6MT BRZ, 6AT FR-S Dyno Comparison - Page 2 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

serialk11r · 06-08-2012, 02:41 AM

Interesting that there's a noticable AFR difference...or not?

carbonBLUE · 06-08-2012, 02:51 AM

Quote:

Originally Posted by serialk11r

Interesting that there's a noticable AFR difference...or not?

to me it looks like could make more power if my AFR matched feedbag, i think AFR and timing were modified on the auto in the last 1000 rpms the preserve the engine and transmission, who knows all i got are theories

OrbitalEllipses · 06-08-2012, 03:39 AM

Quote:

Originally Posted by Dimman

I don't have a super solid understanding of the guts of an auto. But I do know they are full of fluid, and even locked I imagine that stuff is spinning in the fluid. And friction has some exponential relation with speed. So it's not a big surprise that it holds it own at lower rpm but quickly dies past 6k. Depending on what the trans was originally from it is probably spinning faster than called for in the original design was intended (outside its design efficiency range).

The problem isn't the guts, it's the torque converter. A planetary gearset as found in automatic is actually really nifty. The torque converter is what makes a traditional automatic sucky.

Dimman · 06-08-2012, 03:50 AM

Quote:

Originally Posted by OrbitalEllipses

The problem isn't the guts, it's the torque converter. A planetary gearset as found in automatic is actually really nifty. The torque converter is what makes a traditional automatic sucky.

I am including that in the 'guts'. Even when locked the two fan like halves on the converter still have to spin in fluid correct?

OrbitalEllipses · 06-08-2012, 03:57 AM

Quote:

Originally Posted by Dimman

I am including that in the 'guts'. Even when locked the two fan like halves on the converter still have to spin in fluid correct?

From what I understand, yes. The lockup however reduces efficiency loss to the point where it's purely mechanical; loss is no longer resultant from fluid motion. My grasp of automatic transmissions is limited, but made an effort to learn about them some years ago when investigating the 4EAT in my WRX.

carbonBLUE · 06-08-2012, 05:49 PM

Bump

Kevin@COBB · 06-08-2012, 05:57 PM

glad i could help you guys out last night!

huma · 06-08-2012, 07:21 PM

The auto is pretty good for it to have such a small variance from the manual. I was tempted to purchase an auto from how good it felt during my test drive, but opted for manual because I like being in total control and miss driving manual.

Jordo! · 06-08-2012, 11:57 PM

Actually -- I hadn't noticed that. The richer AFR is almost definitely killing the power on the AT.

For a fully locking trans, there should be a negligible difference between the MT and AT locked in gear on a dyno.

I'm not sure why it's running richer, but that is definitely contributing.

Expect closer dynos with the same tune.

carbonBLUE · 06-08-2012, 11:59 PM

Quote:

Originally Posted by Jordo!

Actually -- I hadn't noticed that. The richer AFR is almost definitely killing the power on the AT.

For a fully locking trans, there should be a negligible difference between the MT and AT locked in gear on a dyno.

I'm not sure why it's running richer, but that is definitely contributing.

Yeah but one @feedbag is broken in and if I could lean the mixture out we should still have avout the same power, time will tell...

there are still alot of unknowns still... :/

Symbiont · 06-09-2012, 03:50 AM

Quote:

Originally Posted by Kevin@COBB

glad i could help you guys out last night!

Is Cobb planning on doing any tuning for the BRZ?

feedbag · 06-09-2012, 01:13 PM

Quote:

Originally Posted by Symbiont

Is Cobb planning on doing any tuning for the BRZ?

They have one at their research and development center in Austin, other than that I don't know what they have planned for it.

Jordo! · 06-09-2012, 06:57 PM

By same "tune", although I also mean aftermarket tuning, I really just meant "running the same tune" including the factory values -- I suspect the ECU was reading off of a different set of load cells in the fueling (and maybe timing) map as compared to the MT for whatever reason.

But -- more to the point, I mean that I predict a MT and AT running the same AFR and timing should be closer in the numbers they put down.

Was the AFR that rich for all pulls?

carbonBLUE · 06-09-2012, 10:49 PM

Quote:

Originally Posted by Jordo!

By same "tune", although I also mean aftermarket tuning, I really just meant "running the same tune" including the factory values -- I suspect the ECU was reading off of a different set of load cells in the fueling (and maybe timing) map as compared to the MT for whatever reason.

But -- more to the point, I mean that I predict a MT and AT running the same AFR and timing should be closer in the numbers they put down.

Was the AFR that rich for all pulls?

yes, the AFR almost is a whole difference of 1, thats a lot!

06-08-2012, 05:49 PM	#20
carbonBLUE Reverse Burnouts Join Date: Oct 2011 Drives: 2013 Argento FRS Location: dallas!!! Posts: 2,894 Thanks: 707 Thanked 1,257 Times in 592 Posts Mentioned: 30 Post(s) Tagged: 1 Thread(s)	Bump __________________ 2000 Carbon Blue Toyota Celica GTS 152000 miles (wont forget you) 2013 Argento Scion FR-S 2011 Infiniti G37x

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06-08-2012, 05:57 PM	#21
Kevin@COBB Member Join Date: Jun 2012 Drives: Subaru Location: Plano, TX Posts: 11 Thanks: 0 Thanked 2 Times in 1 Post Mentioned: 1 Post(s) Tagged: 0 Thread(s)	glad i could help you guys out last night!

06-08-2012, 07:21 PM	#22
huma Senior Member Join Date: May 2012 Drives: ITR Location: Houston Posts: 108 Thanks: 15 Thanked 12 Times in 9 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	The auto is pretty good for it to have such a small variance from the manual. I was tempted to purchase an auto from how good it felt during my test drive, but opted for manual because I like being in total control and miss driving manual.

06-08-2012, 11:57 PM	#23
Jordo! Enjoy it, destroy it. Join Date: Oct 2009 Drives: Datsun Racing Hen Location: Blank Generation Posts: 820 Thanks: 6 Thanked 61 Times in 48 Posts Mentioned: 1 Post(s) Tagged: 2 Thread(s)	Actually -- I hadn't noticed that. The richer AFR is almost definitely killing the power on the AT. For a fully locking trans, there should be a negligible difference between the MT and AT locked in gear on a dyno. I'm not sure why it's running richer, but that is definitely contributing. Expect closer dynos with the same tune.

06-09-2012, 06:57 PM	#27
Jordo! Enjoy it, destroy it. Join Date: Oct 2009 Drives: Datsun Racing Hen Location: Blank Generation Posts: 820 Thanks: 6 Thanked 61 Times in 48 Posts Mentioned: 1 Post(s) Tagged: 2 Thread(s)	By same "tune", although I also mean aftermarket tuning, I really just meant "running the same tune" including the factory values -- I suspect the ECU was reading off of a different set of load cells in the fueling (and maybe timing) map as compared to the MT for whatever reason. But -- more to the point, I mean that I predict a MT and AT running the same AFR and timing should be closer in the numbers they put down. Was the AFR that rich for all pulls?

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