cloudzero

iTrader: (1)

So my car really hates the summer time weather and I really hate the extreme engine bay temps I keep getting. So I have decided to help out the airflow going through the intercooler/oil cooler/ac condenser/radiator setup, ha yes i could remove the ac system and I'm sure that would help, but I like my ac in the summer.
So heres the plan to cut out the front area of the hood and install some louvered panels there.

I want to keep most of the frame intact so instead of cutting them out I just drilled some holes through them.


these are the panels I will be using, I could have just installed a huge vent there like some vented hods but I want this for daily driving and want to try to minimize the amount of water and everything else that can get then there.


Problem is I can't decide if I want to mount them from the underside or just rivet them to the top like they are designed. I think it looks cleaner from the bottom but then you can see my not so straight cuts... and from the top cover that all up. Of course its all going to be painted to match my car


I'm pretty sure this will let out a good amount of heat from under the hood and help pull more air through all the heat exchangers up front.

What do you guys think? mount it on top or on bottom?

Vdub2002

under tray would help alot

cloudzero

iTrader: (1)

it does, and I have a full undertray

Evil Aviator

I am confused by your initial assessment. The car has been running fine for over 20 years, so why are underhood temperatures now suddenly a problem?

Anyway, I think the louvers would look better mounted under the hood and painted black. I would normally recommend exhaust ducting from the heat exchangers, but in your case that probably wouldn't be a good idea because the louvers would be too restrictive.

Turbonut

iTrader: (1)

I would think that the louvers or vents should be at the rear of the hood or rear of the fenders as the fesh air through the radiator would pass the engine and bring the hot air with it and have a cooling effect. With the louvers in the front, as you're riding, air will come through the rad and out the vents and never cross the engine.
Old trick, put some spacers between the hood and the hood hinge to keep the back of the hood raised.

clokker

iTrader: (2)

I like the idea (although, like Aviator I wonder why underhood temps have suddenly become an issue) but I think your placement is all wrong.
Your vents, lacking any ducting, are basically passive and require a goodly pressure differential to function.
The position you chose however is a fairly high pressure area of the hood, which will restrict the louver's ability to extract (a condition I would expect to worsen with speed).
Moving the vents to the rear of the hood would take advantage of the low pressure area in front of the windshield and should increase the airflow through the vents considerably.

I think...

cloudzero

iTrader: (1)

Evil you are right about the car running fine for 20 years, that's right about the time I lost a coolant seal. Since then its been rebuilt, ported, etc etc but the biggest issue was the addition of the front mount, I know there are plenty of members that run front mounts and do not have cooling issues. But i also see a lot of them still do not have 20+ yr old ac condensers in the way also. And I'm certain my cheap ebay core does not have the best airflow through it.
And I am basing my decison to do this on the fact that the vehicle cools great while sitting and have no issues with it running and holding 88c with the fan cycling normally like i have programmed in the Power FC. And when it was still top mount it would run about the same while driving. Now since i have switched to the front mount setup the fan is constantly running while cruising but cycles normally while sitting. I have also switched the vehicle over to evans coolant with a zero pressure system.
And I think you are right about mounting underneath, maybe have them painted a nice matte black

Turbonut I am hoping to take advantage of the low pressure area in that location to help accelerate the air through the heat exchangers. The air under the hood should all be a higher pressure than on top of it so this should pull air and heat out of the entire engine bay.

texFCturboII

iTrader: (17)

This may help:

Looks like a high pressure zone there to me.

junito1

Any hole in the hood. will create a vacuum in the engine bay. Hood vents literary suck air through the coolers into the engine bay and out the vents. It will help out.

cloudzero

iTrader: (1)

I believe arrows pointing away from the body are low pressure and arrows pointing towards the body are high pressure. The high pressure would be at the base of the windshield and at the front of the bumper

That Diagram and topic has been beaten to death on here I think so I'll just leave it to this https://www.rx7club.com/showthread.p...ht=aerodynamic

texFCturboII

iTrader: (17)

i stand corrected.

point-blank

iTrader: (9)

it's the other way around arrows out = high pressure, arrows in = low pressure.

Your vents are in the right place (that high pressure area) on the hood as far as I have ever read or heard

texFCturboII

iTrader: (17)

No, he was correct the first time. It is a low pressure area, so the higher pressure inside the engine bay from the heat exchangers should be vented out of it?

Read that link, there's a lot of info in there.

Evil Aviator

A running fan actually restricts airflow at high vehicle speed. The fact that it is still running at cruise indicates there is something wrong, and it could be the fan itself, or maybe the way it is being controlled.

Do you know how to stagger heat exchangers?

Try it and see how it works, but I don't think there is enough differential pressure to move enough air through those little holes to make a significant difference in temperature. I think it would be like if your air filter were a restriction so you tried to make the engine breathe better by adding bigger exhaust tips.

cloudzero

iTrader: (1)

Rivets make it look fast haha, well anyways I'm up for an experiment. I might try running a magnehelic gauge and see if there is any pressure difference between this setup and the stock TII hood.
I just figure I will give it a shot and see. If it works out and helps fantastic, I was actually messing around with it and flowing the air compressor over the hood and it did create enough vacuum to hold a shop towel to the bottom side of the vents.
So if it does make a difference I'll paint it to match the car and make the vents black and if it doesn't work well i will try something else, besides i picked up the hood for $25 from the pick and pull.

Hmm bigger exhaust tips could help generate a venturi effect to help increase the velocity of the exhaust gases thus increasing flow through the intake, I'll have to look into that. lol just kidding, i know what your saying,

staggering the heat exchanger could make a difference, or just switching to a v-mount setup. Do you have any pics or details on staggering them? I think my biggest restriction is the intercooler.
My e-fan is being controlled through the power-fc, its set to come on at 87c and it cools down to 85c before turning off, its set per the directions from banzai and arghx

cloudzero

iTrader: (1)

cloudzero

iTrader: (1)

I know its not to everyone taste, but I did log 7*c temp difference in air intake temp (37 vs 45) from the TII hood to this one in 92* weather. Water temps stayed stable 87-91*c but the fan cycles much less.
Plus my tial blow-off sits directly under the one vents so it just makes it sound about 3 times as loud as normal, its great

dwb87

iTrader: (22)

Good work man!

1SWEET7

iTrader: (1)

That looks very nice!

brian_skotch

iTrader: (6)

Love the way it looks! Is that a steel or aluminum hood?

ben.farnath

that actually looks damned cool. good stuff man. what colour is your sev?

ben.farnath

what are the vents from

cloudzero

iTrader: (1)

It is an aluminum hood

Thanks very much, the color is Satin Gold Metallic. Mazda 1A, the two tone was custom ordered from the dealership. I have the window sticker for it and all the original bills of sale from the previous owner.

I had a Hot Rod Shop that was close to me just pound out some louvers in a couple flat sheets of aluminum, Then I had to form them to the curves of the hood.I thought about just having them do the entire hood, but we have to much bracing on the underside to really do it correctly.

junito1

I like it!

ben.farnath

I thought it was. I work in a panel and paint shop and have access to any colour I want for my full, in and our repaint. After weeks of going through colour cards and looking all over the internet, I like this colour the most, a factory fc colour (never seen one in NZ that colour). Seeing cars like yours, even though the photo light quality isn't the best, it just further cements my choice. It looks retro tough.