So I have a set of Krio's funtional hood louvers. Now there's another manufacturer making them, and various people have fabbed their own over the years. No double I bought them for the appearance/cool factor, but I'm curious as to how airflow effect underhood temps.

I KNOW you can see heat escaping through them while parked and idling. How much difference it makes I don't know, but of course this would only effect sitting in traffic if your car runs hot!

If I'm not mistaken, your average car produces low pressure across the hood at speed, right? ...and underhood you have higher pressure, which at higher speed can actually cause lift, right? Isn't this the reason for splitters and flat underbody panels? -if so, I'd imagine the louvers would allow air to be pulled out of the engine bay, significantly dropping underhood temps.

I may try to actually test this next spring, but in the meantime, I'm just curious what your thoughts are???

 

You asked for thoughts , so here's mine ;

If you are having overheating problems , something else is wrong other than there not being a hole in the hood to let the "excess" heat out (and rainwater IN) . And if you aren't having overheating problems , well , I guess it's a non issue . If you want to do all that work for the perceived "cool factor" because you like the look of louvers well by all means go for it , just don't expect this to be any kinds of "performance modification" like the guys who think a 6" hood scoop is gonna make the car go faster ....

 

Well I just removed the hood vent covers on my fourth Gen Z28 this summer and believe it reduced engine temps as shown on the temp gauge though summer temps had cooled off by 10 degrees by the time I took the covers out. Highway cruise temp was at least 220 while outside temp was 115 here in Vegas. And AC in the car was barely enough to drive with.
After removing the covers (and just leaving open holes) engine temps stayed below 210 and the AC was much, much better. But by that time highway temps were down to 105 degrees so I have to wait to next season again for better comparison.

I do plan to bend up some louver to intrain hot air out of the engine compartment but it's not on the top of my to-do list now.

IMHO I try to manage airflow to and over the louver to entrain the hot air out. The 4th Gen has a steep approach to the windshield which helps this. Regardless I want a louver angle between 15 and 45 degrees. FYI the force of the dynamic air pressure at 100mph is about 1/2psi which is less than 19 inches water column/pressure so a water manometer would be needed to measure it (yes I have done the math for this before).

Hope this helps.

 

Orange Bird, I think you completely missed my point, although that may be my fault. Let me rephrase my question: Do you think the louvers actually affect underhood temperatures? I simply ask because I was watching a build on Youtube where they put functional louvers/heat extractors in the hood, and it just got me thinking, under what conditions, and what kind of car is it worthwhile?

I do, and I did.

My car runs cool as a cucumber, and the louvers, worth it or not, are functional, and I'll take that any day over plastic decorations on the hood.

 

As to the performance question yea I did misunderstand you , I thought you were looking for a performance gain by having the engine a few degrees cooler . Anyway yes I do believe the underhood temp will be cooler with the vents I just don't think there will be a noticeable difference in power with the cooler underhood temp , provided the cooling system is doing it's job and keeping the engine at it's optimum temp .

And Hell yea , done right I think the louvers look far better than the flat hood also , no doubt here whatsoever .

 

Yeah....I did write "performance" in the question. I didn't mean it like automotive performance...I simply meant like "how" do they perform. Even a significant drop doesn't really help me at all per se....I just was curious if they really dropped temps.