hah - I had you figured for a paste eater

Lead paint.

nope, boogers.

The secrets out :rofl:

chinese evo extraction hood vent
thoughts? takers? it's cheap, it's ricey. Wonder if it would interfere with the hood "bubble" at the front.

You first :)

I would (I've already got holes in my hood) but I bet it'll hit my cam gears where it dips down for the extractor since my engine sits almost 2" further forward and 1-1/2" higher than the B. Right now the t-belt is about 3/8" from the hood skin.

I'm actually considering 280zx turbo vents (one has the naca scoop, the other doesn't) IF the angle on them will fit the cowl hood line on the Miata. White car is a vw carbrio- and the vent angle doesn't jive with that squared up cowl line. The Chrysler Lebaron GTS vent would work to IMO - but it's big at 10x14. Has an inch taper on it that will work. I laid a template on the hood - but it IS big.

So the opening is 2" deep, and the vent sticks up 1.5" and hangs down 1.5"? Unless the fiberglass in .5" thick, they need to buy a new ruler.

abuddy put a 280zx vent above the turbo on his 240sx... it worked well and looked good.

with or w/o the naca? I wonder exactly what the naca duct at the front is going to do. Was it engineered by Nissan? I'd hope so. Where's the experts?! ;)

I doubt that naca duct would do anything.

I have these lebaron vents on the jeep hood, they work well
https://www.miataturbo.net/forums/at...6&d=1182440183

NACA ducts suck air in. putting a vent right behind it is ... uhmm... curious.

If the NACA portion of the vent was positioned right in front of the compressor and the vent portion of it directly over the turbine, maybe it would force a cooling path across the turbocharger.

Yeah, if you think of an engine bay like a computer case, where cool air flowing through it efficiently is more beneficial than a shitload of fans simply sucking air in, a NACA duct combined with a scientifically designed/placed extractor would work really well.

BYW cutting holes in the hood with a jigsaw is a BLAST

So I guess the question is- were the Nissan engineers thinking scientifically when they stuck that naca duct there, or was it done for visual impact?

I'm from the "cutting wheel on grinder camp". ;)
http://roadsterrage.com/rob/images/hood01s.jpg

I was thinking about the idea of using a sheetmagnet to cover up the holes for whatever reasons you might decide upon.
How is the magnet going to work, aren't the hoods aluminum? :)

Nice Rob. Way to ruin a perfectly good hood. :nuts:

:hahano:

That hood spent 2 years under a walnut tree. So I suppose someone who owned a dent-popper shop might consider it perfectly good. Ain't no way I'm fixing it. That was pre-subframe-shim, when I was going to cover it up with an early 80s Mustang GT hood scoop. When I saw that it was barely touching, I went with the shims and some trimming of the hood ribs to get it under the hood.

I saw this car via CR.net (http://page7.auctions.yahoo.co.jp/jp/auction/g57592443), but this hood looks pretty interesting, and along the same lines of what's being discussed. Anyone know anything about it, except that it's in Japan?

http://img229.auctions.yahoo.co.jp/u...87p1010021.jpg

That hood looks like a finished version of what I did. I like it.

I put my turnsignals back in, after running around since spring without them.

IAT and CLT temps are both slightly up. My overflow bottle even gurgled a bit yesterday after shut down.

My conclusion is that the fresh air afforded by the open turn signal locations offers some cooling to the motor itself. I am not convinced that TSI type intakes without additional hood venting is a good idea, due to the fact that it would decrese the pressure delta between the front and rear of the radiator/intercooler sandwich. However, a TSI style intake + vented hood seems to be a good way to go.

I would like to also try a NACA headlight lid. But I don't have one.

B

That makes perfect sense to me. :D So are you still running around with blue franken-hood on? or did you create a finished hood from your original?

Yes, my hood is blue. I still need to add another vent over the turbo area, similar to what you drew up. I think that was a couple pages back in this thread.

My dad's buddy owns a body/paint shop, and if I can make the hood look presentable, he'll paint it for me for the cost of paint. Which if I get him to do it at the same time as my hardtop, that's basically nothing. So I think I'll have a summer hood and a winter hood.

Of course, you're welcome to try the blue hood out any time.

B

That looks quite a bit like the RS Aizawa hood. RSpeed should be able to confirm that for you.

I need to hurry up and mod my hood so I can throw it in the mix. :D
I'd like to, but then I'd have to install a hood latch. :gay:

My car is gray, not silver. You'd be pissed.
Yours is silverstone 2 stage, is it not?

It was when it was new. I got it after a repaint from a demolition derby on 285... that's why it was the cheapest Miata in the classifieds... ten years ago.

So I'm super late getting into this thread but I'd like to share my findings with no blinkers...

On friends S/C car I put a thermocouple under the passenger side of engine compartment by the fuse box and we went for a drive. On an 80 degree day the air was as hot as 130 degrees by the fuse box. Removed the blinkers and temps dropped to 102 degrees. Since then we put 2 washers under the back side of the hood hinges and removed the rubber gasket between the cowl and hood. With the hood shut you can see into the engine bay and when you're stopped the heat is just POURING out of the cowl now. Haven't taken temp measurements since then, but just wanted to share our results.

Blinkers:

I bought some 70,000mcd yellow 10mm LEDs off ebay, soldered on resistors, heat shrink, then wired them into the blinkers. Remove the metal clips that hold the stock turn signals in the bumper and run a 3/8" twist bit through the plastic on the bumper. That'll make the hole about 1/32nd larger than it was and the LED will VERY Snugly slip into those holes. The way I wired it was with 2 LEDs on each opening, the outside were wired to blink, the inside were wired to run constant. Works great! Hooked the side marker up to blink too.

pics?
I saw the heat pouring through my hood last friday while stuck in traffic. :eek:

Yeah I'll grab some pictures as soon as possible. Its pretty cool. :D

I think the car looks a lot more aggressive without blinkers.

juan, does this car have loggable AIT and CLT sensors?
at speed, in your OPINION, does air enter through the turn signal area, and exit out the back of the hood?

Some one a few months ago on m.net someone who has knowledge (Emilio or Corky) stated the same thing. It is not that a Miata need vent to let air in but needs more vents to let air out.

I can not remember if the topic was Fans, Rads or Extractor Hood.

I can guarantee a Miata needs holes in the hood when sitting in traffic after being in boost.:firedevil:

i dont see how the raised hood hinges would help. as i heard before and was stated before, they let air IN, not out. plus to cool your engine, you would want air entering through your radiator, not other places. in my opinion, the thing that would work best is get an actual extraction hood that let hot air out after the turbo, this would cool the turbo since it is still cooler than it.
i think this hood and keeping your turn signals in would maximize air flow through the radiator and past the turbo/engine etc.
i dont know much but this makes sense to me.
http://flyinmiata.com/index.php?dept...0%20%201990-97

i just read the testing of the hood i stated above and it proves my theory, plus it looks bad ass. sort of expensive, but totally worth it in my mind.
if your bored, read this.
http://flyinmiata.com/projects/CF_hood.asp

$600!! For that price I can afford to replace my overheated engine. =)

good point but it looks cool. lol

No doubt raising the hood hinges works great when sitting at a traffic light with an engine bay soaked with heat. I suppose that's fine if it doesn't cause cooling problems at speed- and you don't mind the "jacked hood" look.

There's really two issues that can both be solved independently but will impact the other. The trick is to use methods that improve both issues. As proven by FM (and Ben and anybody else using extractors...) extractor holes/vents in the hood work at speed and work at a stop to vent the heat.

I'm still waiting for somebody buy/install one of these and report back...anybody?

all you need is a vent that pulls air out, not pushes air in.
im wondering about that scoop too, it would work just like the 600 track dog racing hood, but cheaper. the only problem i see is that it would weaken the already thin, light, weak miata hood. but who needs a strong hood?

but, there are also a lot of aftermarket scoops/vents that dont work, there just for looks.

the hole would weaken the hood but the extractor "scoop" would strengthen it post hole. Cheap- but nowhere near cheap like Ben's mod.

i agree, but i would do some more searching and find out what makes those type of scoops effective. then look for a cheap scoop that has those features.

You don't need "features". You need a hole. Air travels from high pressure to low pressure through said hole. Done.

Just use a common sense approach.

im just saying, it would probably be most effective to get a scoop that lets air out while not moving and draws air out at speed, to do this, you'll need "features".

plain holes in your hood will let air in at speed, not good.

Brad i think you need to sit down and rethink this abit, i highly doubt they are getting a flow reversion to the point of creating a high pressure zone behind the rad :D a reverse scoop would be alot more effective + no worries about rain if i do mine i will do a reverse scoop for sure.

agree to disagree.:) im sorry, didn't mean to affend anyone who wants to do the "hole in the hood" thing, im just willing to pay for quality. you and everyone else on this forum are diy's, im not. the holes would work fine i guess, but the extraction vents would be best.
probably not worth the money for a street car though. i see your point.

I think you're missing the point. Look what Ben did to his hood much earlier in the thread. He cut a hole in it and formed some of the trailing sheet metal to form something similar to an extractor shape. It worked and it was free.

You're on the right path. But having the scoop over the hole is by far and large cosmetic.

Sure you could have a scooper on the bottom of the extractor, and a little raised lip at the leading edge on top to create a larger pressure delta. They may be slightly beneficial to extraction. But the point is, the air moves through the hole because it is equalizing pressure. IE moving from high pressure to low pressure. The top section of the hood is a low pressure zone. No vent, duct, or scoop can work to counter this. That is why hood mounted Ram Air induction vents are not effective.

Yes, on my hood I bent the leading edge up and trailing edge down. Honestly, if I got a second crack at it, I would just cut out the rectangular vent without bending the edges. I am not comfortable with the body work necessary to make them look right. And by not having the trailing ege come down, the actual vent area would be larger.

My hood was a low cost (almost no cost) experiment. If I had a bunch of extra money, I'd go with a aftermarket extraction hood like FM's or the one that RotorNut posted.

Oh, and I still have not cut a vent over the turbo. But it is my feeling that having a vent behind the radiator to encourage flow through the mouth coolers, coupled with TSI and/or NACA intakes flowing fresh air across the motor surfaces and through a second set of vents closer to the windshield is the ultimate solution. Think of it as a combination of FM's hood and Rotor's hood, but using stragegically located smaller vents.

yeah the scoop thing was what i was trying to say, before spending money on anything, i would look up why and how the bumps,slants, etc. work to get more air out. then id look for the cheapest way to try to copy that.
also wouldn't the engine bay be a low pressure zone? dont know but thats what iv heard, probably wrong.
finally, what u were saying about the holes, i was thinking along the lines of the hood raising and holes back by the windshield, which i know is a high pressure zone.
i personnally dont like the looks of the holes. but thats not what we were going for here.
sorry for the mixup, my bad (...im new here)

ahh, and another experiment I want to try is removing the undertray, or at least the "rear" part of the undertray. Rob's experience w/o undertray was that his hood balloned out at speed. I think he mentioned at around 100mph on the track. Which tells me that there is a wonderful source of fresh air available under the car, but it has to be allowed to escape from the engine compartment if let it. Otherwise it defeats the entire purpose of the effort. But if sucessful, it could be a constant supply of air moving from the bottom of the motor to the top, and out of the hood.

Complete removal of the rear half of the tray may be a bit extreme. A possible solution may be to cut a couple of vents in the tray with a hole saw. If it works, I might be able to leave my turnsignals in the nose. Which I would prefer to do as I like my twilights a lot. Corky Bell says he recommends ditching the undertray completely. I'm not sold on that concept, but find it interesting that he is. Perhaps his cool air scooper and hand made intercoolers are just that damn good.

brad, here are some pics from a car with this same type of mod completed. I know it looks like ass unfinished, but check out this hotness
http://i84.photobucket.com/albums/k6/3genX/NewImage.jpg
More pics:
http://www.rx7club.com/showpost.php?...78&postcount=9
That's with some cleaning of the edges, screen I dunno epoxied maybe, and paint.

wouldn't you want air to come in through the nose and rad?

do you have any pics of your car, i want to see these twightlights.

nevermind, just read your edit and it makes sense.
the rx-7 looks good though, too good, i would NEVER be able to get holes to look that good.

I hear alot about corky bell's recommendations...don't forget that he uses an air scooper for the rad, which moves a ton of air to the front of the radiator.

and so it begins:
 

the future turbo hood vent. Just got through whittling from a block of wood. ;)
http://i158.photobucket.com/albums/t...car/TAvent.jpg

did you whittle out a T/A too ;)

What does that look like on the underside?

I'll start a thread with some pics when I get it... from the NC countryside. It's fiberglass with a metal screen it and not overly large. Should do what I want position right over the turbo.

the stage 21 hood is a really nice extraction hood

http://clubroadster.net/forum/viewto...highlight=hood

He, cut all but one of the rear vents to allow more air flow.

That looks like a good solution- unfortunately none of these after market hoods take my engine swap into consideration. :cry:

Next course of action:
http://cgi.ebay.com/ebaymotors/1981-...QQcmdZViewItem

PS, any of you fuckers bid on that, and I'll ban you. :nono: