69427
The Artist formerly known as Turbo84
Yeah, that was my objection to the way BeeJay did that. He just ended up making a high pressure area under a large horizontal surface.
Near future project: Aluminum radiator support
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Yeah, that was my objection to the way BeeJay did that. He just ended up making a high pressure area under a large horizontal surface.
I'm speculating at his intentions but, the air dam below (what looks like) a splitter is to remove air from under the car.
JPhil
Huh?
Since nobody else has come up with any ideas, here's one.....
I don't know if you have the little factory air dam on the front like my '73 does, but I got some material from a commercial roofer to extend it. It is an EPDM (about 3/16" thick rubber like stuff) mat made to walk on on commercial flat roofs so the thin roof membrane is not damaged. It is flexible enough that it will bend when you bump a parking block, yet stiff enough to not deflect from the wind pressure at speed. It came in a piece 3' x 2', so it is split in the middle. That was the only way to fit it to the contour & curve of the nose anyway.
I looked at semi truck mudflaps first, but they were too thick & stiff, other materials were too thin & flexible.
If you don't have the little OEM air dam to bolt it onto, perhaps you could fab an angle bracket from aluminum or plastic to bolt to the nose piece first.
I would like to make mine yet another an inch or more longer (closer to the ground) as well: it did make a noticable difference in high speed front end float (along with lowering the car too).
I don't know if you have the little factory air dam on the front like my '73 does, but I got some material from a commercial roofer to extend it. It is an EPDM (about 3/16" thick rubber like stuff) mat made to walk on on commercial flat roofs so the thin roof membrane is not damaged. It is flexible enough that it will bend when you bump a parking block, yet stiff enough to not deflect from the wind pressure at speed. It came in a piece 3' x 2', so it is split in the middle. That was the only way to fit it to the contour & curve of the nose anyway.
I looked at semi truck mudflaps first, but they were too thick & stiff, other materials were too thin & flexible.
If you don't have the little OEM air dam to bolt it onto, perhaps you could fab an angle bracket from aluminum or plastic to bolt to the nose piece first.
I would like to make mine yet another an inch or more longer (closer to the ground) as well: it did make a noticable difference in high speed front end float (along with lowering the car too).
Last edited:
69427
The Artist formerly known as Turbo84
Since nobody else has come up with any ideas, here's one.....
I don't know if you have the little factory air dam on the front like my '73 does, but I got some material from a commercial roofer to extend it. It is an EPDM (about 3/16" thick rubber like stuff) mat made to walk on on commercial flat roofs so the thin roof membrane is not damaged. It is flexible enough that it will bend when you bump a parking block, yet stiff enough to not deflect from the wind pressure at speed. It came in a piece 3' x 2', so it is split in the middle. That was the only way to fit it to the contour & curve of the nose anyway.
I looked at semi truck mudflaps first, but they were too thick & stiff, other materials were too thin & flexible.
If you don't have the little OEM air dam to bolt it onto, perhaps you could fab an angle bracket from aluminum or plastic to bolt to the nose piece first.
I would like to make mine yet another an inch or more longer (closer to the ground) as well: it did make a noticable difference in high speed front end float (along with lowering the car too).
That won't work for my application. As I mentioned I need the material to be in an L (or 7) shape so I can bolt/rivet the upper horizontal portion to the aluminum bellypan. I don't have much ground clearance under the PC spoiler and adding a metal angle bracket loses the flex ability of the airdam when I'm driving the car up the trailer ramp or running over the apex bumps.
Here's a picture from last week's track day at Topeka. I'm trying to add a little more spoiler depth for track use, and then remove it for street driving.
69427
The Artist formerly known as Turbo84
Aerodynamically the PVC stuff would work great, but I bottom the car out on occasion and I want the spoiler material to be the weak link and bend, hence the preference for something a bit more flexible.
69427
The Artist formerly known as Turbo84
I was perusing my favorite junkyard last week and found what I think will work for the air dam extension. After striking out looking under every car and truck there (and seeing only broken or wrong shaped material) I stumbled upon a damaged and discarded pickup bedliner. It was tough plastic, with 90* edges at the top, just what I needed. The only downside was the 90* angle on what will be the front point under the pace car spoiler was essentially 180* off. I decided to try it anyway, so I cut the piece out of the right front corner of the bedliner, and after getting it home I cut a notch in the corner and set the piece out in the sun to warm (and soften) it up. I got it bent the other direction now so it's just a matter of drilling a few holes in the bellypan and getting the piece bolted on.
Twin_Turbo
Der Maulwurf
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garage door seal?
69427
The Artist formerly known as Turbo84
Got the spoiler extension material installed a few weeks ago. Ended up with about two additional inches of drop. Put about a hundred to a hundred and twenty miles on the car at a Porsche track day at Putnam Park, Indiana. Spoiler worked well and stood up to a bunch of abuse. I found out I could totally eliminate the spoiler ground clearance during heavy braking a couple times each lap. Scared the crap outta me the first time I heard the material scraping the track, though. Thought I broke something in the middle of the first stinkin' session. I like the thought of choking off the undercar air to help gain a little braking traction, but I don't know if I like that much front dive going on. I had a little more cornering roll than I liked, so I might entertain the idea of slightly higher rate front springs to reduce the roll and keep the spoiler from bottoming out. I was going to look for a bigger front bar (32mm tubular) to reduce the roll (I currently have a modified 30mm Firebird tubular bar), and I still think I'll check out the local junkyards for one. I can swap around the bars and springs next year to see what seems to be a better combination for me.
phantomjock
Well-known member
I'm just thinking out loud -
Front spoiler (Air Dam, Brakes) + Brakes = nose dive +scraping
Now,
Front spoiler + Brakes + nose dive = Front Weight Transfer
Front Weight Transfer = Great Steering because you have made a larger contact patch on front wheels BUT,
Front Weight Transfer = loss of Traction on rear! Bet the front brakes are doing most of the work, and acceleration may chirp the tires (not loaded up).
Did you note any difference in the nose movement at speed entering a turn? Over/under steering? Sway bar might help. Does it change between entry, mid corner and exit?
These would be a few things to check maybe before working a new bar.
You could consider getting a copy of Carroll Smith's Engineer in your Pocket. Its is a great diagnostic tool and could be a useful aid in debugging the set up.
Cheers - Jim
Front spoiler (Air Dam, Brakes) + Brakes = nose dive +scraping
Now,
Front spoiler + Brakes + nose dive = Front Weight Transfer
Front Weight Transfer = Great Steering because you have made a larger contact patch on front wheels BUT,
Front Weight Transfer = loss of Traction on rear! Bet the front brakes are doing most of the work, and acceleration may chirp the tires (not loaded up).
Did you note any difference in the nose movement at speed entering a turn? Over/under steering? Sway bar might help. Does it change between entry, mid corner and exit?
These would be a few things to check maybe before working a new bar.
You could consider getting a copy of Carroll Smith's Engineer in your Pocket. Its is a great diagnostic tool and could be a useful aid in debugging the set up.
Cheers - Jim
