Not sure if it's a part revision but I'm pretty sure I've confirmed that switching the car into Eco drive mode mechanically closes the exhaust valve now, where it didn't in the 2023-2024. I couldn't take a good video. But it does it at cold start and after the car is at running temp.

 

Not sure if it’s a part revision but anyone know how to get the brake lights to show up on the gauge cluster screen? The new 2025 GR Corolla has these 2 red lines that show up on the bottom of the screen when you press the brake, not sure if it’s a different gauge cluster or just a programming thing you can add easily. I have an 2023 Circuit Edition and it’s a small thing I want to add if it’s easy.

Also, does anyone know how the new 2025 GR Corolla gets more torque? I also am trying to see if it’s just a quick ECU factory flash that can give my 2023 GRC more torque easily without voiding warranty

 

No idea on the cluster, but likely just updated firmware. The MY25 uses the same tune as the Morizo according to Toyota (so like an extra pound or so of boost to bump up tq). Toyota is not offering that to older model years, so the best bet would be to just tune your car with Ecutek if you want more power, but that would indeed bring in potential warranty issues.

 

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For the MY2025, there were quite a bit of revisions to the suspension as well as cooling. I have created this thread to document all parts that are compatible with MY2023 and MY2024 vehicles, pending actual confirmation. If any information is inaccurate, please let me know and I will address.

View attachment 30895

The ATF cooler will not be relevant to MY2023 and MY2024. The sub-radiator seems to provide auxiliary engine cooling, but it does not actively cool the transfer case. Quite honestly, it's better to get an aftermarket radiator as any cooler additions would require the MY2025 front fascia. If you are so inclined to retrofit the sub-radiator, see @st165's post below:

Sub-Radiator Part Numbers

The most interesting change is the transfer case cooling duct. Per Chief Engineer Naoyuki Sakamoto, this change will not solve the AWD overheat issues, but it should help.

Engine Service Cover with Duct: 51405-12070
Main Under Cover: 51410-12200

View attachment 30894

These changes are all made to help reduce squat and dive; therefore, reducing understeer characteristics mid-corner and on the exit of corners. The rear sway bar was likely changed to accommodate the new springs. The most important change is the rear trailing arm mount as it is an actual suspension geometry change:

Front Shock Absorber (LH): 48520-80832
Front Shock Absorber (RH): 48510-80C88
Rear Shock Absorber (LH/RH): 48530-80B99
Rear Trailing Arm Mount (LH): 48727-06060
Rear Trailing Arm Mount (RH): 48717-06030
Rear Sway Bar: 48812-12580
Sway Bar Bushings (x2): 48818-12440
Rear Coil Spring (LH/RH): 48231-12N20

View attachment 30893

Finally, some more bolt changes to add rigidity to the suspension and steering system:

Lower Ball Joint Bolts (x4): 90105-12429
Steering Column Bolt (x1): 90119-10A34
Rear Shock Absorber Upper Mount Bolt (x4) 90109-10194

Wondering, since the transfer case temperature is assumed, wouldn't you still need to update the logic for the AWD controller itself to account for additional cooling? Or replace it with something like the Syvecs controller?

I'm thinking just adding the new undertrays on its own wouldn't affect when AWD goes to limp mode for the 23/24 GRCs.

 

Anyone try bolting up the revised undertray yet?

 

So I ordered the leather shift knob and the 2025 under belly panels, shift knob cam the very next day, still no word from my dealer on the panels but for sure they are not in the south-east or I would have had them by bow.

 

2025 under tray pictures. Not my own.

 

Already received the new under tray, but car is at the dealer for an oil leak diagnosis. Only need to order part number 51410-12200 if you want the new tray as it comes with the access panel as well

 

Found on FB, bolt pattern appears to be similar on both

 

So one could juat order the new duck and reuse the original piece. No need to order everything else

 

Update, I just talked to my Toyota dealer and the full cover is on national backorder, but the access cover did come in and he had it. I made the decision to cancel the back order and just put the new access cover on when it's delivered today. The vent in the 2025 cover does look slightly different than the 23/24 but it at least it has one, if not I would have waited. I'm not going track day the car and if I'm honest I I don't beat on it very hard even though I did install a MST V2 intake and JB4 but only have tried map 1. I was disappointed with the stock output power but am more than happy with it now and do not plan on anymore HP mods.

 

Confirmed the new undertray bolts onto a 23 GRC

 

Is there a benefit to this new tray?

 

Really cool to see the upgrades broken down since I just got a 25. Now can anyone tell me how I can get some fog lights?

 

Get some real ones. Rallye 4000 LED - My Hella Lights

 

Or do something like this 😁

 

anyone with toyota system access know if the TPMS part number changed with the 2025’s? i’ll probably have to order some and i know stuff like tire pressures show up quicker and more persistently in the gauge cluster than on the 23/24. but not sure if that’s an ECU or TPMS thing?

 

I'll try to remember to check that today, but I bet they're the same.

 

I can't make any promises about difference in performance, but they're definitely different part numbers, and neither supercedes the other. The part number up to 09/24 production is 42607-19005. After 09/24, it changes to 42607-12040.

 

interesting. thanks!

 

After examining it, I believe the update might extend limp mode by about a minute. They've also tweaked the AWD controller, so the new software likely helps manage heat and mask limp mode a bit longer. What the driver doesn't notice won't bother them, but it could harm the car.
Do you have a source for this or is it speculation?

You suggest changing transfer case and rear diff fluid after each track day? Or just transfer case? Also, u reckon a 75w90 may fare better than the 75w85?

90 weight is made with a different base stock than what the 75 and 85 use from what I understand, so its more robust, period, even if it's only a small margin its still stronger. I'd also be curious how a 75/110 would fare for track use. The heat present in the T-case isn't completely resolved, I have yet to see any explanation why it's getting so hot. There's plenty of reasonable conclusions, but none are proven yet. It could be radiant heat from the manifold/turbo/dp, could be internal strain from the torque, could be friction from the fluids getting too hot and losing film strength. A higher viscosity gear lube will help on all accounts, the only drawback will be a slight loss of efficiency. But I'd still like to understand more about what's causing the excessive heat.

As far as changing it after each track session, oil analysis would answer that question definitively. Of course it's not a bad idea to change it, considering the obvious strain it's under, but with a cooler it might just plain be unnecessary.

Redline and Amsoil also make spectacular gear fluids, Motul isn't the only choice though ccupani sounds like he's has Motul running in his veins lol

 

Fortunately my adapter was only $22, so some GR owner near me will get one for free if they have a 23/24.

 

Has anyone with a MY23 or MY24 added the new rear suspension? I read about the new mounting location. Does that mean it isn't a bolt in affair?

 

yes it’s a bolt in affair I am not sure if anyone has done it yet. Part numbers are out there and people have expressed interest in doing it . Though I have not heard of anyone actually doing it. Some people have already the front naca duct under panel for the transfer case though.

 

I would leave your rear suspension geometry alone.

 

Why do you think this? You don’t think the “improvement” is an improvement? A couple guys on here said the ‘25s noticeably feel different/more planted

 

Let’s see some track video and data.

 

The only difference I've seen so far for the rear is 1- the forward mounting point of the trailing arm is 30mm higher, which improves anti-squat characteristics but reduces grip on bumpy/uneven surfaces during acceleration; and 2- the shocks are tuned slightly differently to be a little more progressive. Its feasible the progressive tuning helps offset the increased compression resistance under acceleration. Someone mentioned it also affects lateral roll center, but I fail to understand how because none of the other geometry has changed.

Other changes may have been made but I'm unaware of them. A suspension geometry engineer familiar with this platform would have to chime in to explain more detail about the finer nuances of what would be affected.

 

I think what you have here is a better set of shocks that everyone is overthinking. That’s what makes it feel better. The 24 and prior dampers were lacking.

 

Absolutely, you'd be pretty hard pressed to feel a difference in the geometry (even a huge change of 30mm) by just driving around the street (besides the headlights rising a little less under hard accel). The shocks are going to be the majority of your perception of feel. Just look at other examples, like cars dropped too low on coilovers (even good coilovers). In a lot of cases, you've just fucked your lateral roll center into oblivion, but you can't really feel that by just driving around. These changes would need to be pushed to some thresholds back-to-back in a controlled environment to understand what's actually happening differently. In that respect, I also wouldn't recommend just changing parts willy-nilly because "newer must be better" mentality, because the whole system is affected.

 

I am one of those people who said that the 25 feels more planted. However, I believe that it's also been said that the mounting points on the car have been moved. This would suggest that bolting the new parts on the old car is not going to work correctly.

Official catalogues disagree with this.

They do, but the "cup" they attach to is what changed, they position the forward trialing arm deeper (higher). I think the subframe is unchanged (and possibly the arm itself is unchanged as well).

Correct. The cup it attaches to is deeper, but the cup itself is bolted onto the car itself. The arm itself is actually the same part number (and so is the camber arm, toe arm, knuckle, swaybar link). The only part needed to do the 25 geometry is the cup itself. The other two notables are a different swaybar diameter (and corresponding bushings), and different struts. So to do the entire rear 2025 suspension upgrade:

Swaybar bushings x2
Swaybar
Trailing arm bracket x2
Trailing arm bracket upper cover x2 (this one might even be usable still from 2024, I can't tell if the 2025 one is much higher up to have enough room)
Struts x2

 

Ok guys indeed people are correct the majority of what those of us who driven 25’s myself included is due to the change in swaybar and or bushings and shocks. Changing the pickup point does reduce squat under acceleration which the engineers even outlined in technical interviews that Savage Geese did. Now the thing to realize is once you put on coilovers and lower the car slightly you are eliminating some of the squat and stiffening up the suspension which will have literally the same effect. One could say then if you want to stay on stock suspension a 25 will handle better stock than a stock 23-24 but once you mod the suspension of a 23-24 you effectively eliminate the differences . So it remains to be questioned is it even worth changing the pickup point on 24 or earlier if you are already going aftermarket coilovers with some lowering ?

 

So it remains to be questioned is it even worth changing the pickup point on 24 or earlier if you are already going aftermarket coilovers with some lowering ?

Most guys won't notice this but at the track on corner exit, I think the pick up point would benefit 23/24 cars to be faster because of how you lose traction on gear changes while exiting a corner. On low speed corners, especially early apex corners, when you're trying to power out in 2nd to 3rd, the car is squatting so hard you always chirp the inside front wheel and lose time. You can avoid this by staying at a higher gear, or significantly stiffer coil settings. For me it's very noticable for VIMC T12 (hairpin, uphill left that opens up). Of course if your local track is a big winding course with long turns, this isn't really going to be an issue. But if you autocross...well that's going to be even more pronounced of a difference.

In summary, you could replicate the anti-squat properties of the 25 with stiffer coils but retaining the old arm layout. But there is a point to make that the 25's will always be faster because of these scenarios:
1) both on coils, same stiffness, 24's will squat more on corner exits, pulling up the fronts
2) both on coils, stiffer on 24's, corner exits are now similar, but now 25's are more stable on other parts of circuit
But again, this is if you're picking at straws here. I'm too garbage of a driver to even attribute time gained/lost on parts like this. It might be for someone, but for most of us mere mortals, it won't change a damn thing lol.

IMO the 2024 bolt changes are even more "not worth it" than the 2025 cup change, but everyone and their dog did the 2024 bolts on their 2023's, so...

 

Is everyone drag racing these things? I track mine HARD and have zero issues with this squat on acceleration. If anything it doesn’t squat enough. Just enjoy the car.

 

ah Carmine the Contrarian😂 Actually that’s not a bad moniker. Ya no most of us are not drag racing the car😂

 

Anybody here have the GR Performance Suspension? It's still listed as applicable to the 2025MY. I wonder how it performs compared to stock 2025, stock 2024, and 2024 with the GR Performance Suspension.