Air dam - good or bad ?

[krash133]

A basic aero explanation of racecar aero is:

Air dam/splitter = bad for aero efficiency/good for downforce(air gets force over the car, not allowed to go under, and creates less pressure under car = more downforce

Flat bottom - good for aero efficiency/good for downforce(air moves faster under car, creates less pressure = more downforce

Rear diffuser - good for aero efficiency/ good for downforce(air is sped-up/made into a lower pressure area at the tail end of the car by increasing the volume under the car, and making flow reattach at the back end of the car better

One thing that might help your aero efficiency at the front end of the car is to block off or seal up any places where the air gets into the front end of the car(Radiator, brake duct holes, and even body seams) to help air from "leaking" into the hood and inner parts of the car and creating buildup of flow and stagnant flow in-front and through the car......Nascar teams tape over their radiators in qualifying(only 2 laps, engine doesn't need the cooling of the radiator) for 2 reasons:
1. Not slow down the car as much by air going into and through the radiator
2. Get that air going over the car and creating more downforce

Taping up a radiator is possible on a street car, but how much to tape up as well as other factors are needed to be known to not overheat the car: your car, your climate, your particular driving speed, and your driving style will all affect how much cooling you need.

[theholycow]

Hypermilers do a lot of grille blocking, not with tape but with more permanent materials. Because we generally do not use anywhere near the full capacity of our engines we are able to block a lot without overheating. In my vehicles I'm able to block 100%, the ambient air and the fan do the job well enough (though perhaps extra fan running is less efficient than allowing some air through). In my truck I removed my grille block, though, because my transmission cooler was unable to do its job and the ATF was getting too warm.

[Jay2TheRescue]

If you redo your turck look at how I did my truck's block. I paid particular attention to the location of the tranny and oil coolers in locating the vent holes.

-Jay

[krash133]

Originally Posted by theholycow

Hypermilers do a lot of grille blocking, not with tape but with more permanent materials. Because we generally do not use anywhere near the full capacity of our engines we are able to block a lot without overheating. In my vehicles I'm able to block 100%, the ambient air and the fan do the job well enough (though perhaps extra fan running is less efficient than allowing some air through). In my truck I removed my grille block, though, because my transmission cooler was unable to do its job and the ATF was getting too warm.

Good info to know, I think how much to block off and where all depends on the particular car and place. I'll bet my current CRX could do fine with 80% or more of the grill blocked off even in city driving in the winter here in AZ, but in the summer in the middle of the day it gets to 120F, I'll bet I'd have to at least make it 50% or less blocked.
I used to have a 91 nissan 240sx that would start to overheat if I sat stationary for too long, and its fans were all working properly it just had a small radiator, a small opening, and a lot of heat to dissipate.

Another thought: Coolant additives like Water Wetter would also be ideal to include into the water system and help the efficiency of the radiator!