Successful Gen III PiP install of Cusco Strut Tower Brace (STB)

Folks,

I had a BT Tech STB on my 2007 Gen II, to good effect.

On my April 2012 PiP, I modded the suspension in this order:
1). Rude person's's center body box brace in early Summer.
2). Rude person's's front body bar brace in late Summer/early Fall.
3). TRD rear anti-sway bar in early November.
4). Cusco STB - today.

...and then I drove the PiP for about 90 minutes in city & country. Just got back.

Point #1: The Cusco STB does mount fairly easily and solidly with one small modification of the brake fluid reservoir's steel brace.
Point #2: the car's handling is again improved, but in a different way. Key improvement now is in a very solid steering. The center box brace unified the previously rubber-banded left and right halves of the car. The front body brace almost eliminated perceptions of ICE / EV function transition, and further tied the left and right car halves together. The TRS anti-sway bar made the rear end come alive with feeling. Now the Cusco STB, in conjunction (harmony?) with the other three mods, makes the car's steering feel like my 1982 BMW R100CS motorcycle felt going into corners with its huge front wheel - you aim it, and that's where it went like on a rail track.

Details:

I chose Cusco over Tanabe to eliminate living with and correctly tuning Tanabe's horizontal end tension nuts.

Disassembly & reassembly (in my driveway - warm day today) took about 1.5 hours, including a small frustrating step.

I followed HAWAIIANBUILT's instructions from his Tanabe STB installation post elsewhere on PriusChat. With the Cusco STB, I discovered two deviations.

Deviation #1: the Cusco STB is designed for right-hand-drive Japanese models. On the US models of Gen III, the Cusco does not completely seat onto the driver's side shock tower top because of a 3-dimensional interference of the thee-bend steel brace which holds the brake reservoir. See picture and the overlap of the Cusco (blue) over the OEM brake brace (black).


Note: the black brake brace is behind the harness cable. This is a test fit with the cowl and wiper assembly off the car. Here I was trying to understand what interfered with what.

Next picture shows my solution: the Cusco has two parts that looked like needing more space: the horizontal base plate in the picture above which needs to mount flat to two of the three tower strut bolts, and one vertical hinge plate (the left one in the picture) which carries the bar hinge and which rides above the base plate.

My solution - the black lines mark two cuts necessary in the OEM brake brace: a "trench" cut on the left side where my finger points to, and a right "trim" cut of 1/8 inch width parallel to the right edge.

Note: the Cusco comes with notably extra thick steel washers/spacers and replacement thinner nuts for the two of thee strut tower bolts that it'll mount on.

After I cut the trench cut shown above and trimmed the right edge of the OEM brake brace with a Dremel tool and a hardened steel-cutting disc, I discovered that the spacer/washer is high enough to make the trench cut unnecessary. This is 3-D assembly and hard to do crammed in a small space under the hood - so others only need to trim the 1/8 inch off the right side of the brace, parallel with its edge. The brace will thus retain its OEM calculated strength and rigidity.

I dismounted the brake fluid reservoir (2 screws) and let it sit in place while I cut the OEM brace sitting on steps right next to the car. There's one electrical mating plug to disconnect as well - easy stuff. The OEM brace is long enough that its other end never got warm. Both Dremel cuts and the later Dremel deburring took maybe 10 minutes altogether.

Here are two pictures of the Cusco mounted, and its bolts tightened down. In the top-down image (#3), you can see the unnecessary trench cut and also the thick shiny steel spacer / washer under the new black nut on the strut tower. In the final picture, I am looking horizontally from the driver's headlight toward the driver, and you can see the blue Cusco base plate and the black OEM brake plate sittin' pretty next to each other. That's the only cut necessary.

 

My browser crashed so I'll attach the two pix described above in this post.


Deviation #2: on the other end of the Cusco, it is important(!!) to feed the electrical harness for the wiper assembly to the inside of the Cusco before you mount it (between the Cusco and the now-missing cowl). Or, unplug the electrical harness from the wiper assembly and feed it through separately after you reassemble the Cusco STb, the lower cowl and the wiper assembly back on the car. the electrical harness is not long enough to loop on the outside of the Cusco. (Damn this laptop has lousy keys on the keyboard!)

That's it. One easy mod and one careful wire feed are the only deviations from HAWAIIANBUILT's excellent instructions for the Tanabe.

Driving - yes there is a very noticeable improvement, but not quite of teh character I remember from BT Tech's STb on my Gen II.. Of course, this is a different car and I already have two other braces and the TRD rear anti-sway bar on the PiP.

The steering was god up to today - but now it is both precise and very "stable" somehow. I usually telescope my PiP's steering wheel to its full extension, and tilt it all the way down. Whereas up to today, when I drove with my hand on the armrest or leg holding the bottom of teh wheel with the palm facing up, the wheel was never quite calm. Now, that thing just sits there motionless unless I roll it. This is new, and a good quality.

Final thought: after 90+ minutes driving in varied conditions, it somehow feels that the anti-sway bar in the rear and the Cusco STB up front complement each other / feed into each other in how the car now drives.

I recommend this accessory. Sorry for the long post.

 

MRSTOP, not at all. The brake reservoir cap and the other reservoir cap are both accessible, and the STB comes nowhere near the fuse box cover. This, and the unwillingness to mess with / monitor the Tanabe STB end tension nuts, is why I chose Cusco.

I did hope to find a way to get around the reported brake interference. My trim cut of the brake bracket did that. The Cusco bar is well tucked in 1/2 way under the lower edge of the wiper assembly cowl, so that its front half shows lengthwise. It clears the engine ribbed plastic cover by at least 1/2 inch.

And most important, it works well.

 

More info: the only problem that just blocked me during the install yesterday evening was during reassembly. Once I remounted the metal pan under the windshield wiper assembly and got ready to bolt down the wiper motor pivot arms (long silver pipe things in HAWAIIANBUILT's pictures) I realized the Cusco blocked the old routing of the wiper electrical harness. I then spent about 30 minutes trying to unplug the #$%^& EVIL PLUG from the wiper motor to reroute the harness under the Cusco - electrical screwdrivers, needlenose pliers, the works. Then I took a 25-minute break and the EVIL PLUG decided to be nice and pop right off when I squeezed its sides. Let's say the plug release is non-intuitive.

This was the only stumper/problem. Wish all car & motorcycle mods in my past life had been that benign

 

Because of interest shown, here are the completed pix. You can see the clearance from several angles.

 

I'm sorry about that. I seem to remember that back in old Prius threads there was a comment about a redesign of the Cusco STB (can't remember where now, or what the redesign entailed).

FYI - I got mine new from Prius Accessories, 2010 & 2011 Toyota Prius Accessories & Hybrid Car Parts, 2012 Prius Accessories: JuicedHybrid.com last month.

MCH

 

I got mine @ Juicedhybrid.com

 

I honestly don't know... but the only fitment mod I had to make is a slight trim off one edge of a fluid reservoir bracket on the car, described in the pix in my post - about 90 seconds with a Dremel tool. Otherwise the bar fits perfectly and doesn't obstruct anything, so... it doesn't matter.

I hope this helps.