Guest Zachb55 Posted February 5, 2003 Share Posted February 5, 2003 anyone know what the coefficient of drag is on a stock 240? or even someones racing one? downforce would also be cool to have, would be thankful for any info you guys have on this topic, thanks, -Zach Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted February 5, 2003 Share Posted February 5, 2003 I wrote this down one time, I don't know where it came from but here it goes: The CD for a 240Z is .476 , and that there is under 20 sq ft of frontal area. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted February 5, 2003 Share Posted February 5, 2003 It is not very good but I would say the headlight covers are a cheap investment that goes a long way in helping and IMO also cleans up the lines. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted February 5, 2003 Share Posted February 5, 2003 A G-nose would be a large improvement as well, towards lowering the Cd. Downforce... I think the stock 240z produces lift actually. Quote Link to comment Share on other sites More sharing options...
zero Posted February 6, 2003 Share Posted February 6, 2003 I know the Z makes lift, though I am not sure how much. Hmm, that is a somewhat high drag coeffecient. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted February 6, 2003 Share Posted February 6, 2003 Got Plywood? The drag # sounds about right... I also recall hearing a VW microbus is only .48, and a 4x8 sheet of plywood is .50!!! Our cars suck for areodynamics.. weird since the car has such awsome lines and agressive stance. go figure. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted February 6, 2003 Share Posted February 6, 2003 This was posted here a while back. (save it to your favs) Early Z Aerodynamics There was a long post about this topic a couple of months ago also. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted February 6, 2003 Share Posted February 6, 2003 I just read that article, and thought it was excellent reading. It makes me wonder about the effectiveness of those toyota supra inspired hatch spoiler (up near the roof... Thoough on the Supra (82-85) they were designed as a sunshade because the rear passengers heads are under the rear hatch glass. I wonder if that type of spoiler.. maybe not that particular one.. but something installed in nearly the same location would really benifit out cars... This kinda goes back to the hightech forum where I started a thread about bellpans.. etc.. to reduce exhaust fumes entering the car.. Hmm I think you could easily test this theory on our cars without drilling holes or making permanent alterations...hmmm If you bent a piece of aluminum into a shape similar to that of one of the many variations of aftermarket/nismo rear wings.. but left a lip that could be tucked into the hatch/seal.. close the hatch and wedge in this aluminum wing...kinda hard to describe, but you could disrupt the flow of air enough for testing..... I think I'll add this over in the other thread as well.. maybe someone with a z (not in winter storage) could try this... Sorry to highjack the topic... Quote Link to comment Share on other sites More sharing options...
Synlubes Posted February 6, 2003 Share Posted February 6, 2003 I have thought about fabing a piece at the top of the hatch(and fully across the hatch)about 3" long pretty much paraell with the gound(maybe a little pitch). It would hug the body and not look so wild. I`m thinking something alittle smaller, but kinda the same(but different) as what Mike kZ has on the back of his car. Pic of Mike KZ`s car Any input? Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted February 6, 2003 Share Posted February 6, 2003 Scottie and I were taking about my wing at the last SE HybridZ meet. I have never noticed any exhaust smells in my car, I think it does have an effect. It's also supposed to add down force over the back wheels. Who knows, I just like the different look! Quote Link to comment Share on other sites More sharing options...
Synlubes Posted February 7, 2003 Share Posted February 7, 2003 I took the MSA catalog to an engineer friend(ME with NASA LANGLEY)and asked, Which of these spoilers/wings would give the best result? He very quickly pointed to the "supra type" wing. With out quoting a long resonse from him, The key point was that the down force was over the rear wheels and not at the back of car. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 7, 2003 Share Posted February 7, 2003 Creating down force is good, but from that aerodynamic article Doug posted, I think preventing lift is the key. The article says the smooth flow over the smooth, uninterrupted hatch acts like a plane wing to actually lift the rear of the car. Makes me wonder if the classic Z rear window louvers would help. How do you measure lift on a moving car? I just bought a BRE style spoiler. The BRE racers were incredibly successful. Figure those guys must know what they were doing. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted February 7, 2003 Share Posted February 7, 2003 I did not want to imply any "fact of evidence"(I don`t have any)and was just making a comment. I probly did not use the best term when I said "down force"(although where the down force takes place would seem to make a difference)(IMO), but I agree with Jim that the flow of air over the car is not very good. Quote Link to comment Share on other sites More sharing options...
Guest Carlissimo Posted February 7, 2003 Share Posted February 7, 2003 There is another, very effective way to combat the high drag of the Z-Car body... MORE POWER !! Quote Link to comment Share on other sites More sharing options...
HS1370 Posted February 7, 2003 Share Posted February 7, 2003 I would think that a small lip, perpindicular to the airflow, right above the hatch should disrupt the airflow enough to reduce the lift. It usually doesn't take much to trip the boundry layer, maybe 1/2 to 1 inch at most. It would be pretty easy to test with some angle aluminum and string taped to the rear hatch glass. Similar to the fences that run parallel to the airflow on NASCAR cars. When the car gets sidewase on the track, those fences disrupt the airflow over the top of the car, helping to keep it from taking flight. Scott Quote Link to comment Share on other sites More sharing options...
Guest bluex_v1 Posted February 7, 2003 Share Posted February 7, 2003 Not exactly a cheap or common item, but it might work. I don't know how wide these things are, but the lines look about right to me. BMW z3 wagen hatch spoiler I've thought about whether or not louvers would help on the hatch too, but from what *little* I know, I thought airflow seperated typically at around 7 degrees or something, and so most of the volume that all but the top most louvers would occupy would all be turbulent anyway. Is that about right? Just something I found: "Twenty years ago an average new U.S. car had a 0.48 Cd; today that figure is 0.33, with the very best mass-produced vehicles achieving 0.28. Pickup trucks and SUVs, with their choppy shape and high ride typically have coefficients of drag that are over 0.44" Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted February 8, 2003 Share Posted February 8, 2003 Doug. The wing over the rear wheels would not neccessarily be more effective.. the wing over the rearmost part of the car will act like a lever, and the wheel will act like fulcrum. Any gains in downforce would be multiplied over the distance from the wing to the wheels (fulcrum) But the idea of the "supra style" wing may not add downforce, but may reduce "lift". My Q stands though.. anyone with a fume ridden car want to try this experiement..I'm not sure I can wait till spring to find out. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted February 8, 2003 Share Posted February 8, 2003 Ya know.. you could paint the aluminum body coloured to kinda hide it, or... or you could make it from Lexan...hmm kinda high tech looking. I made a flat wing from lexan years ago on my Z, and left it clear. looked kinda neat. I'm kinda picturing this in my head...growing on me a bit, as long as its not too extreme looking. Chrome it... hmm my personal fav.. stainless steel (insert mental image of Homer Simpson drooling) Ok I'll shut up. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted February 8, 2003 Share Posted February 8, 2003 Ok so I can't shut my mouth. My brain won't stop working ok? Speaking of the BMW spoiler brought to mind the later model 300zx's 87-89 had a third brake light mounted on the top of the hatch..and it was almost 2" deep, and left a 1.25" vertical drop to the glass. I wonder if that made a difference in handling?.. or was it just their for safety?..Nissan did some unusual things to make mods to their race cars legal. Ie "Gnose", "ZXR" wings etc... I also wonder if it would fit our 1st gens?.. hmm I'll have to look into this further....I recal mine was screwed to the hatch some way.. it just might be removeable.. (maybe for bulb access?) Ok ok..like a fat kid playing dodge ball...I'm out! Quote Link to comment Share on other sites More sharing options...
auxilary Posted February 8, 2003 Share Posted February 8, 2003 Originally posted by Carlissimo:There is another, very effective way to combat the high drag of the Z-Car body... MORE POWER !! Unfortunately, that doesn't cure the problem. The lift and drag still exist, and the Z in stock form will still suffer no matter what power plant is in it. Quote Link to comment Share on other sites More sharing options...
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