So I uhhh... took delivery of a GRC today.

RedVN said:

I’ll add one thing; there is a weakness in the valve train which can be rectified by the addition of rock arm clips from an Australian company. Denstoj Rocker Retainer Kit for FA and FB Subaru/Toyota Engine

This weakness has been discovered by this firm and they’ve developed a fix for what Toyota is aware of for the GR Yaris.

Look into them, I’ve spoken directly with the owner on several occasions. The problem is real and can cause a catastrophic failure of the engine. It has on several GR Yaris in their country, Europe and the UK, mainly from over-revving or money shifts. 👍🇺🇸

Click to expand...

First off all, that link you sent me is for the Subaru FA/FB engine. That's a Subaru designed engine with Toyota's D4-S injection when it's in the BRZ or GR86. The engine architecture and design is all Subaru, but of course Toyota has some input on performance numbers. Toyota said, hey Subaru, we'll give you some money if you make this engine for us with these specifications for our sportscar. And Subaru was like, sure thing boss! That's it. The G16E-GTS and the FA/FB literally have NOTHING in common. Quite literally nothing in common besides being engines. They are not even made in the same factory. They are not made in a Toyota factory. They are made in a Subaru factory.

Did you mean this?

Denstoj Rocker Retainer Kit for G16E-GTS Toyota Engine (GR Yaris & GR

That's like saying an F22C engine(or any other engine for that matter) has weak head studs because stronger aftermarket ARP head studs are available for it. Presence of a stronger aftermarket part does not always mean said stock part is weak or prone to failure. In addition, that's the only company making these retainers. The GRY has been around for 3 years now. Do you not think that if there were widespread valve train problems that more companies would make these rocker retainer kits?

Furthermore, I tried to googled GR Yaris valve train failures and only one thing was non-money shift related. A tuner decided to raise the rev limit to 7600 RPM and the valve springs couldn't keep up. This can happen with literally ANY engine if you electronically and mechanically raise the rev limit without the associated valve train upgrades. In addition, bending valves and destroying rocker arms when you money shift is a thing that happens with ALL modern engines due to high compression pistons necessitating an interference design.

Our first failure! - Valve Springs

Another one I found was isolated to just this one thread.

https://www.gr-zoo.com/threads/apex-yaris-has-thrown-a-valve-rocker-again.1763/

So you see, I did some digging. The guy, Robert Mitchell, that posted this on Instagram(and found its way in to that forum) either owns(or works for) a rental car company for people that want to rent cars and drive them on the Nurburgring. That GR Yaris has thousands and thousands and thousand of hard miles being rented by people who just beat on it all day, day in, day out. That Apex GRY(as its called in that thread) destroyed its valve train initially due to a money shift. They obviously fixed it, but they grenaded the valve train again. Probably due to another money shift, or botched repair. I mean, beat on a car enough and it will eventually fail. Like any other car out there. Didn't GenRacer blow a head gasket on their VN TCR race car a while back? Does that mean that VN head gaskets are weak and prone to failure?

Here's the Gen Racer VN engine teardown video of the blown head gasket: Look through the comments and Dave Marino says the engine as only making around 300-ish horsepower.


Also, this video has Robert Mitchell admit he money shifted his GR Yaris.


There's someone on the r/velosterN subreddit that posts about money shifting at least once every 2 weeks. As a matter of fact, I have read more threads about money shifting with the Veloster N than any other car community I've been a part of. I swear, it's an epidemic. But I don't see or hear anyone saying the Theta II-i has a weak valve train because of that.

None of what you said points to the valve train being a weakness of the G16E-GTS engine or flawed in design, simply because people decided to do something they probably shouldn't have done, or screwed up a shift. In stock form, the G16E-GTS is incredibly reliable. Start tinkering and you risk catastrophic failure. Shift like Vin Diesel and you risk catastrophic money shifts. Just like any other engine out there.

So really, there's one instance of a GRY valve train failing that isn't due to a money shift. And that's because they raised the rev limit. Every other valve train failure on the GRY is due to money shifting. So please, stop spreading misinformation and blowing this out of proportion. I did my due diligence. I tried to prove you right and myself wrong here. I presented links and did some digging. A lot of digging. None of what you say is true. What you are saying, and have been saying about the GRY/C engine is just plain wrong. The absolute truth is that if you money shift or over rev ANY engine, it will blow up. This is not isolated to a specific engine. This can happen to ANYONE. There are no protections against mechanical over rev. None. That doesn't make it a weakness or design flaw. It's user error and/or abuse. Plain and simple.

Case closed.

almazing said:

First off all, that link you sent me is for the Subaru FA/FB engine. That's a Subaru designed engine with Toyota's D4-S injection when it's in the BRZ or GR86. The engine architecture and design is all Subaru, but of course Toyota has some input on performance numbers. Toyota said, hey Subaru, we'll give you some money if you make this engine for us with these specifications for our sportscar. And Subaru was like, sure thing boss! That's it. The G16E-GTS and the FA/FB literally have NOTHING in common. Quite literally nothing in common besides being engines. They are not even made in the same factory. They are not made in a Toyota factory. They are made in a Subaru factory.

Did you mean this?

Denstoj Rocker Retainer Kit for G16E-GTS Toyota Engine (GR Yaris & GR

That's like saying an F22C engine(or any other engine for that matter) has weak head studs because stronger aftermarket ARP head studs are available for it. Presence of a stronger aftermarket part does not always mean said stock part is weak or prone to failure. In addition, that's the only company making these retainers. The GRY has been around for 3 years now. Do you not think that if there were widespread valve train problems that more companies would make these rocker retainer kits?

Furthermore, I tried to googled GR Yaris valve train failures and only one thing was non-money shift related. A tuner decided to raise the rev limit to 7600 RPM and the valve springs couldn't keep up. This can happen with literally ANY engine if you electronically and mechanically raise the rev limit without the associated valve train upgrades. In addition, bending valves and destroying rocker arms when you money shift is a thing that happens with ALL modern engines due to high compression pistons necessitating an interference design.

Our first failure! - Valve Springs

Another one I found was isolated to just this one thread.

https://www.gr-zoo.com/threads/apex-yaris-has-thrown-a-valve-rocker-again.1763/

So you see, I did some digging. The guy, Robert Mitchell, that posted this on Instagram(and found its way in to that forum) either owns(or works for) a rental car company for people that want to rent cars and drive them on the Nurburgring. That GR Yaris has thousands and thousands and thousand of hard miles being rented by people who just beat on it all day, day in, day out. That Apex GRY(as its called in that thread) destroyed its valve train initially due to a money shift. They obviously fixed it, but they grenaded the valve train again. Probably due to another money shift, or botched repair. I mean, beat on a car enough and it will eventually fail. Like any other car out there. Didn't GenRacer blow a head gasket on their VN TCR race car a while back? Does that mean that VN head gaskets are weak and prone to failure?

Here's the Gen Racer VN engine teardown video of the blown head gasket: Look through the comments and Dave Marino says the engine as only making around 300-ish horsepower.

Also, this video has Robert Mitchell admit he money shifted his GR Yaris.

There's someone on the r/velosterN subreddit that posts about money shifting at least once every 2 weeks. As a matter of fact, I have read more threads about money shifting with the Veloster N than any other car community I've been a part of. I swear, it's an epidemic. But I don't see or hear anyone saying the Theta II-i has a weak valve train because of that.

None of what you said points to the valve train being a weakness of the G16E-GTS engine or flawed in design, simply because people decided to do something they probably shouldn't have done, or screwed up a shift. In stock form, the G16E-GTS is incredibly reliable. Start tinkering and you risk catastrophic failure. Shift like Vin Diesel and you risk catastrophic money shifts. Just like any other engine out there.

So really, there's one instance of a GRY valve train failing that isn't due to a money shift. And that's because they raised the rev limit. Every other valve train failure on the GRY is due to money shifting. So please, stop spreading misinformation and blowing this out of proportion. I did my due diligence. I tried to prove you right and myself wrong here. I presented links and did some digging. A lot of digging. None of what you say is true. What you are saying, and have been saying about the GRY/C engine is just plain wrong. The absolute truth is that if you money shift or over rev ANY engine, it will blow up. This is not isolated to a specific engine. This can happen to ANYONE. There are no protections against mechanical over rev. None. That doesn't make it a weakness or design flaw. It's user error and/or abuse. Plain and simple.

Case closed.

Click to expand...

I’ll simply add; You totally misinterpreted my intentions. Do what you like, it wasnt bad mouthing the car, you or anything in general but providing this for informational purposes and a helping hand. Not for dispute, sarcasm or where your thoughts, emotions and actions decide to lead you. That’s on you and it was unfounded and unnecessary.

Not all the information regarding this particular issue is on the internet. I don’t stick my head in the sand with such issues either. I fully research such issues to find or gather information about it. I talk to those who own them and those who work on them as well. Especially, if I’m considering a purchase.

Additionally, this particular shop in Australia has dealt with the issue, not perceived or fictional. They don’t produce such kits without cause. Enjoy the car, I don’t wish or hope for any ill will but be aware they're are particular issues with every design. Manufactures cut corner to meet their means not yours. Just as Hyundai, Subaru, Honda and others manufactures have in the past and present.

You only have to check the NHTSA mandatory recalls from most of the major manufacturers. Example; Subaru and Toyota flat four oil starvation issues which have lead to engine failures, Hyundai 2015-2019 catastrophic engine failure due to poor manufacturing of the block which left millings intact, causing engine failures of the 2.0 Theta II engine.

Do what you wish, the issue is out there and there’s is a viable fix, rather you decide to utilize it or not. Others have, along with the security of knowing it‘s effectively corrected.

You’re not immune to money shifts or similar problems arising due to mechanical over-rev, no one is.👍🇺🇸

One showed up to the track today! Sadly wasn't registered to drive this weekend. I'm less interested in switching anyway, the VN was fantastic, even bone stock. Got pretty good at left foot trail braking thanks to the DCT!

Did my free track day about 2 weeks ago. Couldn't have had the worst of conditions. It was 90-something for that NASA weekend. It was about 70-80 to before and after that weekend so the weather gods said **** this weekend in particular. GRC is stock with PP. Brake fluid was changed to SRF. Oil was changed to 0w30. On to my thoughts and impressions on track. I did 4 20-30 minute sessions. I used Sport/Expert mode and AWD was set to 60/40 and 50/50. Track was Heartland Park(fast 8 configuration) in Topeka, KS. My best lap on the GRC is a 2:01.7.

Engine - Man, the centerpiece of this car is the engine. It did heat soak in 90-something weather, but it wasn't as obvious as say, my Veloster N when it was stock. There's no feeling of power drop off past 5-6000 RPM. For all I knew, the engine felt like it was making the most amount of power it could, without making power loss obvious. Great engine tuning by Toyota here. Often times in most turbo cars, when heat soak kicks in, I'd feel a sharp drop in power. Not with the GRC, even though I KNOW there is power loss due to heat. Engine response is great. On track I'm around 4500-redline so lag isn't an issue. It just gave me power when I wanted it. No complaints, aside from the lack of sound. Oil got as high as 282F but normally hovered around 260-270. I use motorsports rated oil, so this isn't a problem for me. Water temps never got above 210F, so water cooling is efficient. You likely will not have to worry about blowing a head gasket on track with a stock GRC.

Transmission - Rev matching can't keep up. My Veloster N has no issues with rev matching on a road course. The GRC is slower to match revs, as I would have already let go of the clutch and downshifted before the rev matching does its thing. Due to the inability for the IMT to keep up, there were times when I'd downshift and lock the rear wheels due to drivetrain shock. I hope there's a software update in the future that sharpens IMT's response, at least in sport mode. To adapt, I've had to slow my downshifts so that my physical movements align with the IMT. Aside from that, the transmission shifted smoothly, but one must slow their physical shifts down a little to get the car to work with them.

Chassis and Suspension - Disclaimer here. I'm very well versed in driving FWD cars on track. the GRC has 60/40 front rear weight distribution, so at turn in off throttle, it's practically a FWD car. But great chassis tuning from the folks at Toyota. It's stiff and communicative. It weighs 3250 lbs, but tossing it around, it feels hundreds of pounds lighter than it really is. I thought that this would be an understeering pig at corner entry, but I was pleasantly surprised at how neutral it was coming in. That thought was due to the general numbness of its steering, however. At least on the street. Once the chassis is loaded mid corner, it provided better feedback via steering wheel. On long sweepers, it has a tendency to run slightly wide, but lift a little, and the nose tucks back in. I can get on the gas at corner exit pretty early. The outside tires hook up and drive the car out of corners with a vengeance. Get on the throttle too hard and too early and it will run wide. But feather the throttle and it'll get back in line. I do feel that suspension is a bit too soft. There's A LOT of body roll and it would benefit from stiffer springs, even at stock ride height. The damping was pretty good too. I never felt that the car was unsettled even in sketchy parts of the track. The dampers just took it and I never thought about it, which was good. The rear could use a bit more rotation, but that's what aftermarket rear sway bars are for.

Brakes and Tires - The brake pedal remained stiff the entire day. I love how it feels. But I'm not a fan of how grabby the initial bite of the stock pads are. It's hard to gauge just how much later I can brake or how hard I can brake because it lacks progressiveness and modulation of track pads. That being said, I never had fade throughout the day, but I also never pushed it as hard as I would have with my Veloster N because the brakes didn't give me the feedback I would like in a track setting. In addition, there is no brake cooling at all on this car. Yeah, you can install the Morizo ducts, but the rotor dust shield would need to be removed because there are no cutouts for air to get through. Not that big of a deal, but something to address for those seriously tracking the GRC. The tires were decent. They're not the 'S' version so they lacked ultimate grip. But I found them to be willing dance partners. Easily controllable at the limit. I could run a hot lap and be at the cusp of grip with tires squealing the entire time at every corner and feel like I'm in complete control. I found that for the fronts, 36-38 PSI HOT is the magic number. Same for the rear. Normally, I'd have the rears higher than the front for more rotation, but in the GRC's case, it makes more sense to have them all the same due to the AWD.

AWD System - This is where cracks start to appear, though this is due to an exceedingly hot day. I started with 50/50 and it felt great. The drive out of corners was exactly what I would expect. But it overheated at the end of the first session. 2nd session, I did 60/40 to see if it wouldn't overheat, but it still did. The difference between 50/50 and 60/40 is subtle. But 60/40 tends to push a little more than 50/50 at corner exit. I didn't even do 30/70 for obvious reasons. For the rest of the day, I stuck with 50/50 since it was going to overheat anyway. The AWD system is transparent. There' no obvious indication or lurching that it's doing its thing. It just does it and I don't have to worry about it. Obviously, heat is an issue. Heat wrapping the exhaust and installing a rear diff duct could possibly mitigate this issue, even on hot days. Besides that, it's a great system let down by thermal capacity. No doubt the aftermarket will address this.

Misc - The stock seats suck. They barely hold me in while cornering. They could also be a little lower. The gauge cluster is great. I thought I would miss having true shift lights like in my Veloster N, but I was able to make do with how I configured my gauge cluster. It's a well made, solid car. I was afraid that I'd start to hear squeaks and rattles post track day, but nope. Still as solid as she was brand new.

Overall, it's a great and easy car to drive on track. The stock components are lacking, namely in the suspension department and the lack of rear diff cooling, as well as the lack of brake cooling. But those are easily addressed by the aftermarket. Install some motorsports rated coilovers, brake ducts, and rear diff cooler, and the GRC will put down respectable times.

I can't compare the times directly to my VN times due to the change in track configuration. I've only ran the track in the slow 8 with my VN, while I ran the track in fast 8 with the GRC. For reference though, the fast 8 is about 3-4 seconds faster than the slow 8 in most cases. My VN with 200TW tires ran the slow 8 with a 1:59.6. The GRC did the fast 8 with a 2:01.7, so add 3-4 seconds and I'd be theoretically looking at a 2:04 to 2:05 with the GRC. That time actually lines up with my prediction and what the car is capable of in stock form. I have done hundreds of laps in Heartland by now, I have a good idea of what pace a car can run based on power to weight ratio and tires being used. With 200 TW tires, intercooler, and RSB(the same mods as my VN), the GRC can easily match, if not beat my VN's time in the slow 8.