Landracing Forum
Tech Information => Technical Discussion => Topic started by: saltfever on March 09, 2010, 02:34:07 AM
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3E (page 30, new book) says you need ". . . a forward-pointing fresh air intake system pointing at the driver". If you have glass windows where do you put this intake? On a Production Class car can there be a NACA duct on the roof? Can there be a fire-protected tube through the firewall to the front of the car? or?
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What they are attempting to do is two fold:
1. Primarily gives you fresh air so you aren't overcome by fumes
2. Pressurise the drivers compartment to keep fumes, smoke, and flames out.
In my opinion the closed system to the frt would be more predictable in performance
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I also think there has to be an "exhaust or out let vent too"
So air coming in to the driver and a place for the air, smoke, fumes ,, etc... to depart ?
This is how I understand it and how I am doing in on the Stude.
Charles
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Charles, where are you putting your intake scoop? I have seen NACA ducts on lexan windows but have seen nothing on vehicles with glass. How do they get fresh air?
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CK beware of the venting rule
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Run a 1.0" piece of tubing forward thru the firewall from the cockpit past the motor so you get fresh air even if the motor is smoking.
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CK, you have a front motored car, be careful that you don't create a flame path and a supply of fresh oxygen for a fire. Joe T has the correct idea, pipe the air directly to the helmet, put a shut off on it to regulate the air you get... could be a lot at 200.
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I have not installed anything yet.
I will have Lexan side windows in place of the factory door glass. I had planned on a NACA duct on drivers door window(where a front quarter window would have been).. then a reveresed NACA in the Right rear little back seat side window, to "pull"/vent cabin air out.
I thought this rule was to "POINT" fresh air in the cabin and an exhaust vent to Pull the smoke, fumes,dust,, etc... out... that was my plan,,, I was not piping this air to my helmet,,, just pointing the intake duct that direction...
I plan on using a cool air helmet air system piped direct from cooler behind drivers seat to my helmet for B'Ville..
Maybe I am all wrong,,, suggestions ??
Charles
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All I do is crack open the drivers side vent window, never had a problem with tech. Last year when I blew the right turbo and filled the car full of smoke, the smoke cleared out real quick.
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GH,, that is what I was thinking... I will not have a vent/quarter window,, I am using Lexan,, so that is why I thought a NACA would be ok..
Thanks for all youe help and input,,, keep the suggestions coming.
Charles
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Gary, tech might miss it, but I will bet Dan and J.D. won't. The rule says FORWARD FACING. I would check with them about a NACA duct also, but I would think it would be o.k
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I would not put a rear facing duct in the back as it will create a wind tunnel effect!!!
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Charles, where are you putting your intake scoop? I have seen NACA ducts on lexan windows but have seen nothing on vehicles with glass. How do they get fresh air?
Saltfever, One of the cars I have has glass all the way around. The windshield wiper mechanism was removed and the air was ducted through the opening to the drivers’ compartment. This would work on older body styles that had wipers protruding out the cowl top. You also could make the intake a little more cleaner and less aero drag than the on my car. On newer cars without a cowl, use the same concept and just pick up the air below the windshield. Tony
(http://i273.photobucket.com/albums/jj236/maguromic/vent1jpg.jpg)
Inside drivers compartment
(http://i273.photobucket.com/albums/jj236/maguromic/vent2jpg.jpg)
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I would not put a rear facing duct in the back as it will create a wind tunnel effect!!!
Joe, If there is no rear/outlet duct,,, how would the incoming air from the front NACA exit ? Where would any fumes or smoke exit ?
Thanks
Charles
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I would not put a rear facing duct in the back as it will create a wind tunnel effect!!!
Joe, If there is no rear/outlet duct,,, how would the incoming air from the front NACA exit ? Where would any fumes or smoke exit ?
Thanks
Charles
Your car will not be 100% sealed from the air, if it is you should bring it to El Mirage and race it. :cheers:
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Charles, where are you putting your intake scoop? I have seen NACA ducts on lexan windows but have seen nothing on vehicles with glass. How do they get fresh air?
Saltfever, One of the cars I have has glass all the way around. The windshield wiper mechanism was removed and the air was ducted through the opening to the drivers’ compartment. This would work on older body styles that had wipers protruding out the cowl top. You also could make the intake a little more cleaner and less aero drag than the on my car. On newer cars without a cowl, use the same concept and just pick up the air below the windshield. Tony
(http://i273.photobucket.com/albums/jj236/maguromic/vent1jpg.jpg)
Inside drivers compartment
(http://i273.photobucket.com/albums/jj236/maguromic/vent2jpg.jpg)
I was informed the first time the Fairlane was inspected that all holes on the cowl and cowl vents on front engine cars needed to be blocked off in case of an engine fire.
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I was informed the first time the Fairlane was inspected that all holes on the cowl and cowl vents on front engine cars needed to be blocked off in case of an engine fire.
That may be the case. I never drove the car, but it did run at Elmo about three years ago (been running since 1969 on and off) and was owned by one of Kiwi Steve’s friends last and Steve did work on the car. I would imagine that he would have brought up that point. Maybe Steve or JD can chime in. Tony
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I was thinking the same thing,, about those cowl ducts ,,,fire could come in that duct...but I guess a big enough fire could melt Lexan and get in thru the windshield too !!
B'Ville,,,, My cockpit may not be 100% sealed,,, but it is more sealed than an original car..
As to Elmo,, That's a hike for me to go to as a Non Member for only one or two runs... If I lived closer I would try it out, and see how much dust or dirt got in the cabin.
Charles
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Charles, IN YOUR WILDEST DREAMS you won't be able to comprehend the amount of dust that migrates into EVERYTHING at ELMO.
Even at, "5 mph in pit area".
And Muroc, 20 miles away as the crow flies, it's even finer (and whiter).
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Cajun I was just kidden about runnin El Mirage, and was hinting that EM dust gets into the smallest nooks and crannies no matter how great it is sealed. We are still hunting for air leaks in our car, even after 20 years of running it. :-D
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I realize the car won't be sealed perfectly. But I have to agree with Charles if not for another reason. Without adequate venting the inside will be positive pressure. No telling how much. I'm concerned about blowing a door open or a window. Why do you think they require retaining straps on windshields! (I know it is for our "backwards" friends :wink: ) However, multiply only 1 psi by area and you will see the force involved. I don't want a door blowing partially open at any speed. I don’t mean suicide doors. Even a normal door exploding open will upset the car. Yes, that has happened to me. “Exploding” best describes the unexpected and instantaneous event. The door only moved open 2-3” before the prevailing wind prevent further opening. Essentially, equilibrium of pressure was reached and the door didn’t open further. It was still enough to make the car unstable and cause problems. There just has to be adequate venting to prevent positive pressure. Yes, I read the post about positive pressure keeping flames and fumes out of the cockpit. And it is a serious issue. However, positive overpressure is very dangerous. Maybe a focus on excellent sealing should be considered. I wish Dan or Lee would weigh in on this. How do we vent this thing if air flow is required?
Tony, many thanks for the pictures. The dash outlet makes a nice installation and you gave me a idea. I might check out those Experimental aircraft folks and get one of their cockpit variable flow outlets.
http://www.steinair.com/eyeballvents.htm
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Growing up on Hawthorne Airport made my selection of an air inlet very easy. I remembered the canopy reversable (turnable) clear intake in my dad's old airplanes. I bought a pair of them for abouth $10 in 1976 and reccommended them to many competitors.
I remember when Doug brought the BMR coupe to El Mirage; he needed to put 2 oval holes in the windshield to put enough pressure into the car to keep out the dust. Going to Gas Coupe and putting on the running boards solved my coupe problems....JD
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I have to agree with Saltfever's thoughts on the venting of enclosed cars. I worried about the pressure or lack of it in the cockpit of my lakester since I started building it. The only way I could think of to find out what the pressure differential was between the inside and the outside was be to attach sensors and use data recording. The correct placement of the outside sensor would be difficult for me to pick.
I installed a 12v air pumper to my helmet that draws outside air from holes drilled in the body panel at shoulder height and 18" back of the seat. There is no scoop on the panel for obvious reasons. That should take care of my personal need for air and put a little pressure in the cockpit. That being said I spun the tires a little on one run. I didn't feel it but I could smell it! This is a rear engine car and the rear axle is about 9 ft. back of the cockpit! I also smelled hot oil at the quarter on my seventh run. Anybody have any ideas on how the smell is working it's way forward? I was only running about 150 mph tops but can't imagine what kind of air current was bringing the smells forward.
harv
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Tony and all, when I inspected I allowed the stock air intakes for the interior thru the ones infront of the windshield. I have not been to the last 2 inspectors meetings or hearing they need to be blocked off. I only did a few inspection at the October World Finals last year to help out.
As for an engine fire; to me if you hood has a good seal there should be no problem. If it does not you will smell it almost immediately and it should be fixed. IMO If you blow and engine and buckle the hood that much ANY forward facing intake past the hood line will be letting in smoke or fire.
Steve D. should be the one contacted and at Bonneville he, or any Chief inspector, is always available when a contraversy comes up. Steve Batchelor was an "artist" at it....good luck