Landracing Forum
Tech Information => Technical Discussion => Topic started by: wheelrdealer on June 28, 2014, 10:43:59 PM
-
Built a new air dam. Not sure if it will be better than what I had but I can change back to the original air dam in about 10 minutes.
The old version followed the valence panel. It looked to me like an area that could create some lift. I had no issues up to 207 but the D/CBALT record is 27.319 mph higher. See picture with the tow bar.
The new air dam runs along a 1971 Camaro bumper and is currently adjusted to 1.5" of ground clearance. I can adjust the clearance by either flipping the lip up which gives me 2.5" clearance or swapping for another lip with something in between. Turnbuckles brace the low back backside. The idea to use the '71 is from a car I saw at Speedweek 2011.
Think it will help or hurt? Not going to hurt my feelings if you think not. I had fun making it.
BR
-
BR;
Looks very good. I hope it adds a few more mph. I love that year Camaro body style.
Regards, Neil Tucson, AZ
-
Looks good Bill. Kinda reminds me of the TurkBurger Hot Rod Special Camaro:
(http://www.ecta-lsr.net/www/events/2003/jun03/n060306.jpg)
(http://image.hotrod.com/f/incoming/10214163/113_0703_09_z%2bchevy_camaro_aerodynamics%2btest_scoop.jpg)
They have gone 261 with this setup so it must work pretty good.....LOL! :-D
Gregg
-
Turk and Frei's model camaro has a cleaner front end than the '73. I admit studied there car but got the idea to replace the split bumpers with a full bumper from a camera at 2011 Speedweek.
Thanks
BR
-
Got the idea to replace the split bumpers with a full bumper from a camera at 2011 Speedweek.
Thanks
BR
I like the split bumper on street Camaros but I REALLY like the full bumper on your car. Cleans up the front MUCH better!
Gregg
-
I need to build a similar air dam for my car. I was wondering if you could tell me what thickness aluminum yours is made of, and would you have used the same thickness again, or a thicker or thinner piece of aluminum? Yours looks pretty nice.
Also, has anyone made an air dam out of steel? What thickness? I have a spot welder, but no way to weld aluminum so I was thinking steel could be easier for me to fabricate.
I was also thinking of making the bottom 1-2" of the dam out of some 1/4" firm rubber. Good or bad idea? What ground clearance is commonly used?
Thank you,
Jeff
-
The one on the Jag is 22 ga. with a 1/2 inch cold roll bottom reinforcement.
Doug :cheers: :cheers: :cheers:
-
I need to build a similar air dam for my car. I was wondering if you could tell me what thickness aluminum yours is made of, and would you have used the same thickness again, or a thicker or thinner piece of aluminum? Yours looks pretty nice.
Also, has anyone made an air dam out of steel? What thickness? I have a spot welder, but no way to weld aluminum so I was thinking steel could be easier for me to fabricate.
I was also thinking of making the bottom 1-2" of the dam out of some 1/4" firm rubber. Good or bad idea? What ground clearance is commonly used?
Thank you,
Jeff
Jeff:
I thought about steel as well but went with 11 gauge 3003 aluminum. My current air dam was made of 11 gauge with no bracing and help up to 207. 11 gauge is easy to work for a guy with out metal shop tools. I have a homemade sheet metal brake that I broke the center crease and I used 1" piece of DOM and clamps to roll the corners. I braced the air dam back to some aluminum angle I mounted on the bottom of the valence. I used 3/8 tubing and built a turn buckle end on one end with 1/4" eyes for quick pins. On the air dam side I used 8" section of 1/4 aluminum Td to bolt the no adjustable end of the brace tubing. Countersunk the brace Ts from the front and Dzus tabbed the bottom of the bumper with 1/8" x 1 3/4" cold rolled I between the Dzus tabs for support. I'll post some pictures when I get to my office computer.
BR
-
I would appreciate the pictures of the dam and the underlying structure.
Thanks,
Jeff
-
I'd like to see the pictures also :-). Sounds like you are bracing it well. That is really important with that large of a surface up there. Think of you hand out the window at 60 and then all of that area at 4 time 60 mph.
Hooley's air dam is fiberglass and has been braced..
(http://purplesagetradingpost.com/sumner/Hooley%202013/wing--87.jpg)
...well at the bottom in the center, but pictures have suggested that outward from there that it might be bending back at speed. We just finished adding a lot more bracing to the air dam itself and also more support to the rest of the front-end also. Hooley bent a bumper like piece of heavy steel that rides right behind the air dam and I made up some braces that attach it to the frame. Here are a few pictures ....
(http://1fatgmc.com/car/14-Hooley/Air-Dam-Brace-15.jpg)
(http://1fatgmc.com/car/14-Hooley/Air-Dam-Brace-20.jpg)
(http://1fatgmc.com/car/14-Hooley/Air-Dam-Brace-21.jpg)
http://1fatgmc.com/car/14-Hooley/Air-Dam-Brace-23.jpg (http://1fatgmc.com/car/14-Hooley/Air-Dam-Brace-23.jpg)
.... and there are a number more here....
http://1fatgmc.com/car/14-Hooley/14%20-%20hooley-construction-2014-1.html (http://1fatgmc.com/car/14-Hooley/14%20-%20hooley-construction-2014-1.html)
Sum
-
Sum:
I read all of your post and mine ideas from you all of the time.
I had the metal shop shear the sheet on the long end
Then I bent it about 30 degrees on my welding table with some angle iron and strap.
-
Air Dam braces. The braces adjust on one end. The air dam is 1/2" behind the leading edge of the bumper and can be adjusted up to 1" to push it out or pull it in to account for any change in rake to tire swaps. On the second photo you can see the Dzus tabs and the strap in between to mount and brace the air dam to the bumper.
BR
-
Nice work :cheers:
I would consider...
(http://1fatgmc.com/car/car-other-1/air%20dam-1.jpg)
... running some diagonals down under each of the horizontal braces you have now with the same type brackets that you have used to spread the load. Just a thought considering the speeds you will be running,
Sum
-
Sum:
You may be right. I have plants of 1/4" fasteners running along the lip. I can easily triangulate down to them. I have time since I won't make Speedweek 2014. I will mock some things up.
Thanks
BR
-
Bill you put a lot into that project.
It looks great.
Sorry to hear you won't be at Speed Week this year.
-
Bill you put a lot into that project.
It looks great.
Sorry to hear you won't be at Speed Week this year.
Mike:
It is 5,200 miles round trip to Bonneville from my shop in Florida. Right now I have a good motor but not a record setting motor. We can probably get a few MPH's more but we are a long way away from the 27.316 mph needed to match the current record. The car is ready, so I will spend this year adjusting the car and gathering parts to build a more capable engine. May change classes but have not decided.
To have a successful run at the D/CGALT record we will need a perfect motor, perfect gear, perfect salt, perfect tail wind, perfect driving, and all of the stars to align above floating mountain to create a unique magnetic pull to help us with our top speed. In other words, the D record was set by some very talented LSR guys and will be darn near impossible to break with a Camaro. It is that Darn Near part that give us hope.
I know I cannot whine about long haul issues considering the distance a lot of LSR contenders travel from. We just feel is it better to conserve the cash we would spend on 2014 and get our short block together. Our next goal is to get the car in the 220's and see how it handles.
-
I thought I would show how the tow bar and tow loop hooks up. It uses (2) 3" X 1/2" quick pins.
The first photo is the slot in the bumper and the 1/2" hole where the bumper carriage bolt used to live. We reinforced the factory bumper mount and made a slot for the devices to slide into so there is no sise to side movement possible.
The second has the two ring installed. If I had a wider bumper I would have built this vertical instead of on the horizontal for aero reasons.
-
The first photo shows the driver's side tow bar hook up.
The second shows the tow bar installed.
I hope this triggers someone to think of an idea for their car. I have taken so many ideas from this site it is time I put something back into the well. Although my fabrication skills are small ball compared to most of the people posting on this site.
Lesson's learned: 1. With the pivots on an angle they will not rotate up or down more than 20 degrees. Which is plenty flexible for the level salt. Would not work as a place with larger dips or bumps. Someday I will go back and correct this but for now it works fine. Second, I think I will make the next tow bar out of chrome moly. I think it would be a lot lighter. This is a standard Northern Tool 5,000 LBS tow bar. Still easy to install with one person.
BR
-
metermatch said I have a spot welder, but no way to weld aluminum so I was thinking steel could be easier for me to fabricate.
Look at this:
https://www.youtube.com/watch?v=gcgC3V3mkcw
Nick
-
No alum. Welds on the air dam. All the Dzus tabs, braces and turn buckles are steel. Attackers to the alum. Via ss counter sunk Allen heads.
It an easily me made of steel.
BR
-
Cool idea on the spot welding of aluminum. I'm going to take that idea and discuss it with an old engineer friend of mine. He has patents from working at Ford many years ago on developing spot welders for the cars on the assembly lines.
Jeff
-
I'm working on an air dam similar to yours, and have a decision to make.
I can have the air dam situated so that it's vertical, but with no "lip" at the bottom, or leaned back a bit, but with a horizontal lip at the bottom of the dam.
I have read about the importance of the lip, or splitter, at the bottom edge, but don't know what is given up by leaning the air dam back (bottom edge farther back on the vehicle than the upper edge).
I've been messing around with cardboard as a template, and I'm planning to buy the sheel Aluminum tomorrow, so it's just about decision time.
Which is better - vertical air dam with no lower lip, or leaned back air dam with a lip?
Steve.
-
SteveM
Perhaps someone that knows can chime in. I just reproduced what I remembered seeing on the salt. I have mine set slightly forward at the bottom about 3/8" from the top. But I can easily reverse that with the turn buckle braces. The splitter lip can easily be added to the bottom section. Here I thought I was done and you have given me something to think about! :) Actually every time I read someone's build diary I see something I want to do.
BR
-
Same here - almost all of my ideas were "pinched" from someone else's build thread.
To get a splitter "lip" on mine means that I'll have to lay the air dam back whatever the forward projection of the splitter is. It's my understanding of the rules that no part of the air dam (splitter included) can extend beyond 1/4" in front of the forwardmost part of the bumper.
I hope someone with firsthand experience weighs in on this topic.
Steve.
-
I have seen this article before, and just refreshed my memory. It looks like the splitter definitely helps with a vertical air dam...
http://hanchagroup.wordpress.com/2013/01/29/splitter-or-air-dam-which-design-is-best/
This isn't exactly university level peer-reviewed research, but looks valid, nonetheless.
Steve.
-
Steve:
Thanks for the info. I will add the splitter to the bottom. I will have the same challenge on the set back from the bumper tip.
I do have a question for those that are more experience than me. The difference in down force between what I had and what I have is about 2/3rds more down force at 100 mph according to the article supplied by SteveM. My calculations show I need to add about 120 lbs to the front end of my car to get the CG exactly 6" ahead of the CP sitting still. How does the increased down force from my new air dam/splitter play into that calculation? If my down force goes up by an estimated multiple of 3 at 200 mph do I still need to add the static weight to get the CG and CP 6" apart? Or will the down force accomplish the same thing?
Thanks
BR
-
BR:
My understanding of the statics in this situation is that any downforce created by the splitter will be applied as a concentrated load at the location of the air dam / splitter interface. Since the air dam is attached directly to your bumper, it would be like having the load applied to the bumper.
If the downforce is 150 lbs at x mph, then it would be like having a 150# person standing on your bumper. At 200 mph, if the load triples, it would be like having a 450 pound person standing on the bumper.
I guess the difficult thing related to your CG/CP comparisons is that the downforce is continuously changing as the speed increases.
The comparison above is not based on my expertise with aerodynamics, only as an engineer.
Steve.
-
SteveM
Thanks I am certainly not an engineer but I have been known to hang out with some. I guess then the question is, do I set up the CG and CP relationship as it sits in my shop? Does adding down force at speed shift the CG and CP relationship?
My rear spoiler is set flat 0 degrees as I ran it at speed week. I did not spin and the car went straight so I did not add any angle. My new spoiler can be adjusted up to about 12 degrees based on the handling. I gues is I add spoiler angle aka down force to the rear that will have to be considered in my CG and CP relationship.
BR
-
... I guess then the question is, do I set up the CG and CP relationship as it sits in my shop? Does adding down force at speed shift the CG and CP relationship?....
I'll be interested in what others said but I'd figure it "as it sits in my shop". The reason being that if the car starts around then all of those 'aero' calculations can go out the window real fast. They will probably help in keeping the car straight in the first place but once it isn't then it is going to be the CG/CP as figured in the shop that will probably come into play.
In our case when the throttle stuck wide open the car started around when it had been running nice and straight, but once part way around the CP caught the car from going all the way around. If the CG would of required 'aero' help then it might of gone all the way around once that 'aero' help started to go away.
Just my thoughts,
Sum