Best FUNCTIONAL Vented hood for FC3S? [Archive]

Phoenix7

08-19-2008, 05:06 PM

We've all seem the RE-A hoods, the Dmax Hood and others I may not remember right now but WHICH ONE IS THE BEST at getting rid of the engine bay heat?? I mentioned this in Low Impedance's "How Air Works" thread and I thought I'd dedicate a thread to this topic and see where your experiences differ and coincide.

Discussions on other forums don't really yield any real answers other than the vents are a marketing gimmick. At what point does the hoods become just an aesthetic modification and not a functional one though?

If you're familiar with these please post your input.

RE-Amemiya and replicas:
http://i196.photobucket.com/albums/aa81/keycompositesgroup/mazda/h8000cf.jpg

Border Hood:
http://img.photobucket.com/albums/v164/madrx7racer/Our%207s/REX/Exterior%20Ideas/hood7.jpg

Sexy Style Hood:
http://img.photobucket.com/albums/v164/madrx7racer/Our%207s/REX/Exterior%20Ideas/sexystylehood4.jpg

Foresight hood, Excuse the tiny pic:
http://img.photobucket.com/albums/v164/madrx7racer/RX7s/2nd%20Gen/ef8b2555.bmp
http://www.hpmix.com/home/foresight/images/img99.jpg

Foresight Style 2?:
http://www.hpmix.com/home/foresight/images/img117.jpg

Dmax Hood:
Claims 16*C temp drops
http://www.dmax-cs.com/english/bonnet/b1.jpg

Rmagic Hood:
http://carview-img02.bmcdn.jp/carlife/images/UserCarPhoto/800404/p8.jpg

Knightsports Hood:
http://www.knightsports.co.jp/blog/imgs/fsin.jpg

Phoenix7

08-19-2008, 05:09 PM

Out of all the ones I posted, the Knightsports seems the most useless. Maily because of the TII-like Opening.

so, which one would be best at getting rid of heat? Looks are unimportant here.

djmtsu

08-19-2008, 05:42 PM

I am partial to the Border hood. Functional or not.

Hoods like this are easy to make. I have two NA hoods I plan to hack up and try to make my own.

FirstRotaryExp

08-19-2008, 09:01 PM

Personally the RE-Amemiya/300GT hood looks great, and should be decent for removing air in more key area's, namely over the turbo and then again on the intake side of things. I can only imagine what an Efan would do with a hood like that, like de-icing a windshield once the engine's warm.

Im kinda partial to it so theres my opinion, and I think El nene 7 on the other forum has that hood as well.

bbade

08-20-2008, 12:07 AM

Placement of the vents does not necessarily remove heat. While heat can escape over the turbos at idle it won't necessarily while moving.

Someone would need to do a test using string to see how air flows over each hood. You would also need to monitor temperatures at different areas under the hood.

As far as I know nobody has done any real tests on any of this. It would be awesome if someone had a hefty stack of spare hoods and some free time :).

vex

08-21-2008, 03:46 PM

Now the real question is where can you find some of those hoods? I'm afraid to order a gt300 hood from chaser autobody because well... their pictures leave me with a not-so-good impression of what I'm buying. Any tips?

Phoenix7

08-21-2008, 04:22 PM

DOn't know.

I know they are sold on Ebay sometimes but the other choice is to buy them from FDnewbieImports (1600 for FG Dmax hood!!) but it's pricey to get the original stuff from JPN.

vex

08-21-2008, 04:25 PM

DOn't know.

I know they are sold on Ebay sometimes but the other choice is to buy them from FDnewbieImports (1600 for FG Dmax hood!!) but it's pricey to get the original stuff from JPN.

Yeah, i'm not into that price tag at all.

I know chaser aerodynamics has one from c-west and a fiberglass one, but they use the same pictures for both, and they just look like inserts into an aluminum hood, no vents cut out or anything. If that's the case I'd rather just go NA Fiberglass/carbon hood and get it painted.

Phoenix7

08-21-2008, 04:34 PM

actually, I do believe they ARE inserts for rainy days, but I was just like you, I thought it was a useless aesthetic part. You can remove them and make them into functional vents on dry days. Here is an ebay link. I contemplated buying this but I have more important things to waste money on before I do the exterior.

http://cgi.ebay.com/Mazda-RX7-86-91-FC3S-FC-GT300-Fiberglass-Hood_W0QQitemZ280258447480QQihZ018QQcategoryZ10705 8QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I am seriously itching to hit "buy" but I need interior and random engine stuff first!!!

Notice in this pic:
http://i196.photobucket.com/albums/aa81/keycompositesgroup/mazda/h8000cf_3.jpg
You can see the difference in the CF between the vents and the cover that was attached to the underside.

Phoenix7

08-21-2008, 04:38 PM

vex

08-21-2008, 04:40 PM

Phoenix7

08-21-2008, 04:44 PM

yeah, I'm really hoping that as more people join this forum they'll test their previously purchased hoods and post some numbers. As of now I don't see the point in having people spend their money to test something out, especially when the items can get pricey.

On the other hand that hood is CHEAP!!! :willy_nilly:

vex

08-21-2008, 05:04 PM

Higgi made a custom vent for his hood and I'm contemplating doing the same but I'd rather not "eye-ball" it and cut into random sections. I want to KNOW where the vent placement would MAXIMIZE heat expulsion.

well, there's only finite locations where heat will be generated. One is the radiator. Two is the exhaust manifold. Three is the rest of the engine. I say just cut three really large holes over those locations and call it a night.

Or isolate it to create a vacuum effect to pull the heat away from the engine bay and up over the windshield. You should get that with pretty much any lambda flow.

However becareful of making them too big. You'll end up causing a similar condition to that of a convertible/truck bed, in which the wind just creats turbulance and the thermal energy isn't really passed over anything, but kept inside the engine bay.

djmtsu

08-21-2008, 05:04 PM

I was planning on cutting up one of my old NA hoods (Border style) and see how it comes out.

Of course that is after an EMS, turbo upgrade, finish the TII driveline, ahhhhh nevermind.

vex

08-21-2008, 06:49 PM

I was planning on cutting up one of my old NA hoods (Border style) and see how it comes out.

Of course that is after an EMS, turbo upgrade, finish the TII driveline, ahhhhh nevermind.

i often wonder what a modular system would look like. Have an aluminum skeleton and then have different pieces that can be pushed in to have the desired affect. Flat pieces, scoops, vents, cowls, etc. All changed and swapped in at will of the owner.

Phoenix7

08-25-2008, 04:21 PM

Here is another Border unit I found. Seems to be fairly new:
http://infini-fc3s.cyberosity.com/gallery/d/3493-2/DSC04475.JPG

http://infini-fc3s.cyberosity.com/gallery/d/3756-2/DSC04618.JPG

Phoenix7

08-25-2008, 04:25 PM

i often wonder what a modular system would look like. Have an aluminum skeleton and then have different pieces that can be pushed in to have the desired affect. Flat pieces, scoops, vents, cowls, etc. All changed and swapped in at will of the owner.That would be cool but once you find the most efficient piece you wouldn't swap it anymore, right?

vex

08-25-2008, 08:07 PM

That would be cool but once you find the most efficient piece you wouldn't swap it anymore, right?

That would be completely up to the user. For me personally, no I probably wouldn't swap it anymore. But I would be developing more effecient units to be installed in the most idle locations.

Just for instance or an example: Just because you vent heat from one area does not mean that you can not further increase the venting ability of another area by adjusting one part of the hood to a different unit. IE: Venting over the turbo is increased when venting over the radiator is negated.

Phoenix7

08-26-2008, 11:19 PM

That's why I like this hood.
http://www.hpmix.com/home/foresight/images/img99.jpg

Phoenix7

09-04-2008, 01:04 AM

http://www.dmax-cs.com/bonnet/bonnet.html

Whizbang

09-04-2008, 07:48 AM

the biggest thing would be in HOW you compliment the hood. If you want to see what hood style might be most functional, look at what is used in professional racing circuits. What i find interesting when i look at say, Le Mans cars, very very few of them use the same style of venting, some dont even have a vent hood at all. Makes you wonder how well the concept has been researched.

But the other issue to think about is if you want air to EXIT the hood you need to have the area on top of said hood to be at a lower pressure than that in the engine bay. That means your air tract coming in from the bumper needs to be well designed. Meaning the use of at least the factory undertray, good sealing and ducting of air as to give it few options of where else to go.

Phoenix7

09-04-2008, 11:53 AM

well custom underbelly tray and ducting is mandatory. Air will be flowing to the back of the car at all time. Dmax is the only one that I've see showing results though. That alone makes want to get their hood.

Juice

10-06-2008, 05:07 PM

Foresight hood, Excuse the tiny pic:
http://img.photobucket.com/albums/v164/madrx7racer/RX7s/2nd%20Gen/ef8b2555.bmp
http://www.hpmix.com/home/foresight/images/img99.jpg
These look a little different. It may just be the smaller pic. But on the blue car the rear hood vents look to be louver'd. I think I may have seen a larger pic of that car as well with the louvers but I can't find the pics.

Dmax Hood:
Claims 16*C temp drops
http://www.dmax-cs.com/english/bonnet/b1.jpg
On the other forum some of the more knowledgeable people noted that the rear "vent" on this hood is in a high pressure zone and the air would go the wrong direction there. Their animation depicting how it works on their website was also ridiculed. I'm sure it does a much better job than a stock hood though. :D

Don't forget the PanSpeed hoods.

Don't have pics of the Type I.

Type II:
http://img339.imageshack.us/img339/3238/panspeedfc1cf8.jpg

http://img300.imageshack.us/img300/226/image1ry0.jpg

http://img300.imageshack.us/img300/227/image2lz3.jpg

http://img76.imageshack.us/img76/1286/primer1cz7.jpg

http://img178.imageshack.us/img178/1378/primer2rf2.jpg

http://img115.imageshack.us/img115/9881/fronthooddownpaintsn6.jpg

http://img126.imageshack.us/img126/2108/frontpsidequarterpaintom2.jpg

Phoenix7

10-06-2008, 05:13 PM

The other forum has been shown to be full of crap on the most part when it comes to aerodynamics. If you can find a member there to explain themselves you'll make me happy. As of now people like to read diagrams and evaluate them without a single ounce of knowledge.

Most people who claim the high pressure area are looking at an old diagram from Mazda and they go off on high pressure areas and how it will create a vortex and push air back in but I don't see how that makes sense. an elite group of members there are knowledgeable but the rest earned their google search doctorates and are more than happy to talk without prior knowledge.

http://img.photobucket.com/albums/v164/madrx7racer/DSC00626.jpg

Juice

10-06-2008, 05:38 PM

The guy on the other forum supposedly works at NASA. I think it was evilaviator or something.

About the high pressure zone. You know those muscle cars with the big cowl hoods with the opening in the rear? Apparently air flows back under there to the intake. There is even and FC guy that setup his NA intake that way.

Phoenix7

10-06-2008, 05:49 PM

well, they never gave me reasonable explanations. If they somehow find their way in here then they can explain that in detail, that's why I made this thread.

As of now I have yet to see definitive proof of this.

The cowl hood will be elevated closer to the filter in the hood, further forward than the Dmax vent, and it continues towards the windshield which will create that vortex that will draw air into the low pressure pocket (the COWL) and further emphasized by the SUCKING action of the filter and TB(s)/intake system.

The rear vent on the Dmax hood is not remotely similar to the cowled hood. Their openings are in similar spots but that itself does not take away from the fact that the design and effectiveness of one does not apply to the other.

http://www.restoration-world-chevy-parts.com/67-69%204%20inch%20steel%20cowl%20hood.jpg

doesn't seem to be similar to this in any way, shape or form:

http://www.dragva.com/eng/aero/d-max-hood.jpg

BTW The panspeed hood looks great. You're going Vmount, right?

Phoenix7

10-06-2008, 06:13 PM

So, I bought the AD9 FD hood made for the FC (http://www.rotarycarclub.com/showpost.php?p=49098&postcount=78). I'll be testing this hood as soon as I can and will happily post info in here.

djmtsu

10-06-2008, 07:54 PM

I hate you juice, your FC is fuckin retarded (in a good way)

vex

10-06-2008, 08:09 PM

Pheonix7 I'm gankin' your hood.... when I have the funds.... :suspect:

Phoenix7

10-06-2008, 08:32 PM

naw man, pick up the dmax hood.

Juice

10-07-2008, 11:42 AM

The rear vent on the Dmax hood is not remotely similar to the cowled hood. Their openings are in similar spots but that itself does not take away from the fact that the design and effectiveness of one does not apply to the other.I never said they were similar, just said the vent is in the same location of the cowl and thus could have the same effect. Honestly, the whole cowl idea seems kinda strange to me. I always thought those hoods were for extra clearance because they had a supercharger strapped to the engine or something. When someone explained the theory to me I was able to wrap my head around it and understand the logic behind it, but I am still skeptical without seeing proof.

BTW The panspeed hood looks great. You're going Vmount, right?Thanks! Yep, going Vmount with some ducting and sealing against the hood. The IC core will be hard annodized black for a stealth look and supposedly a little greater heat transfer.

Nice find on the AD9 hood. You goin vmount as well?

The reason I wanted to go with a panspeed hood was because I wanted a dedicated vent for the IC that I could seal up nicely and force air through it. I looked at a couple hoods like the AD9 but the design is way different and wouldn't be possible to do what I wanted with them. That hood will probably vent the engine bay air well and still help alot with a vmount no doubt.

Phoenix7

10-07-2008, 09:08 PM

I don't know about Vmount yet. It seems like the most direct way to the manifold but I'm not ready for it yet. It requires a lot of work and my working space is very limited.

Well, I can understand how the cowl fuctions but the vented one doesn't seem to work the same way.

JunpoweR

10-09-2008, 05:57 PM

It seems people here are not educated on these subjects.

Cowl hood
Cowl hood Induction
Hood Vent.

Honestly it dosent matter where the vent on the hood is. Air will leave your engine bay unless your cowl hood has it's own tunnel going back into the engine bay and directed to the air filter.

The cowls you're talking about to make space for superchargers and larger intake manifolds, also still let engine bay air out even tho it is located in a low pressure area. The air comming through the front creates enough + pressure where air will be blown out from under the hood and not enter it as some people believe when " Cowl Hood INDUCTION" comes into play.
There cars have their own pathway seperate from the engine bays air. a tunnel directed to the air filter.
I am sure everyone knows me from the hood vents i started to use and make for other fellow fc owners. There was a big arguement about it's effectiveness on on track so I will be testing and posting some results sometime in the future.

the big argurement was that it lets air enter into the engine bay lessening the effectiveness of cooling the engine bay. It does the exact opposite and lets more air out of the engine bay which in turn lets more air enter the engine bay through the front past the radiator which in turn makes cooling the engine and the bay more effective.You will have a lower + air pressure in your engine bay because more air can escape meaning air has more places to escape at higher speeds.

http://img.photobucket.com/albums/v176/junpower/GTUsFrontMods11.jpg
HOOD VENT

JunpoweR

10-09-2008, 06:17 PM

BTW nice car JUICE

And Pheniox when i got some time i'll bust out the mig and well make u a v mount set up.

Phoenix7

10-09-2008, 07:03 PM

Juice's car is insane!! I can't wait to see it finished!

I'm down to do more work on it but first I need to make sure the car will run well.

The NA is gonna need work soon so I'm honestly more concerned about getting it running well so i can take the NA down for a while while I fix/replace crap. I just found rust by the brake booster and some wire is missing and not plugged in on the driver's side and the suspension is old, and just shit that needs to be done after 200K miles.

Phoenix7

10-10-2008, 04:19 PM

Anyone want to jump on this hood?? WE need to have someone do a test with this hood.
http://www.drifting.com/forums/buy-and-sell-area/25460-dmax-and-daimyo-frp-hood-sale-in-stock-and-must-go.html#post214574

JunpoweR

10-10-2008, 05:17 PM

The hood dosen't need testing it's vented and will work.

Phoenix7

10-10-2008, 05:31 PM

not true. Just cuz it has boobs doesn't mean you can milk them.

You have to test it's efficiency to make sure you spent your money right.

Anyone can buy a hood that has a vent (I saw this on a prelude) but what's the point if the vent goes RIGHT TO THE RADIATOR SUPPORT?????

While Dmax DID test their product I think it would be cool to show the results on a rotary. PLUS, it's a real Dmax hood for under 600 bux. Anyone looking for a genuine product for cheap should jump on this.

nissanconvert

10-13-2008, 10:24 PM

Phoenix7

10-14-2008, 12:05 AM

http://i37.photobucket.com/albums/e58/CapnBoost/fcaero.jpg

This series of articles (http://autospeed.com/cms/A_2159/article.html) is well worth a look. There's far more science here than i've seen in most threads on the subject. But, until someone mentions at the very least wool tufts (preferably pictures at speed) i'm not going to believe that washers or an ebay duct/hood are as functional as the seller says.

Ok, explain that picture to me then. What am I looking at?

From the article you posted:
With extra exit vents in the bonnet preventing any build-up in engine bay pressure, best flow through the radiator is gained. (Of course, you can substitute ‘intercooler’ or ‘oil cooler’ for radiator, if in fact their exit flows are also into the engine bay.)

So the airflow through a radiator doesn’t depend on the pressure in front of the core; it depends on the pressure difference across the core. IOTW, the air exit is just as important as the air entrance – if the air exits aren’t big enough (or the airflow doesn’t pas through them quickly enough), pressure will build up on the downstream side of the heat exchanger, decreasing the flow that’s occurring through it.
The one you posted is a good one but it's of the Aerodynamic Forces of the Rx7 and I'd like for someone to explain it to me.

The ones people should be focusing on are:

http://img.photobucket.com/albums/v164/madrx7racer/RX7s/tech/017.jpg
http://img.photobucket.com/albums/v164/madrx7racer/RX7s/tech/019.jpg

Phoenix7

10-14-2008, 01:12 AM

After reading your article it just proves Junpower right. No testing is necessary since any and all openings will always yield heat expulsion, including hood lifts, right?

With proper ducting to direct air to and through the radiator you'll maximize the radiator's cooling efficiency. If you seal off the bottom then MORE air will escape through the vents in the hood.

nissanconvert

10-14-2008, 10:29 AM

Of course all openings will radiate heat, but you want to maximize the pressure differential across the core. Without wool tufts or a magnahelic (sp) gauge you can't possibly know. Sure you could compare your IAT's before and after but that will be dependent on a number of factors well beyond our control.

There are 2 other articles in the series Part 2 (http://autospeed.com/cms/A_2160/article.html) and Part 3 (http://autospeed.com/cms/A_2162/article.html). I would really like to see someone provide a case for a hood with evidence.

RXVERT

11-01-2008, 12:09 PM

Heres some picts of aftermarket Hoods for ,,, and or customized on the fcs for you :

RXVERT

11-01-2008, 12:24 PM

And some more: And I got alot more but I dont want to be greedy on my postings. But I could always post another day with some more picts, for you, just let me know.

vex

01-11-2009, 11:16 PM

What's the white hood?

Flys

01-12-2009, 02:24 AM

So, is there any under body aerodynamic charts? How does the transmission get cooled off with all of this air exiting before it?

vex

01-12-2009, 09:29 AM

So, is there any under body aerodynamic charts? How does the transmission get cooled off with all of this air exiting before it?

The transmission doesn't need to be cooled. The temperatures that will hit the components of the transmission are significantly less than the engine itself.

stylEmon

01-12-2009, 03:02 PM

the panspeed Type II has my vote!!

Phoenix7

01-12-2009, 09:57 PM

Doesn't the TII tranny have "fins" on the bottom to help cooling??

We have a lot of pics.....I was thinking about it and can't find a good way to test the hoods right now.

I'll do it for sure at the next race event....test the NA hood vs. the vented one on both the NA and TII. Take temp readings after one full run and then try again. Eventually I hope to get more people to do this and get some numbers going for different hoods.

Kelton

01-12-2009, 11:30 PM

DMAX or stick with a TII hood imo

hIGGI

01-20-2009, 07:44 AM

My solution - URAS Erobon :

http://rx7.cz/gallery/?Qwd=./hoodvent&Qiv=thumbs&Qis=M

RETed

01-22-2009, 06:12 AM

Doesn't the TII tranny have "fins" on the bottom to help cooling??

Those ribs are for reinforcement strength, not cooling.

-Ted

JunpoweR

01-25-2009, 11:22 PM

Just use my damm hood lifts and show them!

pachizeron

07-17-2009, 08:51 PM

These hoods look great but in any case, I'd go for a fiberglass carbon hood. The aesthetics thing doesn't matter to me also.

Rotary#10

05-11-2010, 02:06 AM

interesting thread.

4port

08-28-2012, 07:47 PM

nice. i want that hood

rxspeed7

08-28-2012, 08:14 PM

Odula cf hood!!! As far as I know I have the only one in the US! lol score

http://i20.photobucket.com/albums/b232/driftfc/c2e48913.jpg

WankelsRevenge

08-29-2012, 03:46 PM

Raksj04

08-29-2012, 10:26 PM

Id like to see something like this C6R hood where the scoop mounts flush against the radiator. I would think with the V-mount of the stock radiator, plus the available room in the engine bay it wouldnt be that hard to do.

I agree.

I think if you had ducting from the rad to any vent on the hood it would help with under hood temps.

WankelsRevenge

08-30-2012, 01:37 AM

I agree.

I think if you had ducting from the rad to any vent on the hood it would help with under hood temps.

I figured such as well. There would also be room at the top of the hood for some vents to vent some of the hot air in the engine bay. The biggest problem I could forse is getting the hood to open, but im sure theres ways around that.