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> Lifting rear of roof, what are the benefits
porschenut
post Mar 6 2006, 12:12 PM
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How about reversing the airflowin the engine compartment. Pull from the bottom and exhaust up. Create a lot of downforce then
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brant
post Mar 6 2006, 01:59 PM
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QUOTE (porschenut @ Mar 6 2006, 11:12 AM)
How about reversing the airflowin the engine compartment. Pull from the bottom and exhaust up. Create a lot of downforce then

and the underbody scoops that would be necessary to do this would also create a lot of drag...


the simpliest thing to do would be to just install a big honking wing...

but if your vintage class does not allow wings, then focus on reducing drag...

brant
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alpha434
post Mar 6 2006, 05:08 PM
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I don't think there is a problem with the stock fan configuration. It's "soft" air that is moving through that system. Air that is fairly slow moving and low volume, compared to the stuff going on around you at 60. But if you were to reverse the system, it would pick up dirt off of the track, and the hot air off the track, and hot air from the brakes. And I don't believe that it would provide any significant downforce from the mild suction going on there.

But on the other hand, I don't believe that the fan would starve down there without scoops. The top has no scoops. I think you would just need a screen to allow air to freely enter the engine bay when it's sucked in.

Either way, Brant's definately right about going for drag reduction. An exotic fan system isn't likey to help or hurt your aero at all. And so it would be a lot of extra work to get to the same place you've been.

Maybe an underbody kit? But this is a little of topic. I want to hear whether or not the Airtabs worked well.
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drew365
post Mar 13 2006, 08:18 PM
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I had idle hands this weekend so I decided to modify my targa top. I put together what Brent did and what John did. I probably took it a little too far but only a track day will tell.
I added 1" of spacers to the stock latch and used a grinder to get rid of the reinforcement and rear seal area. I now have over 2" of clear space between the targa and the top. I'm a little afraid with that much air passing through that I might start creating lift under the top. If it seems like that is the case I can always remove the spacers and drop it down so I have about !" of clear space.
The first pic shows a side view. Looks kind of weird.
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drew365
post Mar 13 2006, 08:21 PM
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Like I said, pic 1


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drew365
post Mar 13 2006, 08:22 PM
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This one shows the spacers added to the stock latch.


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drew365
post Mar 13 2006, 08:24 PM
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Here's one from the rear.


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race914
post Mar 13 2006, 08:28 PM
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Great Job! Spacers are a great idea, since as you mentioned, you can tune the height of the gap.

I'm anxious to hear how your test day goes.

Any plans to come up to the Buttonwillow event April 15-16?
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drew365
post Mar 13 2006, 08:53 PM
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Probably won't get to that Buttonwillow event. I'm hoping to run the big track at Willow Springs April 22. We leave for a trip to England a few days after so I might be wishfull thinking. The big track at Willow would be the best test for me since the car gets light while turning in to T8 from the back straight. I'm really only expecting this mod to aid cooling in the cockpit more than changing the aero of the car. So any added benefit will be a welcome addition.
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alpha434
post Mar 14 2006, 12:45 AM
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I thiink it looks great. Even as just an accent to the chalon sail panel.
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Mueller
post Mar 14 2006, 01:17 AM
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QUOTE (drew365 @ Mar 13 2006, 07:53 PM)
Probably won't get to that Buttonwillow event. I'm hoping to run the big track at Willow Springs April 22. We leave for a trip to England a few days after so I might be wishfull thinking. The big track at Willow would be the best test for me since the car gets light while turning in to T8 from the back straight. I'm really only expecting this mod to aid cooling in the cockpit more than changing the aero of the car. So any added benefit will be a welcome addition.

whatever you do, don't spin...that roof will last up there for about .05seconds before getting launched into the air (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)
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alpha434
post Mar 14 2006, 01:21 AM
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QUOTE (Mueller @ Mar 13 2006, 11:17 PM)
QUOTE (drew365 @ Mar 13 2006, 07:53 PM)
Probably won't get to that Buttonwillow event. I'm hoping to run the big track at Willow Springs April 22. We leave for a trip to England a few days after so I might be wishfull thinking. The big track at Willow would be the best test for me since the car gets light while turning in to T8 from the back straight. I'm really only expecting this mod to aid cooling in the cockpit more than changing the aero of the car. So any added benefit will be a welcome addition.

whatever you do, don't spin...that roof will last up there for about .05seconds before getting launched into the air (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Hinge the front. And tie a "safety wire" to the back. Or a few safety wires.

Don't want to lose it and scratch the paint.
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Mueller
post Mar 14 2006, 01:26 AM
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QUOTE (alpha434 @ Mar 14 2006, 12:21 AM)
Hinge the front. And tie a "safety wire" to the back. Or a few safety wires.

Don't want to lose it and scratch the paint.

I'd rather have it fly off, if you hinge it, it'll take out the windshield and hood and possibly trash the windshield frame...of course I wouldn't want to be around the place if it becomes a flying saucer (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)
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alpha434
post Mar 14 2006, 01:30 AM
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Yeah. Forget the hinging. That was a bad idea. But put about 10 inches of safetey wire loosely coiled and attached to all four corners. Then when it comes loose, It will pick up enough to break the front latch, and then starighten out and fall back down.

Or put 8 inches on the rear and 10 or 12 on front.

Engineers at work. Everyone stand back!
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alpha434
post Mar 14 2006, 01:32 AM
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And the less you use, the shorter the distance will be when it lands back on the roof. So then it would not hit and damage the windshield.

And you could safety wire the sides, in the midle too, so that it won't come crashing into the cockpit.
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Jeroen
post Mar 14 2006, 06:21 AM
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just use bonnet pins to hold the roof down...
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brant
post Mar 14 2006, 09:20 AM
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QUOTE (Jeroen @ Mar 14 2006, 05:21 AM)
just use bonnet pins to hold the roof down...

hmmmmmm


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drew365
post Mar 14 2006, 09:45 AM
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QUOTE (brant @ Mar 14 2006, 08:20 AM)
QUOTE (Jeroen @ Mar 14 2006, 05:21 AM)
just use bonnet pins to hold the roof down...

hmmmmmm

Could you elatorate a little? (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) Any pics?
Since I rarely spin (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif) I shouldn't be worried. But in the slight off chance that it happens you guys have a good point.
One good thing is the stock latches locked very firmly. I could attach a bracket to make sure the latch can't move off the pin after it's set? The weak point will be the bolts into the top which are the stock holes and seem pretty solid. You guys got me worried.
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kart54
post Mar 14 2006, 12:57 PM
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Drew,

I just did almost the same thing but I did it the easy way and what is required by the SCCA rule book; lag bolts all the way through the roof and the targa bar. Very adjustable and no way to have the top come off without taking off the bolts. (sorry, no digital camera, no pics)

Randy
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maf914
post Mar 14 2006, 01:30 PM
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QUOTE (Mueller @ Mar 13 2006, 11:17 PM)
whatever you do, don't spin...that roof will last up there for about .05seconds before getting launched into the air (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Sort of like the roof flaps that NASCAR added a couple of years ago. When a car spins at speed and starts going backwards the flaps open and break up the airflow over the roof to keep the car from launching upward. Of course their flaps are built a little different and are of course "NASCAR Approved"! These were actually one of NASCAR's best innovations, IMO. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)
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