Snorman

There is obviously much concern about how GM will control tranny temps on the C7 Z for those that are outfitted with the A8. Tadge has stated that they are trying to maximize cooling.
Z51 transmission cooler:


Z06 transmission cooler:

Note that this one appears to have the same fan setup as the Z51, and obviously is a larger core.

Apparently, the same core with a different and larger fan setup:

Not sure if this is the same cutaway car and they changed out the fan or if it is a second car.

S.

NSC5

Snorman,

Interesting photo layout, thanks for posting! The A8 cooler is clearly larger and the different fan setups are interesting. I presume the last photo is probably the A8 specific fan or otherwise maybe some testing is looking at a fan dominant setup (the last photo) which would provide more cooling at lower speed but I wonder if the smaller Z51 fan actually allows more air flow at high speed since much of the cooler can breath freely without being blocked by the shroud.

In any case it is good to see they are addressing this because it will be embarrassing if the transmission goes into protective "limp mode" too quickly in a track oriented platform.

Snorman

I'm curious too. The bigger fan/shroud appears to more fully cover the core. I hope that's the one they'll be using, lol.
S.

MitchAlsup

With 1.36X more power (620/455 = 1.36..), it needs 1.36X bigger radiators just to keep the same temps on track as a Z51 on track.

NSC5

Well it really depends upon how efficiently the A8 transfers power under varying conditions. With manual transmissions heat buildup is mostly resulting from frictional loss in the gears, bearings, etc. and in heavy use even the rather efficient standard needs a cooler. With automatics the biggest contributor to heat is usually the torque converter and the fluid shear that occurs resulting in converter out fluid temperature that will spike to far hotter temperature than the typically displayed sump temperature which is a better average measure (and less frightening to the owner). Clutch to clutch architecture like the A6 and A8 will have some heat generation in the clutch packs during shifts and more frequent shifting generates a lot of heat from this source. The hydraulic pump(s) will generate some heat. Add to this the same friction generated gear heat as the standard transmission and there can be a lot of heat to manage.

One way to minimize heat is to reduce the amount of time the converter clutch is unlocked. Tight control of the clutch packs used for gear selection along with sufficient pressure will minimize heat there. Avoiding fluid pickup problems with the resulting aeration of fluid is critical. Hopefully the A8 will reduce heat generated in addition to having better cooling. Once the car goes into production it won't take long to find out how hard it can be pushed.

dvandentop

considering i was maxing out the z51 tranny temps guage in performance mode at spring mt and 300 degrees last week in 75 degree weather the z is gonna need a beast of a cooler.

3 Z06ZR1

Assume that was an A6! Heat could/will be an issue!

3 Z06ZR1

Not that easy with F/I!

dvandentop

negative all m7 trannys at spring mountain

Snorman

M7's have tranny fluid temp gauges in the DIC?
S.

H2LS3

This is interesting, thanks for posting. I have also noticed they changed the design of the scoop/vent on top of the rear deck to grab more air too.

SBC_and_a_stick

I hope that A8 is an oven and that GM builds heavy duty cooling. Thanks for the pics, it does look like they are working on it. Keeping fingers crossed that all that will be transferred to the M7 making it an ice cold performer. If not, I presume it will be easy to buy and swap.

dvandentop

bottom right corner guage when in track mode and the 4 mini guages displayed in DIC is what i was told was tranny temp bar was maxed out at 300.

BOBSZ06

Yes, the last photo is of the cooler on the A8 tranny.

Snorman

So is the 2nd picture.


S.

ChucksZ06

Good info. I do not believe the stock c7z will be able to be run hard for more than about 10 minutes (on a demanding track) before the temps go up for engine and trans fluids to unacceptable levels. Hope I am wrong.

sam90lx

Trans, maybe....engine, I don't think so.

LT1xL82

If true, shame on GM. I hope that not to be the case. This concern is well known, both outside and inside GM. It's not rocket science. Engineer to reduce heat generated and engineer to dissipate what heat is generated. It can be done.

r1owner

I agree. This car is made to be track ready and as such should be able to do 30 minute sessions in 100 degree days without any problems.

If the car can't do this then its a failure.

Snorman

I think people are jumping to conclusions very prematurely.
S.