[kingofthehill29]

After speaking with another GRC owner (that was way faster than me), my theory it that due to the location of the transfercase it is difficult to put a sensor on it (due to heat soak), therefore Toyota is using a ecu data to run a load based calculation to determine when the transfercase is getting towards its maximum temperature.

The other owner I was speaking to was not triggering the AWD overheat as frequently as me, he also said he has a background with tracking lower speed momentum cars and his belief is that he triggers it less frequently because he drives it like a momentum car and relies less on the AWD to power through a turn. I tried this in my next session (it was hottest session of weekend) and I was able to set my PR without triggering the AWD overheat.

I know this is anecdotal evidence but this leads me to believe Toyota's software is potentially using more than just the ITCC sensor to run the calculations. I wouldn't be surprised it they are using engine load and temperature, along with wheel speed differences. This is just my theory based on experience and conversations at the track with others.

 

[GR-U-CRAZY]

Hi there. Former Evo X MR owner and current GRC CE owner. I do agree with the rear differential overheating issue. It’s unacceptable from Toyota and that should be fixed and addressed in future versions asap.

What I ended up doing was taking the advice on someone in this forum (Apologies for not remembering the link) and heat wrapping + shielding the pipe at the center rear, next to the clutch packs. Did that before any track day (Big Willow & Laguna Seca; back to back weekends) no issue with over heating. Wife was able to track all sessions.

In regards to having a “track ready” car from the factory (Stock) I’ve never seen on a normal street car. I did have an Ariel Atom before and that came ready from the factory. For my EVO X, GRC CE and practically any road car, advertised as a track car, I had to at the very least, change the brake fluid and upgrade the brake pads. So, anyone trying to track a car and not changing any of those things, is not going to have such a nice time.

I hope the OP finds a car they’re happy with though. I’m loving this GRC CE. But full discretion, it’s not my daily. View attachment 28615

This is one of the only mods I have planned for my '23 CE, aside from better rubber and an upgraded oil cooler.

 

[8063]

Just had my first experience on track with the GR Corolla Premium yesterday afternoon. My impression in two words - "Not Good". Bulleted list of issues along with further details below. Ambient temps were high at 96 F. Utah Motorsports Campus - same track that Toyota used for the GR Corolla press launch.

• Rear differential overheated after less than 9 minutes.
• Oil temp spiked to 287 degrees and was flashing red.
• Coolant was literally boiling in the reservoir and spilled over after exiting the track. Video of incident.

How is this acceptable from Toyota? The webpage from Toyota literally says "Built for the track, ready for every day" at the very top! The fact that Toyota offers a complimentary NASA membership and track day should mean something.

My goal with this car was to use it as a daily driver and participate in 5-6 track days each year. At this point, I'm not sure I want to keep this car. I don't think we should be expected to add oil coolers, heat shields, etc. to try and fix a problem that Toyota was already aware of on the GR Yaris. I realize it was a hot day, but these temps are commonplace across the country during the summer.

What adds to my frustration is a buddy joined me on track with his Acura Integra Type S and experienced ZERO issues.

I understand that this is not new information, but wanted to share an additional viewpoint with the community. To put it lightly, I'm very disappointed with the GR Corolla at the moment. Would love to hear others thoughts.

Easy fix. You need 555 Engineering Oil cooler kit, Transfer Box Cooler kit, and AWD control box. Also make damn sure you aren’t running garbage Toyota factory fluid. Use Motul everywhere. Problem solved. ✅

 

[Techdude99]

I guess $3,500 from 555 isn't bad for reliable track time.

 

[Fitted9k]

I guess $3,500 from 555 isn't bad for reliable track time.

I'll just wait for more discounts on these parts.

 

[8063]

I'll just wait for more discounts on these parts.

Kind of what I did. Black Friday special. The owner is pretty cool. If you contact him he may group discount items for you. I’m not a forum person at all but did see group buy wording on his site. He is also directly involved with the GR Yaris rallye team engineers. That’s why this guy caught my eye. I’ve been in this industry for some time. He knows his stuff. No BS.

 

[8063]

I guess $3,500 from 555 isn't bad for reliable track time.

The Transfer Box cooler and the Syvecs control box will solve 90% of your warnings for the driveline. Just use Motul oil also. Wrap exhaust near transfer box and rear differential too. 555 working on rear differential cooler with pump for track use over 70F. We will be testing it on our Morizo.

 

[SckSqzBngBlo]

The other wildcard is driving style.

It's going to be this, better drivers will have less issues.

Still, I can't believe that Toyota market it as a track car when no road cars are going to be true track ready cars. Also, can't believe people would actually believe they are buying a track ready car for $40k, it's not realistic. It sounds too good to be true.

 

[8063]

Well said. It’s never track ready unless it has no VIN.

 

[Techdude99]

To be fair, I had a '19 Camaro ZLE. All it needed to drive below 9/10's for HPDE's was SRF. I bought it new for $59k off the showroom floor in TX and sold it last year for $69k. Crazy times...

 

[8063]

One of the very few. Yes that would definitely be one of them.

 

[8063]

To be fair, I had a '19 Camaro ZLE. All it needed to drive below 9/10's for HPDE's was SRF. I bought it new for $59k off the showroom floor in TX and sold it last year for $69k. Crazy times...

Similar with my Shelby GT350R. $64,995 in 2019. Other than 100F ambient oil temp limp mode needed nothing and was track ready at 9/10ths. Only car I’ve ever had that literally needed nothing was a 991.2 GT3. But that came with an extreme premium and extreme weekend running cost bill. Track insurance being 5 times what the GR Corolla is and anxiety levels being 10 times. The GR is low anxiety. Understated. I like that.

 

[Techdude99]

Both excellent cars.

 

[ExtraBrispy]

Most GRC owners I've interacted with on the internet seem to be relatively mature folks with a realistic view of what this car is and what it isn't. I think many of us just bought one because we think it's neat, not because (e.g.) we wanted a true out-of-the-box track monster but couldn't afford one and also didn't want to buy a Hyundai.

"And also didn't want to buy a Hyundai" OR "spend 50k+ on a riced out civic"

 

[Reddragun3]

Hi there. Former Evo X MR owner and current GRC CE owner. I do agree with the rear differential overheating issue. It’s unacceptable from Toyota and that should be fixed and addressed in future versions asap.

What I ended up doing was taking the advice on someone in this forum (Apologies for not remembering the link) and heat wrapping + shielding the pipe at the center rear, next to the clutch packs. Did that before any track day (Big Willow & Laguna Seca; back to back weekends) no issue with over heating. Wife was able to track all sessions.

In regards to having a “track ready” car from the factory (Stock) I’ve never seen on a normal street car. I did have an Ariel Atom before and that came ready from the factory. For my EVO X, GRC CE and practically any road car, advertised as a track car, I had to at the very least, change the brake fluid and upgrade the brake pads. So, anyone trying to track a car and not changing any of those things, is not going to have such a nice time.

I hope the OP finds a car they’re happy with though. I’m loving this GRC CE. But full discretion, it’s not my daily. View attachment 28615

Just a quick update. I bought the transfer case cooler and engine oil cooler from 555 Engineering. My exhaust has changed to the AWE Touring edition with the Track pipe option also purchased. My wife or I haven’t pushed it yet on the track with this setup. Hopefully we’ll do it this year and I’ll report back if the GRC goes into limp mode.

 

[ND4SPDR]

Just a quick update. I bought the transfer case cooler and engine oil cooler from 555 Engineering. My exhaust has changed to the AWE Touring edition with the Track pipe option also purchased. My wife or I haven’t pushed it yet on the track with this setup. Hopefully we’ll do it this year and I’ll report back if the GRC goes into limp mode.

Did you also get the Syvecs AWD controller? If not you are likely to still cutover to FWD if you’re pushing.

 

[Reddragun3]

Did you also get the Syvecs AWD controller? If not you are likely to still cutover to FWD if you’re pushing.

I did get the controller. The full setup from Michael at 555 Engineering. 👍🏽

 

[ND4SPDR]

I did get the controller. The full setup from Michael at 555 Engineering. 👍🏽

Excellent, the car will be happy to turn laps longer than you can.

 

[Reddragun3]

Excellent, the car will be happy to turn laps longer than you can.

I hope so. Trying to schedule a time to go out this year so I can test this expensive investment for this fun little car.

 

[dpaler]

Ran another weekend at Watkins Glen [I instruct with the local BMW club]. Changes from last year - SIXTH I/C, 555 oil cooler and installed EBC Blue pads F&R for the event. Ambient temps started in the mid 60's and his low 80's over Saturday & Sunday. My OEM tires are now to the wear bars and ready to be replaced.

Car is a blast to drive, handles wonderfully, fantastic brakes and I got 6 laps in the morning [cooler temps] and 5 laps for subsequent sessions. At WGI that equates to about 11-13 minutes on track before it goes AWD>FWD. I was able to turn a few more laps in FWD but then the handling gets less than ideal and I head to the paddock.

The 555 oil cooler did it's job and held the oil temp to max of 250 [nearly 40 lower than without it] and can say that upgrade was definitely worth it.

I need to get deeper into the braking zones & explore the EBC Blue's prowess but working up to it the diff overheats. It'll hit just over 135 on the back straight and turning sub 2:20 lap times. Not too shabby for a daily drive that carries about 10lbs per HP.

At this point I can't justify spending thousands to "fix" the problem Toyota should have [not only from the beginning but for subsequent models] for a car they proclaim to be "track ready".

Now to get the dealer to fix my bumper that continues to come loose...