X25

I wanted to replace my rear fender liners, war-torn from my tire/clearance experiments, and I just realized that the new LR liner has a vent to aid transmission cooler! The part number I have (23208844) seems to be for convertible models. Perhaps that's why it has these vents; it's identical otherwise.

Part numbers(see post #3)
LR: 23208844



The one at the bottom is the original fender liner.



The inside of fender with the liner removed.


The new fender liner, installed.


You can see the transmission cooler core from the bottom vent. I cut the plastic quarter panel ducting a bit more to let more air hit it directly.


I will get to try it this weekend (5/19) at the track. Some suggested that it might make it worse due to turbulence, but the air is not only let in, it's also directional. I have high hopes that it would help. In the worst case, I can always duct tape it. I might also test with/without tape, if I get to have time to test.

AKKutz

Could you post the part number of the LR you received?

X25

Thanks for the reminder, I was planning to post part numbers, but then I forgot:

Part numbers:
LR: 23208844
RR: 23208845

Edit: Below is their (Trunkmonkey) original reply to my part number query:
Now I wonder if I have those vents merely since I've ordered the convertible part? I'm not sure why I went with that part number when I ordered. I'm glad I did, though : ) It'd be great if someone with a 2018 Z51 or GS coupe checks if his/her car has these vents...

Poor-sha

Convertibles don't have the top fender vents that route air to the trans cooler so instead they have to vent the wheel well to get air in. The coupe fender liners don't have the vents so that air will flow from the top fender scoops through the cooler. If you have air flowing in from both sides of the trans cooler you will end up with less air flow through the cooler and less cooling.

When i was having issue with my Z06 trans puking trans fluid on track one thing I had to do was replace the rear fender liner. Mine had also worn through with tire rub and GM felt that could be causing the issue.

X25

Very possible; thanks for chiming in. I'll be at the track for two days, this weekend, and will get to check on the temps. If it overheats all in a sudden, I'll have my tape ready to test it out : ) I'd not be surprised if it helps, too; we'll see.

Avanti

Amazing engineering... flow air directly over a cooler and it works better! I wonder what they get paid?

X25

I tried the setup during the weekend:
Looks like it worked! I usually get into the red in about 45 minutes. This time it stayed right below it, so looks like it might have had about 20 degrees F of a good impact. I'll take whatever gain : )
In one of those days, I'm not busy working on tires, I might do back-to back sessions with duct tape covering the vents in one of them to compare.
Of course, it'd be nice if someone else also tries it and monitors the impact.

bsedwebt

Any further updates on this mod? I was thinking I could cut slits in my current splash shields even larger than the ones provided on these and get better air flow. My concern would be rocks hitting the cooler.

X25

I wanted to wait until I do an A/B testing by covering the inlet during the same day, but this is what I reported in my build thread:
I'd love to see others also give it a shot and see if it makes a good impact. The difference is not huge, but as I've said, any gain is welcome : )

Regarding the idea of modifying the opening, I'd indeed be concerned about letting in foreign materials. You can work more on making the inside ducting block it less, which would definitely help.