The Ultimate Guide - GT Mode tips & tuning guide

[TeaKanji]

Hello everyone, my guide for Gran Turismo 4 just launched on YouTube this evening. No 160-page handbook this time, but I believe (or hope at least) that there's a wealth of info that both new players and veterans can get value out of.



To give shout-outs to GTPlanet members who indirectly helped with this guide, a quick thanks to Famine and TornadoAlley for their PAL and NTSC used car spreadsheets, and Orion_SR for their research into 10,000 Overall Skill B-spec routing and spreading the word of the 'Japanese author'. Hope you all enjoy!

Edit: I uploaded a new version with better audio, so I updated the link.

Edit 2: I made a 'cheat sheet' that summarizes everything in the video in text format. Check it out here: https://docs.google.com/document/d/10mhPkPcvtET5pGUwy7YTL6pPjPqKUMwZm9MZ3CgnHKE/edit?usp=sharing

 

[evodon84]

You rock as always. So much amazing content, thank you!

 

[Makan_net]

You are the one.
Your gt3's UG video made me playing it again and finishing it.


Can't wait to start this one too😍🤗😘

 

[TeaKanji]

Thank you all for the support and kind words! Yesterday I uploaded a follow-up video of sorts, primarily focused on tuning and how to make cars easier to turn. This goes way more in-depth with suspension and gear setup than the Ultimate Guide, and I also included two full tuning examples at the end to contextualise it all. For anyone interested in GT4 tuning, hopefully this provides a baseline that you can work from.

 

[dudejo]

Are there any situations where the minor drivetrain upgrades (clutch, flywheel, driveshaft) are detrimental?

I could never find anything about this, when I searched.

 

[TeaKanji]

Are there any situations where the minor drivetrain upgrades (clutch, flywheel, driveshaft) are detrimental?

I could never find anything about this, when I searched.

From my testing, I haven't experienced this no. Back when I was doing research for the GT3 guide, I heard claims that the twin clutch was better than the triple in some scenarios, but I wasn't properly able to recreate it. The flywheel's text about uphill speed being reduced seems pretty misleading too, as the boost in engine response appears to outweigh any speed reduction. It feels like you always want the racing flywheel, as it allows the car to drop revs faster, leading to faster gear shifts as the RPM needle falls more quickly while gearing up.

The driveshaft is interesting though because it affects inertia, while the flywheel and clutch affect engine response, clutch stall and overall acceleration. A driveshaft will give the car a smoother launch off the line and out of corners. and it opens up the potential for the car's power upgrades and gear setup to make use of it. The inertia effect seems to have been nerfed compared to GT3 though, and I usually don't prioritize the driveshaft unless I'm maxing out a car's performance.

 

[dudejo]

I assume if the heavier parts were simulated properly, we'd see such effects as more torque at low RPMs or, when transitioning onto an uphill section, a longer delay before losing acceleration.

So as far as GT4 is concerned, I can treat those parts as linear upgrades?

 

[TeaKanji]

I assume if the heavier parts were simulated properly, we'd see such effects as more torque at low RPMs or, when transitioning onto an uphill section, a longer delay before losing acceleration.

So as far as GT4 is concerned, I can treat those parts as linear upgrades?

Yeah, perhaps. I did some tests a while back with a Cappuccino climbing up the steep hill in Autumn Ring Mini Reverse, and with the racing flywheel, the boost in engine response gave it more speed entering the hill with no noticeable difference in acceleration while climbing it.

I don't want to speak in absolutes because GT4's physics are far from "solved" and I only have my own experiences and tests to go off, but I think it's fair to treat them as linear upgrades. I'd love to be proven wrong though.

 

[dudejo]

Yeah, perhaps. I did some tests a while back with a Cappuccino climbing up the steep hill in Autumn Ring Mini Reverse, and with the racing flywheel, the boost in engine response gave it more speed entering the hill with no noticeable difference in acceleration while climbing it.

I don't want to speak in absolutes because GT4's physics are far from "solved" and I only have my own experiences and tests to go off, but I think it's fair to treat them as linear upgrades. I'd love to be proven wrong though.

I've just tried a similar test, using a Honda S500 with added ballast and default custom gears (35 mph 1st gear). I tried to launch in the final uphill on Midfield off of idle RPM. With or without lightweight flywheels, the car struggled to get moving.

A heavier flywheel, as I assume the stock unit to be, would have provided superior thrust in this situation.

 

[dudejo]

A'ight so I think I was mistaken about the exact effects of drivetrain parts.

On the one hand, according to the modding topic, driveshaft, clutch and flywheel all modify the same generic inertia variable.

As for its effect on performance, I think I may have noticed a situation where more inertia is preferable.

I was doing lap runs on Deep Forest, using a stock-engined Dodge Ram with custom gears. After a while, I switched the drivetrain to full lightweight but I kept falling behind my ghost. After putting back the stock heavyweight kit, I was keeping up again.

It felt like the heavier engine had better "recovery" when I accelerated out of a corner, which was ultimately more useful than the faster shifting.

Another effect I've noticed, while testing on Test Course, is the vehicle retains more speed when off throttle. I let the truck decelerate from 120 MPH over a distance of 1 km, with a 6th gear ratio of 0.79 and final 5.500. The lightweight drivetrain had 40 mph left while the stock heavyweight kit had 48 mph.

 

[TeaKanji]

A'ight so I think I was mistaken about the exact effects of drivetrain parts.

On the one hand, according to the modding topic, driveshaft, clutch and flywheel all modify the same generic inertia variable.

As for its effect on performance, I think I may have noticed a situation where more inertia is preferable.

I was doing lap runs on Deep Forest, using a stock-engined Dodge Ram with custom gears. After a while, I switched the drivetrain to full lightweight but I kept falling behind my ghost. After putting back the stock heavyweight kit, I was keeping up again.

It felt like the heavier engine had better "recovery" when I accelerated out of a corner, which was ultimately more useful than the faster shifting.

Another effect I've noticed, while testing on Test Course, is the vehicle retains more speed when off throttle. I let the truck decelerate from 120 MPH over a distance of 1 km, with a 6th gear ratio of 0.79 and final 5.500. The lightweight drivetrain had 40 mph left while the stock heavyweight kit had 48 mph.

From my understanding of how these parts work, that all makes sense. Because they allow the car to drop revs more quickly, that would also mean it loses speed more quickly as you let it coast mid-corner. The stock Dodge Ram's torque and power both peak at high-RPM's, so the loss of speed while coasting likely caused it to fall out of the power band, leading to reduced acceleration on corner exit alongside less mid-corner speed.

I guess there's a number of solutions: unequip the drivetrain upgrades so the car holds more speed mid-corner at the cost of faster gear shifts, equip a supercharger so mid-RPM torque is increased and the car pulls out of corners more quickly (it produces less peak power than NA tuning stage 3, though), or make extremely close gears so you can gear down mid-corner to stay at high-RPM's while exiting. The Ram has a tendency to fishtail, so I suppose that increasing the car's mid-corner grip would help a lot too, by stiffening the springs, applying more camber, increasing the LSD initial and decel, or playing around with the ballast.

 

[dudejo]

My gears were already set up into a close pattern so I don't think the powerband was the issue. It felt more like the engine couldn't quite cope with how fast its momentum was dropping and needed a moment to reverse the effect.

Thankfully, the fishtailing wasn't so bad once I got used to it. It was more pronounced with the lightweight drivetrain, probably because the faster deceleration influenced the weight transfer more.

Also, while it's true that the ideal power range is high, it already makes 80% of its torque at almost idle RPM. I think Dodge was already doing variable valve timing engines, at the time.

 

[TeaKanji]

My gears were already set up into a close pattern so I don't think the powerband was the issue. It felt more like the engine couldn't quite cope with how fast its momentum was dropping and needed a moment to reverse the effect.

Thankfully, the fishtailing wasn't so bad once I got used to it. It was more pronounced with the lightweight drivetrain, probably because the faster deceleration influenced the weight transfer more.

Also, while it's true that the ideal power range is high, it already makes 80% of its torque at almost idle RPM. I think Dodge was already doing variable valve timing engines, at the time.

I had a go at tuning the Ram and did some tests of my own. I'm in two minds about no drivetrain upgrades vs. all equipped: the speed loss while coasting mid-corner is indeed noticeable and can cost you some time around wide corners, but it also means that the car holds a wider line and potentially understeers more. For my driving style, this doesn't work well for me, because I rely heavily on engine braking to pivot the car mid-corner. I was losing time to my ghost because I needed to either brake more entering the corner or wait longer before flooring it out, on top of having slower gear changes and reduced engine response.

This is my setup if you want to give it a try, oil change, NA tuning stage 3 and all upgrades equipped excl. racing brakes and rigidity increase:

tyres: medium / soft [S2 / S3]

brake balance: 8 / 2

springs: 5.5 / 5.5
ride height: 184 / 144
dampers [bound] : 2 / 2
dampers: [rebound]: 5 / 5
camber: 1.4 / 1.4
toe: 0 / 0
stabilisers: 3 / 5

gears: final to 5.500, then auto setup to 4, then final to 3.850, then set individual gears to 2.445, 1.777, 1.395, 1.160, 0.975, 0.827

LSD I: 5 / 10
LSD A: 5 / 12
LSD D: 5 / 30

VCD: 10

ASM [O + U]: 0
TCS: 0

I set up the gears a little differently than the usual even-RPM drop close gear setup; by moving both 1st and 2nd all the way left, you can build much closer gears from 3rd through 6th. This works well for the Ram as 1st gear can be exclusively used as a launch gear, while 2nd can be used in sharp corners without causing wheelspin.

 

[dudejo]

I had a go at tuning the Ram and did some tests of my own. I'm in two minds about no drivetrain upgrades vs. all equipped: the speed loss while coasting mid-corner is indeed noticeable and can cost you some time around wide corners, but it also means that the car holds a wider line and potentially understeers more. For my driving style, this doesn't work well for me, because I rely heavily on engine braking to pivot the car mid-corner. I was losing time to my ghost because I needed to either brake more entering the corner or wait longer before flooring it out, on top of having slower gear changes and reduced engine response.

This is my setup if you want to give it a try, oil change, NA tuning stage 3 and all upgrades equipped excl. racing brakes and rigidity increase:

tyres: medium / soft [S2 / S3]

brake balance: 8 / 2

springs: 5.5 / 5.5
ride height: 184 / 144
dampers [bound] : 2 / 2
dampers: [rebound]: 5 / 5
camber: 1.4 / 1.4
toe: 0 / 0
stabilisers: 3 / 5

gears: final to 5.500, then auto setup to 4, then final to 3.850, then set individual gears to 2.445, 1.777, 1.395, 1.160, 0.975, 0.827

LSD I: 5 / 10
LSD A: 5 / 12
LSD D: 5 / 30

VCD: 10

ASM [O + U]: 0
TCS: 0

I set up the gears a little differently than the usual even-RPM drop close gear setup; by moving both 1st and 2nd all the way left, you can build much closer gears from 3rd through 6th. This works well for the Ram as 1st gear can be exclusively used as a launch gear, while 2nd can be used in sharp corners without causing wheelspin.

Ah, you have a maxed out engine. I was running the stock engine, which is probably why I benefited from increased drivetrain inertia. Also, I was running a maxed-out Final ratio to squeeze as much torque as I could out of the stock engine, with the only "limit" being my first gear ratio being no slower than 40 mph.

Also stock suspension, no LSD, VCD at 10, racing brakes. S2 tires both sides.

Gear 1 : 2.270
Gear 2 : 1.640
Gear 3 : 1.250
Gear 4 : 1.045
Gear 5 : 0.895
Gear 6 : 0.790

Final : 5.500

Set final to 5.500 then Auto to 5. Doesn't always, though :/

 

[TeaKanji]

Ah, you have a maxed out engine. I was running the stock engine, which is probably why I benefited from increased drivetrain inertia. Also, I was running a maxed-out Final ratio to squeeze as much torque as I could out of the stock engine, with the only "limit" being my first gear ratio being no slower than 40 mph.

Also stock suspension, no LSD, VCD at 10, racing brakes. S2 tires both sides.

Gear 1 : 2.270
Gear 2 : 1.640
Gear 3 : 1.250
Gear 4 : 1.045
Gear 5 : 0.895
Gear 6 : 0.790

Final : 5.500

Set final to 5.500 then Auto to 5. Doesn't always, though :/

The NA tuning likely mattered yeah, in terms of carrying more speed into corners and having more power at my disposal while exiting, but the soft tyres on rear also had a big effect. The Ram's rear wheel grip is pretty awful, and it barely wears its rear tyres anyway, so it's an easy way to improve mid-corner grip and traction on corner exit with the 90:10 split. It did induce understeer though, so I had to be aggressive with the ride height, springs and stabilisers so it can throw its weight around without feeling unstable. Basically, I had to make a huge number of changes that make the car handle completely differently than stock.

I guess a point can be made for the Ram then that, with mostly stock settings, reducing inertia can make it more difficult to drive unless you can balance out the mid-corner speed loss/instability using throttle control.