Vented hoods...functional?
 

Ok I Have the mazda speed imitation hood. Its the one with the "w" looking hood scoop. When I got the hood the scoop was functional but I had the guy doing my body kit close the vents up. I knowticed people saying that the vented hoods are good for keeping the engine bay cool...but what about water getting in the engine bay? My scoop goes directly over my petit intake and if I left it the way it was water would be falling directly onto my intake filters. Am I missing something here because I would love to have the scoop be functional but don't want to screw anything up. I was thinking of just leaving the very top of the scoop functional and run tubes at the bottom of the scoop to drain any water that collects there. Does anyone have this hood and have the scoop functional?

I know for a fact that the vents do lower under the hood temps. and also on high speed cars lowers the pressure build up in the front of the car, to keep the front end planted when your doing high speeds, but as far as keeping water out i have always wondered about that, because i want to put one on my car. dont drive it on rainy days:D

im pretty sure that the mazdaspeed vented hood you have makes water hit the intercooler. Not 100% sure, but i think that it does hit the intercooler. hope to see other people reply back.

1FAST7

I was concerned about water too until I talked to my tuner about it. I have the Apexi intake and the lower filter is directly under where water will fall. Intercooler gets wet on the other side as well. Unless you're in a torrential downpour, the intake is not going to get that wet. A normal rainstorm wont create enough water runoff into the filter so that the engine floods out - what it will do is make the air more dense and what amount does get sucked into the engine will get vaporized quite quickly.

Downpours are another story and for those, I intend to get some magnetic material and cut it to the size of my vents (I had them grilled) and apply them when necessary to restrict the amount of water dumping in.

what happens if you are in the middle of the highway and it starts raining really hard. And the water gets trough the intake. Will the engine mess up? and what about a closed box intake? are those better with this vented hood?

1FAST7

First I would get a magnetic strip and cut it out to the desire fitting that fits the vents then when it rain I just pull over somewhere and put it on beneath the grilles.

good idea. Thanks

1FAST7

LOL - I wish I had said that :D

Another thought abouth the vents - if it was really a huge deal about the water getting in that area, would Mazdaspeed have designed the hood that way?

There is a type of mesh that is pretty much uni-directional in terms of airflow and waterflow (meaning it will only allow flow in one direction). It probably has a trade name, but I'm not sure what that is. Maybe you should ask around about something like that?

As a couple other have pointed out, don't be too overly concerned with a little rain water in teh intake. Short of a full blown hurricane (which I would not be drving around in anyways), there will be very little water that enters the intake.

There is a big differnce between driving into 2 feet deep water with a custom intake in the bumper opening (like someone I know that owns a Prelude) and having some rain water dribble into our intakes.

As that the (air) intake charge is very hot by the time it gets to the throttle body, any reasonable amount (as expected in most rain storms) will be evaporated.

And, when your vehicle is at speed (my guess 30mph and above), very little rain will make it into the vents. Try driving in rain with your sunroof cracked open about the same as the vents.

Heck, I'm about to install my Aquamist water injection system, so I'll be INTENTIONALLY injecting water, hehe. (actually, water/methanol mix)

As for water hitting the intercooler - that's a good thing. Water on a intercooler will cool it better then simple air flow.

If the thought of water dribbling down into the intake really bothers you that much, cut out a sheet of aluminum and attach it over the filter elements somehow - like an roof of sorts. This way the the vent openings are left open to do thier job, and basically very little water will make it into the intake. A simple flat sheet should do it, and not impede air intake flow.

I just put my mazdaspeed CF hood. Atleast on my car, the left vent, left side, is over the end tank of my M2 med IC. I was hoping it would be behind the IC, so that it would help create a low pressure area and help suck air through the IC, but no luck, its right over it. As far as getting on my filters, I can't even see the corner of my M2 air box, so the filters even if it was an open element like a pettit, wouldn't get wet. Might suck some dripping or flowing water toward the intake but not drip on it at a red light.

Tim Benton

What is the best looking vented hood?

I like the mazdaspeed vented hood. I like the way it looks. Not too much changed. And does the venting function very well.

1FAST7

what about when you waxh your car?? a shit load of water and soap will get there. that is a little more than a few drops of water whaen it rains.

Do you wash your car with your engine running all the time? Don't take it thru a car wash - hand wash it. I'm not going to argue the mech washing vs hand washing thing - that's up to everyone to decide. If you insist on mech washing, don't get a vented hood.

Sheesh, just put a plastic bag over it or something. I do that for various electrical things under the hood when I'm detailing/washing under the hood (when I'm not lazy hehe).

All you have to be is a little more careful when you put on a vented hood. Just use your common sense. The RX7 is not idiot proof to begin with, and it takes someone 'smarter then the average bear' to maintain/care for one.

I was really trying hard to find the words to reply to the last thing but couldn't find them - you said it excellently.

i never said anything about mechanical vs. hand washing. no way dude...i will never run any car that i own through a car wash.

i was just saying when you wash your car, and are rinsing the soap and everything off. when you wash your hood, you're kinda obligated to spray it with water to rinse it. that spraying of water is much more than rain.

so i wanna know....what do you guys with vented hoods do when washing your car??

I have a Mazdaspeed carbon hood and it only gets the intercooler wet in a total downpoor

Just get the aem bypass valve. No water will ever get in your engine that way.

the design of the aem valve is very simple and well-designed. although that is a really good idea in my opinion, lots of people here would refuse to even consider putting something on their rx-7 made by a company that sponsors and encourages modifying hondas and dsm's. i believe the term they use is "rice." however, if aem were to sell the bypass valve patents to pettit or racing beat, they would probably sell like a motherfucker.