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- Ireland
Hello and welcome to this primer for the Subaru IMPREZA Sedan WRX STi spec C (Type-II) '04 and how to tune it for rally events. The goal of this primer is to give you a starting point for tuning what I personally consider to be the best rally car in Gran Turismo 4.
Some context for why I decided to make this primer: for my upcoming guide, I wanted to include a section for beating the Hard events in the Special Conditions hall. Many of you might agree that Grand Canyon and Ice Arena Hard are among the worst-designed races in the game, as the AI drives flawlessly and there’s almost zero opportunities to overtake without being dealt a 5 second penalty. On top of this, dirt and snow surfaces offer very little traction, and your car needs as much grip as possible to keep up the pace. I wanted to see what options are available that don’t involve wallriding.
So, I set out to find out what the best rally cars in the game are. My benchmark was Ice Arena time trials; if a car could set 47’s or lower with a proper gear and suspension set-up, it was in the running. After testing a bunch of cars, the top runners were the Impreza Rally Car Prototype and the Lancer Evo Super Rally Car. The former can fortunately be obtained easily from Capri Rally Normal, but the Evo costs a hefty 1,250,000 from the Mitsubishi dealership. I did some further reading online to see if there was anything I missed.
After going through some very old posts on these forums, a few members mentioned the Impreza Spec C as a good option. I was a little doubtful that it could out-do the purebred rally cars, but I gave it shot. I was blown away almost immediately; I was able to set 46’s with it consistently, unlike any other car prior. Its traction out of corners was incredible, plus it had stability to boot. With some further tweaking, I managed to set my first 45, which is as low as I can probably go with a controller. This performance carried over to dirt also, as I managed to set top times on Grand Canyon and Tahiti Maze.
On a surface level, it makes sense; rally cars are limited to 13 / 18 front / rear downforce, while street cars can get 30 / 30 after equipping a wing. It's heavier than the average rally car, sure, but on a track like Ice Arena, a little extra weight can give enough stability to push for faster times.
From searching through the tuning threads, I couldn’t find many discussions on how to tune the car for snow and dirt, so I figured I might as well make my own thread. So, here we are. I hope this helps!
NOTE: All testing was done on PAL. Since the physics are slightly different between regions, you may want to make adjustments if you're playing on NTSC or NTSC-J.
UPDATE 1 (28/10/2022): This primer underwent a re-write. Previously I didn't think that setting a ride height bias would make much of a difference, so I set the front and rear as the same. However, after doing some testing, I found that setting a high rear gives a similar effect to putting a front ballast on the car. This means the ballast can be moved to the rear instead, improving traction and allowing for faster times. All tunes have been re-done as a result, and a new tune, 'Monster Tune', has been added.
UPDATE 2 (19/12/2022): Some more clean-up. After doing a lot of testing with the rigidity increase, I found that it actually hurts the car's grip. I decided to remove it from the Balanced and Monster tunes.
UPDATE 3 (10/10/2023): Added some new info to the overview that explains grip modifiers and how they allow the Spec C to excel off-road. Also added the Maxed-Out Dirt Tune, which was featured in my "Six Rally Builds You Should Try" showcase.
Overview
To understand why the Spec C is so strong, we need to understand the game's internal data. Each car in the game has hidden 'grip modifiers' in their chassis data (known as performanceF / performanceR in SpecDB, divided by 10 for simplicity), for front and rear. These determine how well the car turns and holds traction mid-corner. You can view each car's grip modifiers in this spreadsheet.The balance between front and rear grip modifiers can also heavily affect the car's handling characteristics. To give an example, the '95 Mazda RX-7 Type RZ has modifiers of 95 / 95, while the '00 Type RZ has modifiers of 98 / 103. While the '00 has more front grip and should therefore turn better, the rear modifier is much higher than the front. This means it has very snappy handling behaviour, causing it to auto-correct when exiting corners, which could be perceived as understeer. The '95 feels more loose and drifts much more easily due to its balanced grip modifiers. It's rare for a car to have higher front grip modifiers than the rear, but one notable example is the Amuse S2000 Street Version, which has a massive tendency to oversteer because of it.
The Impreza Spec C has some of the highest grip modifiers of any 4WD that can equip dirt tyres, with 103 / 105. It's only beaten by the Lancer Evo Super Rally Car, which has 105 / 105, but the Spec C makes up for it in other areas, which we'll examine later. Grip modifiers are crucial for dirt/snow driving, where you constantly need traction on-demand when exiting corners. If you've ever wondered why the Celica rally cars and Delta Integrale rally car struggle so much for traction, it's because their grip modifiers are only 95 / 95. The Spec C's rear grip being higher than the front could also be argued to be an upside from a corner exit stability standpoint.
One aspect that works greatly in the Spec C's favour is its torque and power band. See the engine curve chart below for the car with zero power upgrades and an oil change:
From as early as 2000 RPM, the engine delivers enough torque to smoothly push the car out of tight hairpins. As the torque falls off after 4500 RPM, the horsepower peak stays flat between 5000 and 7500 RPM, giving this car an extremely wide power band. It’s absolutely perfect for rally, coupled with the car’s solid handling.
When setting up the car’s gears, we want to make full use of this wide power band and minimize gear changes. For this, I used an ‘inverse gear trick’. Many of you are probably familiar with the basic ‘gear trick’: set a high final gear, set auto setup to 1, then set the final gear to minimum. This gives the closest possible gears that are long enough to offer high top speeds. The ‘inverse’ of this, is to use an auto setup of 25 instead of 1. This produces the widest possible gears if we set 1st gear all the way to the right and the rest of the gears to the left.
I personally feel that the Impreza Spec C doesn’t need any power upgrades, besides an oil change. While some small upgrades like the computer and muffler can help the car set faster lap times on tracks like Swiss Alps, it will just make the car more difficult to control in technical sections. If you want an all-out power tune though, check out the Monster Tune at the end.
One upgrade to consider, however, is NOS. With the wide gears we’re setting with the inverse gear trick, we can max the NOS power to 100 and use it on long straights in 2nd gear for a huge acceleration boost. This can especially help on Ice Rally reverse, if you’re struggling to keep up with the AI. Don’t get too greedy using it, however, as it can make the car much more unstable.
The custom LSD is a key upgrade, greatly improving the car’s stability when exiting corners. I like to max out the rear Acceleration, set Decrease to 5 / 15 and adjust the front Acceleration to taste. On dirt, only around 30 - 40 is needed, as setting it too high will cause understeer. For snow, however, understeer isn’t a concern and the max of 60 worked best. Adjust the Initial carefully, as small changes can greatly affect the car’s turning.
The nice thing about Impreza’s in this game is that they come with a basic VCD controller for free. I recommend setting it to 50; this will reduce wheelspin on the rear tyres when exiting corners, while also increasing stability.
One of the trickiest tuning decisions for this car is deciding on the amount of weight it should have, and where it should be. Personally I think the car feels the most balanced with just weight reduction stage 1. Doing extra reduction will just make the car feel floaty, which will make snow driving much more difficult. If you set a high rear ride height, it's best to compensate by adding extra weight to the rear. This will improve rear wheel traction on corner exit.
The main thing left to talk about is downforce: like I said earlier, the Spec C has an advantage over purebred rally cars as it can set a max of 30 downforce on either side. The car felt best to me with 30 downforce on front, and between 15 and 30 downforce on rear. This helps plant the front of the car when exiting narrow corners. Downforce will negatively affect A-spec points; if you care about them, consider reducing the downforce and raising the ballast instead.
The game will consider the Impreza well-balanced against the average Hard opponent. You’ll only get 10 A-spec points against the Corolla rally car, but you should get 20-70 points against the Impreza Rally Car ‘03 and Evo Super Rally Car depending on your downforce settings. Against the Group B opponents in Tahiti Maze, you’ll earn upwards of 100 A-spec points, but you should have no issues beating them with clean driving.
Budget Tune
This is the ‘bare essentials’ tune for the frugal-minded. It skips the fully-custom suspension, opting for semi-racing suspension instead, along with inessential upgrades like the clutch, driveshaft and brake controller. The overall cost for the car and upgrades is 106,820 credits (61,820 excluding dirt and snow tyres). With this package, you should be able to take on the Hard events no problem.The semi-racing suspension gives us as much control over the car as we need, allowing us to bring the front and rear spring rates closer together. While we can't set a huge ride height bias, it's enough to work with. Setting the dampers to 3 / 4 gives mild corner entry oversteer and corner exit understeer. The main setting of note is camber: 3.0 / 1.8 for dirt, 4.0 / 2.2 for snow. This will gum up the front wheels enough to keep the car stable, while giving the rear wheels just enough traction mid-corner to drift around hairpins.
Shopping List
custom transmission
R flywheel
custom LSD
SR suspension
dirt tyres
snow tyres
weight stage 1
oil change
rear wing
Gear Setup
final gear to 3.600, then auto setup to 25, then final gear to 2.500, then:
1st: 3.652
2nd: 2.420
3rd: 1.610
4th: 1.120
5th: 0.785
6th: 0.600
Dirt Settings
springs: 4.9 / 4.9
ride height: 125 / 140
dampers: 3 / 4
camber: 3.0 / 1.8
downforce: 30 / 20
LSD I: 5 / 10
LSD A: 35 / 60
LSD D: 5 / 15
VCD: 50
ballast: 25kg at 50 balance
Snow Settings
springs: 5.2 / 4.9
ride height: 108 / 140
dampers: 3 / 4
camber: 4.0 / 2.2
downforce: 30 / 20
LSD I: 10 / 15
LSD A: 60 / 60
LSD D: 5 / 15
VCD: 50
ballast: 35kg at 50 balance
Balanced Tune
This is the no-budget, all-rounder tune, buying most non-power upgrade available (excl. weight stage 2 and 3, racing brakes and rigidity increase). You should see a slight improvement over the budget tune; my times on Ice Arena were about half a second faster on average. My best time with this tune was a 45.106.I opted for the original suspension instead of the racing suspension here. The main benefit it offers is extra ride height adjustment, which is perfect for moving the center of gravity forward for snow. Stabiliser adjustment helps with controlling how the car pitches from corner to corner. 4 / 4 worked well for me, but you can lower the front stabilisers if you want to throw the car’s weight around.
Adjust the brake balance to taste. Increasing the rear brakes can make the car easier to turn into corners, but it also adds the risk of losing stability. 4 / 6 felt well-balanced from my testing. I also decided to max out the downforce on both sides; this will affect A-spec points, but makes the car feel much more controlled.
Shopping List
brake balance controller
NOS
custom transmission
triple clutch
R flywheel
custom LSD
original suspension
dirt tyres
snow tyres
weight stage 1
oil change
rear wing
Gear Setup
final gear to 3.600, then auto setup to 25, then final gear to 2.500, then:
1st: 3.652
2nd: 2.420
3rd: 1.610
4th: 1.120
5th: 0.785
6th: 0.600
Dirt Settings
brake balance: 4 / 6
NOS power: 100
springs: 4.4 / 5.0
ride height: 125 / 168
dampers: 2 / 3
camber: 3.0 / 1.8
toe: 0 / 0
stabilisers: 4 / 4
downforce: 30 / 30
LSD I: 5 / 10
LSD A: 35 / 60
LSD D: 5 / 15
VCD: 50
ballast: 25kg at 50 balance
Snow Settings
brake balance: 4 / 6
NOS power: 100
springs: 4.6 / 5.0
ride height: 76 / 168
dampers: 2 / 3
camber: 4.0 / 2.2
toe: 0 / 0
stabilisers: 4 / 4
downforce: 30 / 30
LSD I: 10 / 15
LSD A: 60 / 60
LSD D: 5 / 15
VCD: 50
ballast: 35kg at 50 balance
Monster Tune
I made this tune after I spent some time with the RSC rally raid car. The RSC suffers from lack of traction due to high power and low weight, and it seemed like gear setup wasn't helping. However, after playing around with the ballast, I realized that putting it all the way to the back improved traction greatly. Only problem was, it made the car much more unstable. The solution to this was setting the VCD controller to 50 and raising the rear ride height extremely high. This moved the car's center of gravity forward, improving stability while not overly hurting traction.After I set a 2:26 on Grand Canyon with the RSC, beating the Impreza's time, I set out to tune a high-power, low-weight Impreza with the same tuning philosophy. This is the end result; my best time after a few attempts is a 2:20. It still handles just as nicely as the less powerful Impreza's, but it'll feel a lot floatier due to the weight loss. Your throttle control needs to be on-point, especially on snow.
We buy every power upgrade that isn't a turbo, as this will preserve the car's power band. After an oil change and the ballast is put in place, it has 434hp and weighs under 1250kg. I opted for the original suspension, as being able to set the front lower on snow makes a huge difference and outweighs the benefits of damper bound/rebound adjustment. Avoid the rigidity increase, as it hurts the car's corner exit grip.
This tune isn't exactly beginner-friendly, so if you want a more well-balanced tune, go for one of the previous two instead. Otherwise, go wild.
Shopping List
R muffler
racing brakes
brake balance controller
port polish
engine balancing
computer
NOS
custom transmission
triple clutch
R flywheel
R intercooler
custom LSD
original suspension
dirt tyres
snow tyres
weight stage 1+ 2 + 3
oil change
rear wing
Gear Setup
final gear to 4.600, then auto setup to 25, then final gear to 2.500, then:
1st: 2.911
2nd: 1.900
3rd: 1.270
4th: 0.885
5th: 0.621
6th: 0.475
Dirt Settings
brake balance: 4 / 5
NOS power: 100
springs: 7.7 / 6.5
ride height: 125 / 168
dampers: 2 / 4
camber: 3.0 / 1.8
toe: 0 / 0
stabilisers: 5 / 5
downforce: 30 / 30
LSD I: 30 / 30
LSD A: 40 / 60
LSD D: 5 / 15
VCD: 50
ballast: 40kg at 50 balance
Snow Settings
brake balance: 4 / 5
NOS power: 100
springs: 8.0 / 6.5
ride height: 76 / 168
dampers: 2 / 4
camber: 4.0 / 2.0
toe: 0 / 0
stabilisers: 5 / 5
downforce: 30 / 30
LSD I: 30 / 30
LSD A: 60 / 60
LSD D: 5 / 15
VCD: 50
ballast: 50kg at 50 balance
Maxed-Out Dirt Tune
I revisited the Spec C once again for my "Six Rally Builds You Should Try" showcase on YouTube. This time, I bought every power upgrade plus the original turbo, then tried to stabilise it. It completely obliterated lap records around Grand Canyon; while the Lancer Evo VIII RS and Skyline GT-R R34 M-spec Nur set fastest laps of 2:23.080 and 2:20.379 respectively, I managed to set a 2:17.395 with the Spec C. Check it out here, timestamp 50:04.This one is dirt-only, as having this much power on snow is just unnecessary and would cause massive wheelspin issues.
Shopping List
oil change
rear wing
R muffler
brake balance controller
port polish
engine balancing
computer
custom transmission
triple clutch
R flywheel
driveshaft
custom LSD
original turbo (from tuner shop)
R intercooler
R suspension
dirt tyres
VCD controller
weight reduction stage 1 + 2 + 3
Dirt Settings
brake balance: 6 / 6
springs: 7.6 / 7.6
ride height: 110 / 120
bounds: 2 / 2
rebounds: 5 / 5
camber: 3.4 / 2.6
toe: 0 / 0
stabilisers: 6 / 7
gears: final to 5.500, then auto to 1, then final to 3.800, then set individual gears to 3.285, 2.209, 1.835, 1.535, 1.301, 1.113
downforce: 30 / 30
LSD I: 25 / 60
LSD A: 60 / 60
LSD D: 5 / 15
VCD: 50
ballast: 85kg at 50 balance
Conclusion
As mentioned at the start, the goal of this primer is mainly to give you a good starting point to tune the Impreza to your own preferences. Play around with the spring rates, LSD Initial, rear downforce and ballast until you're happy. What works for me might not work for you, but hopefully we can all agree that this is a fantastic rally car.Feel free to comment with feedback and your experiences with this car. Thanks for reading!
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