Hood vents/mod ideas?

  • floridaZ
    floridaZ
    Senior Member
    • 2781

    #31
    The scoop I am talking about was an aftermarket one for a first gen RX-7, it's been over a year since I looked at the page but if I find it I will post it up. Almost the exact same scoop, mounted more inboard and a bit further forward than it is on the Z (in relation to the windshield).

    But hey, if you want Z31-specific wind tunnel results, I will provide Zs for testing if you will pay for wind tunnel time.
    Feedback- viewtopic.php?f=18&t=19840
  • michaelp
    michaelp
    Senior Member
    • 9384

    #32
    TurboDreams wrote: Auto manufacturers are more concerned with making pretty cars than aerodynamic cars. You'd think that modern sports cars would be more aerodynamic than an FD RX-7, well guess what? They aren't. The FD RX-7 is pretty much the most aerodynamic car that isn't a Prius or Insight (aka things that aren't high performance at all).
    You realize the Z31 is more aerodynamic than the FD right? LOL
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • Careless
    Careless
    Senior Member
    • 13279

    #33
    TurboDreams wrote: Auto manufacturers are more concerned with making pretty cars than aerodynamic cars. You'd think that modern sports cars would be more aerodynamic than an FD RX-7, well guess what? They aren't. The FD RX-7 is pretty much the most aerodynamic car that isn't a Prius or Insight (aka things that aren't high performance at all).
    Where are you getting this incorrect information?
  • michaelp
    michaelp
    Senior Member
    • 9384

    #34
    [quote]Careless wrote:
    Originally posted by TurboDreams
    Auto manufacturers are more concerned with making pretty cars than aerodynamic cars. You'd think that modern sports cars would be more aerodynamic than an FD RX-7, well guess what? They aren't. The FD RX-7 is pretty much the most aerodynamic car that isn't a Prius or Insight (aka things that aren't high performance at all).
    Where are you getting this incorrect information?
    I agree, since you know…the 370Z is definitely more aerodynamic than a FD…and don't even get me started on the "ugly" GTR.
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • StreetFighter
    StreetFighter
    Senior Member
    • 711

    #35
    New 2 Z wrote:

    guess what? it was made back in the 80's it's a mid 80's piece of shit, back when wind tunnels were JUST coming into the scene. the wind tunnels now are A LOT more efficient then back then.

    the engineers today are a lot better then the engineers then.
    Dude, you're a fucking idiot. Please stop posting crap that you think, because you're a dumbass and it's probably wrong. Your post is not only wrong, but it successfully alerts everyone that you are a moron. These 80's piece of shit is more aerodynamic than most cars made today.
    86 hardtop shell, 93 SC300 engine, 95 soarer bellhousing, 91 supra transmission, 95 Q45 differential hubs and driver's side axle, 1992 300ZX turbo driver side axle and calipers, 2004 350Z Rotors, 87 300ZX front end/hood, 1999 Viper radiator, 1992 Mustang throttle body. Lots of glue and tape to keep it all together.
  • StreetFighter
    StreetFighter
    Senior Member
    • 711

    #36
    I had two different drop vents on my hood.

















    I would not recomend getting a WRX style scoop on your hood. It will reduce the amount of air that can pass through the radiator/intercooler. A drop vent will reduce engine bay pressure, thus increasing cooling system efficiency. A cowl induction hood DOES NOT EXTRACT HOT AIR! Your windshield is a very high pressure area, and your engine bay is a lower pressure area. Air travels from high to low pressure. A cowl hood dumps cold air on top of your engine, and pressurizes your engine bay. It was originally made for carbed V8s where the air filter is directly on top of the engine. It is less aerodynamic to have a cowl induction hood (unless sealed against the windshield), and bad for cooling. They will vent hot air when sitting still, but do the opposite at speed.

    You donot want to add more air into your engine bay than is needed. Most of the air that goes into the engine bay gets dumped out of the bottom, and produces more lift. You want the least amount of air under the car possible. Lift makes cars scary to go really fast in, but 99% of the people on this forum will never go fast enough for any of this to be an issue.
    86 hardtop shell, 93 SC300 engine, 95 soarer bellhousing, 91 supra transmission, 95 Q45 differential hubs and driver's side axle, 1992 300ZX turbo driver side axle and calipers, 2004 350Z Rotors, 87 300ZX front end/hood, 1999 Viper radiator, 1992 Mustang throttle body. Lots of glue and tape to keep it all together.
  • maverickxeo
    maverickxeo
    Senior Member
    • 650

    #37
    I did know what a cowl did; my dad had one on his old 500ish WHP Camaro.

    As for those drop vents… how hard were they to put in on your hood, and would you recommend them for something running less than 300WHP? (Probably closer to 250WHP).
  • inqui-Z-tor
    inqui-Z-tor
    Senior Member
    • 9020

    #38
    Cd

    280ZX .. .385
    300ZX (Z32) .. .32
    RX-7FC .. .31
    RX-8FD(R1/R2) .. .31
    300ZX (Z31) .. .30 "old engineering"
    z33 Coupe/Enthusiast .. .30
    z34 Coupe .. .30
    RX-7FC-aero .. .29
    RX-8FD .. .29
    z34 Sport .. .29
    z33 Track/Grand Touring .. .29
    G35 Coupe .. .27
    GT-R .. .27
    G35 aero .. .26
    '84Z31 GLL turbo|theZenthusiast site: http://www.thezenthusiast.com |

    Originally posted by maronee
    PS - by the way your Z31's famous here in japan, dude!!
  • michaelp
    michaelp
    Senior Member
    • 9384

    #39
    inqui-Z-tor wrote: Cd

    280ZX .. .385
    300ZX (Z32) .. .32
    RX-7FC .. .31
    RX-8FD(R1/R2) .. .31
    300ZX (Z21) .. .30 "old engineering"

    z33 Coupe/Enthusiast .. .30
    z34 Coupe .. .30
    RX-7FC-aero .. .29
    RX-8FD .. .29
    z34 Sport .. .29
    z33 Track/Grand Touring .. .29
    G35 Coupe .. .27
    GT-R .. .27
    G35 aero .. .26
    Actually, 84-85 Z31s are .29 Cd :P
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • SATAN
    SATAN
    Senior Member
    • 6782

    #40
    [quote]michaelp wrote:
    Originally posted by inqui-Z-tor
    Cd

    280ZX .. .385
    300ZX (Z32) .. .32
    RX-7FC .. .31
    RX-8FD(R1/R2) .. .31
    300ZX (Z21) .. .30 "old engineering"
    Originally posted by inqui-Z-tor
    z33 Coupe/Enthusiast .. .30
    z34 Coupe .. .30
    RX-7FC-aero .. .29
    RX-8FD .. .29
    z34 Sport .. .29
    z33 Track/Grand Touring .. .29
    G35 Coupe .. .27
    GT-R .. .27
    G35 aero .. .26
    Actually, 84-85 Z31s are .29 Cd :P
    I thought it was that the 84-86 has like a .27cd and the 87-89 has like .29cd? I do remember that the Zenki's are more aerodynamic than the Kouki's.

    Also people have to remember that your drag coefficient means nothing without knowing the frontal area of the car. If I am not mistaken, the z31 is a decent amount smaller than the Z33 G35, GT-R all of those.
    85 Z31 6.0 LSX turbo 766whp/792wtq
    04 GTO, LS6, big cam, porting, N20… underway for summertime daily driver.
  • TurboDreams
    TurboDreams
    Banned
    • 1127

    #41
    My arguement was going to be basically part of what you just said satan. CD means jack shit. Lotus 7s have HORRIBLE CD but they are so small it hardly matters. Hummers....don't even get me started.

    I have a list that I have compiled based on data from multiple different sites last may. The list is in cda, in other words drag coefficient x frontal area. Not entirely sure how accurate it is but it seems pretty good to me.

    CdA (drag coefficient x area; lower is better)

    Honda Insight - 5.10
    Mazda RX-7 - 5.61
    Toyota MR2 ~5.80-5.90
    Nissan S13 240SX - 5.88
    Mitsubishi Eclipse - 5.92
    Subaru SVX - 6.00
    Acura NSX - 6.13
    Nissan NX - 6.15
    Lamborghini Diablo - 6.17
    Nissan Z32 300ZX - 6.23
    Honda Civic SI (EG) - 6.34
    Honda Prelude VTEC -6.34
    Lotus Elise -6.35
    Toyota Supra -6.43
    Honda S2000 - 6.47
    Honda Civic Del Sol - 6.49
    Hyundai Tiburon - 6.52
    Acura DC2 Integra - 6.56
    Lexus SC - 6.65
    Acura RSX - 6.66
    Chevrolet C3 Corvette - 6.72
    Pontiac Fiero - 6.75
    BMW M3 (95) - 6.77
    Mazda MX-3 - 6.79
    Mitsubishi 3000GT -6.80
    Nissan B13 Sentra SE-R - 6.87
    Saturn SC2 - 6.90
    Mazda Miata - 7.00
    Nissan J30 Maxima - 7.09
    Nissan A32 Maxima - 7.20
    Nissan Z31 300ZX - 7.63
    Acura KA7 Legend - 7.82
    Bugatti Veyron - 8.02
    Lotus 7 ~9.81

    If anyone wants to contribute to the list feel free. Quit trying to argue that the Z31 is more aerodynamic than the FD though without further proof, 2 full points is a lot even for crappy internet information.
  • New 2 Z
    New 2 Z
    Senior Member
    • 1219

    #42
    TurboDreams wrote:

    CdA (drag coefficient x area; lower is better)

    Honda Insight - 5.10

    Lamborghini Diablo - 6.17
    Bugatti Veyron - 8.02

    i'm sorry but i see this i feel this list is wrong.
    so your saying a honda insight is more aerodynamic then a lmaborghnini, and a Bugatti? so, according to you the millions of dollars and HOURS spent on high performance cars on the wind tunnel in not enough, but apparently the honda insight is so aerodynamic is it more then honda's own NSX?

    I find this extremely HARD to believe.

    he gives me shit all the time about the money i spend on my car but he simply doenst understand what type of "high" you get from watching a stock car transform into something alive with as much emotion and feelings as any human.
    Originally posted by PurePontiacKid
    My god… 10 pages and so far he's only pulled the motor out of the donor car, and bought some valvetrain parts for it? way to be proactive guys.
  • TurboDreams
    TurboDreams
    Banned
    • 1127

    #43
    Why? Look a a Veyron, they are big, they have a ridiculous amount of aerodynamic restrictions in the form of it's 10 heat exchangers, etc. Oh and did I mention they have to create downforce which a byproduct of creating downforce is drag?

    The Honda Insight is at the top because believe it or not they weren't designed to be as sexy as other cars, nor to be driven at 200+mph. They are small, they have covers over the rear wheels among other things to decrease their Cd.
  • NissanXRMA
    NissanXRMA
    Senior Member
    • 3245

    #44
    Ha My family just got a Insight. Paddle shifters and everything. LOL 1.3 L. It's very aerodynamic. Wicked fuel efficient.

    They use to have rear covered wheels. They don't anymore. They look way better now.
  • TurboDreams
    TurboDreams
    Banned
    • 1127

    #45
    The model I had info for WAS the old model.