[Mk2] [Turbo] Bonnet Vents ??

[Martin F]

I am looking at cutting a hole behind the radiator to allow air to flow through my chargecooler and coolant radiators, to make this work I require a bonnet with holes to let the air flow through.

Anyone have ideas they can throw at me or pictures of where I could go with this.
The border bonnet looks nice but it has small vents which wouldn't help with my plan much,

thanks for any advice in advance

[ashley]

Search google images for MR2 Border bonnet...lots of ideas there

Just be careful how much you cut of the front bulkhead behind the rad's, it forms a box section that supports the the mounting brackets for the front tie-rods...

[C35Rob]

aren't the border style vents too far fwd to vent anything from the frunk?

you'll need something like this



or an ask sport one



or something like this Nismo style vent




obviously you'll want to rig some ducting to direct the air out of the vent like this




I've also considered a couple of large circular holes, with vent ducting flanges like this



with some flexible vent ducting like this



exiting the bonnet via some big NACA ducts like this



which, whilst not flowing as much air as a gigantic hole in the frunk bulkhead and bonnet, will be a much cheaper, simpler install, and will keep the frunk dry

[bri0905]

Ask sport is a good choice.

[ashley]

Sorry- I just meant that if you google search for border bonnets you get a lot of other ideas coming up. I like the Ask design a lot...

Not sure about NACA ducts- they're designed as air inlets, not outlets

[C35Rob]

Sorry- I just meant that if you google search for border bonnets you get a lot of other ideas coming up. I like the Ask design a lot...

Not sure about NACA ducts- they're designed as air inlets, not outlets

Yeah I know, I can't see any issue with one being an outlet if it was fitted "back to front" though.

like so



it's just a hole after all, with the high pressure of air from the front of the car pushing the air through and out and air passing over the top of the bonnet creating a venturi effect to aid the air coming out - as long as the outlets aren't in the high pressure area at the base of the windscreen I can see it working quite well. But then aerodynamics/fluid dynamics aren't my forte really, I could be missing something.

[ashley]

That could look pretty cool actually- nice and subtle

[bobhatton]

Just be careful how much you cut of the front bulkhead behind the rad's, it forms a box section that supports the the mounting brackets for the front tie-rods...

I went into this a few years ago.
You have to weld on a frame around the part of the metal that is going to be cut out, once that is done the metal can be removed.

None of this is going to help with any cooling, it just may help with removing air from under the car

[ashley]

Just be careful how much you cut of the front bulkhead behind the rad's, it forms a box section that supports the the mounting brackets for the front tie-rods...

I went into this a few years ago.
You have to weld on a frame around the part of the metal that is going to be cut out, once that is done the metal can be removed.

None of this is going to help with any cooling, it just may help with removing air from under the car

Yep...





I think once I've got ducting in place that seals the rads to the gap in the bumper, and then seals the back of the rads through the frunk and out the bonnet, it should make a significant difference to airflow- hopefully everything above the front splitter will now go over the car...which in turn (I hope) will make high speed stability better

[Martin F]

Thanks for the input guys

I think the Ask sport one looks pretty good and fit for purpose, not sure where I am going to source one from though

[2mad]

Thanks for the input guys

I think the Ask sport one looks pretty good and fit for purpose, not sure where I am going to source one from though

I had a full carbon ask bonnet .. sure they still sell them ... price could be a problem not cheep

[C35Rob]

Thanks for the input guys

I think the Ask sport one looks pretty good and fit for purpose, not sure where I am going to source one from though

there was a slightly damaged carbon one for sale for ages on here a while ago, ideal for repair and painting body colour. Not sure who bought it or if they're using it though - you never know, it could be gathering dust in a garage somewhere

[Martin F]

Thanks for the input guys

I think the Ask sport one looks pretty good and fit for purpose, not sure where I am going to source one from though

there was a slightly damaged carbon one for sale for ages on here a while ago, ideal for repair and painting body colour. Not sure who bought it or if they're using it though - you never know, it could be gathering dust in a garage somewhere

Noticed that, sent him a pm

[Martin F]

Thanks for the input guys

I think the Ask sport one looks pretty good and fit for purpose, not sure where I am going to source one from though

I had a full carbon ask bonnet .. sure they still sell them ... price could be a problem not cheep

Yeah dude,

I am in no rush, so can hang about for the right one, shame no one made the mould so you could just cut a hole in your bonnet and then fit it....

wish I kept an old bonnet now, could have worked something over the winter

[2mad]

Ask do a fiberglass one .. i tryed when selling mine to get carben to buy it and do a mold , its a mega bonent .. best of luck in your endeavors

[jimGTS]

Confused by the original question.

There is already a huge area behind the rads for the air to flow through and down under the car.

This is plenty sufficient for cooling!!

What folk are suggesting, although badass, is a huge amount of work and expensive.
Something maybe and I mean maybe worth looking into on a race car, but a road car, it's ott.

A bonnet is simple enough, but expensive to buy. By itself doesn't do anything other than for looks.

If you want to make it function you are looking at custom work to cut the frunk, make a scoop to feed it into the huge hole in the bonnet (it would need to be huge otherwise you'll be limiting flow worse than standard if you plan on blocking off/extending the undertrays).

Hell of a task for no cooling gains, aside from maybe a bit of aero.

[Martin F]

Confused by the original question.

There is already a huge area behind the rads for the air to flow through and down under the car.

This is plenty sufficient for cooling!!

What folk are suggesting, although badass, is a huge amount of work and expensive.
Something maybe and I mean maybe worth looking into on a race car, but a road car, it's ott.

A bonnet is simple enough, but expensive to buy. By itself doesn't do anything other than for looks.

If you want to make it function you are looking at custom work to cut the frunk, make a scoop to feed it into the huge hole in the bonnet (it would need to be huge otherwise you'll be limiting flow worse than standard if you plan on blocking off/extending the undertrays).

Hell of a task for no cooling gains, aside from maybe a bit of aero.

I can imagine the air going through the chargecooler core, then the radiator before hitting an angled brick wall.
Surely a fair chunk of this air is going to cause a bottle neck compared to it being able to travel straight throw and out the bonnet.

Every little helps, In theory anyway

[2mad]

my brother in law fitted a hood scoop ish (in white) .. il find out were he got it from if interested

[Martin F]

my brother in law fitted a hood scoop ish (in white) .. Image Replaced With URL For Quote http://www.jt-culture.com/images/okishi ... 00sx_1.jpg il find out were he got it from if interested

It fine, I managed to source an Asksport bonnet

Thanks anyway dude

[2mad]

my brother in law fitted a hood scoop ish (in white) .. Image Replaced With URL For Quote http://www.jt-culture.com/images/okishi ... 00sx_1.jpg il find out were he got it from if interested

It fine, I managed to source an Asksport bonnet

Thanks anyway dude

Top man i had an ask-sport .. top bonnet