This post is to help anyone conteplating suspension mods on their STi, especially the GR STi of which I have one, a 2013 hatch. The GR's started life as underpowered, fragile porkballs, the opposite of the joy derived from the intuitive driving experience from GD generation STi's which felt like they were exploding with an elan to go fast and be good at it. While GR's have faster lap times than the previous GD's and the 2011+ GR's feel better at the limit than many factory cars such as 335 BMW's or Infiniti G37's, they still suffer from a chassis that is squirrelly and oversteers when you don't want it while braking, yet understeers on power. This having to slide the rear end around while braking (fast in) and feather the throttle to steady the rear end rather than rotate it (slow out) is very unintuitive and above all not fun to drive. The body roll and vague feeling on the steering compared to what it could be also makes attacking back roads, autocrosses or track days a lot less fun than their GD brethren. If only Subaru charged another 5k for the GR STi and included stiffer everything with coilover like dampers, and had a factory tune similar to the GD's capable of 104mph trap speeds, then GR owners could drive home with pants and pockets full of spunk, er, um Viagra.
If you ever felt disappointed in your GR STi lusting after that happy memories of driving a GD STi that gave you the feeling of an eager elan so great in the twisties, look no further. There are some posters who are well respected because they know all about high power setups, let me be your guide through the same process through the twisties of suspension modding because I've done it.
I regularly track and autocross my STi and have done most of the suspension mods toying with different settings. The most important take home point with suspension is the lag times of tuning it are much greater, as is the labor. In other words, if you put on power or motor related bolt-ons, all you need is a few runs on the street or dyno, and at most in a few hours of a capable tuner's hands your car will be ready to charge hard, run smoother and snap your neck harder than before easy, peasy lemon squeezy. It's not like that with suspension where everything has to be planned and changed in unison or the car just won't handle as well as before.
We all know you want to do things like make better turn-in, lessen understeer, enable controllable power oversteer while increasing the limit only to attempt these things with what seems like simple bolt ons, and the car feels good to a point until it falls apart maybe on the autocross or your favorite back road. The odds are that just slapping on parts thinking stiffer here or there or everywhere is better may lead to a false sense of security. A rear sway bar may trick you into thinking you've cured your STi's understeer until having to swerve to avoid some little kid chasing his ball when your car starts doing 720's without even lifting off the throttle when you imagine just how lustily your rear bumper wants to hump a telephone pole. So a seemingly good setup that is not planned correctly actually has a lower limit than stock and falls apart when pushed hard.
Then it's back to the drawing board of having to either adjust parts, change alignment, buy new parts and you go crazy because even changing one swaybar setting takes almost as long as it takes to actually tune a car. Pay to play is the word with power mods, you have to pay when you crack a ringland, grenade your motor and spin a bearing. Pay to play with suspension is different, you have to be willing to buy all the supporting mods bushing, shock, swaybar and be willing to pay for multiple alignments or re-installs if you're not able to change out some parts yourself. It's not cheap, on the other hand many of the STi's handling woes, particularly for a street driven car, can be improved without so much as upgrading a single suspension component.
On the other hand, if you are willing to stay the course, then by laying the groundwork for good driving and a responsive driveline and chassis, you are getting the most bang for your buck for what you spent, creating the most reliable setup, getting the most out of everything, and being as safe as you can be.
Stage 0: The Driver Mod
While modding is so much fun because you think that anything can be improved with modding, in reality the stock GR STi, for its disappointing demeanor and behavior compared to its predecessor, can still be driven fairly fast by a skilled driver. The earlier GR's kind of sucked though. Anyhow, provided that the design is not faulty (which you the modder can very easily create by an improperly tuned setup described above!), any halfway decently built vehicles' perceived handling inadequacies can be overcome to a certain degree by driving style. Understeer can be scrubbed off or oversteer might be induced at the right time yet avoided at the wrong moment simply by being smooth with control inputs. High Performance driving is beyond the scope of this essay but is the foundation upon which all driving fun is built, without which you might as well relegate yourself to the dead Dentist part of "Dentist Killer" as the old Porsche 930 Turbo's were called.
Most high performance driving education either happens at driving schools, which can be extremely expensive, or through car or driver clubs like SCCA, NASA, Hooked on Driving, SCDA, BMW CCA, PCA and others. Or start small by enrolling in local autocrosses. Some tracks have their own autocrosses and sponsor educational events like Lime Rock Park's Open Autocross. Other driving schools might sponsor their own autocross like Advanced Driving & Security Inc HPDS. Go ahead and sign up for a track day or instructional motorsports event, get some education and learn how to maximize your car's handling capabilities on the stock suspension with street tires. These skills will keep you out of trouble by acquiring the art of finesse so undesirable happenings are less likely to occur while driving because you know to anticipate problems and avoid them. These educational skills make driving more fun so you don't always crash up against the wall of understeer with the ever present spectre of sudden snap overseer luirking to strike any moment. This alone will improve your driving experience to the point where you can make nearly any car fun, not just the ones you can pummel the throttle and make the rear end do power-pirhouettes.
I am now ready to qualify as the least fun statement ever made on iwsti: once you've mastered your Subaru's handling potential as measured by the occurrence that any other driver you consider very skilled cannot obtain a time that is significantly faster than yours, then you can mod. Sad but true. Come back after a few track days, and if you come home thinking you need to fix a handling trait from the stock car with some mods, only come back to this essay once you start getting faster than other drivers.
If you ever felt disappointed in your GR STi lusting after that happy memories of driving a GD STi that gave you the feeling of an eager elan so great in the twisties, look no further. There are some posters who are well respected because they know all about high power setups, let me be your guide through the same process through the twisties of suspension modding because I've done it.
I regularly track and autocross my STi and have done most of the suspension mods toying with different settings. The most important take home point with suspension is the lag times of tuning it are much greater, as is the labor. In other words, if you put on power or motor related bolt-ons, all you need is a few runs on the street or dyno, and at most in a few hours of a capable tuner's hands your car will be ready to charge hard, run smoother and snap your neck harder than before easy, peasy lemon squeezy. It's not like that with suspension where everything has to be planned and changed in unison or the car just won't handle as well as before.
We all know you want to do things like make better turn-in, lessen understeer, enable controllable power oversteer while increasing the limit only to attempt these things with what seems like simple bolt ons, and the car feels good to a point until it falls apart maybe on the autocross or your favorite back road. The odds are that just slapping on parts thinking stiffer here or there or everywhere is better may lead to a false sense of security. A rear sway bar may trick you into thinking you've cured your STi's understeer until having to swerve to avoid some little kid chasing his ball when your car starts doing 720's without even lifting off the throttle when you imagine just how lustily your rear bumper wants to hump a telephone pole. So a seemingly good setup that is not planned correctly actually has a lower limit than stock and falls apart when pushed hard.
Then it's back to the drawing board of having to either adjust parts, change alignment, buy new parts and you go crazy because even changing one swaybar setting takes almost as long as it takes to actually tune a car. Pay to play is the word with power mods, you have to pay when you crack a ringland, grenade your motor and spin a bearing. Pay to play with suspension is different, you have to be willing to buy all the supporting mods bushing, shock, swaybar and be willing to pay for multiple alignments or re-installs if you're not able to change out some parts yourself. It's not cheap, on the other hand many of the STi's handling woes, particularly for a street driven car, can be improved without so much as upgrading a single suspension component.
On the other hand, if you are willing to stay the course, then by laying the groundwork for good driving and a responsive driveline and chassis, you are getting the most bang for your buck for what you spent, creating the most reliable setup, getting the most out of everything, and being as safe as you can be.
Stage 0: The Driver Mod
While modding is so much fun because you think that anything can be improved with modding, in reality the stock GR STi, for its disappointing demeanor and behavior compared to its predecessor, can still be driven fairly fast by a skilled driver. The earlier GR's kind of sucked though. Anyhow, provided that the design is not faulty (which you the modder can very easily create by an improperly tuned setup described above!), any halfway decently built vehicles' perceived handling inadequacies can be overcome to a certain degree by driving style. Understeer can be scrubbed off or oversteer might be induced at the right time yet avoided at the wrong moment simply by being smooth with control inputs. High Performance driving is beyond the scope of this essay but is the foundation upon which all driving fun is built, without which you might as well relegate yourself to the dead Dentist part of "Dentist Killer" as the old Porsche 930 Turbo's were called.
Most high performance driving education either happens at driving schools, which can be extremely expensive, or through car or driver clubs like SCCA, NASA, Hooked on Driving, SCDA, BMW CCA, PCA and others. Or start small by enrolling in local autocrosses. Some tracks have their own autocrosses and sponsor educational events like Lime Rock Park's Open Autocross. Other driving schools might sponsor their own autocross like Advanced Driving & Security Inc HPDS. Go ahead and sign up for a track day or instructional motorsports event, get some education and learn how to maximize your car's handling capabilities on the stock suspension with street tires. These skills will keep you out of trouble by acquiring the art of finesse so undesirable happenings are less likely to occur while driving because you know to anticipate problems and avoid them. These educational skills make driving more fun so you don't always crash up against the wall of understeer with the ever present spectre of sudden snap overseer luirking to strike any moment. This alone will improve your driving experience to the point where you can make nearly any car fun, not just the ones you can pummel the throttle and make the rear end do power-pirhouettes.
I am now ready to qualify as the least fun statement ever made on iwsti: once you've mastered your Subaru's handling potential as measured by the occurrence that any other driver you consider very skilled cannot obtain a time that is significantly faster than yours, then you can mod. Sad but true. Come back after a few track days, and if you come home thinking you need to fix a handling trait from the stock car with some mods, only come back to this essay once you start getting faster than other drivers.
