veritech-z Posted May 26, 2006 Share Posted May 26, 2006 I've been searching to see if using a roof scoop would change the aerodynamics of my car in a way conducive to not dying of smoke inhalation, or if it would in fact do the opposite and promote more fumes getting drawn in through the back. I went out driving the other night to help my buddy put some miles on his bike, and while I was sitting by my car with it's dead battery waiting for him to go home and get his car(I made the thrilling discovery that my alternator isn't charging properly at 3am) I was trying to come up with solutions to my fume situation. I know I've got bad seals on my tail lights, and i've got a big gaping hole in my hatch where my fuel cell is residing, but my exhaust extends out a good six inches from the back of the car and is angled out to the passenger side (which i was hoping would put the fumes out far enough to keep them from getting drawn in, but evidently not). Also I know for a fact that my manifold gasket is leaking on number six, and that problem will be solved when I go back to fuel injection soon. So my possible solutions I came up with are like this: roof scoop (which if placed over the driver's head has the added benifit of more helmet clearance if needed), turning the inspection panels in the hood into ducted scoops that come out of the dash where the ac vents used to be, and removing the rear quarter windows for clear ealanor style scoops epoxied on to plexi replacements. Aesthetics (and I know that I need to patch up these known problem areas before doing any creative ducting) aside, would scooping more air into the cabin from the front of the car increase or decrease the fumes? I know fumes have been beaten to death, but I haven't come across anything that really deals with the effects of scoops on the problem... Quote Link to comment Share on other sites More sharing options...
johnc Posted May 26, 2006 Share Posted May 26, 2006 Maybe just fix the problems with your car before trying any modifications... Quote Link to comment Share on other sites More sharing options...
veritech-z Posted May 26, 2006 Author Share Posted May 26, 2006 Well, that was kind of the plan, I was just curious ducting air from the front would work for the better or would it make it worse all other things being equal? Is it really even possible to totally eliminate the fuel smell? I've never been in a z that didn't have it, but I admit that my experience with them is not nearly what most people on the site is... Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted May 26, 2006 Share Posted May 26, 2006 Why not just add a 90 deg down on the end of the exhaust? I have a 90 deg down on my exhaust which finished at the end of the diff and I've never smelt anything. Dave Quote Link to comment Share on other sites More sharing options...
johnc Posted May 26, 2006 Share Posted May 26, 2006 The exhaust fumes tend to enter the cabin when the cabin pressure is lower the the air pressure outside the car - driving with the windows down as an example. Anyhting you do to make the air pressure inside the car greater then the air pressure outside will keep exhaust fumes from entering. Closing the windows while driving and having the vents all the way open, adding a roof scoop, etc. And yes, early Zs can be made gas and exhaust fume free if the 30 years old gaskets and hoses are replaced and the engine is kept in proper tune. Quote Link to comment Share on other sites More sharing options...
olie05 Posted May 27, 2006 Share Posted May 27, 2006 I agree with john, and will share my personal experience. I had the same problems with my z, exhaust fumes when I would cruise at high speeds with the windows open, and faint fumes with windows closed. I fixed it by going into the hatch area and sealing up all the little holes I could find, and by replacing the tail light gaskets. That was it! for me at least. My advice to you; Fix the leaks first, and then if you really want a roof scoop, install it. But don't install a roof scoop and expect it to make your fumes disapear. Quote Link to comment Share on other sites More sharing options...
MIBPreacher Posted May 27, 2006 Share Posted May 27, 2006 Veritech My tail lights leaked in my 300zx, is it possible to pick up a tube of black silicone and seal them off? I used it in the crack between the lights and the body and I havnt leaked since. The water runs right over it. You cant really tell its there unless you are looking for it. Quote Link to comment Share on other sites More sharing options...
olie05 Posted May 27, 2006 Share Posted May 27, 2006 I used the light-duty light blue silicone to seal off the cracks (from fumes) on my tail lights. Quote Link to comment Share on other sites More sharing options...
veritech-z Posted May 27, 2006 Author Share Posted May 27, 2006 So taking my car and it's myriad problems out of the equation (I'm acutely aware of all the areas my car needs work in, I was just trying to set the mood for what got me thinking about cabin ventilation), would the front of the windshield be a better place to route in air, the roof with a low profile scoop, or by the rear quarter windows? Quote Link to comment Share on other sites More sharing options...
olie05 Posted May 27, 2006 Share Posted May 27, 2006 i'm no aerodynamicist (sp?) but the roof seems like the best place if you want air in the cabin. let me explain my reasoning: there is alot of airflow over the roof of the car, in fact the air sticks to the downward slope of the roofline towards the hatch (creating lift). This would give you alot of air going into the car. Compared to the high pressure air accumulation by the bottom of the windshield, it seems that the roof would give you more velocity, and more pressure with the air coming in, than say, the stock fresh air vents on my 280z, which would almost be the same as putting the intakes on the inspection lids. I wouldn't do functional "ealonor" style quarter window intakes, because when you open you windows you get lower cabin pressures, so it seems that putting the vents that close to the windows would maybe not be as effective in getting air into the cabin as the roof scoop. Quote Link to comment Share on other sites More sharing options...
veritech-z Posted May 27, 2006 Author Share Posted May 27, 2006 A forward facing scoop that actively draws in air should be a little different than just opening a hole in what would otherwise be a flat surface, similar to a forward facing scoop on a hood to feed a carburator versus just cutting a hole in the hood with no scoop. Isn't rear window scoops the way they do it in nascar? This picture comes from www.race-cars.com, and it clearly has some kind of scoop in the window there...I know making an "elbow scoop" (hanging one elbow out the window) draws in plenty of air that would otherwise go right past the car...As for using air by the windshield, high pressure air should try to force itself into any hole that was there, that's why cowl induction works,right? So I suspect it wouldn't be a bad place at all to draw from. I think I need to do something though, because here in florida, no climate control and no windows is just not an option from a temperature standpoint, let alone fumes. *edit* upon closer inspection, that scoop looks like it's ducted to the brakes on that car...but that should mean it still gets decent flow, right? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 27, 2006 Share Posted May 27, 2006 You should look at the aerodynamics threads and that will tell you more, but my understanding is that the flow over the roof separates from about the middle of the roof back and that this is not a high pressure area. You could put a vent in the leading edge of the roof like the late 90's Subaru rally cars and that would work. The cowl area is a high pressure area, which is why there is a fresh air vent in the cowl from the factory. Fix the problems first though, and do your vents later if you still feel they're needed. Quote Link to comment Share on other sites More sharing options...
2003z Posted May 27, 2006 Share Posted May 27, 2006 the roof is a low pressure area. It is basic aerodynamics, just like an airplane wing. as the car travels through an airmass, the mass has a farther distance to travel over the top of the car than the bottom, thus creating low pressure, or lift. That is why convertibles with their tops up look like they are inflated at speed. Quote Link to comment Share on other sites More sharing options...
Jason Jarvis Posted May 28, 2006 Share Posted May 28, 2006 Does this only happen in jet mode, or do you have the same problem in guardian and battloid ? You know the aerodynamics are substantially different... Sorry, I had to..... First, I agree with fixing the problems first, the roof scoop may be the most effective, but have you ever tried to fix a hole in the roof of one of these cars, that subtle curve is hell to ever get right once the roof has been molested. The NASCAR pic you posted is a good idea if you really want to try something, a Lexan window with a NACA duct should increase the cabin pressure and be removable later if you want. Otherwise, you might just try a duct in the front of the car routed to the cabin air intake, should create more pressure than the "fresh air" system is capable of, and again, be removable later. Check out places like pegasus racing for what you would need, as long as you are willing to spend a little money on it. Jason Quote Link to comment Share on other sites More sharing options...
veritech-z Posted May 30, 2006 Author Share Posted May 30, 2006 So far just in jet mode, my battleoid actuator lever was disconnected by the previous owner, and the protoculture matrix came out for overhaul shortly after I got it, necessitating the use of the vastly inferior su carbs until the RDF processes my request for protoculture replenishment... As far as spending any serious money, the forecast isn't looking too good, at least until my wife starts her new job next week. Whichever way I decide to go, I'll post some pictures when I'm done. I went to borrow a friend's alternator tester, and found out my car is totally running off the battery right now, so that is the first thing on the list to figure out. I'm not sure yet if it's in the wiring or in the component, I haven't had a chance to really look at it. It's not my daily driver, so it's kind of a back burner issue really. Also at that time I decided to put a vacuum cap over the vent port on my fuel cell, and man did that make a difference. I'm not sure if it will affect my fuel delivery or not, I haven't driven it that far since then to find out, but it was definitely a step in the right direction. Plus I bought some new 5-.8 nuts for the tail lights, since they were mostly missing, and just the plastic clips were holding them in. I'm sure that will help a lot. Quote Link to comment Share on other sites More sharing options...
Jason Jarvis Posted May 31, 2006 Share Posted May 31, 2006 So far just in jet mode, my battleoid actuator lever was disconnected by the previous owner, and the protoculture matrix came out for overhaul shortly after I got it, necessitating the use of the vastly inferior su carbs until the RDF processes my request for protoculture replenishment... I think a disproportionate number of Z fans are also Anime fans, a buddy in our Z club has Fujiwara Tofu Delivery decals on the side of his Z31 and a NERV license plate.... Jason Quote Link to comment Share on other sites More sharing options...
veritech-z Posted May 31, 2006 Author Share Posted May 31, 2006 I'd rock a nerv license plate if I had one...Misato drove a 280zx in that series until it got rolled over by an angel attack. Quote Link to comment Share on other sites More sharing options...
Jason Jarvis Posted June 2, 2006 Share Posted June 2, 2006 I didn't realize that, I'd pull Eva out and watch it, but I have tapes, and no VCR any more.... Jason Quote Link to comment Share on other sites More sharing options...
Owen Posted June 4, 2006 Share Posted June 4, 2006 "You guys have way too much free time", writes Owen, as he glances up at the two Rei figurines sitting atop his monitor.... What was this thread about again? Owen Quote Link to comment Share on other sites More sharing options...
veritech-z Posted June 10, 2006 Author Share Posted June 10, 2006 As Max puts down his Super Sayan Goku piggy bank, and adjusts his 1/12 Mach V race car, he glances over at his guardian mode Roy Fokker Skull 1 veritech toy, wondering how he managed to get married to an actual girl..."I think it was about the aerodynamics of keeping exhaust fumes out of my cabin on the z using scoops, but it's no longer possible to be sure..." Quote Link to comment Share on other sites More sharing options...
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