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My GS is a 17 and it does have a center air dam in addition to the front splitter. There are two short air dams on either side near the front tires and one in the middle. Below is the microfiche and its part number 26.
I know that the air dams are not installed on the car until after the dealership takes delivery so I told the salesman that when my 2018 arrives, do not let a tech put on the air dam. I plan on lowering my C7 the same as my C6, and my air dam on the C6 scrapes every time I pull out of my driveway and it's super annoying. I realize it might be slightly risky but it's a risk I'm well aware of and still have made up my mind, the air dam is a no go for me.
Have you tried reaching inside the bumper cover and just use a new threaded clip?
That is what I did for the extra holes I had to drill to install my splitter.
I haven't tried that yet. Is it easy to reach behind there to place those clips? The plastic is still intact that the dam screwed into and my hand/arms are kind of big. Do you have a part number for the new threaded clip by chance?
I haven't tried that yet. Is it easy to reach behind there to place those clips? The plastic is still intact that the dam screwed into and my hand/arms are kind of big. Do you have a part number for the new threaded clip by chance?
I appreciate the help.
There is a large opening on each side behind the air dams. I ordered extra bumper cover screws and u-nuts online from clipsandfasteners.com (I used the u-nuts because the factory screws are an odd thread) http://www.clipsandfasteners.com/sea...p?Search=20339
Did it actually tear the clip out of the plastic support, or just pull the screw out?
The screws holding the air dam should be threaded into a metal clip. If the place where the clip attaches is broken, you may still be able to have the screw go all the way through the support, through a flat washer, and then the nut. You can see how I did that when mounting my splitter since there were no holes in the bumper for the leading edge of the splitter for clips to slide in to.
Here is one of the openings....
Arrow is extra flat washer under end of splitter to make it sit level and flush.
Hmm, strange! The Grand Sport, like the Z51 and Z06 should not have one!
Originally Posted by JerryU
^^^
I outlined the tech info about air dams in post #2. If you don’t like them then of coarse you can do as you wish, but suggest not justifying it by saying you don’t travel fast or race your car!
As mentioned In post #2, the Chevy Volt has an air dam (as do many cars) that is about as low as the Vette! Some Volt owners also complain about it scraping! As GM states, it’s there to improve gas mileage, by reducing air drag. Drag is a major user of gas at highway speeds. The splitter does not reduce drag significantly, it increases downforceat high speeds! It is not as low as the air dam, in fact several inches higher, FWIW. Under certain conditions it can scrap but the air dams scrape first!
TECH INFO WHY Z51, Grand Sport & Z06 Don’t Have A Center Air Dam
Perhaps not of interest to you but may be to others. I bought an early C7, Z51 (September 2013 build) and it did not come with a center air dam. It was supposed to have one, like my C6, Z51, but was removed at the last minute, we were told, after road testing. Lots, of speculation and what now appears to be “marketing speak” as to why for several years. The truth came out, IMO, from several ststemements by Tadge, the Corvette chief engineer!
The GM chief aerodynamicist had said in an article published in 2014 that the center air dam was removed for performance reasons at high speed but did not elaborate. He also stated in that article that air dams are effective at highway speeds to reduce drag and provide downforce at high speeds. Tadge, in a video re the Z06, when it was introduced, said the center air dam was causing too much downforce at high speeds creating slight oversteer where they prefer understeer at high speeds.
In a more recent post to an answer on aero with all model C7s he elaborated and said GM desires a modest understeer at high speeds and carefully controls that balance.
As an owner of a modified Corvair years ago we knew full well what oversteer was all about. We and Porsche owners in the day had a saying, “if going into a turn too fast you’ll go off the road and hit a tree; best hit it with the rear and not plow head on with the front!”
Actually oversteer was fun but when exceeding the limit you must steer into the skid as when on ice! A normal reaction is to steer the car to the center of the road as with an understeer car. You have to be prepared to react as you only have a split second to do it right or the rear end slides off the road!
I’m sure GM did want to give Ralph Nader material to wright another book!
PS: Some "marketing speak" said it was to get better rear brake cooling etc (but not from Tadge.) Could be a small factor but not the reason, IMO!
Good Info in Post #24! Looks like the Grand Sport with the standard short "Side Skirts," (table calls them rockers) and "Small Splitter" DOES have a center air dam. It would appear the aero front/rear downforce balance with that combo, meets the GM criteria!
Note from the link in Post #24, all Z51 and Z06 C7s or my Grand Sport with the Stage 2 aero option (CFZ) that has full length side skirts, what is called a large Splitter and rear Spoiler Wicker extensions does NOT! Aero is NOT intuitive!
I tried to glue it back together with super glue, didn't hold. Have now epoxyed with fiberglass cloth on back side, if this doesn't hold I'll order a new one.
There is a large opening on each side behind the air dams. I ordered extra bumper cover screws and u-nuts online from clipsandfasteners.com (I used the u-nuts because the factory screws are an odd thread) http://www.clipsandfasteners.com/sea...p?Search=20339
Did it actually tear the clip out of the plastic support, or just pull the screw out?
The screws holding the air dam should be threaded into a metal clip. If the place where the clip attaches is broken, you may still be able to have the screw go all the way through the support, through a flat washer, and then the nut. You can see how I did that when mounting my splitter since there were no holes in the bumper for the leading edge of the splitter for clips to slide in to.
Here is one of the openings....
Arrow is extra flat washer under end of splitter to make it sit level and flush.
I really appreciate this post. I am not very mechanically inclined but you make it sound pretty reasonable to repair.
I have get under the car again and look. My screws are still attached to the air damn but the metal clips were probably ripped off when the damage occurred.
Thanks again!
Last edited by Slappy3243; 10-25-2017 at 10:47 AM.
I tried to glue it back together with super glue, didn't hold. Have now epoxyed with fiberglass cloth on back side, if this doesn't hold I'll order a new one.
Assume you used epoxy designed for plastic. It is different and about twice the price.
My first air dam split so I bought another...it split too, so I’m gonna see what happens without it.
Have to believe GM has made a dam material change. Too many recent forum reports of ripping. My C6 center air dam scraped every time I left my driveway. I also scraped the “skid pads” several times and they are higher. All I did in 6 years was sand paper the bottom a few times to remove the rough edge.
On my 2014 Z51 scraped the side dams a occationaly. No problem. They provided the needed early warning minimizing my scraping the aluminum “skid pads.”
Doubt you’ll be able to measure the reduction in gas mileage when you remove it! High speed front downforce reduction would not be noticed unless traveling 100 to 150 mph! Even then unlikely you would feel any difference with it removed, unless you’re a Pro or pushing the limits when Tracking.
I know that the air dams are not installed on the car until after the dealership takes delivery so I told the salesman that when my 2018 arrives, do not let a tech put on the air dam. I plan on lowering my C7 the same as my C6, and my air dam on the C6 scrapes every time I pull out of my driveway and it's super annoying. I realize it might be slightly risky but it's a risk I'm well aware of and still have made up my mind, the air dam is a no go for me.
FWIW, when they were doing the PDI on my car, the tech got the salesman to phone me and he ended up convincing me to install the air dam after all. I'm having my C7 lowered this weekend, so I'm hoping the air dam isn't going to scrape as much. If it does though, I've decided to just live with the noise (or turn up the radio louder)
Sure the more air you can reduce going under the car the lower the drag the faster the speed.
Just how much? You tell us!
What I’ve gathered is the front air dam was removed on certain vehicles (z51,gs and z06) to reduce downforce and increase understear at speed. Extra downforce usually equates to lower top end. So what I’m curious about is if you have a vehicle equipped with the front air dam would the removal of it possibly help mile an hour?
What I’ve gathered is the front air dam was removed on certain vehicles (z51,gs and z06) to reduce downforce and increase understear at speed. Extra downforce usually equates to lower top end. So what I’m curious about is if you have a vehicle equipped with the front air dam would the removal of it possibly help mile an hour?
Items like spoilers increase downforce and increase drag.
The air dam on a Chevy Volt is there to decrease drag ( by reducing air going under the car) add mpg and would increase not decrease top speed. Just how much in a Vette, try both ways in a 1/2 mile and find out!
Items like spoilers increase downforce and increase drag.
The air dam on a Chevy Volt is there to decrease drag ( by reducing air going under the car) add mpg and would increase not decrease top speed. Just how much in a Vette, try both ways in a 1/2 mile and find out!
Haha yeah I’ll report back with my results when ever the opertunity presents itself
10-22-2017, 10:36 AM
Looks like the Grand Sport with the standard short "Side Skirts," (table calls them rockers) and "Small Splitter" DOES have a center air dam. It would appear the aero front/rear downforce balance with that combo, meets the GM criteria!
