dyno, 1st run 155hp, remaining 4 runs 172hp. wtf? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

ZDan · 05-26-2018, 04:32 PM

I just dyno'd the BRZ (2017 PP), the first run was significantly low on power up top relative to the rest:
131.5 lb-ft @ 3250, 154.5hp @ 6600
Torque rose linearly from 122 lb-ft @ 5000 to 127 at 6150, then began falling off.
92 lb-ft and 130hp @ 7400

The remaining four runs were all practially identical:
134 lb-ft @ 3300 and 6750, 172hp @ 6800
Torque rising linearly from 126 lb-ft @ 5000 to 134 @ 6750
106 lb-ft and 150hp @ 7400

A/F was a remarkably constant 13.0 - 13.1 for all runs from 2700rpm to the rev limiter.

If I had to guess I'd say the VVT wasn't working on the first run, is there anything that could prevent it from engaging?
The car sat for a while before the first run, but it wasn't too too far from normal operating temperature, nowhere near stone-cold.

Anyway, pretty pleased with the last four runs but would like to figure out why the first run was so different.

NoHaveMSG · 05-26-2018, 04:51 PM

I'd guess that oil wasn't up to temp on the first run. I know that on my car even when water temp starts to get into the 180-190 range the oil temp is significantly cooler and doesn't hit 190 for quite a while.

humfrz · 05-26-2018, 05:23 PM

Oh, I'd suggest you just average the results from the last runs …… and call the first run an "outlier".

humfrz

tomm.brz · 05-26-2018, 06:01 PM

Your 2017+ US cars have a strange logic.. With wot Closed loop and "power" afr and other stuff...
That s also why Openflash went with old logic for v4 tunes

Vvt takes long to activate if oil is quite cold, specially after reflash or dtc reset

Jasonb · 05-26-2018, 06:16 PM

Is the car stock?

Stock ECU tune?

ZDan · 05-26-2018, 06:56 PM

Engine, intake, exhaust, tune all totally stock.
Oil temp was down for 1st run, coolant closer to normal.
So if vvt is sensitive to oil temp that must be it.

For the other runs, I've never seen multiple dyno runs so close together, and A/V as well. Nice...

Teseo · 05-26-2018, 07:32 PM

Which octane gas used?

Irace86.2.0 · 05-26-2018, 09:01 PM

A/c was on for the first run.

Snake · 05-26-2018, 09:36 PM

100% because oil not up to operating temperature.

I used to have a Renault that would not allow me to rev it to the 7250 RPM limit until the oil was up to temp. Once water was up to temp you'd need to drive it around for another 5 mins before it'd let you rev it past 6500.

Probably a similar thing to do with the vvt not engaging fully until oil temp is to the correct level.

Sent from my RNE-L02 using Tapatalk

ermax · 05-26-2018, 10:44 PM

Stock tune also has IAM set to 0.7. So the first pull wouldn’t have full timing.

CSG Mike · 05-26-2018, 11:45 PM

Could be many causes; without a log I wouldn't be able to guess, but the car is otherwise totally happy!

ZDan · 05-27-2018, 01:53 PM

Quote:

Originally Posted by CSG Mike

Could be many causes; without a log I wouldn't be able to guess, but the car is otherwise totally happy!

Yeah, totally fine. If oil has to be at full normal operating temperature for VVT to be in effect, then that's it for sure. It probably sat for over an hour before we ran it. Car seems happy enough

tomm.brz · 05-27-2018, 02:04 PM

it doesn t need to be full normal temperature, it just must be warmed for about 3 minutes or less
i think with vvt off you could do less than 155hp

i think ermax is right, was easy actually, it s just the AM at 0.7 at start that need some heavy pulls to go up

NoHaveMSG · 05-27-2018, 03:19 PM

Quote:

Originally Posted by ermax

Stock tune also has IAM set to 0.7. So the first pull wouldn’t have full timing.

Does the stock tune reset to .7 on each startup? I haven't been on one for a while and never checked.

05-26-2018, 04:32 PM	#1
ZDan Senior Member Join Date: May 2011 Drives: '23 BRZ Location: Providence, RI Posts: 4,671 Thanks: 1,437 Thanked 4,011 Times in 2,097 Posts Mentioned: 85 Post(s) Tagged: 0 Thread(s)	dyno, 1st run 155hp, remaining 4 runs 172hp. wtf? I just dyno'd the BRZ (2017 PP), the first run was significantly low on power up top relative to the rest: 131.5 lb-ft @ 3250, 154.5hp @ 6600 Torque rose linearly from 122 lb-ft @ 5000 to 127 at 6150, then began falling off. 92 lb-ft and 130hp @ 7400 The remaining four runs were all practially identical: 134 lb-ft @ 3300 and 6750, 172hp @ 6800 Torque rising linearly from 126 lb-ft @ 5000 to 134 @ 6750 106 lb-ft and 150hp @ 7400 A/F was a remarkably constant 13.0 - 13.1 for all runs from 2700rpm to the rev limiter. If I had to guess I'd say the VVT wasn't working on the first run, is there anything that could prevent it from engaging? The car sat for a while before the first run, but it wasn't too too far from normal operating temperature, nowhere near stone-cold. Anyway, pretty pleased with the last four runs but would like to figure out why the first run was so different. Last edited by ZDan; 05-26-2018 at 04:49 PM.

05-27-2018, 02:04 PM	#13
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,277 Thanks: 515 Thanked 1,121 Times in 811 Posts Mentioned: 70 Post(s) Tagged: 0 Thread(s)	it doesn t need to be full normal temperature, it just must be warmed for about 3 minutes or less i think with vvt off you could do less than 155hp i think ermax is right, was easy actually, it s just the AM at 0.7 at start that need some heavy pulls to go up Last edited by tomm.brz; 05-27-2018 at 05:00 PM.

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05-26-2018, 05:23 PM	#3
humfrz Senior Member Join Date: May 2013 Drives: 2013 FR-S, white, MT Location: Puyallup, WA Posts: 30,409 Thanks: 29,794 Thanked 32,812 Times in 16,830 Posts Mentioned: 715 Post(s) Tagged: 2 Thread(s)	Oh, I'd suggest you just average the results from the last runs …… and call the first run an "outlier". humfrz

05-26-2018, 06:01 PM	#4
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,277 Thanks: 515 Thanked 1,121 Times in 811 Posts Mentioned: 70 Post(s) Tagged: 0 Thread(s)	Your 2017+ US cars have a strange logic.. With wot Closed loop and "power" afr and other stuff... That s also why Openflash went with old logic for v4 tunes Vvt takes long to activate if oil is quite cold, specially after reflash or dtc reset

05-26-2018, 06:16 PM	#5
Jasonb Senior Member Join Date: Jul 2017 Drives: 17 Series Yellow BRZ Location: Wilmington, NC Posts: 190 Thanks: 20 Thanked 47 Times in 40 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Is the car stock? Stock ECU tune?

05-26-2018, 06:56 PM	#6
ZDan Senior Member Join Date: May 2011 Drives: '23 BRZ Location: Providence, RI Posts: 4,671 Thanks: 1,437 Thanked 4,011 Times in 2,097 Posts Mentioned: 85 Post(s) Tagged: 0 Thread(s)	Engine, intake, exhaust, tune all totally stock. Oil temp was down for 1st run, coolant closer to normal. So if vvt is sensitive to oil temp that must be it. For the other runs, I've never seen multiple dyno runs so close together, and A/V as well. Nice...

05-26-2018, 07:32 PM	#7
Teseo Senior Member Join Date: Jun 2014 Drives: frs Location: Gunsai Posts: 4,951 Thanks: 7,463 Thanked 2,978 Times in 1,801 Posts Mentioned: 23 Post(s) Tagged: 2 Thread(s)	Which octane gas used?

05-26-2018, 09:01 PM	#8
Irace86.2.0 Senior Member Join Date: Mar 2017 Drives: Q5 + BRZ + M796 Location: Santa Rosa, CA Posts: 7,884 Thanks: 5,668 Thanked 5,810 Times in 3,300 Posts Mentioned: 70 Post(s) Tagged: 0 Thread(s)	A/c was on for the first run.

05-26-2018, 09:36 PM	#9
Snake Senior Member Join Date: Dec 2012 Drives: ADM Toyota 86 GT Location: Australia Posts: 117 Thanks: 32 Thanked 63 Times in 37 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	100% because oil not up to operating temperature. I used to have a Renault that would not allow me to rev it to the 7250 RPM limit until the oil was up to temp. Once water was up to temp you'd need to drive it around for another 5 mins before it'd let you rev it past 6500. Probably a similar thing to do with the vvt not engaging fully until oil temp is to the correct level. Sent from my RNE-L02 using Tapatalk

05-26-2018, 10:44 PM	#10
ermax Senior Member Join Date: Sep 2017 Drives: 2022 BRZ Limited Silver Location: Jacksonville, FL Posts: 2,533 Thanks: 883 Thanked 2,048 Times in 1,190 Posts Mentioned: 68 Post(s) Tagged: 0 Thread(s)	Stock tune also has IAM set to 0.7. So the first pull wouldn’t have full timing.

05-26-2018, 11:45 PM	#11
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,562 Thanks: 8,942 Thanked 14,211 Times in 6,854 Posts Mentioned: 970 Post(s) Tagged: 14 Thread(s)	Could be many causes; without a log I wouldn't be able to guess, but the car is otherwise totally happy!

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