mx5cartalk.com

Hi,
I've done all the research, googled up plenty of pics, and I like this;
http://oddballkustoms.com/?p=663
I'd like the same (but fewer) vents, nearer the hump. Cut out the bracing, cut the vents, weld/glue the bracing back in, paint.
My NA has a Nissan engine so runs quite warm. I don't like bolt in vents and want something subtle and effective.
So, which hot rodding garage cuts vents in Melbourne?
Bruce

Make sure to put your vents in the low pressure areas to encourage the air to be 'sucked' out of the engine bay.

What beavis said.

Consider something cut vertically down. I'll use charlie's car as an example because its pretty.

^ Thanks for my new desktop Awesome photo!

I saw the pressure pictures. I'd be putting a louvre either side of the NA hump, so the lower the figure the better ie. -1.25
I don't have that much room to cut vertically down. Plus those home made louvres look ghetto and are not subtle.

Has anybody on this forum actually had louvres stamped into their NA bonnet?

There are aftermarket bonnets available that have vents already installed.

However in QLD for anything other than OEM the GRP needs to be at least 1.5mm thick to comply with road safety laws.

Will the car be track only?

Charlie did a very neat job on his bonnet vents, however all the bracing was removed.

I want to louvre the original bonnet. Aftermarket bonnets are expensive and the quality usually rubbish. OEM is the best.
Street car only so want to retain original bonnet and bracing, thus the stamping of louvres.

I have a GV bonnet and its quality is far from questionable!

Whilst placement of vents is important knowing the pressure under the bonnet is even more important. In addition the negative numbers indicate downforce and positive lift. If you place a vent in an area of downforce and the pressure in the engine bay is less air will be drawn in! Plus you need to know are the measurements absolute or relative, as well as at what speed and if relative where was the baseline taken?

Like vented indicator lights can actually decrease air flow because the air comes out of them and not in! Have a look on you tube a various wool tuff testing and you can see what I'm trying to explain.

Get a spare bonnet and do some of your own testing with wool ruffs, it is cheap simple and shows what is happening. You can also use a water/oil mixture to trace what is going on.

I also assume that your car is mod played for the Nissan engine?

Really Bruce??????????????????????

Your gunna do the NON-mx5 thing you rebel

try JC classics in Mt Evelyn, not sure where you are but there's a place arround the corner from our Ballarat workshop,
Griffs who do Mustangs but I'm sure I've seen other cars in there,gotta be the cleanest and most organised shop I've ever seen.

Or go and buy a hot rod mag, good reading and plenty of adds .

Terry

Maggie, a GV bonnet is not cheap.
Yup, vent placement is not as straightforward (plus a difft motor so difft under bonnet airflow).
Yes, car is the only Engineered sr20det I know of in Vic.
I will chase up hot rodder shops. Car may get turned into a rat-rod!

The link to the silver NA looks great. The problem would be in retaining the bonnet frame.

Get your hands on a second bonnet and cut out the sections you want the louvers pressed into. Get them pressed and then cut and shut these pieces into your bonnet. (or cut up yours press and then re-weld)

The second option would be ideal as manhandling a bonnet in a louver press would be a real bastard especially keeping your louvers strait and finding one with a mouth deep locally would be a stretch...


There are guys in the Hot Rod scene who have made their own presses that would work quite well with the cut and shut method. I spend hours on the HAMB reading the tech articles on metal working some of these guys have too much talent for one person...
http://www.jalopyjournal.com/forum/threads/tools-low-low-buck-louver-press-tech.5581/

I'm subscribing as I really like the idea. Good Luck!

I agree. Finding a press with a large enough mouth for a bonnet could be difficult.
Ideally remove/replace frame then stamp the vents would be first option (as blending in separate vent could be ugly).

Bonnet is aluminium for the weld some in crowd.

Those Singular vents are not pretty and are not very subtle.