996 GT3 mesh to protect rads - airflow affected?
Discussion
Got a hole in the centre rad due to stone chip. Whilst having the rad replaced, I'm also adding a black mesh grille across the gap in the centre of the bumper.
Question is if I also add a mesh grille to the two side air ducts so the front doesn't look odd, is there any materially significant impact on cooling?
Question is if I also add a mesh grille to the two side air ducts so the front doesn't look odd, is there any materially significant impact on cooling?
Yes it affects the airflow but it is unlikely to have a serious effect in the UK.
These cars will have been designed/engineered to perform when the engine is working at a high level in warmer climates than ours, and so I would imagine that the system can probably handle a slight reduction in airflow, due to the cooler ambient air of the UK.
The airflow through lots of tiny holes (a la mesh) will be far less than the flow through an equal open area (aperture area equal to the sum of the area of the holes), and I imagine that the difference will be even greater at speed, however I'm not aware of anyone having an issue following doing this mod (I certainly didn't on my 996t).
These cars will have been designed/engineered to perform when the engine is working at a high level in warmer climates than ours, and so I would imagine that the system can probably handle a slight reduction in airflow, due to the cooler ambient air of the UK.
The airflow through lots of tiny holes (a la mesh) will be far less than the flow through an equal open area (aperture area equal to the sum of the area of the holes), and I imagine that the difference will be even greater at speed, however I'm not aware of anyone having an issue following doing this mod (I certainly didn't on my 996t).
Harris_I said:
Got a hole in the centre rad due to stone chip. Whilst having the rad replaced, I'm also adding a black mesh grille across the gap in the centre of the bumper.
Question is if I also add a mesh grille to the two side air ducts so the front doesn't look odd, is there any materially significant impact on cooling?
A risk of running grilles is this leads you to a false sense of security regarding the accumulation of trash. The mesh keeps the big fluffy stuff out but lets the fine stuff through. This fine stuff will accumulate and form a nasty blob of corrosive muck. But because you can't see any trash -- the light fluffy kind -- you think everything's cool.Question is if I also add a mesh grille to the two side air ducts so the front doesn't look odd, is there any materially significant impact on cooling?
Until the condenser or radiator spring a leak.
If the mesh is too fine this at speed can act as a wall and prevent air flow, cut down on air flow through the duct. The fan will come on sooner but the engine will probably not suffer from running noticeably any hotter.
There is also the possible impact to the air through the condenser (at least) obtaining suitable linear flow from the added turbulence the mesh creates.
But you'll see the effects of this or you won't.
I got mine off Ebay, there is a Polish vendor, very fast shipping and careful packaging.
Choice of mesh hole shapes and sizes.
Re airflow reduction?
Puleeezeee...
Sure if you could measure it there would be.
I just wonder what the airflow is when any car, mesh or not, is stationary or slow moving in traffic. They seem to cope well with absolutely zero non-assisted airflow and effectively none at all through the centre rad, so if the mesh reduces airflow by 5% it's neither here nor there.
Most of the crud that I found trapped seemed to be decomposing vegetation so the mesh should take care of an overwhelming majority of kerrapp.
I attached the mesh to the grilles using thin black cable ties. The mesh is practically invisible unless you get down on your knees.
It's quite time consuming to cut up the first side one, but then you flip it and use it as a template for the other side.
Choice of mesh hole shapes and sizes.
Re airflow reduction?
Puleeezeee...
Sure if you could measure it there would be.
I just wonder what the airflow is when any car, mesh or not, is stationary or slow moving in traffic. They seem to cope well with absolutely zero non-assisted airflow and effectively none at all through the centre rad, so if the mesh reduces airflow by 5% it's neither here nor there.
Most of the crud that I found trapped seemed to be decomposing vegetation so the mesh should take care of an overwhelming majority of kerrapp.
I attached the mesh to the grilles using thin black cable ties. The mesh is practically invisible unless you get down on your knees.
It's quite time consuming to cut up the first side one, but then you flip it and use it as a template for the other side.
the mesh will reduce airflow but effect varies depending on size (obviously) and mounting location (less obviously).
fitting the mesh inside the opening greatly reduces the effect on flow.
as for the Cup mesh, its looks pretty ropey up close (as with most race car stuff). you also need to remove the bumper opening trims if you fit adding to the less than polished finish. its aim is also to stop rubber from slicks clogging up the rads rather than debris puncturing the radiators.
you can get far nicer mesh and do a job that will stand up to close quarter viewing if you do it yourself. its also worth considering fitting it to the radiators themselves rather than to the bumper openings. you can remove the ducting and fit the mesh infront of the radiators then refit everything. with the bumper on you wont even see that its there. this is also the position of least impact on air flow.
fitting the mesh inside the opening greatly reduces the effect on flow.
as for the Cup mesh, its looks pretty ropey up close (as with most race car stuff). you also need to remove the bumper opening trims if you fit adding to the less than polished finish. its aim is also to stop rubber from slicks clogging up the rads rather than debris puncturing the radiators.
you can get far nicer mesh and do a job that will stand up to close quarter viewing if you do it yourself. its also worth considering fitting it to the radiators themselves rather than to the bumper openings. you can remove the ducting and fit the mesh infront of the radiators then refit everything. with the bumper on you wont even see that its there. this is also the position of least impact on air flow.
thegoose said:
Not if you want to keep selling lots of radiators & condensers.....
Google Zunsport grilles - made to measure for specific models & look very neat.
I fitted Zunsport grills to my Cayman. They are indeed very nice pieces of kit. Wouldn't hesitate in picking up a set for the new car when the time comes. Google Zunsport grilles - made to measure for specific models & look very neat.
Zunsport are definately worth a look.
I recently provided my 987 gen2 as a 'donor car' for the manufacture of the prototype grilles for this model and was given a tour of the factory unit. Whilst not cheap, the product is very well engineered for fit and the materials used are highest quality - hand made manufacture and guaranteed for the life of the car. The company is a small family business and they are thoroughly nice guys to boot!
BTW I know they were looking for a donor vehicle to produce the new Cayman grilles - you get a free set in return for two visits to the factory to measure and final fit the grilles. If of interest to anyone please contact Peter at Zunsport or pm me for contact info.
I recently provided my 987 gen2 as a 'donor car' for the manufacture of the prototype grilles for this model and was given a tour of the factory unit. Whilst not cheap, the product is very well engineered for fit and the materials used are highest quality - hand made manufacture and guaranteed for the life of the car. The company is a small family business and they are thoroughly nice guys to boot!
BTW I know they were looking for a donor vehicle to produce the new Cayman grilles - you get a free set in return for two visits to the factory to measure and final fit the grilles. If of interest to anyone please contact Peter at Zunsport or pm me for contact info.
996TT02 said:
I got mine off Ebay, there is a Polish vendor, very fast shipping and careful packaging.
Choice of mesh hole shapes and sizes.
Re airflow reduction?
Puleeezeee...
Of course there will be. Choice of mesh hole shapes and sizes.
Re airflow reduction?
Puleeezeee...
Even if you maintain the open area, the flow through a mesh arrangement will be far less than through a straight opening of equal open area.
At a complete guess, I reckon guess the reduction in airflow by adding the mesh would be somewhere around 25% (it will vary according to speed), but as I said above, these cars are engineered and tested to perform in much hotter climates than ours, and so can probably handle this reduction without issue.
996TT02 said:
I just wonder what the airflow is when any car, mesh or not, is stationary or slow moving in traffic.
The airflow when stationary will be zero. (negating any ambient wind effects).
When a car is stationary or slow moving in traffic, the engine and ancillaries aren't working particluarly hard and don't require much (any) cooling airflow.
At higher speeds however, the reduction effect of adding the mesh will be more pronounced.
monthefish said:
The airflow when stationary will be zero. (negating any ambient wind effects).
When a car is stationary or slow moving in traffic, the engine and ancillaries aren't working particluarly hard and don't require much (any) cooling airflow.
At higher speeds however, the reduction effect of adding the mesh will be more pronounced.
We can go on forever of course, but I wonder whether your car has aircon, and whether you have ever (personally) removed the condensers and radiators.When a car is stationary or slow moving in traffic, the engine and ancillaries aren't working particluarly hard and don't require much (any) cooling airflow.
At higher speeds however, the reduction effect of adding the mesh will be more pronounced.
If you did you must realise that each condenser covers and practically seals a very visible (rather than wild estimate) estimated 75% of each side radiator, and furthermore, a condenser (just like a regular radiator) is designed to ensure maximum heat transfer within a limited size thus the airflow is restricted to a degree that makes the effects of any mesh seem positively beneficial.
That is one part of the story. The other part is that what we care about is, ultimately, not airflow at all.
What we care about is heat transfer. Fact is that as with any system of this or any other sort, the laws of diminishing returns kick in rather rapidly. What this means is that if there is a temperature drop of "x" degrees from rad inlet to outlet at reasonable-airflow "y" metres per second, if you doubled the airflow you would not get "2x" temperature drop but far less. And with every increase in airflow, the temperature drop would be far smaller. This is due to several factors, such as the fact that no radiator is 100% efficient, that air itself is a poor conductor, that heat transfer itself is dependent on temperature, that heat transfer takes time, and so on.
In simple terms a scientist could discover that any airflow above the equivalent of "z" miles per hour gives an insignificant added cooling effect, therefore one concludes that since the radiators cope well at 150mph with the cooling effect that could potentially only be a little better than it is at 25mph, if at just 40mph the effects of mesh (let alone the condensers) reduces the airflow by 5mph the effect is neither here nor there.
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