RonKMiller

I was sitting around yesterday thinking about my old chemistry professor mumbling something about how every 10 degree increase in temperature causes chemical reactions to double in speed. And then I realized that summer is just around the corner and had visions of my engine screaming at me for help. I've been contemplating a "vented" hood but it just did not seem to make a lot of financial sense considering the cost, shipping, painting etc. Plus, who knows how well they work? - and then there's the rain issue...... Here's what I came up with: (and true to my Scotch ancestry this is very thrifty as well)

1. The NACA side fender duct on the passenger side of
my 93 touring does absolutely - nothing. So why not
put it to work ventilating the engine compartment?
Yeah - that's the ticket! So, off comes the fender
and out comes the 3" metal cutting hole saw.
On the inside top of the inner frame you will see a
4" square that has been already been cut out -
perfect for my cut, and inside it there is really
nothing except part of a wire harness in the engine
compartment to watch out for when making the cut.
Wham - a new 3" hole now exists and looks like
this:

RonKMiller

Damn server.......GRRRRRRRR. Anyway - on with the new thread!

I then lined the hole with strips of foil tape to create a "tunnel" to the outside:

RonKMiller

OK -

Now we get some foil (not plastic!) clothes dryer 4" super flexible ducting and tape it to the "square", bend it, and cut out an oval section on the interior plastic liner duct to mate it to. Seal both ends with foil tape.
I sealed off the forward end of the duct, as
well as other seams to create a leakproof routing for the exiting hot air. I could have cut off some of the ducting but chose to leave it stock in case I decide to add an extra oil cooler in the future- this way I could just poke through the foil tape to make it functional again without taking the entire fender off:

RonKMiller

And here's the view of the completed ductwork with some additional aluminum sheet to complete a sealed duct that will interface with the NACA duct. I repeated the process for the driver's side. How well does it work? I intend to do temperature measurements with a calibrated pyrometer (a $1K instrument I just happen to have laying around the shop) at different locations and speeds inside the engine compartment with/without the duct sealed and post them later. Stay tuned sports fans!

Flybye

Pictures are taking too long to load.
Take your $10 Naca duct and shove it

RonKMiller

HAHAHAHA! Would that be with KY or without?

Hmmm, you wouldn't be selling vented hoods per chance? (It's actually more like $7.50 for the foil tape..)

Flybye

A vented hood? I drove around WITHOUT a hood
You know, a naca duct attached directly to the turbo manifold may prove to be interesting....

Freaky Monkey007

Now just take a hair dryer and mount it to that and the intake.. You will have a T-100 then and be makin mad HP.

RonKMiller

To quote Dire Straits: "Money for nuttin' and my chicks for free!" I like it but it would exceed my personal budget by at least $10.00 for "cheap ghetto mods that you won't find anywhere else"

ninetyfourfd3s

Let us know how it works out... if it works well maybe you should add some fans to push more hot air out. It might not be flashy, but hey if it gets the job done...

Manolis_D

iTrader: (2)

AHHHHH!!! you cut a 3" hole in an FD

edit-- seriously though... I'd imagine that Mazda put that metal on the frame there for a reason! Maybe i'm misunderstanding what you did with that holesaw...

I have a <much more common> 1990 FC, and i'd NEVER drill a hole in it anywhere...

RonKMiller

If it works the way I envision, the suction created by the NACA ducts will provide alot more evacuation of the underhood air than could ever be provided with fans.
Only by measuring the temperatures will I find out - I'll keep everyone posted on the "science" part as it evolves. Later.

Flybye

Are you gonna take temp readings in different locations of the engine compartment?

RonKMiller

Yep, the pyrometer has teflon coated wire with a sensor tip that I can run to multiple areas under the hood. It's accurate to within 2-3 degrees F, and even better if I calibrate it with a reference standard thermometer which is total overkill . I'll also do it over a range of speeds. Also records ambient temperature. I'm also going to stick it through a hole and measure the temp INSIDE the stock airbox above my K&N to see if my "ghetto cold air intake" actually works as well. (that mod almost broke the bank at around $20 for two pieces of choke heat riser tubing and some plastic epoxy putty...but I digress...) This may the first and only ever "real time" measurements ever done on an FD3S. Now when we say are cars are hot little bastards underhood we'll have some real numbers in Farhenheit to toss around! I'm so into dense air.......it's got to be the cheapest hp out there.

RonKMiller

Yeah, not one - but two! (But it's only sheet metal and you can't see 'em so they don't count!) I can just imagine the engine sitting in my lap one day - french frying my nuts - after a head on and me thinking, "damn, I never thought about the crumple zone enginering on this sonafabitch!"