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Discussion Starter · #1 · (Edited)
From everything I've read and seen, the GR Yaris had inconsistent dyno numbers from back to back runs on the dyno. They were also able to solve the issue. Let's figure out if that's the same case for the GR Corolla, and how to dyno it correctly for consistent numbers. Being AWD, this can be a challenge. So far, there is one dyno test done on the GRCorolla, that I know of, thus far.

On the GR Yaris:
It appears that the rear wheels are overdriven compared to the front wheels, and the drive system will fight the 4wheel drive dyno, until it settles on a reduced power mode... which is obviously not correct, not consistent, and not giving you what you want... the correct hp reading, at where the rubber hits the road, when your actually driving it.

Background: Typically, an AWD car will lose 20% power from the crankshaft through the flywheel, transmission, differential(s), driveshafts, spindles/knuckles, wheels, then to where the rubber hits the road. FWD loss is 14%, RWD loss is 17%, typically. With bigger&heavier wheels, those losses can vary up to 5% more.

The accepted dyno (aka dynanometer) in the USA, to give correct dyno numbers is a Dynojet. Other dynos may read higher or lower... but, basically when a new car is ready to be released in the USA, SAE (Society of Automotive Engineers), a regulatory board in the USA, will follow a set procedure and put a car on a Dynojet to find the reading. They then do a reverse calculation, and inform the manufacture the highest hp number the manufacture can advertise/state, without going over. Typically, today, in modern performance cars, they are rated much less than the number SAE is giving them. Example 306hp fk8 CTR puts down 290whp (wheel horsepower), which 306hp is clearly underrated by Honda. The 275hp Veloster N puts down 235whp, which is perfectly correctly rated with 14% loss. The 286hp Elantra N DCT puts down 280whp. The 276hp Elantra N manual puts down 260whp. Typically autos are making more whp than manuals, despite equal or similar ratings due to stricter db sound restrictions placed on manuals, than the auto.

And finally,
From what I've read and seen on the GR Yaris, it was necessary/found to put it in FWD mode, and then they were able to get consistent hp readings. They were able to do this [once on a 2wheel dyno] by simply pulling the hand brake. Motive Garage, in Austraila, also mentioned that they pulled "the plugs" under the back seat, which I assume to mean electrical connectors, as an extra precaution... After studying this further, it seems that the GR Yaris has an AWD test mode (aka dyno mode), which you have to enter a sequence of pedal&handbrake presses AND ignition on/off sequences. It's not just simply pulling the handbrake.

I also believe that Toyota put in this feature for ease of towing, on a tow dolly, where two wheels are rolling (the front wheels) and two wheels are on the tow dolly with the parking brake on. Can someone please look in their owners manual and see what it says under "towing your vehicle?" See post #5 in this thread here.

There have been 7 dyno tests done so far, 258.6awhp (dynojet), 252awhp (Mustang Dyno), 219ahhp (Dynapack), 247fhhp (Dynapack), 299fwhp (Mustang dyno, same as the one that read 252awhp, but was put in dyno mode), 271whp (Dynojet), and 305whp with a +6hp catback exhaust (dynojet). awhp=all wheel hp; ahhp= all hub hp; fwhp= front wheel hp; fhhp=front hub hp.

From acceleration testing against an FK8 CTR, I would estimate that the GRCorolla would put down 280whp, vs 290whp CTR. Losing 20whp because of the fight against the 4wheel dyno, seems about right. We need to figure out if that fight is the case for the 260whp, OR if 260whp is just what it is because of the extra loss to the rear wheels (doubt it), AND/OR if we can get a 2wheel drive dyno test/solution to get the correct reading.

We now have 2 dyno tests we can trust, 299whp and 305whp w/catback exhaust, because:
1) they used the proper dyno mode
2) consistent back-to-back results
3) peak power was at 6400rpm (Toyota states peak power is 6500rpm)
4) they were able to take it to the limiter of 7200rpm (not artificially limited at 6800rpm) like Just driven had

Here's the 1st dyno done, from carson.menendes (258.6awhp, dynojet)
Rectangle Purple Slope Plot Font


2nd dyno done, from Limit+1, all wheel test (252awhp, Mustang Dyno)

3rd & 4th dyno done, from Just Driven (247fhhp, and 219ahhp, but w/artificial limiter at 6.8k rpm, dynapack)
They are currently reevaluating it, and I sincerely hope they figure out if there is an issue, or if relative to other cars they dyno'ed, this is correct.

5th dyno done, from Limit+1, in dyno test mode (299fwhp, dynojet)
They are going through a re-calibratiom procedure, to double check everything.

6th dyno done, not in dyno mode from 6th Element Engineering (270.68whp, not in dyno mode)
Photograph Product Rectangle Azure Font
Product Rectangle Output device Font Slope

They will be redo'ing their test in dyno mode.

7th dyno done, in dyno mode from 2-J Racing (305whp with +6hp cat back exhaust (6hp gain from exhaust is assumed, not tested))

Here's the final conclusion, in theory, on how to properly dyno the GR Corolla [for consistent numbers]:
Enter Inspection (Chassis Dyno) mode:
1. Engine is off, handbrake on
2. Turn ignition switch to on
3. Release handbrake
4. Press brake pedal and hold
5. Turn engine on
6. Pull handbrake
7. Release brake pedal, then press 2 times, and hold
8. Release handbrake, then pull 2 times, and hold
9. Release brake pedal, then press 2 times, and hold
At the end of this procedure, VSC and TRAC will automatically also be disabled, and verify by seeing TRAC OFF and VSC OFF in the cluster. You can also verify by putting the front of the car on jack stands and watching the front wheels rotate easily with the parking brake applied. Your GRCorolla is now FWD and ready for a 2wheel dyno.
10. Turn off car when done, inspection/dyno mode will end. Leave car off for 60sec, as turning car back on within 60sec, you will re-enter dyno mode.

I have developed a criteria to define a correctly done dyno test, if it meets all 4, then I accept it as a correctly done dyno:
1. Car is said to be tested in dyno mode
2. Back-to-back runs show consistent numbers of + or - 2hp (example Limit+1 dyno'd 296, 299, 298)
3. Peak power is at 6400rpm or higher (Toyota states peak power at 6500rpm)
4. There is no artificial limiter, and the dyno graph shows reading through 7200rpm (unlike Just Driven showing 6800rpm, and their test met none of these)
Also, remember that a dynojet is correct correct reading, not low, not high, and a correction factor must be used (STD or SAE), incase of high altitude (low barometric pressure), etc.

Only Limit+1 in FWD, and 2J-Racing, meet the criteria. The rest meet #4 maybe.

If you just want to defeat VSC and TRAC without going to FWD:
When the VSC off switch is pressed and held for 3sec or more with the vehicle stopped, you have entered VSC off mode (TRAC will be off, VSC will be off). TRAC OFF and VSC OFF will be illuminated in the cluster. You could use this on the street/track/4wheel dyno. At your own risk. Lets see if you can do a drift now, and not crash, lol.

Please, correct me where I'm wrong, and please add what you have found.
 

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As far as the difficulties in dynoing the GR Corolla, that is my understanding. The rear wheels are slightly over driven, and under normal operation the clutch packs in the rear diff are used to compensate for that. This causes issues with testing the car on a dyno.

I believe that the preferred method of dynoing the GR Yaris is to cut all power to the rear and dyno it like a FWD car. Though I am not sure on the specific methods. The numbers would still be a bit off as FWD will see less power loss, but it should he a lot more consistent which is important for tuning the car.
 

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Discussion Starter · #3 ·
My thoughts exactly

Just in FWD mode, it may be as high as 300whp, but it also depends on how efficient the system is at distributing the power to where and when it's needed, and cutting power and losses to when it's not needed.
 

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From everything I've read and seen, the GR Yaris had inconsistent dyno numbers from back to back runs on the dyno. They were also able to solve the issue. Let's figure out if that's the same case for the GR Corolla, and how to dyno it correctly for consistent numbers. Being AWD, this can be a challenge. So far, there is one dyno test done on the GRCorolla, that I know of, thus far.

On the GR Yaris:
It appears that the rear wheels are overdriven compared to the front wheels, and the drive system will fight the 4wheel drive dyno, until it settles on a reduced power mode... which is obviously not correct, not consistent, and not giving you what you want... the correct hp reading, at where the rubber hits the road, when your actually driving it.

Background: Typically, an AWD car will lose 20% power from the crankshaft through the flywheel, transmission, differential(s), driveshafts, spindles/knuckles, wheels, then to where the rubber hits the road. FWD loss is 14%, RWD loss is 17%, typically. With bigger&heavier wheels, those losses can vary up to 5% more.

The accepted dyno (aka dynanometer) in the USA, to give correct dyno numbers is a Dynojet. Other dynos may read higher or lower... but, basically when a new car is ready to be released in the USA, SAE (Society of Automotive Engineers), a regulatory board in the USA, will follow a set procedure and put a car on a Dynojet to find the reading. They then do a reverse calculation, and inform the manufacture the highest hp number the manufacture can advertise/state, without going over. Typically, today, in modern performance cars, they are rated much less than the number SAE is giving them. Example 306hp fk8 CTR puts down 290whp (wheel horsepower), which 306hp is clearly underrated by Honda. The 275hp Veloster N puts down 235whp, which is perfectly correctly rated with 14% loss. The 286hp Elantra N DCT puts down 280whp. The 276hp Elantra N manual puts down 260whp. Typically autos are making more whp than manuals, despite equal or similar ratings due to stricter db sound restrictions placed on manuals, than the auto.

And finally,
From what I've read and seen on the GR Yaris. It was necessary/found to put it in FWD mode, and then they were able to get consistent hp readings. They were able to do this [once on a 2wheel dyno] by simply pulling the hand brake. Motive Garage, in Austraila, also mentioned that they pulled "the plugs" under the back seat, which I assume to mean electrical connectors, as an extra precaution.

I also believe that Toyota put in this feature for ease of towing, on a tow dolly, where two wheels are rolling (the front wheels) and two wheels are on the tow dolly with the parking brake on. Can someone please look in their owners manual and see what it says under "towing your vehicle?"

The dyno test that was done on the GRCorolla, so far, was done on a 4wheel dyno, and it read roughly 260whp. From acceleration testing against an FK8 CTR, I would estimate that the GRCorolla would put down 280whp, vs 290whp CTR. Losing 20whp because of the fight against the 4wheel dyno, seems about right. We need to figure out if that fight is the case for the 260whp, OR if 260whp is just what it is because of the extra loss to the rear wheels (doubt it), AND/OR if we can get a 2wheel drive dyno test/solution to get the correct reading.

Here's the 1st dyno done on a GRCorolla (from carson.menendes)
View attachment 6033


Please, correct me where I'm wrong, and please add what you have found.
It says do not tow with any wheels on the ground or damage will occur
 

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Discussion Starter · #5 · (Edited)
It says do not tow with any wheels on the ground or damage will occur
Darn! I was hoping there was a description on how to tow with 2wheels on the ground. Doesn't mean it's not possible, they just don't describe how.

Like... put rear wheels on dolly, pull parking brake, lock steering wheel left or right from center, and leave shifter in neutral position. This is how I've towed an AWD vehicle in the past, obviously just being in neutral is OK, without disconnecting the driveshaft.

Edit: Towing can be done this way, by entering dyno mode (aka inspection mode, aka FWD mode)... but the ignition will need to be left on. So, do this at your own risk. You will also need to tie/lock the steering wheel in one position (you can use the "seatbelt trick," or "The Club", since the key will still be in the ignition and steering wheel will not lock
 

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I believe that the preferred method of dynoing the GR Yaris is to cut all power to the rear and dyno it like a FWD car. Though I am not sure on the specific methods. The numbers would still be a bit off as FWD will see less power loss, but it should he a lot more consistent which is important for tuning the car.
You are pretty much spot-on. People have dyno'ed Golf R as FWD just like you described.

I remember coming across GRY has a FWD service/debug mode (whatever way your like to call it). I can imagine GRC should have it.
 

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Discussion Starter · #9 · (Edited)
If the rear wheels are on a dolly they aren't on the ground.
You catch on quick! Front wheels are the ground, correct. Reread the description on how I've tow'ed an AWD vehicle with a tow dolly.

"put rear wheels on dolly, pull parking brake, lock steering wheel left or right from center, and leave shifter in neutral position. "

You are pretty much spot-on. People have dyno'ed Golf R as FWD just like you described.

I remember coming across GRY has a FWD service/debug mode (whatever way your like to call it). I can imagine GRC should have it.
Exactly. The question is, how do we do that? Just pull the parking brake while on the dyno? Should we electronically disconnect the rear end sensors (if any)? Or, do we have to buy a special AWD controller first? Or, even worse, disconnect the driveshaft to the rear wheels.

Edit: We found the solution. See the bottom of the 1st post. It's called "inspection mode" (aka dyno mode, aka FWD mode)
 

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Discussion Starter · #10 ·
We were wondering the same thing last night once we unstrapped the car. We plan on looking into it further with time but we just wanted to get a pretty good baseline visual. We were in and out pretty quick last night too because it was the end of a long work day and I was freezing my ass off from the fans lol
Can you give any insight on the consistency of the runs, back to back? Did you see any inconsistencies in the same gear? Are you sure that 3rd gear gave more power, while 4th gave more torque, and it wasn't an inconsistency issue regardless of the gear?
 

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Exactly. The question is, how do we do that? Just pull the parking brake while on the dyno? Should we electronically disconnect the rear end sensors (if any)? Or, do we have to buy a special AWD controller first? Or, even worse, disconnect the driveshaft to the rear wheels.
It is like a "pedal dance". If you want to try it, do so at your own risk


From the looks of it, this is designed to be used on a dyno.
 

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Discussion Starter · #16 · (Edited)
It is like a "pedal dance". If you want to try it, do so at your own risk


From the looks of it, this is designed to be used on a dyno.
From what I've read [on that video, and the one it references], this is not for FWD mode, this is for full power mode, without having stability and traction control interfering. It's suppose to give roughly 6hp. Possibly on an AWD dyno, this would help, but I think trying to dyno it in FWD might be best and easier. Don't know yet, for sure.

I might have to try and ask the guys in the UK that did that ultimate intake test, how they were able to get it dyno'ed in FWD mode.

Here's the text version, of how to get into this "full power" "AWD test mode" on a GR Yaris:
1. Engine is off, handbrake on
2. Turn engine on
3. Release handbrake
4. Turn engine off
5. Press brake pedal and hold
6. Turn engine on
7. Pull handbrake
8. Release brake pedal, then press 3 times, and hold
9. Release handbrake, the pull 3 times, and hold
10. Release brake pedal, then press 3 times, and hold
You should see AWD test mode displayed
You will also see TRAC OFF and VSC OFF
Can someone try this on their GR Corolla?

Edit: This does not apply to the GR Corolla. The procedure is similar, but not the same. On the GR Corolla, once you turn the car off the 1st time, you exit the "test" mode.
 

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Discussion Starter · #17 · (Edited)
i believe this is outlined in the repair manual under the inspection mode section.
Nice! That (brake control system, page 3) says... To put the car on a 2 wheel chassis dyno, you need to enter inspection mode and enter VSC off mode

1) enter VSC off mode:
When the VSC off switch is pressed and held for 3sec or more with the vehicle stopped, you have entered VSC off mode (TRAC will be off, VSC will be off). TRAC OFF and VSC OFF will be illuminated in the cluster.
2) put car in inspection mode...very similar procedure as outlined in getting to the AWD Test Mode on a GR Yaris, except, you don't turn the car on then off then on, and instead of 3 it says "2 times", but I also read that 2 or more works. At the end of this procedure, VSC and TRAC will automatically also be disabled, and verify by seeing TRAC OFF and VSC OFF in the cluster.

Edit: See bottom of 1st post for the procedure
 

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Discussion Starter · #18 ·
We have now solved how to dyno in FWD mode, in theory, until someone with a GRC can verify. The manual says you can put the front of the car up on jack stands to test that the front wheels rotate.

I'd like to thank Noogie and madbikes for finding this. Simply amazing!
 

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Discussion Starter · #19 · (Edited)
Here's the final conclusion, in theory, on how to properly dyno the GR Corolla [for consistent numbers]:
1. Engine is off, handbrake on
2. Turn ignition switch to on
3. Release handbrake
4. Press brake pedal and hold
5. Turn engine on
6. Pull handbrake
7. Release brake pedal, then press 2 times, and hold
8. Release handbrake, then pull 2 times, and hold
9. Release brake pedal, then press 2 times,
and hold
At the end of this procedure, VSC and TRAC will automatically also be disabled, and verify by seeing TRAC OFF and VSC OFF in the cluster. You can also verify by putting the front of the car on jack stands and watching the front wheels rotate easily with the parking brake applied.
10. Turn off car when done, inspection mode will end
 

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Discussion Starter · #20 ·
If you just want to defeat VSC and TRAC without going to FWD:
When the VSC off switch is pressed and held for 3sec or more with the vehicle stopped, you have entered VSC off mode (TRAC will be off, VSC will be off). TRAC OFF and VSC OFF will be illuminated in the cluster. You could use this on the street/track/4wheel dyno. At your own risk. Lets see if you can do a drift now, and not crash, lol.
 
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