JMortensen Posted December 20, 2006 Share Posted December 20, 2006 I think that's contrary to the popular belief, OTM, but we may find out for sure soon. Quote Link to comment Share on other sites More sharing options...
haukenes Posted December 20, 2006 Share Posted December 20, 2006 Yeah i was under the impression that the Z's 'unique' areodynamics made it such that *most* (which i say reservedly, and in good taste) aftermarket areodynamic modifications will improve the overall drag coef. and turbulence issues, since the 'not quite teardrop' shape of the z-body leaves quite a bit of lift and drag at the backend... I'm not an expert by any means, i actually do biology, not physics or areo, but it seems that it would help the air off the back end a bit, not to mention the BRE style spoilers look pretty sweet Quote Link to comment Share on other sites More sharing options...
Carl Beck Posted December 20, 2006 Share Posted December 20, 2006 I think that's contrary to the popular belief, OTM, but we may find out for sure soon. Hi John / OTM (everyone): It is certainly contrary to what Car & Driver found in their tests in 74. Stock: 140 lbs of Lift on front wheels @ 70mph 20 lbs of Lift on the rear wheels @70 mph BRE Front Spook canceled 105 lbs of Lift and increased gas mileage by 0.4 mpg BRE Street Spook (no brake ducts) canceled 115 lbs of Lift BRE Rear Spoiler added 75 lbs. of down force @ 70 mph and 0.2mpg C & D custom 7" rear spoiler (at 50 degrees from horizontal) Added 160 lbs of down-force to the rear but off loaded an additional 20 lbs from the front. It also hurt gas mileage by 0.6 mpg. FWIW, Carl B. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted December 20, 2006 Share Posted December 20, 2006 I see you've made it over to HybridZ Carl Beck! Welcome on over here! Thanks for those awsome specs! Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted December 20, 2006 Share Posted December 20, 2006 someone had chimed in on vortex generators awhile back. anyway, now being whored on ebay! btw, carl-welcome to the 'dark side'! http://cgi.ebay.com/ebaymotors/Vortekz-Universal-Vortex-Generators-Black-10-Pieces_W0QQcmdZViewItemQQcategoryZ42611QQihZ019QQitemZ290063921879QQrdZ1 Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 20, 2006 Share Posted December 20, 2006 hmm... well I did something to my carbies at the same time I pulled my spoiler or something...I know that I gained MPG...lol Quote Link to comment Share on other sites More sharing options...
JIM73240Z Posted December 20, 2006 Share Posted December 20, 2006 1. can some one PLEASE past in the article from JM so i can see them PLEASE. 2. those vgs on ebay are faily cheap at $20. i bought the air tabs for around $45. they are a little wider than those on ebay. jimbo Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted December 20, 2006 Share Posted December 20, 2006 http://cgi.ebay.com/ebaymotors/Vortekz-Universal-Vortex-Generators-Black-10-Pieces_W0QQcmdZViewItemQQcategoryZ42611QQihZ019QQitemZ290063921879QQrdZ1 OMG COOL!! this is awsome! Quote Link to comment Share on other sites More sharing options...
Carl Beck Posted December 21, 2006 Share Posted December 21, 2006 Hi PrOxLaMuS© / 1_tuff-z (everyone): Hi Guys - thanks for the welcome. I've been a lurker here for a long time - ever since pparaska started harassing me and I like the way jmortensen administers/moderates.... just been too busy with a hundred other things to get involved in any of the very interesting threads. The subject of Z Car aerodynamics however sucked me in this time... If you don't have a copy of the 74 Car & Driver article, e-mail me and I'll let you read my digital back-up. It will be interesting to see how the HybridZ wind tunnel results match up... or not... Carl e-mail: beck@becksystems.com Quote Link to comment Share on other sites More sharing options...
biohazard53188 Posted December 21, 2006 Share Posted December 21, 2006 It wouldn't be very ricey if it actually worked. For what it's worth the Mustang that I used to beat up on at the track (I was 5+ seconds faster last time we were both out @ Buttonwillow in 2000) is now posting times a full 10 seconds faster than my old times, and it now has a big ol wing on the back, and I'm pretty sure it's faster than John Coffey's ROD too. 10 seconds and faster than the ROD makes me think I could deal with the embarrassment of having a big ol wing on the back of my Z. Of course the wing is an actual racing part and is ~$1000, not a Wings West special... Hahaha.... I like the first line. I have a friend thats really into civics, i think im gonna pull that one on him. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 22, 2006 Share Posted December 22, 2006 From a different thread about fuel cells and diffusers: Strakes are really not needed in our application. You just need sides to the diffuser. I mounted my Borla muffler vertically on the left side of the fuel cell and the fuel pump/filter frame on the right side had a sheet of CF wire tied to it. I'm sure the whole setup generated about 5 lbs of actual downforce but I felt it made about 50, so I drove faster through the corners. In that sense it worked. I'm ready to mount my cell, and I've been thinking about the strakes and diffusers for a couple days now. I think I am going to mount my cell backwards so the pickup is in front, then lean it 7 degrees so that the tank acts as a diffuser (a little bit anyway). I did some reading because I wasn't really aware of the purpose of the strakes in a diffuser. Apparently keeping the air separated into separate channels helps to keep the flow attached to the diffusers and helps to keep the air from turbulating. There was also some mention of using vortex generators at the leading edge of the diffuser to keep the airflow attached. Then I was thinking of the aero article where they used the airtabs under the nose of the Insight. Just thinking out loud... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 22, 2006 Share Posted December 22, 2006 Well, that one kinda didn't go anywhwere... I went out and tried to put a tube across the rear area to see what kind of angle I can get with the cell, and the max angle I was able to acheive was about 4 degrees. I think I'm going to mount the cell flat and if I feel like I need a diffuser later on I'll add a separate piece of sheet aluminum. Quote Link to comment Share on other sites More sharing options...
Michael Posted December 23, 2006 Share Posted December 23, 2006 Finally stumbled on this thread.... so THIS is the source of the planned wind tunnel test campaign! There is much to discuss here, but let me mention just a few points... 1. Please note the distinction between static pressure, total pressure and dynamic pressure. Keep this in mind when pondering the stalled airplane wing tuft problem. 2. Cars are bluff bodies; bluff bodies behave rather differently than streamlined bodies (airplanes) - an important distinction which challenges the intuition. 3. Turbulent flow can be separated or attached. Turbulence is not necessarily bad. 4. The total pressure in a vortex core is lower than in its periphery. The total pressure outside of the core is constant, but static pressure is exchanged for dynamic. 5. The slope of the Z's hatch was rather unfortunately chosen; massive separation is hard to avoid. A "Pantera" hatch is possibly a solution. 6. For many applications it is admissable to have enormous mismatch in Reynolds number between an experiment and full-scale. This is why scale models - again, depending on application - work quite nicely. 7. For the engineers out there - please use caution in applying textbooks principles to car aerodynamics. Yes, the equations are still valid, but good luck specifying the boundary conditions. 8. Beyond a certain point it, brute trial and error might give a better solution than an attempt at armchair analysis. This is where laymen - paradoxically - can have an advantage over the engineers. As I've been discussing in PMs, there are strong advantages to subscale testing in university wind tunnels, rather than the full-scale testing in North Carolina. However, the North Carolina group is well-organized and has impressively thought things through. I am optimistic of their success. Quote Link to comment Share on other sites More sharing options...
Carl Beck Posted December 23, 2006 Share Posted December 23, 2006 Has anyone been following the Dodge Ram SRT-10? 500HP Viper engine.. 150MPH top end and sub 5.0 second 0-60mph? At any rate some interesting "aero" devices on this truck - developed via CFD Modeling/Visualization plus wind tunnel and on track testing. See: http://www.dodge.com/srt-10/ Note the size difference between the Ram SRT-10 and the Ram Daytona rear aero devices.. Then an interesting article related to Daimler/Chrysler - Dodge and aero design efforts/processes.. http://www.creativemac.com/articles/viewarticle.jsp?id=25605 FWIW, Carl B. Quote Link to comment Share on other sites More sharing options...
SHADY280 Posted December 23, 2006 Share Posted December 23, 2006 i put the low pro whale on my car and havent noticed any affects such as drag on my car or lower mpg, it seems to plant it down pretty good in conjunction with the front air dam at high speeds. i figured that on the street the regular whale tail would possiblly produce more drag, so thats why i chose the low pro, but on the race on the other hand, itll get the full version. Quote Link to comment Share on other sites More sharing options...
haukenes Posted December 24, 2006 Share Posted December 24, 2006 hey all, got sidetracked in the aerodynamics discussion and forgot to get an answer to my original question, do they make a BRT style spoiler for the 280ZX or do you have to get one that fits another car and *tweak* it on? Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 24, 2006 Share Posted December 24, 2006 Michael.... Thank you for posting in this thread... Yes this thread seems to be the kindling for the fire... I think most of us had come to the conclusion that anything more than a basic correlation to any aircraft shapes was leading to more confusion... We have pondered the effects of minor roof modifications to upset the airflow either at the top lip of the windshield... or rearward at the top rear hatch line.... much of the debate has been about using vortex generators or just a simple lip... It seems that the VGs might have less drag... where the lip might be more effective at a shorter height... The Pantera hatch was discussed as another way to get rid of some lift without sticking anything out in the breeze(less drag)... With the addition of a pantera style hatch... How high would a rear ricer-style wing need to be mounted to be effective??? The rear lip spoiler discussion is moot until we get the testing done... There is only one way to mount most of those rear lips.. they are what they are... I have it on good word that the 3 piece style rear wings are best because they actually wrap around the rear of the car... The local land speed 2nd gen. Camaro guys have what look like 3 piece lips on steroids... they remind me of a turkey tail... Turkey bird Trans-AM... Obviously we will be testing these things in the wind tunnel... but it would be nice to have some input on where to start... We have to build these things with some room for adjustment.. It would be nice to know what general range we should be working in... otherwise we just look at what others have done and start from there... Quote Link to comment Share on other sites More sharing options...
Cethern Posted December 30, 2006 Share Posted December 30, 2006 I have one of Paulo's wings the bigger of the two. I got it put on before the blizzard here in Denver so I have not gotten to really get a good feel for it. But I did make a run across town and the rear of the car had a loose feeling Before the wing Now after my trip across town it felt tight. But the next day or so it snowed a little.. I will still need to block sand it and stuff but the over all fit seems pretty good. Quote Link to comment Share on other sites More sharing options...
haukenes Posted December 30, 2006 Share Posted December 30, 2006 Yeah.... stupid blizzards. I was actually really surprised at how well my 280ZX did in the snow Never got stuck, which is more than some of the stupid 4 wheel drives around here can say. Dang! i should have gotten some good pics of the Z covered in snow! (when i say covered, i mean completely.... it was more of a bump...) Quote Link to comment Share on other sites More sharing options...
Carl Beck Posted December 31, 2006 Share Posted December 31, 2006 "Paulo's wing" looks a lot like the 7" by 30 degree rear spoiler that CD Tested. It added 120 lbs. down-force at 70 mph to offset the 20 lbs of lift in the stock Z. The BRE Rear Spoiler added 75 lbs of down-force, drag was the same for both - they increased gas mileage by 0.2 mpg at 70 mph. Increasing the angle of attack of the 7" spoiler to 50 degrees, resulted in 160 lbs of down-force, but increased drag to the tune of a loss of 0.6mpg at 70mph. That 160 lbs of downforce on the rear also lifted 40 lbs off the front... Maximum down-force might not be the best answer.... FWIW, Carl B. Quote Link to comment Share on other sites More sharing options...
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