Improving a Prius's suspension?
 

I have been thinking of buying a second generation Prius for a long commute; the one thing I'm not sold on is the way a lot of late model Toyotas handle (my wife drives a 2005 Camry). I'm not looking to win an autocross, but I am wondering if there are any inexpensive ways to make it corner flatter, turn in faster, make it less biased towards understeer, and in general make it a bit more rewarding to drive. And preferably on a budget. For example, I've heard of a Corolla sway bar swap; does anyone have more information on that?

I figured if anyone had good information on improving the suspension on these, it would be on this forum.

Have you driven one? I would see how you like it to begin with before looking into mods.
Priuschat would probably be the best place to get advice. There are chassis braces that are under $100, and someone said unhooking the front sway bar made it understeer less.

Well, bumping up the tire pressure alone is going to help with turn in/responsiveness. :)

Daox (forum admin) put a rear sway bar on his Prius and swears by it.

I just poked him -- hopefully he'll chime in or add something to his Prius thread: http://ecomodder.com/forum/341500-post1.html

While this may reduce understeer body roll will be increased. Matched front and rear bars the best way to go imo.

I've heard that stickers- lots and lots of them- make cars faster.

Only if they are for car parts.

Not yet, but I haven't driven very many cars where I was happy with the factory suspension tuning out of the box.

Thanks for the links about Priuschat and Daox's build; I'm looking them up now.

You can use other things than stickers. :eek:

http://forums.trinituner.com/upload/...50px-Ricer.jpg

I don’t have a Prius, I have a Celica, but here are some of the ways from my personal experience to help with a cars handling.

First, you have to have good tires on your car. I removed basically new low profile 205/50R16 tires from a budget brand off of my Celica when I first got it and replaced them with 205/65R16 high profile Michelin Energy Savers. I fully expected the handling to get worse, from the taller sidewall and the low rolling resistance tread pattern, but surprisingly it got noticeably better. I since moved on to 195/65R15s of the same type and also like them. Make sure you have a good quality tire to start with.

Aftermarket sway bars would be the next best upgrade for cornering. Matching front and rear, or for a budget build just replace the end links and bushings on the stock ones. I noticed a decent handling improvement on my Celica when I installed the aftermarket sway bars, but on my big heavy pickup truck just replacing the front bar made a significant night/day difference. On my Celica the back one was easy, but the front one was difficult enough that most people would have taken it to a shop. Do a little research and budget DIY/shop labor accordingly. Note there will also be a slight loss in comfort from stiffer sway bars, as bumps on one side affect the other side more.

Next, stiffer springs also will aid in cornering and responsiveness, but at a small loss in comfort. I chose to go with springs that will make the car sit slightly lower (less than an inch drop) but have about 50% more spring rate. This upgrade is best when timed along with replacing your shocks/struts.

Shocks/struts can also aid handling, but remember they are a limited lifespan item so don’t blow the bank getting a set. It is better to get moderate/decent ones and then replace them when they get bad.

When I was blowing my workday on Jalopnik, we came to the conclusion that the first and best money is spent on tires. After that, suspension upgrades (bushings, springs and struts or shocks), then bars or brakes depending your priorities.

The rear sway bar that I put on my Prius is made by Progress. Its inexpensive (around $100) and its made for the Corolla. I really like it because it reduces the understeer and stabilizes the car (less tail wag).

BenNelson has Eibach springs on his car and they definitely make it feel more planted and aggressive. I think the Progress rear sway bar with Eibach springs would make a very competent feeling car. I prefer the stock springs for a softer ride, Wisconsin roads can get a little bumpy.

There is also a chassis brace across the bottom of the the exhaust tunnel in the back. There is a company that made an aluminum one that is beefier. Some guys say it helps out, I never tried it myself. I forget the price, but I thought it was overpriced.

Thanks! I test drove a Prius and was pleasantly surprised as I had pretty low expectations (wife drives a Camry, I figured a Prius would be even worse). That sway bar sounds like a good mod - maybe a good set of shocks if the ones on it are blown, too. I wonder if Corolla XRS ones will fit?

I just did the suspension on my MR2, one thing to note is that if the car has some miles on it and the shocks are old, getting new shocks with stiffer springs might not compromise comfort. My car is more affected by bumps now, but the better dampening makes each bump slightly more comfortable. I pumped up the tires a little more than usual afterward, so I think overall the ride is a tiny bit worse.

I didn't get fatter sway bars since I didn't want to spend the money, but the stiffer springs reduced my body roll and I find that inspires MUCH more confidence, especially since I don't have camber adjustment to compensate for crappy suspension geometry.

If cornering is what concerns you most, and you want a car with the shape the Prius copied from the Gen 1 Insight, test drive a Gen 2 Insight... It likes corners.
The G2 responds well to higher tire pressures too, in my experience.

Unfortunately, I can't find a second gen Insight in my price range, and I need four seats, so that rules out a first gen. A Civic Hybrid might work, but doesn't seem to get the same level of mileage or have quite as large an interior.

I would think that the XRS sway bar would fit. However, I would be willing to bet that the Progress bar is stiffer.

i second a rear sway bar. if you want to dial out understeer, then u need to increase rear stiffness. forget matching sway bars. On my autocross car i still have the stock front sway bar, but a huge rear bar (+6mm diameter over stock).

my next choice would be firmer shocks. or a match spring/shock kit.

sway bar endlinks and bushing will have no noticable effect. and likely the same for strut bars and subframe connectors. Those things I would do last (cost benefit ratio is low)

Sway bars are measured in diameters. Find out which is what and use that as a reference. The gen 2 insight shares a lot of parts with the honda fit, so many of the parts will work. Me and a few use a progresstech rear sway bar in addtion to tanabe springs. I went a step further to front and rear sway bars, a b piller brace, under frame brace and rear hitch. Yes, the rear trailer hitch isnt used for towng, but to square up the rear end and having that 35lbs below the axle line really helps to keep the rear tucked un around corners.

I dont autocross, but its the only advantage I have on the open road is out cornering the a holes around me. I never forget the day I just bolted up everything and was on a long winding merge lane 2 wide and no one would let me in the left lane, which is what it reduced to in a mile. I just kept my signal on and accelerated to the previous speed limit as everyone was doing 45. No one bothered to race me, or pace me. Once I was 3 cars ahead of the lead car I merged over and went abou my business. Of course once the road straighten out I was still going 65mph and everyone passed me like I was standing still. :eek:

You can find a lot of these bars on ebay under the name ultra racing for the insight.

MadScientistMatt, whats your current vehicle? Im looking for a full size sedan about same kbb as me, 10 grand. I was looking for like an 09 or up impala, charger, mini van, etc.

It is easy to go TOO STIFF with sway bars. After I lowered my Coupe I thought I'd really make a handling machine outta her by putting the thicker sway bar from an automatic trans car on it. Turns out, the car already cornered very flat due to the lowering and the stiffer spring rates and the new struts and the better suspension link geometry for cornering and the slightly wider alloy wheels, such that adding the bigger sway bar only served to roughen the ride. Stock bar went back in, cornering still good, ride much better.