6MT BRZ, 6AT FR-S Dyno Comparison

[feedbag]

Tonight at COBB Tuning Plano's First Thursday meetup I met up with @carbonBLUE and @5hairpins, owners of Argento and Asphalt FR-S's respectively.

Towards the end of the night they wanted to put our cars in the dyno, myself and @carbonBLUE accepted. A far as I know this is the first time a 6AT and a 6MT have been put on the same dyno with the same environmental conditions just 20 minutes apart from each other.

Thanks @Kevin@COBB for putting together such an awesome event.









Here are the results: (kept you waiting )

[mrha]

Wow 1100 for 11 less actual horsepower

[Lytheum]

how many miles on both cars?

[Guff]

This is awesome!!

[feedbag]

Originally Posted by Lytheum

how many miles on both cars?

500 on BRZ (yeah yeah, break-in, I've been loading the engine well and let it warm up for a good amount of time), 1700 on FR-S, both running 93 octane.

[carbonBLUE]

Needs front page mod!

[Dimman]

Been waiting for this for a while.

Thanks a lot!

[Jordo!]

Wow -- that's a bummer. I'm honestly surprised. How many pulls for each car? Intake temps?

I'd wait for some more data to confirm that big of a difference. Also, the difference might be inflated given that dyno reading is pretty low relative to dynojet numbers.

Well, one more reason for boost.

[feedbag]

Originally Posted by Jordo!

How many pulls for each car? Intake temps?

Three pulls, outside temperature was 85 though it could be lower than that due to air flowing from the air conditioned garage.

[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).

[ashtray]

Very interesting how the FRS tails off so early!

And frustrating for me to see graphically how my break in rpms are all in that valley. I spend most of my driving between 2500-4000 rpms, where torque is decreasing and hp is flat at best. Can't wait for 800 more miles and I'll finally be able to get past that valley and into the fun zone! (car is still pretty fun in that valley though)

[Indestruct]

Makes me glad I got the MT!!!

[exmayol]

Actually the difference is surprisingly minimal... especially for daily driving. While 10hp sounds like a lot the difference is only between 6K...7K range. How often does one drive revving that high?

[carbonBLUE]

Originally Posted by ashtray

Very interesting how the FRS tails off so early!

And frustrating for me to see graphically how my break in rpms are all in that valley. I spend most of my driving between 2500-4000 rpms, where torque is decreasing and hp is flat at best. Can't wait for 800 more miles and I'll finally be able to get past that valley and into the fun zone! (car is still pretty fun in that valley though)

yeah but my engine also runs richer but still produces good numbers!
imagine if i ran at the same Air Fuel Ratios as @feedbag, still interested in tuning solutions and whats possible

[serialk11r]

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

[carbonBLUE]

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]

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]

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]

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]

Bump

[Kevin@COBB]

glad i could help you guys out last night!

[huma]

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.