Bonnet vent modification

[Chris_Blue]

Yes- couldnt get those to fit within the bonnet frame

[Czar]

Yes- the Cooper S scoops, and the Cooper Works i think, have a subtle scoop at the front that blends in with the line of the bonnet
Never had a close up look at it tho, and it has had its fair amount of slating for its styling- but does it work would be my consideration

The bonnet scoop on the 2nd generation (THP engined) BMW MINI Cooper S and JCW are cosmetic styling only, they offer no air collection and guidance into the engine bay whatsoever, if you take a look at the scoop opening, you will see that just inside the scoop is a Black plastic grill, which has 85% of the lattice moulding closed off, the remaning 15% is open, only to aid in the low pressure air pass over the bonnet.

On a further note, I removed the Black plastic grill from the bonnet scoop on my BMW MINI Clubman to see if it made any difference to under bonnet temperatures on and off track, and you've probably guessed by now, it made no difference whatsoever.

[Chris_Blue]

Ah well. The mere thought of aiding cooling in the engine bay area makes me feel happy. Life isnt all about fact LOL
And it is a fact according to my Torque pro app that my engine intake is lower#Happy days eh? :-)

And at least now I have lower air pressure over the engine (I did the vents for that all along TBH)

[Czar]

Ah well. The mere thought of aiding cooling in the engine bay area makes me feel happy. Life isnt all about fact LOL
And it is a fact according to my Torque pro app that my engine intake is lower#Happy days eh? :-)

And at least now I have lower air pressure over the engine (I did the vents for that all along TBH)

Chris, I was referring directly about the bonnet scoop on the BMW MINI 2nd generation Cooper S and JCW, with it's forward facing non functional bonnet scoop, this is far different from the vents you have cut in your bonnet.

Aiding the evacuation of under bonnet temperatures is tricky, the placing of bonnet vents, reverse ducts and scoops is critical to allow them to function, get it wrong, and they become nothing more than cosmetic endorsements.

Low air pressure: fast moving air flow.

High air pressure: slow moving air flow.

Engine bay: is neither of the two above, in the engine bay we have turbulent uncontrolled un channelled air, so your thoughts on having low pressure over the engine are misguided, the top face of the bonnet is a natural low pressure area, until the air flow hits the windscreen, this reduces the fast air flow, which creates slow moving air flow high pressure.

Utilising this slowing down of the air flow high pressure area in front of the windscreen can be advantageous for air intakes, reverse ducts and scoops!!

Your bonnet vents will help with reducing the immense under bonnet temperatures, as for creating any low pressure over your engine, this is not and never will be the case, air unless channelled will ALWAYS take the path of least resistance!!

[Chris_Blue]

Your bonnet vents will help with reducing the immense under bonnet temperatures

Thatll do me Jimmy. Thanks Czar

Ed- You may have noticed that the grill secured over the cut vents, are angled differently. Thats because the air goes in one way and out the other ;-)

However- when i fit the central scoope for intake, both will be angled for easy hot air exit, and all will be fab ;-)

[Czar]

Thatll do me Jimmy. Thanks Czar

Ed- You may have noticed that the grill secured over the cut vents, are angled differently. Thats because the air goes in one way and out the other ;-)

However- when i fit the central scoope for intake, both will be angled for easy hot air exit, and all will be fab ;-)

I don't want to rain on your hard work, but your concept of the air entering in one direction and exiting in another is wrong, as I've already mentioned, unless the air flow is channelled, air will and does only take the path of least resistance, and in your bonnet vents, they are un channelled and only allow turbulent air to vent.

The addition of a front facing open scoop will be completely useless and render your vents useless too, your front facing scoop will capture a small almost insignificant amount of the air flow, this will in turn create a partial reverse flow from your bonnet vents, pulling air in, not venting while on the move, the partial reverse of air flow is aided by the stalling effect of the now incoming air flow against the bulkhead!!

[Chris_Blue]

Bosh, another idea bites the dust

[Czar]

Bosh, another idea bites the dust

Leave the vents alone, forget about the front facing scoop, and think about ways to channel the front pressure flow of air, directly through your intercooler, to maximise it's thermal exchange efficiency!!

What you have to remember and think about is, just because the intercooler is at the front, doesn't mean it actually benefits from much passing through air flow, i'le say it again just to remind everybody, unless channelled/directed, air flow will ALWAYS take the path of least resistance, and as the intercooler is a rather large obstacle, albeit with open air channels, unless the air flow is actually channelled, with no other path of less resistance to follow, to pass directly through the intercooler, then the intercooler is not working efficiently!!

[Chris_Blue]

Right. A big funnell toward the intercooler then.

Will get my thinking hat on :-)

[colganraz]

Is my thinking wrong that the style of vents seen on the focus RS, with air passing over them would act like a venturi and vaccum hot air from the engine bay?

[Czar]

Is my thinking wrong that the style of vents seen on the focus RS, with air passing over them would act like a venturi and vaccum hot air from the engine bay?

Your thinking is not wrong, bonnet vents can produce a top surface partial pressure vacuum, this is relative to the air flow pressure differential between the top and underside planes of the given surface.

[av8tor1990]

hi chris this is abit of topic but where did u get the eye lids from?
they look awesome .
is that the triple r spliter as well?

[Chris_Blue]

hi chris this is abit of topic but where did u get the eye lids from?
they look awesome .
is that the triple r spliter as well?

Thanks av8tor- the eyelids are just sprayed plastidip, after masking off the whole area.
If you look on you headlights, you can see a faint perspex line around the line bewteen the wing and the front vallance

No- its the Leon Cupra R splitter. Fits almost perfect, just a bit of trimming either end. Fix with self tappers after taking original rubber off, or just straight on if you have no rubber skirt.

[av8tor1990]

Thanks av8tor- the eyelids are just sprayed plastidip, after masking off the whole area.
If you look on you headlights, you can see a faint perspex line around the line bewteen the wing and the front vallance

No- its the Leon Cupra R splitter. Fits almost perfect, just a bit of trimming either end. Fix with self tappers after taking original rubber off, or just straight on if you have no rubber skirt.

sorry im new to this just picked up a thp ,
is there a part number for the spliter?

[Chris_Blue]

Not that I know of, just put "Leon Cupra R splitter" into ebay/ search engines
Hope u r enjoying your THP.. sure you are