1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome to Speak EV, the electric car forum for all EV owners and enthusiasts.
    Our aim is to create the best, most inclusive EV forum for all makes and models of electric car.
    We'd love for you to join up and join in. It's quick, simple and free! Join Speak EV.
    Dismiss Notice

Keep it clean!

Discussion in 'General EV Discussion' started by Martin W, Jan 2, 2017.

  1. Martin W

    Martin W Member

    Messages:
    59
    Likes Received:
    10
    Location:
    Rayne, braintree
    If you want to save electric in your car, you need to keep your EV clean! It won't cut through the air well covered in dirt and crap
     
  2. cah197

    cah197 Well-Known Member

    Messages:
    1,100
    Likes Received:
    739
    Location:
    Europe
    EV:
    Tesla Model X
    Well don't drive it in the wet then...
     
    BarryP likes this.
  3. Siraff

    Siraff Well-Known Member

    Messages:
    2,019
    Likes Received:
    1,178
    If you're that bothered you should go round it with a hammer putting small dimples all over it.
     
  4. Martin W

    Martin W Member

    Messages:
    59
    Likes Received:
    10
    Location:
    Rayne, braintree
    Oh dear
     
  5. Martin W

    Martin W Member

    Messages:
    59
    Likes Received:
    10
    Location:
    Rayne, braintree
    Don't comment if you haven't got something good to say!!
     
  6. Siraff

    Siraff Well-Known Member

    Messages:
    2,019
    Likes Received:
    1,178
    Well the original post is about keeping it clean to save fuel. There is so little difference there is no way you would ever notice but on the other hand dimples aid aero slipperiness - hence why a golf ball looks the way it does.
     
    LeafAlex and p juster like this.
  7. Martin W

    Martin W Member

    Messages:
    59
    Likes Received:
    10
    Location:
    Rayne, braintree
    Well I have never known of a manufacturer who tests a new car covered in crap must a new thing.
     
  8. Siraff

    Siraff Well-Known Member

    Messages:
    2,019
    Likes Received:
    1,178
    Which manufacturers do you know then?
     
  9. Martin W

    Martin W Member

    Messages:
    59
    Likes Received:
    10
    Location:
    Rayne, braintree
    Why don't you tell me I mean you mean to tell that don't get there figures of 90 mile range with clean polished car???? Isn't that what a wind tunnel is for?
     
  10. Siraff

    Siraff Well-Known Member

    Messages:
    2,019
    Likes Received:
    1,178
    They get the figures with allsorts of nonsense. Tyres at 60psi, no heating, etc - that doesn't mean it's going to do it in real life. When they are building and designing a car of course it's clean - all the parts are new.
     
    mclarkie and Martin W like this.
  11. Sandy

    Sandy Zoe Devotee

    Messages:
    5,853
    Likes Received:
    2,654
    EV:
    Renault Zoe Q210
    Devils advocate, I always give my car a good wash and detail before a big trip away from home. 1. It looks nice. 2. It cleans better when you get back and 3. It does improve your mileage however low that improvement.
     
    Martin W likes this.
  12. qwerty

    qwerty Active Member

    Messages:
    114
    Likes Received:
    83
    Location:
    Cambs/Herts
    I doubt it makes much difference. My nissan Leaf - 21 months, 25k miles, washed 4 times, final wash number 5 will be in 14 weeks just before it gets inspected.When you can't read the rear number plate, it's time to start to think about getting it washed.
     
    p3te likes this.
  13. drum

    drum Active Member

    Messages:
    206
    Likes Received:
    78
    There's a rear number plate?
     
    howartp likes this.
  14. donald

    donald Well-Known Member

    Messages:
    11,777
    Likes Received:
    8,221
    I'm not entirely convinced. Surely some additional roughness on the surface would help trap a boundary layer and promote lamina flow close to the car body, which is where you get minimum aerodrag (low Reynolds number versus friction factor - I still recall my Moody's diagram from my research time with fluid flow in pipes ;) ).

    Why do you think smooth paintwork reduces aerodrag?
     
  15. SHL-Kelso

    SHL-Kelso Active Member

    Messages:
    105
    Likes Received:
    38
    I seem to remember an episode of Mythbusters that tested a car with golf ball dimples did get improved mpg over the same car with straight bodywork.
     
  16. E Geeza

    E Geeza Moderator

    Messages:
    616
    Likes Received:
    508
    EV:
    Mitsubishi Outlander PHEV, Nissan LEAF 30
    Always worth keeping your car clean, makes visibility better and you can spot anything needing attention when closer up.
    There may be something in the OPs original thought re miles per kWh, but could be due to a reduction in weight as much as anything. I often wonder about the mass of crud that gets removed from wheel arches when jet washing during winter time.
     
    Martin W likes this.
  17. People's Front of Judea

    People's Front of Judea ㋡

    Messages:
    671
    Likes Received:
    547
    Location:
    Essex
    I can't believe dimples would work on a low, ground based vehicle that isn't spherical or spinning. I think this is a lot like the old window argument i.e. it's better to keep your windows closed for fuel economy and use the aircon on a low setting, whereas having the windows open has a negligible effect and the aircon has a huge one.

    Interesting though!
     
  18. Zomb

    Zomb Active Member

    Messages:
    411
    Likes Received:
    228
    EV:
    Audi A3 e tron
    Waste water with cleaning products in... bad for the environment that.

    I was doing my aerospace engineering when Airbus announced the use of riblets on the A320. For a flight at high speed, they estimated 1% (maybe up to 2% the article says) fuel saving. With the much lower speed, I doubt a dirty car has even near 1% difference in fuel consumption either way. Unless maybe you consider a few stones worth of mud.
    https://www.flightglobal.com/FlightPDFArchive/1989/1989 - 2384.PDF (article on riblets use by Airbus)
     
    ianatkin likes this.
  19. Disgusted

    Disgusted Active Member

    Messages:
    288
    Likes Received:
    217
    Location:
    Tunbridge Wells, Kent
    Reminds me of people polishing their inlet manifolds to improve the flow of air into the engine. If you study the flow of air, the boundary layer barely moves anyway, so the gains are tiny, if there at all.

    Definately improves the appearance, preserves the paintwork and improves visibility though (y)
     
  20. donald

    donald Well-Known Member

    Messages:
    11,777
    Likes Received:
    8,221
    Actually I think there is some logic to this. Intake manifolds these days are either pipework or better castings. In older days, the interior surfaces of manifold castings were as rough as a rough thing that's been roughed up deliberately. maybe not even a uniform casting thickness, so long as it looks 'nice' on the outside (where it counts for nothing!).

    Production standards are a world removed these days and I think you are probably right that these days any such port polishing is a left-over from past times.

    On the rivlet thing - yes this is what I recall seeing back then, it was contemporaneous for me with that pipe flow work I was doing so was all very interesting. If you keep the boundary layer close then there is no surface-to-turbulent air interface and the surface-lamina and then lamina-turbulence is slightly more efficient, aerodynamically.

    I can virtually guarantee you'll never see an impact on fuel consumption from a dirty car, unless there are physically lumps of mud hanging off it.

    in fact, that is an interesting line of discussion because the aero turbulence within the wheel arches is not at all insignificant and mud stuck all over it might have a slight effect, either improving or worsening things.
     
Loading...

Share This Page