if so......



Anyway... I put my faith in my guts and what works.....



Everyone that seems to have a problem with it.. doesn't have it.... what should that tell everybody????????



have can you have a problem with something you don't have, unless your just driven by fear?



It would one thing is there were not overwhelming reviews in its favor.. but not proof is good enough for some.. so why bother proving at all?.. they can buy it if they want to try it.. otherwise mosey on.


I keep bringing this point up over and over, but the naysayers can't respond.

They are too afraid to jump, but yet can't walk away for fear thier missing something!.. LOL!...



I had a friend like that which lost his shirt in the stock market.. I wonder why?

 

<div class='quotetop'>QUOTE(syclone @ Mar 28 2007, 08:31 AM) [snapback]413521[/snapback]</div>

I don't think that most people would get the Inquisition reference. But excellent point.

 

The tests discussed here don't seem to make any sense because they are Static tests. The improvement provided by the BT plate relate to Dynamic forces on the frame. I would suspect that under Dynamic loading, the main feature provided IS to prevent the two connected rails from moving away or toward each other. Shurly the car does not twist from side to side, i.e. right rear and left front corers moving up while left rear and right front are moving down.

Here is a test someone should do. Install an array of electronic accelerometers to measuse forces in various axis on each side of the body around the Plate as well as electronic linear distance guage across the gap and a stress and strain guage on the plate itself. Connect all these sensors and the OBD II connector to a laptop computer. Drive the Prius on a test track with know radius curves at various speeds and record all the data with the OEM Plate, No Plate and BT Plaste.

Or just install the plate and enjoy. I added the plate last night and I did notice a difference driving arond the block at 25 MPH. Then I noticed a big improvement on my drive to and from work today.

 

<div class='quotetop'>QUOTE(NoMoShocks @ Mar 28 2007, 10:34 PM) [snapback]413942[/snapback]</div>

Exactly!... no matter what tests is done.... too many people can't believe fat meat is greasy and won't be convinced.
They want someone else to go to hundreds and thousands or dollars of expense and man hours to prove something they so they can make sure they don't blow 165 bucks!

No matter what test is done, though it may convince a few, it will only create more skeptics because it is not perfect.

Just buy the plate and enjoy.... its sure a good thing people don't scrutinize thier MacDonalds hamburger half that much or thier definately wouldn't be _____ billion sold!

 

<div class='quotetop'>QUOTE(donee @ Mar 28 2007, 04:49 PM) [snapback]413874[/snapback]</div>

Hi donee

I really appreciate your analysis of the plate. In fact I would not have come back to the question except for your views on the matter. I do not have the tools which you describe and did not anticipate the need for them. I do, however, see possibilities for the BT plate that I did not understand until now.

I recognize that my board and nails was not sophisticated, but it did give me consistent results with what I tried to do.

This exchange is so much more useful to me than the cycle of browbeating and sweet talk without much substance. That teaches little or nothing.

I didn't expect to learn that there was no difference in the overall vehicle twisting between no plate and the OEM plate using John's test. But as Presto said, that could mean that the OEM plate did nothing regarding the twisting force you and John mention. That is why I would like to see John's test done with a BT plate. If that shows a reduction in the amount of twisting which the car permits compared to no plate, I would be impressed.

That would only take a short time and would cost nothing to a BT plate owner with stock suspension.


Windstrings

Look at the difference between your approach and donee's. Which would you rather be on the receiving end from? What do you loose by being polite and treating a questioner as though they might be sincere?

 

<div class='quotetop'>QUOTE(donee @ Mar 28 2007, 10:08 AM) [snapback]413636[/snapback]</div>

Hi donee

I went out and did the measurements again. I think you will approve a little more of my method. I did find some twist in the parallel direction which you alerted me to but not much. My method of measuring magnifies the actual twist which the plate would sense by a factor of about five (the length of the moment arm of the squares I used compared to the one inch spacing of the bolts holding the plate). Therefore the offset which I measured (in the secod photograph) of about 1/16th of an inch translates into a movement of the plate of about 1/80th of an inch. That is .0125 inches. My checkbook cover is.04 inches thick.

The car has about a five foot average leverage arm to work on that one inch space between those bolts. That multiplies the forces involved by something like 60 times. If the forces were, say 600 pounds (I suspect they are more like 1500 pounds) that means that the plate would need to resist 36,000 pounds of force successfully without bending.

But even if the plate was totally successful in resisting that 1/80th of an inch of movement, what is there to say that the rest of the flexibility in the body would be arrested?

It might make a teeny tiny difference as the body just begins to flex. But so would adding a sand bag or changing the tire pressure a couple of pounds.

Call me what you like. I have sound evidence for my conclusion. The BT plate can't do much.

(The third picture confirms that there is no spreading while the body twists)

Edit: Excuse me, the top picture is wrong side up. (It was taken before the body twist)

To those who are critical of static tests, I ask how can the body twist dynamically more than statically without permanent damage? By that point, if it bends more, something is going to break or bend without returning to its original shape. It is not so much the extent of twist as the rate of twist up to that point which is significant to dynamic testing.

If it helps you to feel better to say those things, fine, but good evidence is better for making decisions if you like to make good decisions.

 

Hey, let's talk about how to improve the Lexus 400h (350, 250), and the Camry since they all use the same stamped-steel Toyota plate.

After all, they deserve the better handling they were designed for than the commuter SIRS Prius.

 

Allannde,
How much trouble was it to turn the car upside down for that first picture?

 

<div class='quotetop'>QUOTE(Allannde @ Mar 29 2007, 12:47 AM) [snapback]414000[/snapback]</div>

This thread has been going for quite some time now and been recently revived.... some of the frustration you hear is prob from the past attempts at people to try and totally botch what so many love just because "they" don't understand or are not comfortable with it and are not even willling to buy it.



Anybody willing to actually "buy" the plate in my book has rights to bitch or commend..... but not otherwise!!!



I get tired of peoples fears driving them to speak things they know not of and they accuse others who do own the plate of being feeble minded to think it works and can't see all along that they are the feeble weak minded that can't accept anything without fear dominating the decision.





My hat is off to anybody that first is not so cheap that they will at least buy the plate, and second willing to take the time to actually make a credible test that is not too vulnerable to be picked to pieces by every "nonbeliever" out there.



Tests are hard to do well.... if there is anything I don't have faith in.. its not the plate.. but rather lack of faith in the likelihood that those who just "will not be convinced" will be swayed though you do an elaborate test.



Some people just can't be pleased.



If someone wants to do it for fun and is willing to get tons of criticism by the hecklers, then more power to them... like I say.. my hats off to them.....



Nice pics too BTW!

 

<div class='quotetop'>QUOTE(Allannde @ Mar 29 2007, 12:58 PM) [snapback]414388[/snapback]</div>

Alright.. again, this is assuming you know the properties of the plate, which you don't. If the plate wasn't able to handle the flex, there'd be a lot of broken plates right now. I would've broke mine dozens of times by now. There is a lot of flex to cover throughout the whole body of the car. The BT plate only handles a small, but significant area, and there are other pieces for the rest of the car. The BT plate is not the magic solution that will stiffen up the whole vehicle, but every piece counts. The plate works as promised. If you want much better handling then TRD and Tom's is the next, logical step.

 

<div class='quotetop'>QUOTE(Presto @ Mar 29 2007, 06:35 PM) [snapback]414540[/snapback]</div>

I agree..... Toms brace is nice, but quite elaborate, hard to install and cost a few more coins for sure!.....



The BT plate is so stinkin simple because of its strategic placement.... it makes it hard to believe it does much..... but although if you want to take the car out on the track, Toms plate may be the ticket.... I think there are much simpler ways to do major improvements that are cheaper with easier installations.



So often, you get 80 - 90 percent improvement in the simple and then have to pay 4 times more to get the refined 20 percent left over. Most are not willing to see the cost effectiveness of paying for that extra 20%.

 

Hi Allande,

That looks like good backyard engineering there. You are seeing twist of the horizontal plane of each bolting surface.

You say your measurement multiplies the twist by 5. But think about where the rear axle is attached, and how far out that is from those bolting surfaces. Also think about how little a front to back displacement would be needed to cause a 60 mph car to be steered out of a highway lane in a second. That is 88 foot long triangle by maybe 2 feet wide, or 1.3 degrees. The two mounting points are about 4 feet apart? So that is a deflection of about 1 inch. Do that same thing in 2 seconds, and the deflection is only 1/2 inch. And so on.

What happens if besides front to back axle attachment movement there is up and down. I do not know how to do the math for that however. Specifically, how much steering results from one axle attachment point being up or down a certain amount.

Here is how you can see the other two twists that can occur.

Look end on the yellow square heads (straight up from the ground). Without load the set the squares inline, and the tips towards the ground flush. Underload do the tips of the yellow square heads deflect in the front to back direction of the car with respect to each other?

Bolt the blades to the a horizontal surface of the aluminum angles. The third twist would cause the blades to deflect as in your pictures.

As to static versus dynamic testing, I mostly agree. But one needs to apply the force statically, that would occur dynamically.

For the cross-wind situation one would need a wind tunel or computational fluid dynamics prediction to get the center of pressure and the load precisely. For approximation - If the side Cd was near .6, then the 25 mph side force would be approximately 1 lb per square foot, and about 2.5 lbs at 40 mph (see http://www.madsci.org/posts/archives/mar98...99316.Ph.r.html ) . Guessing the Prius has about 300 square feet of side surface. So a 40 mph gust generates about 750 lbs centered 1/3 th way up the B pillar. Are you pushing that hard You might need a air-filled bladder to avoid damaging the car for this test.

For manuever dyamanics F=MA is a good start. That is static radial acceleration. Say .5 G accelleration. Mass is 1500 kg. A is .5 times 10 m/sec/sec. - which means the car wheels are pushing on the car a total of 7500 Newtons, or about 1700 lbs. Have you been pushing sideways on the wheels 1700 lbs worth ? This assumes the car leans into a turn, and the outside wheels take most of the force. But I also only calculated for only .5 G.

I am looing forward to the pictures of the car hanging by two of its two passenger side wheels!

I also think the use of the high-strength steel has something to do with this. Higher strength materials tend to be higher Q (less vibration damping), but with the same modulus (slope of the Hooke's Law curve). To make a car lighter, one can use less of a higher strength material and have the same strength that in a ligher car. But that also makes the car more springy, the material still has the same modulus, and there is less material. In the Prius this is good and bad. In a crash its good, because less mass has to be decelerated. But there is kinda of a backend shimmy too, the bad.

 

<div class='quotetop'>QUOTE(donee @ Mar 29 2007, 04:15 PM) [snapback]414561[/snapback]</div>

Hi donee

Thank you so very much for your comments. I don't think I have ever read one of your posts without learning something which was very valuable. PC is very fortunate to have you and others like you to help us learn more about our amazing car. If I get nothing more for my efforts, I will have been well paid.

Frankly, I need to come back to your post and study it again. I think I did what you suggested and did not find deflection. But I will try again. I confess to be operating at the edges of my thought power with your post.

It would be wrong to say that I had proven more than I can see and have reported. I know more than I did and it still does appear to me that the BT plate is not in a position to be critical to the handling of the car. I have a lot better idea of the the environment in which the BT plate works. No where in this thread have I found an explaination of how the BT plate works. I am learning as I pose questions. It would be so much better if this information was out there already. After all, I don't think I have learned it all, yet, but that is not for lack of trying.

Yes, I certainly agree that a small deflection can cause a great result. But what actually happens? When the wheel position is changed by a bump or a maneuver, first the spring gives. But then the shock dampens the spring movement and transfers energy to the body. Then the closest and most flexible part of the body gives. When that reaches its limit of flex, the energy is tranmitted to the next most flexible body part and so on. Eventually it gets to where the plate is installed and the properties of the plate come into play. How much energy remains at that point to absorb is the first question and the second question is how much energy that the plate is able to absorb without flexing.

That is a riddle which I can not solve. I suggested that a ballpark guess was that 38,000 pounds (19 tons) of twisting force might be a reasonable guestimate. But even if I was WAY off and it was only about 1/20th of that it would still be a full ton of twisting force. Could the BT plate resist that amount of twisting force without twisting?

If it twisted at that amount of force, it would have ceased to provide added stiffness to the body.

How do we know how much twisting force the BT plate can withstand? Must someone purchase a BT plate and send it to a laboratory for a test to destruction to find out?

It frustrates me, but I can see the reason for the comments to the effect, "just try it". The reason it frustrates me is that I swear that my car drives better right after I wash it. I know full well that the car has not changed a whit mechanically but there is no question that it drives better. I absolutely believe that I would have the same feeling just after I installed a BT plate. And I know just as well that I would tell myself that this was just in my head. With objective data that the plate really has a changed effect, I can discount these thoughts and feel confident that this is a good thing to do. I hope that this thread will get to more than just mutual reinforcement and encouragement. That is nice, but does not really inform and tends to polarise the "good guys" from the "bad guys" who do not play the game.

The more we discuss the objective realities of the car and (in this case the BT plate) the more we all will learn. This isn't about winning. That is for wars and football games. We are not better for defeating the "bad people". We are better for knowing something we didn't know before which we can use from now on.

One of the gems of PC is that it affords the possibility for us to have reasoned exchanges.

Isn't that a good thing?

 

<div class='quotetop'>QUOTE(Presto @ Mar 29 2007, 03:35 PM) [snapback]414540[/snapback]</div>

I don't claim to know the properties of the plate. If one must purchase the plate to learn what those are, this is the first time in my experience (which is far longer than yours) that I have encountered that. Usually, the seller is happy to inform the possible purchaser of the merits of his or her product.

As to your second comment above, there is another possible explaination. That is that the BT plate isn't doing anything either. How would I know the difference?

With all due respect, I can not tell if you are a genius or a fool. It is the information which you share which tells me the difference not the experience which you describe. Anecdotes about what did or did not happen are not informative because I do not have the context of that event.

You are certainly invited to explain what I appear not to know.

 

<div class='quotetop'>QUOTE(Allannde @ Mar 29 2007, 07:28 PM) [snapback]414653[/snapback]</div>

I'm not calling into question your testing and results, but I'm not gunna let it slide when you proclaim with such certainty that the plate doesn't work. It insults me, the people who have the plate, and Brian. Keep doing your tests if you like, but until you have actually tried the plate, I'm gonna keep popping up whenever you conclude the plate doesn't function.

 

<div class='quotetop'>QUOTE(Allannde @ Mar 29 2007, 06:16 PM) [snapback]414614[/snapback]</div>

I think that one of the problems is that while we drive the same basic car, we are different in how we drive it and where we drive it (heck, we don't even get the same gas mileage). Reasons given for buying the plate is the handling on freeways and curves. Since we don't all drive the same commute and the same way I suspect the results will vary. I mean, if I don't need it because of the way I drive on my commute doesn't mean that another Prius owner wouldn't benefit from it. I see the BT Plate as a solution to a problem and when I see a post about a complaint about handling, I try to mention the plate.

Because of we are all different I can't believe it's all placebo, surely we'd have a tiny percentage of people that don't notice a thing. I've seen one post about not much difference and a mention that the Prius now finds the lines on the freeway more, but all the other posts I've seen are positive.