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What are these black plastic flaps under the front bumper?
Hello everyone, long time lurker, will be picking up this corvette soon and had this question. What is this? I will be adding a splitter and don’t want these things poking out??
Those pieces enhance aerodynamic performance. The center piece is only on the base Stingray. The side pieces remain on the Z51, which move air around the front wheels for better aero performance.
Prior to release of the first 2014s, GM discovered that the center piece compromised the effectiveness of the extra cooling components (front and rear brake cooling ducts, trannie, and diff coolers, etc.) installed on Z51s, so it was removed from Z51 production models just prior to release.
OP, of the above posts, this is the only accurate explanation and is mostly correct but some Grand Sports also have center air dams. I’ll add some additional info, including what I show is the real reason why some C7s don’t have a center air dam. Perhaps of interest for whoever wants the correct terminology when friends ask, “What are those ‘funny things’ sticking out from under your car?”
DETAILS
First they are called air dams. The GM chief aerodynamicist says on a Chevy Volt, that has one as large as the Vette, they increase the gas mileage at highway speeds! If you look carefully you will see many cars have them usually along the bottom front of the car. It reduces the amount of air going under the car and pushes it around the sides. Air under the car must pass around suspension parts, engine etc and is turbulent, increasing what is called drag. That takes hp to overcome, more as you go faster. That requires more gas!
Turbulence is also created around the front wheels before air flows smoothly over the body. Again at highway speeds that creates more drag (drag is proportional to speed squared.)
FOR GEARHEADS!
Now the $64 question. Why do some C7s, like most cars with air dams, not have a center air dam? It is not only the Z51 that only has side air dams but also the Z06 AND Grand Sports with the Stage 2 aero package (like mine) and the Z07 performance package that don’t have one. However the base Grand Sport does.
This is a long explanation and I realize many will just role their eyes or not read!
For those continuing, this will also explain the other often misunderstood function of air dams! It is one sometimes used by folks who remove them because they don’t like the looks! Air dams at high speed create downforce or in most cars (and C7s) reduce lift as the Vette and most car shapes look lilke and airplane wing and cause the car to “lift” at high speeds.
My history for following this issue: I had a C6 Z51 with a three section air dam, one on each side, deflecting air around the front tires and one in the center like the base C7 (and some other C7’s.) I had one of the early C7 Z51s, built in September 2013. It was shipped with all three air dams to the dealers who were told Not to add the center section. No formal explanation! However some speculation about why they were not there from some GM representatives But not Tadge, the Chief Corvette Chief Engineer or the Chief GM Aerodynamicist! In fact, in a 2013 published article the chief aerodynamicist said air dams reduce drag at highway speeds and reduce lift at high speeds! He said the center air dam was removed from the Z51 for aerodynamic reasons, but no further explanation. Some GM representatives said it was removed after last minute testing and it helped improve rear brake cooling! Sounded like “marketing speak” to me and did not match what was said by the chief aerodynamicist! Cooling may have been a factor but IMO was not the real reason. For those accepting the early marketing speak of rear brake or heat exchanger cooling, the base Grand Sport has rear coolers and high performance brakes AND a center air dam!
The mystery continued for me until the Tadge stated in a video why the Z06 did not have a center air dam when it was introduced! That was reinforced in a recent post Tadge made in this forum about C7 models aero data, drag and lift! He said GM has very critical criteria for front and rear downforce to assure slight understeer at high speed. It reinforced what I knew from experiance having added a large air dam (and rear spoiler) to my 260Z years before to counter high speed lift and owning a modified Corvair!
Tadge said at high speeds the center air dam in the Z06 was providing excess downforce and causing more downforce than desired. It was providing oversteer when slight understeer is preferred at high speeds. Now those of us with Corvairs and early Porsches knew all about oversteer. If going too fast in a high speed corner the rear would slide out in the direction of the turn. An understeer car will just not turn enough (also called plowing) and the safe natural reaction is to turn the wheel more. Just the opposite is required with an oversteer car, you turn into the skid! Not a natural reaction and when it occurs it requires very quick action to counter the slide or you’ll be off the road, rear first! Ralph Nader made a name for himself writing an inaccurate book about the Corvair and no doubt GM did not want to give him info to write another!
In the forum post Tadge said GM has very critical requirements to assure slight understeer at high speeds! Aerodynamics is Not intuitive! Just why some C7’s have center air dams, like the base and some Grand Sports, and not others, Chevy knows. Today computer simulation programs come very close to wind tunnel tests in predicting aero effects. GM no doubt has run the different models through these programs as well as conducted many expensive wind tunnel tests. Of interest, in his forum post Tadge shows only the Stage 3 aero pacakage Z06 and the Z07 provided significant downforce at high speeds, the other aero elements like splitters, side skirts (to some degree) and rear spoilers are mostly countering lift! Note is was just published that with its aero elements including a high wing the ZR1 provides 900 pounds of downforce. Also, side air dams mostly just reduce drag, which is why they are on all C7’s.
When I installed my splitter I kept them on and you can't notice them at all unless you are looking under the car. The splitter pretty much hides it.
They're air deflectors. They're supposed to provide additional brake cooling and also serve as helping to let you know if you may scrape something really important. A lot of people take them off without adverse effects. If you plan on tracking it, you may want to keep it.
St. Jude Donor '05-'06-'07-'08-'09, '14-'15-'16-'17-'18
IIRC, Corvettes used to have that air dam in 3 sections all the way across underneath the car but for the C7 Z51, engineers saw that without the longer middle section, airflow/cooling was enhanced so they went to production without that section.
Those pieces enhance aerodynamic performance. The center piece is only on the base Stingray. The side pieces remain on the Z51, which move air around the front wheels for better aero performance.
Prior to release of the first 2014s, GM discovered that the center piece compromised the effectiveness of the extra cooling components (front and rear brake cooling ducts, trannie, and diff coolers, etc.) installed on Z51s, so it was removed from Z51 production models just prior to release.
My 2017 non-Z51 Stingray's got em:
Maybe because it's got the FE2, code option of; MSRC/Z51RearDeckSpoiler - the look alike Z51 exterior cosmetics? I dunno.
Those pieces enhance aerodynamic performance. The center piece is only on the base Stingray. The side pieces remain on the Z51, which move air around the front wheels for better aero performance.
Prior to release of the first 2014s, GM discovered that the center piece compromised the effectiveness of the extra cooling components (front and rear brake cooling ducts, trannie, and diff coolers, etc.) installed on Z51s, so it was removed from Z51 production models just prior to release.
OP, of the above posts, this is the only accurate explanation and is mostly correct but some Grand Sports also have center air dams. I’ll add some additional info, including what I show is the real reason why some C7s don’t have a center air dam. Perhaps of interest for whoever wants the correct terminology when friends ask, “What are those ‘funny things’ sticking out from under your car?”
DETAILS
First they are called air dams. The GM chief aerodynamicist says on a Chevy Volt, that has one as large as the Vette, they increase the gas mileage at highway speeds! If you look carefully you will see many cars have them usually along the bottom front of the car. It reduces the amount of air going under the car and pushes it around the sides. Air under the car must pass around suspension parts, engine etc and is turbulent, increasing what is called drag. That takes hp to overcome, more as you go faster. That requires more gas!
Turbulence is also created around the front wheels before air flows smoothly over the body. Again at highway speeds that creates more drag (drag is proportional to speed squared.)
FOR GEARHEADS!
Now the $64 question. Why do some C7s, like most cars with air dams, not have a center air dam? It is not only the Z51 that only has side air dams but also the Z06 AND Grand Sports with the Stage 2 aero package (like mine) and the Z07 performance package that don’t have one. However the base Grand Sport does.
This is a long explanation and I realize many will just role their eyes or not read!
For those continuing, this will also explain the other often misunderstood function of air dams! It is one sometimes used by folks who remove them because they don’t like the looks! Air dams at high speed create downforce or in most cars (and C7s) reduce lift as the Vette and most car shapes look lilke and airplane wing and cause the car to “lift” at high speeds.
My history for following this issue: I had a C6 Z51 with a three section air dam, one on each side, deflecting air around the front tires and one in the center like the base C7 (and some other C7’s.) I had one of the early C7 Z51s, built in September 2013. It was shipped with all three air dams to the dealers who were told Not to add the center section. No formal explanation! However some speculation about why they were not there from some GM representatives But not Tadge, the Chief Corvette Chief Engineer or the Chief GM Aerodynamicist! In fact, in a 2013 published article the chief aerodynamicist said air dams reduce drag at highway speeds and reduce lift at high speeds! He said the center air dam was removed from the Z51 for aerodynamic reasons, but no further explanation. Some GM representatives said it was removed after last minute testing and it helped improve rear brake cooling! Sounded like “marketing speak” to me and did not match what was said by the chief aerodynamicist! Cooling may have been a factor but IMO was not the real reason. For those accepting the early marketing speak of rear brake or heat exchanger cooling, the base Grand Sport has rear coolers and high performance brakes AND a center air dam!
The mystery continued for me until the Tadge stated in a video why the Z06 did not have a center air dam when it was introduced! That was reinforced in a recent post Tadge made in this forum about C7 models aero data, drag and lift! He said GM has very critical criteria for front and rear downforce to assure slight understeer at high speed. It reinforced what I knew from experiance having added a large air dam (and rear spoiler) to my 260Z years before to counter high speed lift and owning a modified Corvair!
Tadge said at high speeds the center air dam in the Z06 was providing excess downforce and causing more downforce than desired. It was providing oversteer when slight understeer is preferred at high speeds. Now those of us with Corvairs and early Porsches knew all about oversteer. If going too fast in a high speed corner the rear would slide out in the direction of the turn. An understeer car will just not turn enough (also called plowing) and the safe natural reaction is to turn the wheel more. Just the opposite is required with an oversteer car, you turn into the skid! Not a natural reaction and when it occurs it requires very quick action to counter the slide or you’ll be off the road, rear first! Ralph Nader made a name for himself writing an inaccurate book about the Corvair and no doubt GM did not want to give him info to write another!
In the forum post Tadge said GM has very critical requirements to assure slight understeer at high speeds! Aerodynamics is Not intuitive! Just why some C7’s have center air dams, like the base and some Grand Sports, and not others, Chevy knows. Today computer simulation programs come very close to wind tunnel tests in predicting aero effects. GM no doubt has run the different models through these programs as well as conducted many expensive wind tunnel tests. Of interest, in his forum post Tadge shows only the Stage 3 aero pacakage Z06 and the Z07 provided significant downforce at high speeds, the other aero elements like splitters, side skirts (to some degree) and rear spoilers are mostly countering lift! Note is was just published that with its aero elements including a high wing the ZR1 provides 900 pounds of downforce. Also, side air dams mostly just reduce drag, which is why they are on all C7’s.
My 2017 non-Z51 Stingray's got em:
Maybe because it's got the FE2, code option of; MSRC/Z51RearDeckSpoiler - the look alike Z51 exterior cosmetics? I dunno.
All C7s have the two small side air dams in front of the wheels. The question was about the center piece, which is on some cars and not others.
Base C7s do have both side and center pieces, Z51s do not have the center air dam. To make matters more confusing, some widebodys do and some don't have the center piece. The choice of which model does or does not have the center piece was apparently the result of aerodynamic testing along w/ cooling issues.
Not clear to me why a base GS (presumably that means 1LT) would have the center air dam and the 2LT and 3LT don’t, when the differences are conform features within the cabin. Mechanically it’s the same car.
1LT, 2LT, or 3LT packages have nothing to do with it. While all cars within a particular model may be mechanically very similar, they are not identical, and there are important differences.
For example, the Z51 comes standard (1,2, or 3LT) with a much more aggressive spoiler than the base car creating a different aero signature. Z51 (1,2, or 3LT) also have front and rear brake cooling ducts, as well as trannie, and differential coolers not on the base car at any level of trim. Both the GS and Z06 also have different aero packages available within those models.
All of these cooling and aero "tweaks" make a difference and why GM puts the center piece on some cars and not others.
Not clear to me why a base GS (presumably that means 1LT) would have the center air dam and the 2LT and 3LT don’t, when the differences are conform features within the cabin. Mechanically it’s the same car.
According to a table posted a few weeks ago, it’s not a 1LT, 2LT or 3 LT issue its the base Grand Sport has a center air dam and those with the Stage 2 aero Option, as mine, or the Z07 performance package do not and the ones with just the “poverty” splitter and 3/4 side skirts, do!
A poster provided the info published by GM to help dealers know which model C7 has what options. Explained why some with Grand Sports had center air dams and some did not!
Have to ask Tadge why for sure but read my long post #12 it may help! But only Chevy could say for sure!
Found the table, see below. The center air dam is called a center deflector in the table. The CFV/Z part numbers are the two Stage 2 aero options. Both are carbon fiber, one painted carbon flash the other visible carbon fiber. That includes the splitter, full length side skirts and carbon flash painted rear spoiler wing extensions.
I would guess that stage 2 aero and ZO7 both have a larger "chin spoiler" vs. poverty splitter which I would guess has much less of am aero effect than stage 2 and 3 which are purpose built aero bits.
I assume that this difference is why they would add the center piece to the poverty splitter as it lacks something vs the actual aero packages.
The only problem with that theory is that the Z51 has no OEM chin spoiler, and no center piece. That's why I think cooling is also part of the decision equation.
The only problem with that theory is that the Z51 has no OEM chin spoiler, and no center piece. That's why I think cooling is also part of the decision equation.
The chin spoiler changes the downforce and therefore the aerodynamic profile.
Z51s and cars with the Z07 package probably do not cool as well versus the cars without those features. I'd guess that downforce has a big part to play, as well as each models cooling needs.
11-25-2017, 11:11 PM
What are these black plastic flaps under the front bumper?
OP, of the above posts, this is the only accurate explanation and is mostly correct but some Grand Sports also have center air dams. I’ll add some additional info, including what I show is the real reason why some C7s don’t have a center air dam. Perhaps of interest for whoever wants the correct terminology when friends ask, “What are those ‘funny things’ sticking out from under your car?” 
