Rear Downforce Wing
- Thread starter Alky V6
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I've found a tire pressure that is controlling tire slip very well. Soon I'll be slowly increasing the top end boost level. I'm going to see how far I can go before I have to go back to working on the aero of the car.
I have modified the rear deck lid bumpers so that I can adjust the closed height of the back of the deck lid. It's up about 1/4" from stock.
I finally have a launch tune that I'm very happy with. Hot Air recently made me start thinking about aero again, and I wanted to put down some ideas that were popping in my head.
Since we don't have an Advanced Tech section that we can throw ideas like this around, I decided this was probably the best place to put down the ideas. If the ideas turn into fab projects, then it'll all be in one thread.
Front air dam replacement or modification.
I want to extend the front air dam 1-3 inches. I'm toying with the idea of creating an extension that can be quickly mounted and dismounted from the stock front air dam (1984 full air dam style). I can get away with one more inch of air dam and still easily get the car in and out of the trailer, but anything over an inch will require me to be able to remove the front air dam or extension.
I'm going to keep the shape simple at first, just to see how much of an improvement an extended air dam can provide. If it shows some improvement, then I may design something a little more fancy.
Mid-section air dam or ground affects device.
I'm thinking of using the X-frame to mount some sort of mid-section air dam or ground affects device.
I would like this device to provide the following:
A low pressure zone under the car starting midway back.
A way to funnel liquids away from the rear tires in the event that a radiator hose pops off or a catastrophic engine failure occurs.
Vacuum or blow dust off the track ahead of the rear tires.
The device would include a splitter section.
Since we don't have an Advanced Tech section that we can throw ideas like this around, I decided this was probably the best place to put down the ideas. If the ideas turn into fab projects, then it'll all be in one thread.
Front air dam replacement or modification.
I want to extend the front air dam 1-3 inches. I'm toying with the idea of creating an extension that can be quickly mounted and dismounted from the stock front air dam (1984 full air dam style). I can get away with one more inch of air dam and still easily get the car in and out of the trailer, but anything over an inch will require me to be able to remove the front air dam or extension.
I'm going to keep the shape simple at first, just to see how much of an improvement an extended air dam can provide. If it shows some improvement, then I may design something a little more fancy.
Mid-section air dam or ground affects device.
I'm thinking of using the X-frame to mount some sort of mid-section air dam or ground affects device.
I would like this device to provide the following:
A low pressure zone under the car starting midway back.
A way to funnel liquids away from the rear tires in the event that a radiator hose pops off or a catastrophic engine failure occurs.
Vacuum or blow dust off the track ahead of the rear tires.
The device would include a splitter section.
Squid4life
Well-Known Member
- Joined
- Jul 5, 2004
- Messages
- 6,275
Don, you talking about something like this:
http://www.turbobuick.com/forums/fa...ion/332512-fabricated-front-airdamn-pics.html
I would imagine you could add a little length and angle in order to push them forward and down at the same time. Knowing you, I am sure you could add some type of adjustable turnbuckle to raise/lower/ fine tune the front valance, and maybe have one end of it removable with a pull pin. Something like this (only not ricer)
Attachments
Thanks for the link. Just in time. That is a very nice looking piece. He's off to an excellent start.
What I may end up doing is replacing the stock air dam with a mounting system that would incorporate using Dzus fasteners to fasten the new dam. The new air dam would fit to the front of the shorter support structure and be quickly fastened with simple Dzus fasterners. Removing the air dam when time to trailer the car would be a breeze. A system like that would not put a limit on me as far as how low the air dam could be set up. The support structure would also add some needed support if a splitter was also to be worked into the plan.
That link was perfect for getting my creative juices flowing. Thanks again for the link!
What I may end up doing is replacing the stock air dam with a mounting system that would incorporate using Dzus fasteners to fasten the new dam. The new air dam would fit to the front of the shorter support structure and be quickly fastened with simple Dzus fasterners. Removing the air dam when time to trailer the car would be a breeze. A system like that would not put a limit on me as far as how low the air dam could be set up. The support structure would also add some needed support if a splitter was also to be worked into the plan.
That link was perfect for getting my creative juices flowing. Thanks again for the link!
Squid4life
Well-Known Member
- Joined
- Jul 5, 2004
- Messages
- 6,275
I will have to think on that one, not sure how to attach one, with it being adjustable. I would be interested to do something like the below link, albeit not adjustable, to see if it feels different, then if it seems to work, think about the adjustability part and consider an upgrade. Is your deck lid steel or fiberglass? I would think if it did work well, and you want something truly adjustable, that having the adjustable portion on the top of the lid may prove difficult. Maybe you could have the adjustment portion under the lid, and use a polylock style adjust/lock setup to make adjustments. May be way left field, but depending on how high the wing or spoiler was finding a way to adjust it ouside the trunk could be tough. Will think some more on it...
How to: Under $15 Gurney Lip - evolutionm.net
How to: Under $15 Gurney Lip - evolutionm.net
has anyone mentioned this rear adjustable deck lid spoiler yet?
FE3XConcepts - Purchase FE3X gound effects
(down near the bottom)
FE3XConcepts - Purchase FE3X gound effects
(down near the bottom)
Squid4life
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- Joined
- Jul 5, 2004
- Messages
- 6,275
That adjustable rear spoiler is clean! Nice design. I would assume aluminum would be best suited for that type of application, unless you had mad carbon fiber skills...
I'm back to aero on the car now. The front grill block off is doing a good job of creating a low pressure zone under the hood. On a quarter mile pass the cutout in the hood is getting pushed onto the throttle body and causing signs of contact. 
I don't think I need to worry about the hood wanting to take flight. I might have to fab up a support to attach to the throttle body that will catch and support the hood when it tries to push down onto the throttle body.
I still want to play with a wing in the rear, but I want to extend the front spoiler first.
It's going to be somewhat of a Frankenstein creation. I'll cover the fab of it in this thread.
The first job will be to trace a pattern off of the front of the existing OEM spoiler so that I can trace out a mounting flange for the new spoiler support structure.
I don't think I need to worry about the hood wanting to take flight. I might have to fab up a support to attach to the throttle body that will catch and support the hood when it tries to push down onto the throttle body.I still want to play with a wing in the rear, but I want to extend the front spoiler first.
It's going to be somewhat of a Frankenstein creation. I'll cover the fab of it in this thread.
The first job will be to trace a pattern off of the front of the existing OEM spoiler so that I can trace out a mounting flange for the new spoiler support structure.
I've been doing more studying on aero and I've decided that where my car is really lacking right now, as far as downforce pressure balance goes, is in the rear. I'm going to move back to a rear wing, and maybe ground effects from the rear axle on back.
I've been looking at different wing ideas and came across this. Not a tradition 2 element wing. I thought this was interesting.
YouTube - Mercedes 190 Judd V8 hillclimb DTM
I'm going to start off by mounting some vertical tail fins along each side edge of the trunk lid. The height will extend to just above the roof line. I'll then string some lines across the back of the fins at different heights and tie some stringers to those lines. With a video camera, I'll then record what the stringers are doing at speed to determine where there is turbulence and where there is straight flow off the back of the rear window and trunk lid area. Where I see there is straight flow is where the rear wing will be mounted. I think I'll mount the wing slightly offset off the back of the car, also.
I'll be retaining the stock rear spoiler.
I'm thinking of a 2 element wing.
I've been looking at different wing ideas and came across this. Not a tradition 2 element wing. I thought this was interesting.
YouTube - Mercedes 190 Judd V8 hillclimb DTM
I'm going to start off by mounting some vertical tail fins along each side edge of the trunk lid. The height will extend to just above the roof line. I'll then string some lines across the back of the fins at different heights and tie some stringers to those lines. With a video camera, I'll then record what the stringers are doing at speed to determine where there is turbulence and where there is straight flow off the back of the rear window and trunk lid area. Where I see there is straight flow is where the rear wing will be mounted. I think I'll mount the wing slightly offset off the back of the car, also.
I'll be retaining the stock rear spoiler.
I'm thinking of a 2 element wing.
turbofabricator
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- Joined
- Mar 7, 2004
- Messages
- 4,261
Donnie,
You might just want to try a belly pan first. A sheet of aluminum from the lower rear bumper flange forward to clean the air up UNDER the car. Easy to fabricate. Look at the '80's NASCAR Buicks. They ony had the 6" rear wing and they were running sustained 190mph. I read once that one Buick team tack welded the rear bumper on and just before the last few laps, a team mate got behind and the lead car tapped thier brakes, and POP! the rear bumper departed company. It was claimed to increase speed better than 2 mph. Something to consider. Getting air from out under the car is just as important as controlling it over the car. Get the nose of the car down low, put an air dam on it that dang near touches the ground, and keep it from re-entering behind the wheels. And the rear bumper looks like a parachute hanging down back there. Fix that first.
You might just want to try a belly pan first. A sheet of aluminum from the lower rear bumper flange forward to clean the air up UNDER the car. Easy to fabricate. Look at the '80's NASCAR Buicks. They ony had the 6" rear wing and they were running sustained 190mph. I read once that one Buick team tack welded the rear bumper on and just before the last few laps, a team mate got behind and the lead car tapped thier brakes, and POP! the rear bumper departed company. It was claimed to increase speed better than 2 mph. Something to consider. Getting air from out under the car is just as important as controlling it over the car. Get the nose of the car down low, put an air dam on it that dang near touches the ground, and keep it from re-entering behind the wheels. And the rear bumper looks like a parachute hanging down back there. Fix that first.
All good advice. I understand the advantage of doing all the things you mentioned. I just feel that even with those changes, a rear wing is still going to be necessary. Ground effects works much better when you can get the bottom of the car much closer to the ground than I will able to do with this car the way the rear axle is setup. I would really need to tub the car to get the body low enough to the ground to take full advantage of ground effects.
I do plan to cut out the middle section of the rear bumper so that I can create a nice tunnel venturi from the rear axle on back to the cutout section of the rear bumper, like what was mentioned earlier in this thread by DailyDrifter. I may smooth the bottom all the way to the firewall, but I just don't feel there is going to be a big gain due to the running height of the body.
One good thing. The front end of the car does appear to pull down on the top end, giving the car a good rake, so maybe some ground effects might be realized with the smoothed bottom.
I really don't want to install side skirts, unless I really have to. That would be a last resort.
The front air dam does need to be lowered. I may just get the full length one that is available instead of making one. I believe it is about 1 inch lower than the original '84 air dam. I've learned that lowering the air dam too much can actually create a trade off of downforce with increased drag, so for now, I don't want to get too carried away with the air dam.
The pressure balance of the car is clearly showing a lack in the rear, so that's what I want to concentrate on first.
I'm using a scale GNX diecast model to mock up some wing mounting devices (fins). I'll post some pics of the different designs to get some feedback.
I'm thinking of mounting the wing between two fins mounted at the side edges of the trunk lid, instead of mounting the wing using the other option which is more centrally on the wing. The last youtube link I posted being an example of a centrally mounted wing.
Doing a search for street hillclimb racing on youtube will give a lot of video on cars of different classes with many different wing designs.
I'm thinking of mounting the wing between two fins mounted at the side edges of the trunk lid, instead of mounting the wing using the other option which is more centrally on the wing. The last youtube link I posted being an example of a centrally mounted wing.
Doing a search for street hillclimb racing on youtube will give a lot of video on cars of different classes with many different wing designs.
It's interesting to see some cars that you would think don't have a whole bunch of rear turbulence still choose to mount the wing pretty high to get the wing in clean air. Very important when using a wing. Especially noticeable on the obvious professional setups.
Dusty Bradford
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- May 24, 2001
- Messages
- 5,802
157 in 5.0 seconds and I still don't need a wing for top end stability.
When a car sits like a 4 wheel drive truck in the rear....no wing is gonna help it IMO.
When a car sits like a 4 wheel drive truck in the rear....no wing is gonna help it IMO.
We'll just have to find out for sure then, won't we. Pure speculation is not the best method for coming up with a concrete opinion. I think I've already proven that on a lot of fronts.
To take full advantage of ground effects, the bottom of the car would need to be within 3-6 inches off the ground. Deminishing returns as the car height is increased. Unless we're talking about a full tube chassis setup, that clearance is not very practical with a stock frame and OEM rear four link configuration. In today's economy, I'm not looking to build a Pro stock or Pro mod chassis. I want to see what I can get out of this setup. It might become powerful knowledge for others that can't afford massive chassis modifications.
Even with ground effects as part of the equation, a rear wing is going to contribute to a large percentage of the total downforce that can be created, especially in the rear. A rear wing cannot be ignored, whether ground effects is used, or not.
Even with ground effects as part of the equation, a rear wing is going to contribute to a large percentage of the total downforce that can be created, especially in the rear. A rear wing cannot be ignored, whether ground effects is used, or not.
