260DET Posted October 5, 2006 Share Posted October 5, 2006 Rear, for the 280ZX coupe. Considering drag and downforce, reasons why would be useful too. http://www.thezstore.com/page/TZS/CTGY/7RSW1 Like the look of the first one but am guessing the whale tails would work better. Perhaps a rearward extension plus Gurney lip on the first one? Quote Link to comment Share on other sites More sharing options...
260DET Posted October 5, 2006 Author Share Posted October 5, 2006 And there is this one. Should be mounted as far back as possible? Quote Link to comment Share on other sites More sharing options...
veritech-z Posted October 6, 2006 Share Posted October 6, 2006 My personal preference is the bigger of the two whale tails, but that's just because I like the look. Seems like most of the race cars used the whale tail (280zx's anyway) in one form or another. There was a lengthy thread about aerodynamics and drag on S30s some time ago, but I don't remember anyone really getting too into the S130 besides mentioning it solved some of the problems inherent to the S30, and I want to say that most of the spoiler discussions I've seen focused on the duck bill BRE style. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 6, 2006 Share Posted October 6, 2006 My personal preference is the bigger of the two whale tails...There was a lengthy thread about aerodynamics and drag on S30s some time ago... Yes, the whale tails are seriously efficient at producing downforce. As I remember the thread (one of 'em anyway) someone of note stated that getting the air to off the car as far back from the Z as possible was advantageous for aerodynamics--that means that a whale tail that protrudes from the back of the car will actually do a lot of good. Davy Quote Link to comment Share on other sites More sharing options...
ZXR_KiD Posted October 6, 2006 Share Posted October 6, 2006 the last one on the list is the closest to the whale tail most the racecars used (as well as the 280ZXR) so I'd say its the best off that basis Quote Link to comment Share on other sites More sharing options...
260DET Posted October 6, 2006 Author Share Posted October 6, 2006 Like avatar car? A favourite Quote Link to comment Share on other sites More sharing options...
veritech-z Posted October 6, 2006 Share Posted October 6, 2006 Avatar car looks like a raised up version of the larger spoiler, you can see the lip that runs all the way around its edge. Do you know anything about that car? what engine is in it that has a passenger side fender exit exhaust? Doesn't look like one of the big team cars, is it a privateer? Check this out: http://www.conceptcarz.com/vehicle/z10214/Nissan_280ZX%20Race%20Car/default.aspx Now THAT'S a spoiler... Quote Link to comment Share on other sites More sharing options...
RedFive Posted October 6, 2006 Share Posted October 6, 2006 You might get some downforce out of those whale tails, but the pressure drag you create will be enormous. There will be so much separated flow that didn't used to be there, that I don't know if you will gain anything. What you really want is an inverse airfoil which creates negative lift. I found this picture on the net real quick, but it makes things clear: http://techcenter.davidson.k12.nc.us/fall013/1stgroup/airfoil.gif You want that, but upside down. The best thing to do is to look up NACA series airfoils and pick one and determine how much "downforce" you'll create at whatever speed you intend racing at...and then make the thing out of fiberglass or cf. If you guys want I might be able to get a scale model Z in the windtunnel.... Quote Link to comment Share on other sites More sharing options...
veritech-z Posted October 6, 2006 Share Posted October 6, 2006 I remember Olderthanme was trying to build his own miniature wind tunnel, and people were telling him he would have to pressurize it to some ludicrous pressure to compensate for it being miniature, or else accelerate his windspeed to a rediculous amount...would this situation be adressed with your scale model wind tunnel testing? If so, then by all means, git r dun! http://forums.hybridz.org/showthread.php?t=111438&highlight=wind+tunnel Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted October 6, 2006 Share Posted October 6, 2006 Yup, it is basically always a tradeoff - downforce v. drag. Higher downforce is going to produce more drag. Quote Link to comment Share on other sites More sharing options...
jhaag Posted October 6, 2006 Share Posted October 6, 2006 370 pounds of downforce at 100 mph There was an article about the 1979 280ZXR in the Escape Roads section of the 6/9/03 issue of Autoweek that stated the following. "The good news was the new ZX was cleaner aerodynamically than its predecessor. Like most cars, however, the 280ZX developed lift at speed, so Datsun racer Don Devendorf and John Knepp of Electramotive shaped a whale tail spoiler to press the car into the pavement. Racing rules being what they were, though, that big wing couldn't be used unless it was homologated--accepted as a standard-issue part on production models. Homologation for IMSA meant 1000 units, and a cooperative Nissan obliged by producing exactly that number of special models with the huge tail. Officially a $399 option package, the special model was dubbed the 280ZXR and had a large 'ZXR' on the two-tone blue and black tape stripe down each side. Matching stripes went on the hood, and the only color available was silver mist. The cars were all the same, with no options save air conditioning. Not even alloy wheels were included. The spoiler, made of molded rubber, was unpainted. The spoiler was the real deal, generating 370 pounds of downforce at 100 mph. Racers could buy the spoiler out of the Datsun Competition Parts Catalog." When I bought this competition whaletail years ago (still not installed on my ZX), I remember the catalog suggesting that a front air dam be used with it for street applications. John Quote Link to comment Share on other sites More sharing options...
RedFive Posted October 6, 2006 Share Posted October 6, 2006 Yeah, uh....that guy made a circular wind tunnel and didn't even know how to scale the velocity down. You need to use Reynolds equation...and circular test sections create all sorts of issues. The best thing to have is a square or rectangular test section. Plus, he doesn't have any screens or honeycombs to get rid of turbulent or angled air. I don't know wtf they're on about the tunnel being pressurized. Most wind tunnels are below atmospheric pressure when they're running. Anyways, I'm currently trying to do a project in conjunction with Dreyer's Ice cream to save their trucks around 5% gas on the highway. But I'll see if I can get some more time to throw a Z model in there. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted October 6, 2006 Share Posted October 6, 2006 Avatar car looks like a raised up version of the larger spoiler, you can see the lip that runs all the way around its edge. Do you know anything about that car? what engine is in it that has a passenger side fender exit exhaust? Doesn't look like one of the big team cars, is it a privateer? Check this out: http://www.conceptcarz.com/vehicle/z10214/Nissan_280ZX%20Race%20Car/default.aspx Now THAT'S a spoiler... I used the first whaletale pictured on my car with decent success and I was able to power a 6cylinder car to above 160mph according to a stalker radar gun. I was also able to use the same setup with my 383 stroker/T56 combo cruising rock steady at 155mph. The only adverse affect was that the body seem molding where the spoiler sat on the hatch showed stress cracks. I noticed ZERO loss in power with both power plants due to negative drag effect. Mike Quote Link to comment Share on other sites More sharing options...
bjhines Posted October 6, 2006 Share Posted October 6, 2006 damn... this thread says WHALE TAIL!!! All the WAY baybeee!!! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 6, 2006 Share Posted October 6, 2006 Here's a good wing (not spoiler), if you have the $$$: http://www.g-stream.com/ I like the bit where it says the struts must be capable of handling 400 lbs EACH... Quote Link to comment Share on other sites More sharing options...
veritech-z Posted October 6, 2006 Share Posted October 6, 2006 I don't think my HATCH could support that kind of downforce... Quote Link to comment Share on other sites More sharing options...
icice9 Posted October 6, 2006 Share Posted October 6, 2006 go whale tail!!!!!! ive got a 280ZXR replica on mine.. not as big as the whale tail but i like it!!!! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 6, 2006 Share Posted October 6, 2006 I don't think my HATCH could support that kind of downforce... You're right, it probably wouldn't for long. But if someone were to make a support to transfer that force to the frame rails underneath... Iceice9, your sig pic is too big. 600 wide x 200 tall max. The pics of the full size whale tail and the smaller version is pretty helpful though, so thanks for that! I like them both. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted October 6, 2006 Administrators Share Posted October 6, 2006 You *gotta* wonder about someone that installs a whale tail AND a shadow kit. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted October 6, 2006 Share Posted October 6, 2006 First of all, the whale tail spoiler will have virtually 0 drag increase. This is due to it redirecting the air at the very back of the car upwards, and more effectively allowing the air going under the car to flow upwards and fill in the space behind the vehicle. This reduces the separated turbulent region behind the vehicle and reduces overall drag. Refer to McBeath and or Katz and or any Nascar for further evidence of this. If it were me, I'd be making a simple alu sheet angled spoiler for its tunabiliy. Easier to find the appropriate front/rear balance by extending the spoiler and or making it steeper. Oh and as soon as a `spoiler' allows air flow between it and the car, as in that high/rear mounted 280ZXR, it becomes a wing. Wings work better higher as they receive cleaner air, and rearward because they place more force on the vehicle with a longer lever. Get a proper wing multi-element wing, as well as a smaller wing placed very close to the car down low which even MORE effectively pumps the air upwards and out from under it. Oh and while you're there, full venturi tunnels would be the go. I've just drawn up scale sketches for this on an S30, as well as designed radiator/intercooler/3 oil cooler placements and ducting. Probably make the car slower.. hehe. Dave Quote Link to comment Share on other sites More sharing options...
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