small mesh or large mesh

[mpk490p]

just noticed you are in Daventry!
not a million miles away, its hard for me to gauge how much better it will be unless i can find a day with the same weather etc etc, i dont have any intake sensors etc i run a FB but hope i should notice soime difference

Mark

[RedRummy]

I heard once that for certain types of generic mesh, going above about 50mph create so much turbulence around the mesh that very little air flows through it at all.

air hits the mesh and gets scattered and very little actually goes through it. kind of bow wave effect

[od404]

I heard once that for certain types of generic mesh, going above about 50mph create so much turbulence around the mesh that very little air flows through it at all.

air hits the mesh and gets scattered and very little actually goes through it. kind of bow wave effect

My thoughts are that putting a step restriction in the airflow like mesh (or a plate with a hole into an exhaust) will create recirculating flow behind the restriction.  This causes the flow to stagnate (slow down or even stop) in that area.  I the case of one hole it isn\'t too bad, but with a mesh where there are holes adjacent doing the same thing to the airflow, you may find that the recirculating air actually blocks off flow through some holes, thus greatly reducing airflow.

To what extent this occurs and at what air speeds is however, a complete unknown.  When you look at racecars, some have mesh some don\'t which makes me think it\'s more a case of judgement as to whether there is a detrimental effect to the engine rather than actually looking at the airflow itself.

[Nik da Greek]

I heard once that for certain types of generic mesh, going above about 50mph create so much turbulence around the mesh that very little air flows through it at all.

air hits the mesh and gets scattered and very little actually goes through it. kind of bow wave effect

Spot on. The mesh becomes like a brick wall after a certain speed, where the air hitting it simply can\'t get through fast enough, so backs up in front, forming  a standing wave. Not only does this knacker your cooling really badly, it meets the incoming air on the way back out of the bumper aperture and creates loads of turbulence which creates drag and knackers your aerodynamics. And makes loads of noise, for what that matters.


If you can live with all that, small holes look better, big ones work better (slightly)! :Thumbs-up. Both will look ****e after a year or two when they\'re all corroded and dented and manky, and you\'ve got fed up losing your fingertips trying to clean what is essentially a giant cheese grater! :yes

Mesh-free ftw!

[Cycaduk]

heres a thought,
 if you run with nothing there does the air still get through the radiator?
I think it does, so as long as the effective area of each of the holes in the mesh is bigger than the holes in the radiator then you wont see much change in the flow.

I say effective area because the holes through the radiator aretrapezoidal in shape, whereas most meshes are circular.

If my science is still correct the flow is going to depend on the square of the area. so even only slightly bigger holes will give a big benefit.

A further thought is that a thicker screen with \'aerodynamicly\' contoured (front to rear) holes may be very much better than a very thin screen with straight holes.

[NurburgRob]

My bumper is meshed with the expanded stuff which is not strictly a flat surface as the edges of the holes are as such slanted.  I totally agree that this is not as effective as no mesh but during my 1000 miles trip to the nurburgring my temps were lower than when I had a standard bumper with no mesh.  Bearing in mind though that the hole in the front of my C-west bumper is about 3 times the size of standard.  I wouldn\'t mesh a standard bumper.

[FEED Addict]

I have the answer you are all looking for.....
 
Don`t mesh around with your bumpers dudes!:rollin
 
 
 
Seriously though, any mesh will help stop stones etc popping your rad which has to be a good thing! unless your car overheats that is!:cool

[Nik da Greek]

In another life I worked in conservation. One of the techniques we used for maintaining sand dune habitats (bear with me here, it is relevant, honest) was to simply erect chicken wire fencing along the areas that were being eroded by the wind. The way this worked is that the effect of passing through the mesh of the wire slowed the wind speed enough that it lost so much energy that it was no longer able to carry the sand particles it was removing, so they dropped out of the wind stream at the fence line. You just left it, went back a week or two later, and as if by magic, there was a new sand dune where your fence had been.

Now if you extend that theory to meshing your bumper, and compare the size of the mesh in chicken wire to that in bumper mesh and think about the profound effect that it had on how energetic the air flow was on the dunes, well.... What you\'re doing is reducing the amount of air getting through in the first place, and reducing the capacity of the air that does get through to deal with removing heat energy once it finally gets where its going.

Do it cos it looks nice (ish), yeah,  but don\'t expect it to be anything other than a perfomance downgrade!

[Jake]

Race cars and the Time Attack cars in Japan seem to run with mesh.  If it really affected performance I\'d imagine they wouldn\'t run with it at all, especially the Time Attack cars where they are not going to spend much time behind other vehicles that could throw up stones etc.  The FD3S Time Attack cars run v-mounts and I\'d imagine even if they had their coolant under control their air temps would suffer with a restricted flow to the intercooler if the mesh was really having a negative effect.  I don\'t know any of the physics behind it at all but surely if it hurt performance race cars wouldn\'t do it.  Especially given that they could just replace stone chipped components after each race.