Thoughts on TRD Rear Sway bar....

Oh. Well, I just picked mine up from JuicedHybrid.com, and that's what it measures. Also, the endlinks are little dry. I'm taking them apart to repack with Mobil 1 synthetic suspension grease.

 

Yep, I know that road well. My dad used to live in Cathedral City and my son spent some time at Twentynine Palms. Every time I had a business conference in Vegas, I'd take Goffs and Amboy roads down to 62.

 

First time I took the Prius through the 62, the crosswinds felt like they were going to blow the car away and I had to constantly steer the car in line. With TRD sports springs and TRD rear sway bar installed, I simply plow through the 62 at 80-mph. Sure I could still feel the crosswinds, but I don't feel like I am being tossed around in a bad turbulence.

 

I bought my 2010 with 65,000 hard miles on it. The suspension felt spongy especially in high winds on the freeway. I just bought 4 kyb struts, not installed yet. I already switched to scion tc 17" rims and feel it is more steady and controlled on the freeway. I will report the effect of the new struts when I install them in the next few days.

 

OEM setup definitely felt spongy, even with 4 miles off the dealer lot. My initial thought was "Volvo S80".

 

So, feeding back with my 3-day seat-of-the-pants assessment of the TRD rear sway bar. My 2013 Prius Model Two is stock as it relates to performance mods. My intent was (and still is) to cure the car of its more notable handling deficiencies, while retaining the stock characteristics, which I regard as efficient, relaxing, and versatile enough for winter mountain travel (i.e. I don’t want to plus-size my tires/rims, nor lower the car). The Prius is my commuter and road-trip car, not my play-car (that's another vehicle). Excessive body roll was a problem I noticed in the stock setup, but wallowing from small mid-corner bumps was the major problem I was aiming to solve.

The bar was straightforward and easy to install, and could actually be achieved without detaching the rear shocks. However, I did have to put the rear on jackstands in order to afford my body the room to do this. YMMV.

The end-links felt a little dry, and the ball-end boots were a little warped at the shaft end, so I took them apart and packed them up with some more high-pressure, synthetic grease. The ball-end boots remain a little warped, so I will keep an eye on them for contamination and wear.

The ends of the bar/end-links come within ¾” to the inside of the rims, which is a decent amount of clearance. Less pleasingly, the bar reduces the ground clearance near the rear wheels by about 1”, and of course sticks out into the underbody airstream as much. I shall keep an eye on fuel consumption.

I like what this addition has done overall to curing the car’s more notable handling deficiencies, but I think it’s a little stiffer than I’d like as it currently stands on my car. Body roll is now very controlled, but to an extent that I regard as bordering on overkill. Body wallow from mid-corner bumps as it relates to typical freeway on/off-ramp speeds is almost non-existent. I have not had the opportunity to test on faster corners as of yet, nor hard weight-transfer corners (i.e. downhill switchbacks). However, the ride is noticeably harsher (not a lot, but noticeably), especially as relating to high-frequency vibrations. A literal seat-of-the pants approach might miss this observation, as the seats do a great job at damping these out… but put a hand on the dashboard and the change is obvious, esp. at street-level speeds on rougher-paved (I don’t mean potholed) avenues. In some instances, I have been able to produce noise from the dashboard in this 2-month-old car. I have since reduced tire air pressures to 40/38psi (from 42/40psi).

Whereas the bar does succeed at what it sets out to do, I see that it would work better as part of the overall Plus Package, where the larger contact patches can potentially generate higher lateral loads that would be more appropriate for this sway bar to resist. Also, the lowering springs lowering of the body by ~1” at the rear negates the intrusion of the bar into the lower airstream. And the total Plus Package has no pretension about trying to maintain a stock feel, but rather aims to outright transform it into something else.

As it stands, I will keep the bar and see if the urethane bushings that locate bar start to soften after some more use, which would then have the effect of softening the bar. I do not know of any softer alternatives, and the bar as it stands solves more problems than it generates. I shall feed back updates as it becomes relevant.

 

The Plus Perf sticks real well in corners on the street. It is not a track car but it is nice ;-)

Mike

Mobile on my SGH-i717

 

Yes, it was the PTR11-47010 kit as sold on JuicedHybrid.com

I did not *have* to re-pack the link ends, but I did it because 1) I figured it was a good idea, 2) at this point it wasn't hard (the part wasn't installed yet), and 3) I was hoping that in the process the ball-end boots would would un-warp. Everything else went according to plan, but the boots didn't really unwarp.

It does need to be noted that as much as I do desire to keep the stock ride and noise levels, the net effect of this modification seems to be a positive for both the the overall characteristics of the car, and its ability to be driven efficiently, i.e. carry more speed safely through corners that I would otherwise have to slow further for. My primary complaint is that this could have been achieved (for me and my particular aims) at a lower level of sway resistance, i.e. a thinner bar, and that it would have achieved the vast majority of the positives with less of the negatives as it currently manifests for me (high-frequency vibrations, etc.).

It would be nice if TRD could produce a variant product that is a slightly thinner bar, but I wouldn't hold my breath. This is the most OEM bar you will find right now... and probably in the foreseeable future. The Prius is not exactly what people think of when they think of tuning a car. Those of us willing to stray at all from OEM is probably a small community, hence, market.

 

I had my sway bar thrown in by the salesman since he did not get blizzard pearl for me as promised but classic silver instead (last of the 2013's left in the province). I have the 17 inch plus wheels too.

As for as commenting on the bar, I don't have a baseline 15'inch wheel without rear sway bar to drive around beforehand but I can say that the bar looks nice from the rear! Not a lot of cars you can see on the road has this visible from behind. In regards to performance, I think there's still a lot of lean in cornering and off ramps. Hoping to upgrade the springs / shocks in the future. For now, will leave the car alone since I still have to pay it off!

 

Addendum/update after (merely) a week of the TRD/Plus RASB.

It has softened quite a bit. I take back most of my prior comments about the modified ride characteristics. The car still corners considerably flatter than stock, but it has lost a bit more of the anti-wallowing characteristics than I'd like. So I have just put in an order for the RAV4 FASB ( Inexpensive front sway bar upgrade | PriusChat ) to reclaim a bit of the overall sway/roll/wallow resistance, and also to balance out the sway/roll resistance on the front, which I believe is desirable (to a degree, as with everything suspension) for evening-out the lateral load so it's not excessively on the outside rear tire, and also that the Macpherson-strut-type suspension does not gain appreciable amounts of negative camber upon compression. Will update as necessary.

 

How are you guys testing this out? Regular day to day pace driving, spirited driving?

Reason I note this is unless you take it to the track where you can duplicate a test, it's somewhat hard to tell. After a few track sessions(not with the Prius) did I learn the limits were a lot higher than I you think. It took me a while to get up to the 8/10th or 9/10th of the car's limits. Learning to "dance" around the turns is a lot of fun AFTER you know what you're doing. In the Prius and street level driving where I maybe get up to 6/10th, the car under steers as expected. So does the rear sway reduce under steer or just body roll?

With my Plus spring I think the benefits were very obvious as it lowered the car substantially and reduced a lot of roll. This sway bar is technically a stiffener that reduces twist of the trailing arm. If I had to guess, in the order of magnitude for the Plus package pieces, from largest to smallest, it would be wheel/tire combo, springs then sway bar. Since I have the first 2, I'm a little curious to see what the sway bar does. A friend of mine has a Plus package so I should ask him for a test drive.

What' funny about performance upgrades is in the Prius, I mainly did it for aesthetics as there simply isn't the power to enjoy it in the twisties. The handling does help a little in the turns so I don't have to slow down to save gas.

Oh, and keep in mind those who have 15" and 17". I think that's a major factor here.

 

Well, I used to autocross, and at my participation peak I did a year of a points series (middling, if you must know; more wiling to wrench than exert proper driving discipline). I've been running mountain roads for over 20 years.

That said, I have no intention of tracking a Prius... so no matter how repeatable, assessments at 10/10ths means nothing in terms of how I want to drive this car. Trying to extract maximum performance from a Prius, IMHO, is total folly. There are a hundred better ways to start that quest and reach more rewarding ends than with a Prius. That said, I would like my Prius to behave in the way that I prefer, so that I can get to where I want to get to with some amusement and possibly some grace.

So, no, I am not tuning for maximal performance. I am aiming for an experience maxima in the role I intend to use this car, which is at a near-stock ride quality (for daily commuting and thousand-mile road trips) and clearance (for snow and rockfall), with the narrowish tires of the 15" rims (fuel efficiency, then snowfall).

 

Right, that's how I interpreted it. So slight improvements are felt at mpg conscious speeds?

 

Sway bars are far from "slight improvements", esp. relative to a stock car. Ride in a before-and-after and see for yourself.

It almost sounds like you've never had sways before. Are you sure you're not confusing this with STBs?

 

My setup is quite different than your's so my guess is the result will be. The Plus springs flattened out the car substantially.

I'll test drive my friends and see as his has the full Plus package. Expectation are low at this point though.

 

I would put a rear sway bar as one of the biggest suspension improvements you can make on most cars. I haven't tried it on the Prius, but in general, unless you radically change the stock suspension (WAY stiffer springs or otherwise changing the suspension substantially) a sway bar is a huge bang for the buck. It should make the car respond to steering inputs much quicker, stabilize it in transitions, all while having a relatively minimal impact on ride quality.

 

I've managed to install the RAV4 FASB, and am continuing the feedback for the two sway bars in this thread:

Inexpensive front sway bar upgrade | Page 3 | PriusChat