baddriver Posted May 11, 2004 Share Posted May 11, 2004 most of the discussions about the aerodynamics of the Z seem to agree that stopping air from getting under the car is the number one priority. Managing air at the rear of the car seems to be less of an issue, but I've seen several references to spoilers improving airflow and reducing drag. A wing is for providing downforce, but will a wing have the same benefits as a spoiler, or would a spoiler be a better choice? The wing I have in mind is the small standard wing from MSA, vs. one of the simple inexpensive spoilers. I like the look of both, but I think I like the look of the wing better. Which would be a better choice for an early z? Specifically a 260 w/ stock body. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 13, 2004 Share Posted May 13, 2004 There is an absolutely classic write up about early Z car aerodynamics that has been posted here several times. Unfortunately I can't find a link on my work machine. But it would be worth your time to do a search to find it. The article started at the front end of the Z and worked it's way back to the tail. Among it's more lucid conclusions were that 1) it is not just the air going under the car that is a problem, it is also all the air going through the huge radiator hole that causes front end lift. And 2) the smooth, uninteruppted shape of the back hatch works too much like a wing and causes rear end lift at speed. So the answer to your wing vs. front end spoiler questions are yes and yes. The Z can greatly benefit from both. For front air dams, do a search. Quite a number of good options. Probably the best is the plastic lawn edging that people use to get the front dam right down on the deck. If it scapes in a hard turn or on a speed bump, then you are out 10 bucks. In the rear, my choice is the BRE type rear spoiler. Fits the era and lines of a Z classically. I guess you could use a wing. I don't know which would be better from a performance point of view. But, IMO, wings look out of place on a classic Z car. Too much of a Honda wannabe look about them. But that is just personal preference. Go with whatever works best. BTW, the aerodynamics article I mentioned suggested contouring the body at the top of the hatch to break up the air flow before it slides down the back end of the car. Don't know if I have ever seen anyone do it that way. Quote Link to comment Share on other sites More sharing options...
innerware Posted May 13, 2004 Share Posted May 13, 2004 Hi ya. Someone just posted that link to a question that I had a week ago. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=33720&highlight= This is the link. I hope it works, I have never posted a link before. If not it is in the exhaust forum and look for posts by me. Good luck, Quote Link to comment Share on other sites More sharing options...
tannji Posted May 13, 2004 Share Posted May 13, 2004 http://zccw.org/Tech/Body/09-97EarlyZAerodynamics.html Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 13, 2004 Share Posted May 13, 2004 Yeah, thats the link! Thanks guys. Quote Link to comment Share on other sites More sharing options...
260DET Posted May 15, 2004 Share Posted May 15, 2004 IMHO early Zeds look silly with a wing, but emphasise, IMHO. Perhaps more importantly a wing will almost certainly cause more drag than a conventional spoiler. IIRC those spoilers actually reduce drag. Quote Link to comment Share on other sites More sharing options...
Guest BigWhyteDude Posted May 15, 2004 Share Posted May 15, 2004 If it were me i would go with one of the BRE spoilers as well. Great looking on the Z's. Andrew Quote Link to comment Share on other sites More sharing options...
crazy280 Posted May 25, 2004 Share Posted May 25, 2004 hi i'm no aeronautical engineer, but i've always heard that a rear spoiler creates a lot more drag than a wing. how it looks on a z is a different story though Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 25, 2004 Share Posted May 25, 2004 The wing can produce negative lift, with the penality of induced drag. The rear spoiler will create a high pressure area in front of the rear spoiler that counters the low pressure developed by the roof's (and the hatch) shape with the penalty of drag as well. My thoughts are the wing would ultimately be more effective if maximum downforce is the goal. My personal experience in "seeing" the effect of a rear spoiler was to see a downforce actually created by it as the Z reached speeds in the 70+ mph. It was an enlightening experience. Guessing from the amount of weight that was affected as a result of the experience, I'd say there was no less than 30 pounds of downforce applied to the rear of the hatch at highway speeds. Granted, this aint much, but it's a lot better than negative pressure back there. This was caused by the spoiler in the following picture: BTW, this was my first "Z" fiberglass project before the BlueOvalZ. Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted May 25, 2004 Share Posted May 25, 2004 Ah, so you did finally get together with the owner and get some pictures of your old car? Cough them up Terry , we all want to see! !M! Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 25, 2004 Share Posted May 25, 2004 Dang memory like an elephant! I guess nothing gets by you. Here are a few more. It was a bad day for photography when I took these, but I didn't know when I'd get back around for another opportunity. As stated earlier, this was my first Z fiberglass work, and looking in hindsight, I learned a lot (made some blunders) and applied the lessons learned to the BlueOvalZ. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 25, 2004 Share Posted May 25, 2004 This has been brought up several times, and although the front end of the car has issues, the rear aerodynamics should never be overlooked. Downforce Vs. Drag has always been a serious issue, but one that needs to be applied to the application of the vehicle. If you are running the car at constant speeds never reaching above 100MPH, most likely a smaller "BRE" style spoiler will suffice. However, When we generate speeds in excess of that 100MPH mark, things tend to get a little iffy, especially with rises in the course or road, and with the already handicap of poor CD built into the car. A couple of good examples of tragic results of poor aerodynamics have been used in the past... One being the infamous Benz team cars experiencing undercar lift at the front of the vehicles while cresting a rise at Road Atlanta back in 1998/99 timeframe. The other is the Mazda RX7 from the Saltflats timed runs.. That car in particular is a good example of bad rear aerodynamic management, while the Benz example is a good example of dirty air under the front of the car, and building presure at the wrong time, causing the whole car to lift off ground and flip BACKWARDS at speed, end over end. In my own testing over the years, I've run several different types of smaller deck mounted spoilers, as well as several designs of the infamous whaletail spoiler. One of them being a ripoff of the 933 Turbo tail, and the other being the California Whaletail, which is cleaner with no lip on the trailing edge. Both spoilers generate significant downforce, to the point of cracking the fiberglass at the decklid mounting area. At speeds below 100MPH no evidence of serious downforce could be seen in the paint, finish, or fiberglass. At speeds well above 150MPH, there was evidence that the wing was under serious presure and that the bond/ body seam sealer was deformed to the point of chipping off fresh paint. This was experienced on the Yellow Z with an L6 motor/ MSA Front bumperspoiler combo/ sideskirts/ rearbumperspoiler combo/ California Whaletail, and then on the white Z with a V8 Conversion/ traditional bumpers/ MSA Standard spoiler with brake ducts/ 933Turbo Style rear wing/ rear flares. Doug, Pete and I have discussed this issue several times over beers and food and the bottom line is to get the car as low to the ground as possible, clean up the front area around the grill and below the grill, and then focus on something to aid in stabelizing the rear of the car. Some of the more modern import wings would probably aid in stability at the rear, but may not provide enough true downforce. The spoiler Terry shows in his pics of the red car would certainly show significant downforce, but would hender CD efficiancy and creating a drag management issue. So, how do you find balance? Good question. Chin Splitters, underbody trays, defussers, and side skirts are being employed, but can be deadly if the right testing isn't done. If you don't have access to a wind tunnel (And trust me, they are NOT inexpensive) then you are really just guessing and hoping, and likely making a bigger problem. I refer back to the M-Benz team at Road Atlanta in 99. Those cars were aerodynamic wonders to behold... Until they took flight. I'm not sure what the answer is, and if I were, I could retire from the gig I have and make serious money consulting for race teams... But if someone has the magic combination for a given circuit, then It might help to post their combos... However, you won't know if something works until you get it to the track AT SPEED, and I'm not sure there are more than 15-30 guys who take their cars to track events. So you can see that practical analysis is gonna be a challenge for this problem... Excellent topic for this board, NO? Mike Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 25, 2004 Share Posted May 25, 2004 I have an MSA air dam on my 73 240 with lt-1 and t-56. Regulary see speeds over 130 at track events. Car si stable up to about 135. After that the front end starts to dance a bit. No rear spoiler or wing. Mark Quote Link to comment Share on other sites More sharing options...
baddriver Posted May 25, 2004 Author Share Posted May 25, 2004 Thanks for all the replies here guys. I was originally looking for the difference between a rear spoiler and a rear wing, but reading through the lines it looks as though there isn't a big difference, they both make downforce at the cost of increased drag. I am planning on getting the front of the car straightened out first, and I'm looking at a 1" drop, I can't go any farther than that and still be able to get into some of the driveways around here. Other than that, headlight covers are on the wish list, along with vented inspection covers and/or a vented hood. I don't have anywhere local to hit the speeds at which the Z really becomes unstable, so I'll probably just go with what looks best to me an not worry too much about it. Thanks again! Jeff E. Quote Link to comment Share on other sites More sharing options...
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