Landracing Forum
Bonneville Salt Flats Discussion => Build Diaries => Topic started by: wheelrdealer on January 14, 2013, 01:31:23 PM
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I am enjoying my winter rebuild or as I like to say, "Rattle Can Restoration."
I have a question that I am sure has been asked but I cannto find the answer. What is the best way to get fresh air to the dirve that is approved by SCTA? The car orinally had a 1 1/2" piece of muffler pipe bent to follow the wheel well. It opened just behind the turn signal light and was welded to a plate the entered where the original wiring harness passed thriugh the fire wall. The pipe seemed to work other than it had no filter so a lot of salt entered into the car.
I have some NACA ducts but on my car there does not seem to be a good plase to install them. Except the front of the side window but I am not sure I want the air blowing right at me.
Also, there was no provision for the incoming air to escape, i.e. a duct out of the back of the car. Should there be an air exit duct?
Thank you for any thoughts you may have?
Bill
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Extend your duct to pick up air in front of the car, not it a spot that the wheels can throw a lot of salt dust.
Or rig a cowl duct for fresh air, make it one you can regulate air coming in.
Most of the off the shelf plastic NACA ducts are not very effective.
When you put it in, it needs somewhere to go.
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Be careful about ANYTHING entering the driver's compartment from the cowl area.... For years on our Vega, we had an opening in the cowl for the purpose of pressurizing the cockpit with air (we all know that the cowl is a high pressure point on the front of coupes and sedans) ...it did what it was supposed to do quite well....
Now.... enter some new inspectors who have the thought that a fire could come up the back of the firewall and be pressured in to the cockpit theough the open cowl.... (plauible, I guess) ....They, from that point on, required the cowl area to be sealed from/to the outside..... We now take the air through a metal tube from the front of the car....
There are other ways it can be done as well.... we considered a small hole in the roof just rearward of where the roof curves up from the windhield and about two inches toward the axial center of the car drom the driver's door that would have a tiny forward opening/facing scoop shape..... several cars have setups like this but we figured that, if a regular fire could go int othe cockpit through the cowl, a BIG fire could come up and over the roof and enter the car through there as well.... so....
Lots of ideas....
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Thanks for the ideas and insight.
A question on the tube to the front of the car... Should it open through the front bumper to front area air or just behind the front bumper? If it is in the front area air will put too much air in the car at speed? I don't want to push my windows out at speed.
When I bought the car the tube opening was just behind the front turn signal lens.
I was thinking I will run a tube out the back from the rear firewall through the rear valence panel.
Thanks,
Bill
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This has always puzzled me. In 24 hours a human inhales 340 cu ft. That's a cube 7' on a side.
I can imagine a streamliner MIGHT have a problem after 1 hour, but unlikely. That a cube 2.4' per side.
There must be a reason for the "forward human air" rule, but I don't know what it is. It has nothing to do with air supply.
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Thanks for the ideas and insight.
A question on the tube to the front of the car... Should it open through the front bumper to front area air or just behind the front bumper? If it is in the front area air will put too much air in the car at speed? I don't want to push my windows out at speed.
When I bought the car the tube opening was just behind the front turn signal lens.
I was thinking I will run a tube out the back from the rear firewall through the rear valence panel.
Thanks,
Bill
You can't push your windows out with ram-air effect. It's not enough.
Blasphemy but my "fresh air" comes in from where the factory put it, which is the rear of the driver's compartment. I trust GM. I've been scolded about it, but I have enough air for over 10 hours in the cab.
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Racer, the air's not for you to breath. The idea is to slightly pressurize or at least ventelate an enclosed cockpit in case of fire or smoke, so it will be retarded in it's entry to the compartment.
As to your point of view on windows not being pushed out with ram air...... Yes they can and do push out. You forget the negitive pressure on many cars on the outside of said window. The differential makes it very easy for the the window to "push out". Happens all the time.
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Racer, the air's not for you to breath. The idea is to slightly pressurize or at least ventelate an enclosed cockpit in case of fire or smoke, so it will be retarded in it's entry to the compartment.
As to your point of view on windows not being pushed out with ram air...... Yes they can and do push out. You forget the negitive pressure on many cars on the outside of said window. The differential makes it very easy for the the window to "push out". Happens all the time.
Thanks.
Somebody can check my math, but I'm getting less than 1 PSI at 200mph in ideal conditions for ram air. If there is a exit path, that drops radically.
High speed air + flammable liquid raises the temperature of the flame. Static air keep the temps down. ie - your firesuit will survive longer if there is intrusion. Kind of a mixed blessing. If the ramair does not keep fire out, the fire will be far more intense.
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Racer, the air's not for you to breath. The idea is to slightly pressurize or at least ventelate an enclosed cockpit in case of fire or smoke, so it will be retarded in it's entry to the compartment.
??? Am I misreading?
3.E DRIVER'S COMPARTMENT....All enclosed driver compartments shall be equipped with a forward-pointing fresh air intake or breathing system directed to the driver and adequate venting to carry away fumes.
Mike
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Mike, I read or. Probally will be changed to "and" next year now....
You can bet that in tech they will advise you to pressureize your cockpit, especially at El Mirage.
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". . . pressurize your cockpit, especially at El Mirage."
And experience (bad) has shown that that includes Street Roadsters with windshields.
Stan
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Thanks, Mike!
I wonder how one would test for "adequate venting to carry away fumes" :mrgreen:
Mike
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Ok, adding some positive pressure to the driver's compartment makes sense. I did not consider that. In that case I will replace what I had.
Thanks for your thoughts,
Bill
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"I wonder how one would test for "adequate venting to carry away fumes"
Thats why there is a space for a test dummy - er - alternate driver on the entry form.
DW
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It would probably be best to keep a canary in a cage inside your car. It's worked for hundreds of years.
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JustaRacer:
New enclosed car rule requirement?
:)
BR
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Canary and canary cage will need to meet all requirements of Section 3A through G. Not sure on availability of canary configured Hans device. vic
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Up to 175, requires one canary.
176-250, requires two.
250+ requires three.
Canaries must SFI (South Florida Indigenous) and be checked for signs of life every 2 years.
For Classic classes the canaries must be over 5 years old, and must be fed only organic birdseed.
Swallows can be used as a substitute ONLY if they are African Swallows, and can carry a coconut.
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We have an opening in the rear window of the Sonoma, ducted through a filter to an electric blower that feeds the drivers helmet. You don't have to have a forward facing vent. The rule states that OR a fresh air breathing system.
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(http://i264.photobucket.com/albums/ii177/saltracer1/vent_zps7c114671.jpg)
Would this little vent mounted to the roof qualify? Phil
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Yeah -- and you can buy old-fahioned drawer pulls for a buck or so that will do the same thing -- and CHROME, maybe.
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We put one on the top of the canopy of the Stanley and Manchen, now Fred Blachard, lakester.
DW