New Prius Touring --best bang-for-buck handling improvements

<div class='quotetop'>QUOTE(awai08 @ Aug 25 2007, 07:01 PM) [snapback]502185[/snapback]</div>

You are probably going to start a spirited debate, but here goes.

1. Stiffen up the chassis. My experience with a Touring edition is that the chassis still needs stiffening. If your mod budget is limited, you probably should look into the BT plate. There is a very long thread about the BT plate. Check it out for the details pro and con. If your mod budget has some latitude for expenses in it, you will want to check out the TOM'S suspension braces. I put on the Front (upper and lower) and Rear suspension braces and the car is definitely much improved in the handling department.

2. Further stiffen the suspension. If you want to go for a further stiffening of the suspension (than you presently have with the Touring edition's springs and shocks), you are looking at the TRD Sportivo springs and shocks. The downside with TRD Sportivo is ride height - you will lose ~1 inch in ride height. You may also suffer some increased ride harshness, but I do not have personal experience with the Sportivo.

3. Widen the tires. The Touring edition has 195mm wide tires. It is possible to go out to 205mm with no clearance issues (I presently have 205/60-15 tires (I swapped out the OEM tires and wheels so that I could offset any friction increase from the wider tires for lower rotating mass and ended up gaining ~1 mpg for my efforts) with no clearance issues) or speedometer & odometer accuracy tradeoffs. Beyond 205 is unexplored territory for me (on the Prius).

4. Not necessarily a handling improvement, but while you are at it, consider swapping the OEM brake pads for ceramic (Hawk) pads. You will see an improvement in stopping distance (especially when combined with wider, stickier tires) and there is no dusting of the wheels.

The above is what has been done to my Touring edition. By way of comparison, the car handles way better than the car did before the TOM'S bits went on. It won't present any challenges to my MINI, but if a MINI is driven by someone who doesn't know how to drive it, you can shock the MINI driver by passing them in a turn.

 

<div class='quotetop'>QUOTE(awai08 @ Aug 26 2007, 11:00 PM) [snapback]502591[/snapback]</div>

What is the difference in a touring edition?

 

<div class='quotetop'>QUOTE(awai08 @ Aug 26 2007, 09:00 PM) [snapback]502591[/snapback]</div>

No BT plate; just the TOM'S bits. The BT plate conflicts with the TOM'S Rear suspension brace (they use some of the same mounting points, so it is one or the other, but not both). I have the TOM'S Front (upper and lower) and Rear suspension braces. The front braces are two: 1.) one for the strut towers (which is the Upper Front Suspension Brace), and 2.) one for the lower front suspension (which is the Lower Front Suspension Brace). The TOM'S Floor strengthening plate has clearance problems with the catalytic converter. Based on feedback from the MINI community, the floor strengthening plate will only provide results at the extreme end of the handling margin (autocrossing). However, Presto has purchased the TOM'S floor strengthening plate and is threatening to install it, so stay tuned on the feedback regarding the strengthening plate.

<div class='quotetop'>QUOTE(awai08 @ Aug 26 2007, 09:00 PM) [snapback]502591[/snapback]</div>

You can certainly try putting on the front braces first. I did that and while the front was significantly improved, it tended to highlight the remaining marshmallow ride quality of the rear (with a bit of understeer remaining thrown in for good measure). A week after putting the front braces on the car, I placed the order for the rear brace. It was like a small pebble in my shoe - I had to see what affect the rear brace would have. The e-ticket ride is with the front (upper and lower) and rear braces on the car. Now, the car tracks as if it is riding in a slot in the roadway. No wallowing in the turns. No understeer. And, and, and.

<div class='quotetop'>QUOTE(awai08 @ Aug 26 2007, 09:00 PM) [snapback]502591[/snapback]</div>

The Touring edition is kind of a mid-point in spring and strut performance between the base Prius and the TRD Sportivo suspension. The downside with the TRD Sportivo is the resulting lowering of the car. (And there may also be an additional ride harshness with the TRD Sportivo.) My personal opinion is that the Touring edition combined with the TOM'S bits is the perfect solution for what I am looking for regarding ride and handling.

The wheels that I replaced the factory wheels with are forged Motegi Tracklites in 15x6.5 inches with a per wheel weight of 10 lbs (actually 9.99 lbs when kilos are converted to lbs). The lower wheel and tire weight offset the additional friction from the wider tires. Also, the replacement wheels and tires do not stick out past the wheel wells on the car; they are very understated.

<div class='quotetop'>QUOTE(karlakk @ Aug 26 2007, 11:13 PM) [snapback]502632[/snapback]</div>

Tuned shocks and springs (vs. the base Prius), 16 inch wheels with 195/55-16 tires and a 1' wider rear spoiler. You also get a different set of plastic wheel covers.

 

<div class='quotetop'>QUOTE(awai08 @ Aug 28 2007, 12:59 AM) [snapback]503132[/snapback]</div>

I would probably characterize it that the rear brace was the final piece of the puzzle. With the front being all tightened up with the upper and lower braces, the rear end's wiggly-ness became that much more noticeable. With the rear brace on, all is well.

For a source for the TOM'S bits (and other Prius items), try http://www.sigmaautomotive.com

 

Steve Ganz at Carson Toyota can hook you up with all the Tom's Parts you need. He is the only authorized Tom's dealer in the USA.