STI suspension work

[JSSheridan]

The STI handles very well already, but I think it could be improved. Cars that have wishbone setups generally handle better than cars with struts like the STI. The struts are cheaper and easier to manufacture, so I understand why Subaru uses them. I don't have any hands on experience, so I'd like to know a few things. Would it be practical, would it be labor intensive in other words, to replace the stock suspension on the STI with a wishbone setup? Would the returns be worth the cost? Finally, is there anyone who makes a wishbone setup that would fit onto an STI? I didn't see anything like this at Cobb Tuning or other sites that came up on my search.

I am thinking about getting an STI later this year. I would do some suspension work on it to close the gap in handling that people claim exist between it and a car like the S2000. Thanks in advance.

[SabreKhan]

Woah, nelly. That's a lot of extra work that doesn't need to be done. A small upgrade in the stock suspension will go a long ways on an STi. Try a set of coilovers and some upgraded swaybars and a set of tower braces. A little camber offset and you're good to go. Just camber settings, swaybars, and springs should make a vast improvement. I drive a regular WRX, and springs, swaybars, and camber have made it a better-handling car than 75% of the cars at any given autocross. The STi can be made to handle as well as an M3 or a ZO6 without re-engineering the suspension.

The S2000 (or M3 or Vette) is going to handle far differently than an STi anyway, though. "Better" or "worse" is just a matter of opinion. Track times are the only way to gauge improvement. Your STi, with a few (very) minor tweaks (alignment, weight reduction) should outpace a stock S2000 on the track (as always, depending on the track). The S2000 will handle more naturally because it's a rear-driven, natural-balance sports car. The STi will plow a bit more on the way into a turn, but the rear-bias AWD will allow it to muscle through the center of the corner and accelerate out better than the Honda. Once you get used to the feel of it, you will then feel like your STi handles "better" than the Honda because it's more sure-footed. "Better" and "worse" are, again, matters of opinion. "Faster" and "slower" are the true measure.

I have no scientific data to back this up, but my gut tells me that a stock STi would outpace a stock S2000 on a road course. I know it would require some weight reduction or camber change or something for the STi to outpace one on an autocross course because the S2000 is so ridiculously light.

[JSSheridan]

What you say is true of course, the goal is setting a car to match a given course and then learning how to get the most from that setup. My understanding is that the double wishbone gives you more freedom to find a setting that matches the course well and is easy to control whereas the struts are more limited.

[Jay!]

You = overkill.

Start by identifing the specific areas in which you see the need for improvement...

You can upgrade your drivetrain and suspention mounts/bushings to STI GroupN hard rubber or aftermarket urethane and you'll kill any existing slop in the system.

After that, you can get adjustable sway bars, adjustable shocks on progressive springs, adjustable camber/caster links and adjustable rear lateral links and fiddle with the settings until the hows come home. Or, until you find the configuration that best matches your driving ability in a given set of conditions.

[freakray]

What if I told you the STI has wishbones in the front?

Before you start switching out the standard STI suspension for a overkill system in a car of this nature, fully understand what the differences are between double wishbone, single wishbone and strut suspensions as well as which components are common to more than one.

As for the STI, it utilises the same suspension setup as the Impreza WRC and I'm certain Prodrive wouldn't be tuning a system which was less than optimal for the car, especially when the Impreza is designed for the WRC with the suspension setup in mind - hence the Impreza is designed to opitmize the setup it has.

As Jay says, switching out the springs or the complete coilovers can help improve over stock, adjustable sway bars will help, and tower braces can help more.

All I did on my car was springs and Perrin adjustable sway bars and the difference is night-and-day over factory.

[Jay!]

Originally Posted by freakray

and tower braces can help more.

Do the USDM STIs not come with tower braces? (I gotta stop looking at so many JDM Spec-Cs! )

Because, yeah - them too!

[JSSheridan]

Sorry for not replying for so long.

Originally Posted by freakray

What if I told you the STI has wishbones in the front?

Wouldn't that be what an Evo has?

Originally Posted by freakray

As for the STI, it utilises the same suspension setup as the Impreza WRC and I'm certain Prodrive wouldn't be tuning a system which was less than optimal for the car, especially when the Impreza is designed for the WRC with the suspension setup in mind - hence the Impreza is designed to opitmize the setup it has.

Depending on WRC rules, the WRC car might be required a use a similar setup as the production car. The production car isn't built only for performance, but to be a good buy also. Producing something for mainstream consumers is a compromise.

Originally Posted by Jay!

You = overkill.

When the body rolls and the struts lean which results in understeer as I understand. That would be something I'd like to eliminate. Talking about it doesn't make it overkill, but doing it would. We free thinkers are a dangerous bunch, and it take some practical fellas to keep us honest. Thanks again, I got what I was after. I'll be looking at minimizing the roll, among other things.