Hi guys, this is Jacob from customCFshop.
I've noticed a lot of threads about how the RX-8 runs hot and how many of you are looking for a vented hood to help the engine bay breathe a little easier.

i'm no artist by any means, but here's an i dea i came up with and i wanted to get your input on it.

here's what we make now:

http://home.comcast.net/~dong.shin2/Mazda_RX-8_2_copy.jpg

here's where we would place the vent:

http://home.comcast.net/~dong.shin2/Mazda_RX-8_vent.jpg

the idea is the keep the same great look and to utilize the rotary symbol but make it a functional vent. we would cut the rotary symbol out, drop it about 1" in the front, and create an opening that reaches about 1/3 of the way down on each side of the rotary symbol.

i know other companies are developing more aggressive designs for vented hoods so this may not be for you if that's what you're looking for.

let me know what you guys think!
thanks,
Jacob

Interesting idea. Another thought is if the rotary symbol were RAISED above the level of the rest of the hood (maybe 1/2 inch... not much!) and the front were open as you show.

that could work too... but where would the air go?
i noticed under the rotary symbol is where the engine cover sits. is it better to extract hot air or induce cold air?

Good idea, bad implementation....

1 - That vent is too far back and is inside the high pressure area in front of the windshield. If any air does go thru it will be 'in, not 'out'.

2 - When the car slows, and the pressure dissipates, the air will come out, right into the cabin air inlet....and we all know how much the owners are going to appreciate THAT.
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doc

what if the vent wasn't opened to cover 1/3 of the rotary symbol? perhaps just about a foot on each side? that would be more towards the center of the hood and not the back.
same difference?

or what if we raised it like Omicron suggested? will cold air induction at that point going to help?

Personally, I am looking for one like this, someone posted.....

Bigger rear facing vents, off to the side, and tapering to the back.

Love it!
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doc

I second the Doctorr response!!!!!

I like this better just 3 on each side dont mind the quality of my paint shop skills

That probably wouldn't do much...

maybe two scoops or reverse cowls in front ( for those with intake / and will cool if w/o ) and two in the back. Sans the rotary symbol

It looks kind of too busy with all those vents in a row




Horrible MSPaint below

Or even a raised rotary accent that is a scoop and possibly fabricate something under the hood directing air onto the engine or around it ( possible cut or redesign the stock engine cover)
The newer celicas have a scoop and a metal "guide" under the hood to cool the header

The picture is one I had posted using Photoshop and the Scoot Style hood from an RX7 that was taken from Chuck's sight.

Aside from functionality, I believe this design complements the shape of the 8 best.

I agree with AlexCisneros!

http://www.rx8club.com/attachment.php?s=&postid=408631

so this design?

how about something similar, like a Top Secret design?

top secret

DROOL

If you're looking to cool the engine, I think two relativley small scoops along the edges of the rotary imprint would work nicely. IMO, it's somewhat important, asthetically, to keep the lines of the car intact. You could create a channel under the hood to direct air down towards the engine. They'd definitely have to be raised though, as any of you who've driven in the rain and have seen the water dance on your hood know there is some funky turbulence going on there.
As far as induction goes, you could just create a hood with the back edge of the rotary imprint having a greater curve.

That dancing water is the reason I'm afraid of hood scoops / vents. I already spend enough time trying to keep the outside clean. I don't want to be wiping down the entire engine bay every week to keep excess dirt from building up from rain water + road dirt.

But, seriously, someone has mentioned high / low pressure differences. Is there any way to test all that in the real world? As I've said before, I would like to see an engineered approach to this, not just a "this style looks cool". I like function a little better than form. Are there any science fanatics that want to see what they can come up with? Maybe one of these CF people could make a hood that was custom designed for the RX-8 to really cool off the engine bay.

Or, hell... if you get really bored, and want to figure out a way we could USE the excess heat that rotaries produce to do something good (is converting heat to electricity viable or just a pipe dream... some small turbines might create some electricity as air escapes from the engine bay). I think I'm just day dreaming...

Alexs' quick PS of the sc0ot design on a RX-8 would need to have the vents moved further back. As they are in his picture theyr'e directly over the battery and intake boxes.

The only vented hood for an 8 that I know of is the R-Magic one. the vents on that start about 1/4 of the way up the hood. though I dont find the design particularly appealing.

Moving the vents further bach on the scoot style hood by Alex would make them more functional.

agreed... Given the angle of the radiator I think (I'm nowhere near qualified to know) it would help to increase the flow rate through if the vents were further back. When I 'chopped it, I may have made the vents larger (I'm really no expert on PS). The vents would likely be were scoot has them on the RX7. It would still flow nicely with the car.

Ok, I have no life... and I still suck at photochopping.

The blue tape is where the airbox ends and probably the place that would make the most sense to begin venting (however not the most aesthetic)

If we move the vents back like on the original scoot hood it would look something like this:

and for the ricers...

we can leave the scoop that most likely does nothing other than swallow low flying birds ;)

Just for the record, I still like my original Idea and if you have ever placed your hand on the airbox/battery/fuse box after a good run... I'm sure beginning the vents lower will not be a bad thing :D

Plus arent they sealed up pretty tight? At least the battery cover actually covers the complete top of the battery and everything else seems to be sealed up. I still like your original Idea.

Definitely not as appealing with the vents that far back Alex. I was thinking of them beginning about 1/3 of they way back then flanking the rotary indent. That would move them to a lower pressure area of the hood and should present a better compromise between looks and function. I also liked them big, it may have been a quick PS job but the porportions looked good.

Originally posted by robertdot
But, seriously, someone has mentioned high / low pressure differences. Is there any way to test all that in the real world? Simplest thing I can think of is to tape little pieces of paper in each area of the hood and watch them as you drive at various speeds... both for the direction they they flip and how fast they flip around. Might look stupid, but it would at least give you an idea.

Question is... Where does the air that passes the radiator go? Down and out? or up and out?

As someone mentioned... Putting the vents too close to the windshield may cause a type of cowl induction and bring air in. I have no idea what that would do at speed, but my guess would be create lift as I can only see it traveling in one direction...down. Might that also affect how air traveling through the radiator flows?

At low speed or stopped, again I'm no expert, wouldn't hot air rise one way or another? If at speed, wouldn't the air entering through the bottom of the car and through the radiator/oil coolers/etc more easily continue to travel up and out vents placed at the front?

I wonder if rotarygod knows anything about aerodynamics :D

I think the vents should not be placed anywhere else than the sides. Our engine cover was also made to direct air towards the sides into the fender openings where the strakes attach. This is why someone here pointed out that the cover helps heat desipation. By making a vented hood with the vents on the center, you'd have to remove the enine cover to make it functional. Other than that, it's all just aesthetic.

AlexCisneros' design would be more functional, but I would make the vents a bit smaller and further back.

I don't use my engine cover ;)

Doc- could you email me and tell me where you got that picture? I want that hood.

from me...

Chuck at:

http://www.rotaryextreme.com

Is going to make them. Contact him ;)

any idea on price^^

not yet...

...Ask Chuck :)

Last time I chatted with Chuck about the vented hood, he told me he was only going to produce a hood when he has 20 committed pre-paid buyers......have things changed? That was on June 20th.....???

--Landon

we had an RX-8 come by the shop today and we studied his car pretty thoroughly and here's what we came up with.

we could very easily modify a top secret supra hood in the shop and place the vents along the rotary symbol. i know someone said it might suck in air more than vent it out, but if that's the case, you'll still have more air moving through the engine bay and it'll continue to vent out through the fender grilles.

we're determined to get a vented hood built for you guys!

DO IT

Less typing. More molding. :)

Any pics for reference on the Top Secret hood?

--Landon

Originally posted by customCFshop
we had an RX-8 come by the shop today and we studied his car pretty thoroughly and here's what we came up with.

we could very easily modify a top secret supra hood in the shop and place the vents along the rotary symbol. i know someone said it might suck in air more than vent it out, but if that's the case, you'll still have more air moving through the engine bay and it'll continue to vent out through the fender grilles.

we're determined to get a vented hood built for you guys!

we make this in carbon:

http://store3.yimg.com/I/ntnsracing_1785_29490707

(this is not an advertisement. we have no affiliation to this vendor.)

just run with no hood thats how u get awesome at being cool

is that a yes on the top secret hood?

Dunno how functional it would be as it is now... the front two sets of vents on either side would be directly over the air intake box and battery cover. Maybe just with the rearmost two vents, plus maybe a couple more further back?

5 vents on both sides? that's not a little overkill? we can put the vents wherever you guys want them.

I have not been able to use my engine cover since installing the SR Motorsports intake. Like AlexCisneros, is there an advantage to the cover? Or better yet, will there be a disadvantage for not using it??

As far as I know... The cover is purely aesthetic

My guess is that the car manufacturers want you to open the hood and say ooooh, aaaaah

Not... Hey, where's the rest of the engine?!? It is a 1.3L ;)

Originally posted by customCFshop
5 vents on both sides? that's not a little overkill? we can put the vents wherever you guys want them. No, no, I mean 3 vents on each side, but start them further back.

How about this? The first pic is of where the vents would go. The front middle would be wide and narrow and act as a scoop, the three per side would vent towards the rear and to the side.

A clean copy without the arrows.

That's more along the lines of what I was thinking of!

Simple, wide intake vent which would vent air across the top of the engine and out through the side vents to which would cause air to vent upwards and to the sides pulling more air out of the engine compartment from all areas, including that which is beneath the engine and that wich has passed through the radiator. This front vent would have to be forward enough to force a draft accross the major components. This should have a screening on the rear side to keep debris from flying in. It desn't have to be raised above the present surface since there is already a curvature at the front of the hood. The rear side vents are what would create the out draft. Presently, the air passes out of the side vents through a very narrow shaft. My suspicion is that most of it just passes out the bottom of the car. I don't think this is very efficient and this is why the engine area gets rather hot.

i like your concept D...although i think even though someone stated it being ricey..the "viperish" center vent would function more here than a linear type vent for the induction..you want to introduce as much air "scooped" into the compartment then channeled across the internal components to the side vents for extraction...with the viper style your channeling the air flow into a scoop which will disperse the air in a more "usable" fashion, with a linear 'slit' you won't have as much direction on the incoming air and it won't be as 'forceful' as needed to actually provide a "cooling" affect...

i;m sure you grasp what I'm saying D, but for those that think this type of scoop is ricey I can provide a drawing later on that will put side by side comparisons of the two different types of venting for induction of air in to the engine bay...the viper style would greatly benefit over a linear slit..

In a sense that is what that would be, as it would be scooping air into the engine compartment not just a line across the hood, an indentation like the viper's but not as narrow. The rear side of the "scoop" would be higher than the front side as there is a curvature of the hood at that point. Air would not simply draft accross the top but be caught as in the scoop and channelled through the engine bay then out the top side vents.

But you already have a scoop... The front air dam

unfortunately it will not work that way...the internal air flow was designed to flow straight in and out the bottom...you can watch this with a fogger system and a high powered fan...i have these since I used to be in many bands and have done some testing...and the air that enters the front air dam is not really routed to flow out the side vents...of course I can't accurately simulate winds over 60mph or even close but still...when watching the fog enter the front..it is dispersed through the bottom of the car...the side vents act as a means of heat escape by turbulent air created in the bay while at cruising speeds...it's not purposely routed that way from the front air dam..at least I hope not because from the little testing I have done the fog doesn't even make it to those vents when being somewhat forced through the front of the car...

also when i shut the hood...after testing ..opening it shows how much air is actually trapped in the bay...it was like a plume of smoke..so there is an actual FUNCTIONAL need for hood vents...

i'm no engineer...but i did sleep at a holiday inn express one time..

try opening the hood and doing your fog experiment again. You might be able to throw some beach towels across and simulate where the vents would be.

...but then I doubt your fan is strong enough to blow air past the radiator which will result in the air bouncing back and under the car

it made it through the radiator..and I have another means to bypass that just to simulate the air flow...

I actually tried it several different ways because i figured since it's not a windtunnel the radiator may have slowed the air flow down enough to collect in the bay..but that not the case...if I bypass the radiator, it still collects heavily in the bay...and eventually will leak out the vents but dumps alot of it out the bottom undercarriage..

you did give me an idea....i have some cardboard that i can use and cut out a hood prototype and simulate vents...that may work...

keep us posted :D

I must have been looking at AlexCiseros' ricer version for engulfing low flying birds in a way that you look at those trick posters, because for a minute there, I saw a Maranello. It then got me thinking. How does that hood work. I haven't been one of the fortunate to have seen what lies beneath the hood of such a car (in person anyway).
I would think that a small - ish scoop, or recess I suppose, in the very front of the hood, like the aforementioned, would force cooler outside air into the engine bay, mixing with the hot air, resulting in an overall cooler temp surrounding the engine. The hot air would LEAK out the side vents and under the car rather than flow in any linear fashion since there wouldn't be an actual channel for the air to flow. I wouldn't think you'd have to worry about any type of lift from air escaping from under the car because it will be moving around in such a random way that there will simply not be any directional force. Besides, the air passing under the car would be moving much faster than the air escaping and would probably "pull" that air with it.
Then again, I am actually talking out of my arse.

Bump for discussion :)

Leg Motorsport hood...

Yeah but I think that hood is designed to get air in not extract it. Looks bad ass though.

The hood has vents to let air escape as well. I will look for the pic that shows air flow.

http://img30.imageshack.us/img30/8467/000066x.jpg

Ah hah. I wonder what that bad boy costs.

Found them :)

http://www.leg-sport.com/cate/gt_995-2.jpg

http://img249.imageshack.us/img249/8315/gt9951.jpg

Sweet............

Before shipping from japanparts.com. The Yen has gone up since the last time I price checked when the FRP was $973.

As of today:

FRP: $1107
CF: $1572

Damn it.

Unfortunately it is not cheap :( I want this hood but very difficult to justify the price.

Yeah the heat this summer is rough and I am getting some major heat soak when I drive hard.

I know it seems kind of ghetto but you could put spacers in to raise the rear of the hood to let air escape until you come up with a solution.

nice hood. nasty price.