GR Yaris GR Corolla engine

L

Lanman

Obsessed member
Joined
Dec 19, 2021
Messages
290
Reaction score
433
Location
Brisbane
The Corolla engine according to Autocar is 300bhp 270 torques ! Not a simple tweak . Bigger valves and piston oil changes x 3 and less resting exhaust ! Great mini noise clip on R and T. . So no quick upgrade for GRU ers !
 
Bigger valves? I am sceptical. The valves are already that big, they actually cut angular through the gasket in the "corners" of the bore. This has been proofing to be a potential weak spot when adding boost and power. So bigger valves in terms of bigger diameter would be problematic. Any detailed information on this yet?
 
GRunt said:
Bigger valves? I am sceptical. The valves are already that big, they actually cut angular through the gasket in the "corners" of the bore. This has been proofing to be a potential weak spot when adding boost and power. So bigger valves in terms of bigger diameter would be problematic. Any detailed information on this yet?
Click to expand...
Was my first thought too. BS. Just no room.

Toyota themselves have confirmed the extra oil jets and that the exhaust helps. With no GPF and an ECU tickle you’d easily be at 300hp so I can’t see much else being needed.
 
Duke said:
Toyota themselves have confirmed the extra oil jets
Click to expand...
Technical detail tends to be lost in press releases...

I'm having trouble imagining more than the previously unseen 3 oil jets per piston(!) the Yaris already has....
 
To me, a quick causal glance the torque and power measure up with software and less restrictive exhaust only. Peak torque isn’t increased too much, and the torque held for slightly longer I think if memory serves me this is about the same results as a typical aftermarket exhaust achieved. Perhaps they fitted stronger valve springs

I doubt they have done much to the cam profile (lift duration etc) physically. As the Yaris already has pretty aggressive lift. Any wilder lift surely would negatively impact low rpm performance. Maybe they tweaked the map but that’s it.
 
Hm. Stronger springs and more oil jets could indicate a higher red line. That would indeed help to increase power.

The exhaust only wouldn't be enough to gain 40 hp I think. But the engine showed its potential. There are many buttons to push to increase power. But the most likely one will not cut too much in to physical engine design. The internals are able to handle about 500 ps before the gasket fails, so why changing them?
 
Japanese engineer on the US launch video said the increased power was due to exhaust and different pistons
 
Different pistons? Okay that can have two reasons. Stronger, to handle more boost. Not necessary as the Yaris pistons can handle way more boost and power. So the other reason would be lighter. That would indicate higher rpm as well.

Things like other piston rings aren't traded as other pistons I guess. And as I said, no reason to change pistons /-rings to gain more power.

I am pretty curious to get to know more information about that engine.
 
GRunt said:
Different pistons? Okay that can have two reasons. Stronger, to handle more boost. Not necessary as the Yaris pistons can handle way more boost and power. So the other reason would be lighter. That would indicate higher rpm as well.

Things like other piston rings aren't traded as other pistons I guess. And as I said, no reason to change pistons /-rings to gain more power.

I am pretty curious to get to know more information about that engine.
Click to expand...

Or just different compression ratio.
 
Found this interview with chief engineer Naoyuki Sakamoto :
www.caranddriver.com

2023 Toyota GR Corolla, Explained by Its Chief Engineer: 'Americans Demand Power'

Naoyuki Sakamoto gives C/D the details on everything from engine design to chassis welds—and laughs out loud at the idea this car's AWD and a RAV4's have anything in common.
www.caranddriver.com www.caranddriver.com

So, yes. More boost and to compensate the upgraded exhaust system.
 
Peak power also is 6.5k so unfortunately higher rpm is not the case as well. To bad. I like high rpm machines.... looks at K and F series.
 
....maybe tighten head down bit more stop gasket leak AND increased comp ratio:D
 
Some more information:

"The pistons are made from a stronger material, though Toyota is keeping mum on the exact alloy used, and the same is true for the exhaust valves. Those exhaust valves are larger, too, with stiffer valve springs. The ball-bearing turbocharger, which is integrated directly into the exhaust manifold, now runs 10% more boost. Top Gear reports that the GR Yaris' turbo runs around 20.3 psi of boost, meaning that in the GR Corolla, the boost is set to about 22.33 psi. That's a lot, so it's a good thing that GR Corolla also gets a higher capacity oil cooler. Increased boost pressure isn't the only source of the power increase, too. The central tailpipe on the GR Corolla helps reduce back pressure, further increasing horsepower."

www.roadandtrack.com

Here's What Makes the Toyota GR Corolla's Engine Unique

To boost output from 257 to 300 hp, Toyota tweaked its amazing 1.6-liter three-cylinder. The result is a true piece of automotive exotica.
www.roadandtrack.com www.roadandtrack.com

Sooo... indeed bigger valves with stiffer springs on exhaust side and the before mentioned exhaust upgrade. Coupled with more boost and to compensate stronger pistons.

The post on the oil cooler makes me scratch my head though... don't they mean intercooler??
 
You must log in or register to reply here.
Back
Top