The question though, at speed, would there be some sort of turbulence (maybe not the right word) behind the hood, which would trap any escaping air and force it back into the engine towards the radiator?

Did you even read the thread?
At all?
Even half-way?

Why do that? Hell you might learn something.

so i see your suddenly backing away from the air cooled engine theory... good idea

did you read this p0st? https://www.rx8club.com/showpost.php...7&postcount=76

I can see your [sic] suddenly backing away from the substantive comprehension of the English language.
If you somehow actually construed that I was advising that the Renesis is air-cooled, then you have completely gone off the deep end.

You are this forum's Bill O'Reilley, you know that?

You are now officially on my ignore list. Enjoy!

lol^
Dam it! I was just at Homedepot today. Now I have to go back today ;) and buy some of this stuff that Expo1 used :)

.............You are this forum's Bill O'Reilley, you know that?..........

FWIW, I would consider this to be a compliment.


Removed the rubber strip and am using a small piece of hose to prop up the center of the hood. Cant really tell if it helps. The hood gets extremely hot (no plastic covers). This car really needs some water/oil temp gauges. This is my next mod.

Oh, and during a rain shower I noticed the water drops being gently pulled in at the center of the hood. But this may be dependent on how much of a gap I have, how fast I was going, etc. Even if air was getting sucked in I would still maintain the hood gap for stop and go driving situations.

Something else I do is open the hood when I get home. Having a garage helps. I figure over the years this will help hose longevity among other things. Probably not necessary but it cant hurt.

Impossible, everyone knows the mod works because "We are simply giving the air that goes through the radiator more choices for an exit."

Sounds to me like you got the faulty result the rest of us who actually took time to find out what was going on found - no air escapes, rather slight amounts get pulled in... which hoses the above comment :cwm27:

That is particularly sad. You do know B.O'R's history, right?

Pulled into the gap? In a ride to Tucson through the Rain on Saturday (first rain I've driven in in almost a year), the rain sprayed quite distinctively at the windshield once it left the lip of the rotor crescent.

Just done this mod & this morning the water on the hood did go round & back under. This was at 60mph, it doesn't mean rain will though as it's in the air flow & not under tension to the hood.

its a conspiracy :uhh:

Which front bumper do you have?

MazdaManiac: Most of the detractors of Bill O'Reilley are from the far left who attempt to silence or vilify anyone they do not agree with. I am not of the far left. And even though Bill can come across as arrogant I find his common sense approach very refreshing. So we may not agree on political issues, I do agree with you on the hood mod

Let me state it this way

Do I have the hood mod
yes

Does it work
Based on testimonials given in this thread I would say so

Does air move in or out of the hood
My understanding is that there is a high pressure area at the base of the windshield (center only, not the sides?), so air should move in. But this may depend on how fast one is going, size of the gap, etc. I dont really know.

I have no plans to undo this mod. My only concern is the high hood temps under certain stop and go situations. I am thinking about reinstalling the engine cover. I guess this would help. Not really sure. Maybe I am concerned about a problem that doesnt exist.

And what the pressure is under the hood as well. :banghead:

Heat = High
Cool = Low

I have moderate experience as a pilot how this stuff works. Aerodynamics and Weather play a part here. High pressure will always move to low pressure. That is why thunderstorms are storms.

You heat up a sealed bottle of water, what happens? It goes to the lower pressure, outside the bottle.

Leading edge of a wing: realitive wind hits leading edge of wing and is directed up, creating a high pressure over the wing. The top surface of the wing is low pressure. The wing want to go to high pressure, above the wing. That is called LIFT.

Only makes sense if the engine bay is hot, it want to get get out to the lower pressure. If you speed up, venting will increase if venturi is formed over the hood. Same way fuel is drawn into a carb, with air movement.

I removed the back seal on my hood a long time ago, seems to work some. Need more vents though. Don't want to drop a bunch of money into a vented hood.

I use a fog machine for DJ gigs. I am going to use that and some fans to see where the highest pressure occurs on the hood. That would be the best place to exit the heat under speed. Standing still, there maybe a better place to vent.

My question is, what engine bay area(S) have to stay dry?

almost none. plugs, wires, coils. wires and connectors are generally shielded and protected and don't need much thought put towards them. That said you don't want them to be immersed in water, so don't drive into a lake.

you do not vent INTO a high pressure zone, depending on the relative pressures of the zones you are connecting you could stall or even reverse airflow within the duct.

I think you may be better off to make a LONG hollow stick/pointer and blow the fog/smoke out that while you're on a long empty stretch of freeway.

I wouldn't think fans would give enough airflow at speed, nor would they give you nice smooth airflow without the long straightening section.

Oem

(edit) with engine cover still in place

I will try that.

awesome, be sure to post pics/video up if you do - I've been wanting to do this on the gf's RX8 and my Supra. (be interesting to see over bonnet stream, and where smoke near the engine bay intake went)

Any idea on what the best (and safe) thing to create a good 'solid' smoke would be? I wouldn't have thought the dj/disco fog machines create enough (or thick enough) fog to see clearly.

I did this hood mod. It works great! I recomend it to anyone who has a 8 thats in the hot spots of the US.

Since I'd likely be painting my hood silver (I don't really dig the mixed body panel look), I thought this might be a nice alternative. I haven't heard anyone talking about fiberglass hoods though. Any pitfalls with them?

http://www.aerokits.net/cart/index.p...oducts_id=2443

Those are the guys that gave me my GT-Factory vertical door kit after SEMA two years ago.
I visited their shop in Baltimore - they seem like a good bunch of people.
The hood you are looking at is made by GTP, who has mixed reviews.
Certainly cheap enough. I might have to get one of those.

I like the underhood shots. Gives me a little more confidence.

MM, have you seen under Todd's Seibon? Does it have bracing like this?

I will have to nag him about that on the other forum.

It just has the "frame" around the edge.
I don't think there is much in the middle.

hehe. The webpage says it's 150 lbs and it's $150 to ship.

So much for lighter!

Someone said the Siebon is 2 pounds heavier than stock. I am sure the bracing shown on this hood will push a little more weight.

I would rather have the bracing than not. Driving the 8 at 60+ in a cross wind the rear of the hood moved so much I pulled over and checked the latch! It was bucking up and down at least 1/2 inch.

A vented aluminum hood would be even nicer. I can imagine the cost.

I think they left out a decimal somewhere. Hopefully not in the shipping cost.

Yes, this is the only vented hood kit I would ever consider. Just about all the other vented hood kits look like crap to me. The only exception would be the aborted mazdaspeed hood, but people keep having trouble doing the height of the triangle bump correctly and/or don't cut and make it vented... Anyway, the below is a nice hood.

Still though, the whole rain or car wash issue makes me pause a bit...

http://www.aerokits.net/cart/images/...770-is_LRG.jpg

some S2000 people cut up their OEM hood.

Before you dismiss doing this, make sure to check out the results!

I wish I had the tools handy to do likewise on the 8 :)

http://www.s2ki.com/forums/index.php...pic=324009&hl=

now this is how you do a hood vent to evacuate air out and increase radiator cooling...

https://www.rx8club.com/attachment.p...1&d=1189371994

Need to put some tape on that hood or it might fly off, lol

I like the fake MazdaSpeed (GT3) paint job.
That'll work too, but it isn't particularly more effective unless you have gotten the battery and airbox trays out of the way.

absolutely and dont forget to get your fans turned on earlier.
The S2 idea i like.
OD

The S2 idea is interesting, but personally I think that's a little TOO much venting, unless that is a track day only car.

The hood that sosonic posted looks ok, but its a little much I think. Though, I could see a hood like that one, but with smaller vents.

I wonder what a "ram air" style hood would look like on the 8. I own a grand am with such a hood, and it does help with air circulation once you remove the stock baffling.

or like any good RX8 racecar, have the engine compartment gutted and a 13b-rew and a gigantic intercooler put in place of the renny...

https://www.rx8club.com/attachment.p...0&d=1189341590

This is where you and i will have to disagree.

while harsh, currently it seems to be unfortunetly true in most cases -sigh-

Depends on what you are talking about specifically, I suppose.

I think Vmount is one thing most can agree on...

I suppose if you bought an OEM hood off of this forum at a discount getting/making a vented hood for cheap with little risk isn't such a bad idea

Two things:

1. I did the rubber stopper thing in place of the rubber seal on the rear of the hood. It wasn't extremely hot today, but judging by my normal driving habits and what I'd expect from the coolant and engine temps, the engine remained where it usually does (180F), but with all the boosting I did, I expected 200F coolant. Instead, it stayed 180 - 190F the entire time.

So an extremely unscientific first glance says that this mod does help, to the tune of 10 - 20F range. As an added bonus, I can hear my BOV much more distinctly now. But I don't have the underhood material in place (because of #2 investigations - see below)


2. I checked with a friend who has cut up his hoods before (He had an old vette that he did some flame cuts for the engine that pokes out the hood). And it looks like the bottom edge of the hood by the latch has a good 6" of space that has no rivets that I can mess with. I'm thinking about a set of 2 horizontal vents per side of the hood in that area. It's far down enough that the only thing that'd get wet is the radiator area where the OEM setup already vents excess coolant.

seems like everyone that has tried this has noticed an improvement . Very cool :)

It cost $1.99 for 4 rubber stoppers, and $0.99 for some #10 screws with nuts.

I need to get one more rubber stopper since there's one more spot left without it (but they sell them in boxes of 4), and maybe some paint. From inside the car, you can't see them, but when you pop the hood, it's apparent.

Also it doesn't really bend the hood. There's a bit of resistance when you shut it, you can feel the rubber stops compressing, but the hood looks the same from the top.

what height did you make your stoppers ?

expo1 posted a pic of the rubber stoppers he got at Home Depot. I printed out the pic and picked up the exact same thing. So if you can find that photo, you'll have the answer. It's not posted in this thread though.

Expo says 3/8" thick - they look thicker .

on the ram air note.................. its not to add presure ....................its to add cooler outside air in to the motor instead of air comming through the radiator at 190 degrees