Why or How Does the Air Dam Effect Work?
- Thread starter Sandpiper
- Start date
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Can someone explain how such a blunt front end on the 4Runner helps it get better mileage? Or does it? My 4Runner spends most its time on the 4 lane highway and I thought I would remove some of the plastic shielding so I get to the front tow hooks. I am pretty sure I have seen this on Indy cars. Thanks.
mikey's2010SR5
New member
You started another thread about the exact same thing? Why not ask the question in the other thread?
Jesse1983
5th Gen Moderator
1engineer
Moderator
Sure, I'll explain it. You are assuming that in order for an object to be aerodynamically efficient, it has to be pretty with big sloping graceful lines and such. This is sort of true, but only to a point. The teardrop shape is the most aerodynamic, with the "big end" forward. This shape allows for the greatest laminar flow. Now, getting back to the 4runner. I did not design this vehicle nor do I know its coefficient of drag but I would bet it is not the most efficient in toyota's lineup. What it DOES have though is little tricks like the front spoiler, the side rocker panels and the rear valance that, put all together, can add up and boost the efficiency of the vehicle while maintaining its tough image. Those lower components I just mentioned don't make the 4Runner's more slippery by changing the effective cross section of the vehicle, it makes the vehicle more efficient by CHANNELING the air around the vehicle. Take the front lower spoiler: Yes it's blunt, but it is also only one piece. When you are going down the road at 70 mph the vehicle is punching a hole through the air and the front spoiler is doing it's job by hitting the air and moving it around the vehicle. Without the front spoiler, there are several items underneath the vehicle (such as axles, transmission, exhaust, springs etc) that will each have to "punch" a hole through the air and each of those components will cause as much or more drag than the front spoiler. This is why a group of 6 cars in NASCAR all lined up in a draft can go faster than one car. That first car is acting like a spoiler and the vehicles behind are helping push the car through the air. Most of the time people get graceful confused with aerodynamic. Think of the stealth fighter or a battleship. They are aerodynamically sound but they sure aren't graceful. And last but not least there is the image the vehicle has to project. It has no bearing on efficiency but if the vehicle does not project the correct image no one will buy it. Imagine a 4Runner shaped like a teardrop or a Farrari shaped like a brick. Hope this helps. I kept the tech talk to a minimum.
scanny
Senior Member
Thanks, I think I was referring to the tow hooks covers too: ) I think I need to take a good look under the truck.
Sorry to bump an old thread, but does anyone have any current input on removing all that plastic junk? Would I really notice any difference in aerodynamics, MPG or keeping parts "cooler" from the airflow?
I want to remove the air dam and spoiler but if there is good reason to keep it I'm trying to be open minded.
I want to remove the air dam and spoiler but if there is good reason to keep it I'm trying to be open minded.
Salvo Jimmy
Member
Modern US subs with the Albacore hull design are a good example of the teardrop concept and more graceful in the lines. Blimps also come to mind.
Simpleman74
New member
6 years later someone finally agrees with [MENTION=66316]1engineer[/MENTION]
read the 2nd post in this thread from 2011......:wacko:
Jhalko
New member
Just take it off. I'm sure it makes some tiny difference, but I had mine on for a couple years, then off for the last two+ and once you mod the truck I doubt that air dam does anything for mileage. AT tires likley have a greater effect.
There are air "channels" that seem to go towards the front brakes likely for cooling, but both Antman and I got 90k out of our OE brakes without it.
Toffees
Member
There's probably much more reason for Toyota to install these items to meet CAFE calculations than there is reason for you to keep them on. But there will be effects (both increased drag and potentially less cooling airflow) for you if you remove them. But it's not like people who put on an aftermarket front bumper find that their rigs break down due to less aerodynamic properties of the new setup.
Ron4RNevada
New member
Mine have been off for over two years - only affect is a bit more grab to the front tires = affects steering the MTs.
