New Prius Handling Components to be available soon!!

<div class='quotetop'>QUOTE(mikepaul\";p=\"115787)</div>

What is this, Communist Russia?

I have the right to have more exacting standards, without being called an elitist, just as you are welcome to content with mediocrity, if you so choose.

 

<div class='quotetop'>QUOTE(mikepaul\";p=\"115787)</div>

Not at all. This is a free country. That permits some to have higher standards than others.[/b][/quote]His last sentence either blew right by you, or fit like a glove so you didn't care.

You'll let us know which one, I hope...
[/b][/quote]
I wasn't going to reply b/c I felt that each of our arguments were not going to convince each other and any reply have would just fan the flames. But you since you basically asked how I felt, I do feel obligated to reply to your inquiry. Ultimately, there is a lot of stuff way off topic at this point, so I'm going to stick with talking about the plate.

At this point, I still want to see if the new Toyota brace exists and hope that someone out there can provide some quantitative evidence of improvement of the BT Tech. Maybe it's hard to do and beyond the means of anyone here. But I do appreciate that Godiva has been nice enough to offer her car for a test drive which I think is really sweet.

Maybe I'll try it out since I can probably spare $160 and I can give a brief review of this mod from a average, non-performance driver point of view who currently doesn't see any chassis stiffness issue. This will probably be of interest to at least mikepaul, and I hope others. I'll see when the next batch of plates becomes available.

 

Remember folks. Toyota already made incremental improvements in mid year. We discussed this a while back.

Here's one of the posts.

http://www.priuschat.com/forums/ukaustrali...id-vt10070.html

They made some changes that were specific to european driving tastes, but one of the changes they made to ALL prii was to stiffen the chassis.

"a package of changes to increase body rigidity – thereby ..... improving handling" (among other benefits).

They also changed the spats in front of the rear wheels, which I suspect is a straight line stability issue.

There was also the "added front suspension tower brace"

Bottom line is that Toyota recognized that the car needed a stiffer chassis, and they did it.

Those of us with older models can only work with what we have, but, whether or not Toyota changed this particular brace in their upgrades, it's clear to me that the car will benefit from a stiffer chassis.

Really, any car will. If you read the reviews and blurbs, the "20% Stiffer Chassis" claims come with every new car roll out. Much of the development of high strength steels in auto applications is for just this purpose.

Another old link

http://www.priuschat.com/forums/toyota-rev...ius-vt8478.html

http://www.newcarnet.co.uk/newsarchiveitem...l?id=4570&pos=1

"Body rigidity has been increased and the springs and dampers have been tweaked, delivering greater straight-line stability and ride comfort."

 

i've installed bt plate couple of days ago and noticed car handles stiffer then before.
The ride is quiter and smoother and overalll the car feels thigher then before. All i can say is it's worth spending 160 ...

 

<div class='quotetop'>QUOTE(starcross\";p=\"115812)</div>

So maybe I'll find you in town and see the thing AND figure out how you get that MPG here. We can't!

 

^^ welli been averaging 50 consistently but after i switched to shell gas i noticed about 4 - 5 mpg increase, also i been using mobile 1 oil as well.

 

http://www.theautochannel.com/news/writers...cruss/1013.html
http://circletrack.com/techarticles/73538/
http://www.osc.edu/education/su_programs/s...chassisproj.htm

Well, after finding a few websites about I googled about chassis rigidity (above) and re-reading this all the posts in this thread relevant to the BT Tech plate, I think I understand the physics/mechanics of it a bit better and I'm interested in trying this thing out. I do want to make sure I do understand things correctly, so I hope some knowledgeable sorts won't mind confirming or correcting my interpretation of things.

There's two things involved here, the chassis and the suspension. In order for the wheels to maintain constant relation to each other to maintain camber/toe-in/whatnot the chassis should be as rigid as possible. If it flexes, then these things are not constant and the car is out of the carefully designed specs which should have been determined for a certain level of handling. Since roads are not perfectly flat, the car must accommodate some movement of the wheels in relation to each other. It is the suspension's job to shift each wheel within (a) certain predetermined degree(s) of freedom. When a chassis flexes, the suspension can't do its job.

Also, noise can be reduced simply because when things flex, they tend to make noise.

There is no high wind speed stability added b/c that is a function of aerodynamics which is what Brian's aerodynamic mod fixes. I think this got propagated since Brian's original post said that high wind speed stability was a problem which sort implied that this stiffening plate would fix, when in fact it was a issue fixed by a separate mod. This got repeated enough to become a sort of pseudo-fact, some more knowledgeable sorts noticed and are trying to quash as heresy.

Does that sound right?

 

Here's some more fuel for the fire:

My first impression is that the Prius feels heavy and undertired. The car lacks some stability on the freeway, especially when mixing with big trucks, and any change in crosswind seems to affect its stability, causing me to have to make constant minor steering corrections. Road and Track long term test Jan 2005

Negative comments have dealt more with its highway abilities; its Goodyear Integrity all-season tires are noisy and the car is extremely susceptible to crosswinds. Road and Track long term test by Mike Monticello

The Prius offers a comfortable ride with a soft but capable suspension. The electric power steering is very light and, at highway speeds, it has a floaty feeling and the tires tend to catch the grooves in the pavement. At times, the car seems disconnected from the road. This is probably due to the low-resistance tires (Goodyear P185/65R15) and its relatively light curb weight of 2,890 pounds. Although there is a fair amount of body roll, the Prius handles well. Edmunds full road test.

Not as stable in crosswinds as vehicles with lower-profile bodies. Tight turning circle a help in close quarters. Pleasingly consistent steering effort, though a bit light, artificial to some testers. Consumer Guide

Handling and steering are the Prius' weak points. The steering effort is easy, but it's numb and detached from any road feel. Canadiandriver.com roadtest

The steering is fine in the city, and reasonably accurate when cornering, but at arterial road/highway speeds it is devoid of feel and quite vague. You have to constantly trim the wheel to keep the Prius pointed straight. NRMA, Austalia

The steering is relatively light and less than communicative. www.thecarconnection.com

Mother nature also blew in gusty crosswinds - and the Prius hated it. So did her driver. As is the case with many very low drag cars, the Prius (cd = 0.26) is susceptible to crosswinds. Constant corrections are needed to keep the car on the straight and narrow, and with an unfortunate (electric assisted) steering system that lacks feedback and has a slow ratio around centre, the outcome is tiring and tedious. Article from autospeed.com, cross country drive in Australia

The Prius' electric-assist power steering is an interesting mix. There's decent steering weight and precision but there is very little driver feedback. This isn't a major concern in most urban conditions but it is noticeable on the open road where the Prius is easily unsettled. Autospeed.com, original road test of 2004 Prius

 

You've got right with just this addition. Brian's contention along with others is that the lack of stability some of us feel in the Prius is not just a function of cross-winds. The Prius in my opinion sometimes feels like it's hinged in the middle. With a flexible or compliant chassis, many disturbances like passing trucks road crown, freeway grooves, corrections by the driver can make the car act like it has a hinge in the middle. So Brian is addressing some of the route causes with the plate as well as trying to mitigate something that induces the instability with the spoiler. But I think you did a very good job of summing up the fact that you want the "compliance or movement" in the suspension component that were designed to control those movements in a controlled manner. One that minimizes the geomentry changes. Good job!

 

It also says they rolled these changes out in most markets. It did not say that all Prius have these improvements as far as I could read. Where's the US announcement of this or did I miss it? We're getting lleather seats!

 

Thanks for the references.

If the stiffness plate's job is to control the parallelism of the two sides of the car, I can understand why a thicker one would help. However, when neither plate is supposed to actually bend in operation, I can't see where one would keep the wheels in track better than the other. We can't be talking about more than a millimeter's travel for more than a moment when the OEM plate 'flexes' more, can we? Otherwise I'd expect the plate to wear out, and so far that hasn't been mentioned.

I'm not sure I'd miss the 'extra play' that I must be getting out of the OEM plate, but I'd hate to spend money and find out I do. Maybe if it comes up as a Toyota TSB or something someday, I'll think about it...

 

But would 3 extra centimeters of flexing be more than the suspension could handle to keep the tires on the road? What does it take to make the wheels not track correctly? Anyone?...

 

Well if you look at the toe in spec it's only 0.0 deg +/-0.2 deg or 0.0" +/-0.080" (thats only about 2 mm) so it's quite precise. Now a couple of cms of flex in the middle of the car in wrong direction could be significant. I say "could" because I'm not presenting proof I'm only trying to shed some light on the magnitude of what were talking about and the precision of alignments. With some modes of flex one wheel could conceiveable gain on one geometric thing like toe-in and the other loose a like amount as well so it could be even worse. I like the idea of minimizing what flex you can where you within reason (cost and degree of difficulty). For me the $160 is resonable enough given my degree of frustration with the handling.

 

Any plate can flex either in bending or torsion and not wear out. It all depends on if the material has been taken beyond it's elastic limit (beyond it's ability to spring back to the original shape). Given that, a wimpy plate might flex a lot and not provide much rigidity to thechassis and yet not wear out. If the chassis is so weak that it allows the wimpy plate to flex too much the plate deformation might be permanent. But I don't believe this to be the case.

A more rigid plate would flex less given the same loads and therefore limit the chassis movements or flexing to a smaller amoutn. I've done some preliminary analysis (FEA) runs on approximations of the plates. I plan to finish the exact models this weekend for Brian and provide him with some data on both plates. But I can tell you now that his plate is much more than 10 times as stiff as the stock plate and should in fact minimize any chassis flexing due to the stock plate not being strong enough. Sounds like Lawyer speak I know but if I say more I'm liable to get swamped with requests for skid pad tests, entire vehicle analysis, etc from the critics. So I'll just present what I know and you can draw you're own conclusions from that. But my plate from Brian is in the mail and will be on my car Monday!

 

Has anyone looked at the rumoured changes on an updated Prius? Is the new plate any thicker? Is there a shocktower brace under the hood? Can these parts be ordered from Toyota and bolted on to previous models?

 

Best guess is the shocktower brace is the bar at the top?

http://www.eadperformance.com/catalog/popu...94ea9f116543425

What does it do, prevent deformation of the engine compartment?

Not much space for one in a Prius...

 

While I don't know about if the new stock Prius has new chassis stiffening components, there are chassis brace/suspension parts availabe via TRD.

http://newtoyotaparts.com/model/struct.php..._id=43&cat_id=7

I didn't realize the shocktower brace went at the top of the engine compartment, but this appears to be the TRD equivalent.

http://newtoyotaparts.com/product/?id=1740

 

I test drove a Godiva's car today. I did notice an improvement. I dont know if it's exactly a $160 improvement. I would buy a plate if it was cheaper.

 

These changes have been announced for the Australian market by Toyota in Australia and the European market. I could not find any mention of this on any Toyota site nor any confirmation that we're getting anything besides cosmetic upgrades. Not even the improved electronic Power Steering, which may be a big part of all of these problems, is not going to be offered here. I even emailed Toyota and they said the same thing about all these options, they are NOT planned for the US market at this time. It's really very disappointed which is why I think someone like Brian should only be encouraged.