Are you talking about this one below?

It's nice but not really where needed the most. The Underside of the car has lots of openings. Where the top side is sealed. The car need the vent the most is the hood. The OEM design channels all the cool air that come in from grill out to the underside openings.

Also, you can cut baffles on the under panel to channel more cool air up, then buying expensive ARC aluminum under panel, 500 bucks, which is more for the looks.

However, if someone make a reasonable replica, like Richie did for ARC bar,
I may consider.

Richie, time for a new project, ARC replica under panel

 

Yes, that is the panel I mentioned. I believe, someone has begun to fab this, but dunno for sure. I am installing the ARC one on my G next week.

 

OK, Joker,

Here is a close up:

 

Update:

After a car wash,
a whole day of rain, check the vent, no water came in.

 

Interesting.

Perhaps in colder weather you will be able to see if lots of hot air is escaping or not. Have you measured in the inside temp before/after this mod?

 

Yes, I have being collecting data on that. I tied up a Thermometer in the Engine Bay next to Battery chamber. I log Engine bay temp. vs. out side Temp. to have a better control for logical conclusions.

I measure it after same 15 mile high way trip from work to home.

Before,
Out side 70F, Engine Bay 100F
Out side 90F, Engine Bay 120F
The Engine Bay T seems to be 30F higher than out side T. when
measured after just stopping the car.

After the Vent:
Outside 60, Inside 80.
I need more data when weather warms up a bit. However, the differntial
Inside vs. outside Temp. has dropped 10F. My Engine Bay is now 20F higher than outside rather than 30F higher as before. The single 2x5" Vent has lowered Engine Bay Temp. by 10F.

Another interesting finding, I found out that Engine bay Temp. rose another 20F After the car parked for two hours with hood closed & the heat stays for several more hour as there's no escape. This means that when out side is 100F, The Engine Bay will be 130F running & 150F when parked with hood closed for a while. Hot enough to be blamed for my Optima SLA battery premature death (It lasted only 1 yr in my car). SLA battery biggest weakness is low heat tolerance. SLA battery (such as Optima) can live only 6 month under 140F (60 C). Perhaps, people live in hot weather with SLA batteries should leave the hood open after parking in non air conditioned garage, or relocated it to the trunk or at least cover up the battery chamber with heat reflective tape.

This site has a lot of good info on SLA batteries:
http://www.stealth316.com/2-dynabatt.htm

 

A 10 degree drop sounds pretty good. I bet it compares well temp wise with that horrific hood with all the vent slats in it, except this one is a much cleaner job.

 

Thanks.

There's room to cut another one just like this,
I'll leave it to next summer if there's need.