i've tried this mod as well...but one thing that I quite worry...will water sip in to our engine bay? if yes, what will happen???

my country is raining season now for this month. Also worry when car wash, water will go in.

 

No need to worry. I had mine "vented" for about 3 months in the hottest part of the summer. Rain and car washes were not a problem.

 

Update: for those of you with Mazdaspeed/AEM CAI...

Well, I assumed the cowl effect would occur so I never bothered to do this modification. However, this past weekend I removed the tray that typically goes underneath the intake box. What did I see? The radiator and radiator fan :D I realized that removing the box would just cause the air to flow into the engine bay rather than under. I also pushed around the whole high low pressure thing and decided to try it. With the intake box tray removed + hood tilt theoretically the air will be pushed through the rad and go over the engine out the vent (with some help of the fan if your engine gets hot enough). This morning I did some hard driving (mostly 2nd/3rd gear 50-95 stuff) for about 15 min then cruised home another 35mi. I believe the temperature was about 80 or so. Not only did the car feel VERY responsive the entire time, hen I arrived home I left the key in ign on start and popped the hood. My rad fan did not turn on. My ecu is reflashed to turn on #1@87C and #2@90C.

In traffic having the tray is fine because the hot air will go up + out the vent regardless, thats the nature of heat.

The hood is tilted ~1" w/the weather stripping in the trunk. The only reason I felt such a raise did not compromise integrity is that I have hood struts that have a plate that goes from above the top bolt to below the bottom - the washers go between the new bolt and the plate. My dilemma is of how this looks :O Sure may seem silly but IMO the hood tilt looks better on plain/square hoods (not our curved rotor stamped hood) and is a tad bit rice at my cowl height. However, it seems to be VERY functional. Because I'm a function>form type of guy I am sure I will leave it, merely commenting.

This weekend I will be relocating the battery to the washer fluid reservoir location (+ lighter battery to attempt to offset the higher position) to try to free up the other rad fan/help flow even more. Lastly I will wrap my intake tubing as it did feel warm-ish due to the hot air blowing on it (still a cooler renesis is a happier renesis, Im sure the intake tube temp diff is negligible).

Oh, and I found this funny:

Sold for $45 + ship on japanparts.com - I did it for $5 + gas to OSH

Oh, and I will log some hard evidence on this once the sCANalyser arrives...

 

Ok I did not yet read this thread past this post (quoted below), but it was just too hilarious for me to not give it praise. A+

 

Its not as much fun without the pictures!

 

If only I could have included them! So anyway, this looks like a simple thing to do in any case. I just put in a turbo, so this seems like a good idea to me.

 

I just recently did the hood mod ala expo1.

What do most of you have for height of the bumper + washers as a whole?
I was using 3 - 1/16" washers with the 3/8" bumper.

So far can tell it has been working but also showing at least for the Vegas heat the inefficiency of the stock coolant that was in the car when I bought it about a month ago.

On top of this it has been aiding the A/C coolant line wrap mod to pump out better air in the cabin.

 

This may be a silly question, but does this mod in any way affect fogging/defogging of the wind shield? Could this make it fog up easier or make it more resistant to fogging up?

 

Depends on the weather vs your cabin temperature.

What causes glass to fog up?

 

Same thing that causes your dive mask to fog. Warm moist air against colder glass.

 

someone should get this. it'll vent really nice. lol

http://japanparts.com/images/ImageFr...ase=1&no=16353

 

you mean all 12 washers?

 

VERY subtle! lol

 

I lost count

 

did someone say "rice" ?

 

Kinda like a poor mans vented hood, LOL
I remember a guy on the is300 club with that mod said its practical way to lower engine bay temps.

 

Funny thing I did this mod 7 years ago to my FC and got flamed!!
The windshield will not fog up because the hot air warms up the windshield enough where water evaporates.
You do get the engine bay air and heat comming through the intake for the cabin ventalation which is located right under the windshield. If you have an exhaust leak in your engine bay wear a gas mask while driving or hit the RECIRCULATE button on the logicon to shut off the fresh air.

And yes it does lower engine bay temps but getting hot smelly engine bay air in the cabin sucks!
Remember use the RECIRCULATION setting on your car at all times unless you like the smell of your rotary!

Here a few pictures of it on my 89 GTUs

 

I didn't do this vent mod yet, will soon, but I recently got a scangauge to check out engine codes, and according to that, my temps, even though ive got a front mount turbo, are below 210. I've seen 211 as my highest when I went up a steep hill. Ambient temp at the time was 82. Does all that sound about right? I'm sure itd get much hotter in the high 90's of summer months. Also, that was driving about 18 miles, would driving farther end up getting it much hotter than that? That's my commute to school, thats pretty much as far as I'll end up going on a daily basis.

 

Friends and i have been doing this trick on hondas for many years now. i havent paid much attention to the RX-8 Hood Mounts yet byt we used to buy 4 bolts 1" longer then stock and buy either small aluminum pipe or spacers for the bolts and would raise the hood 1" or a little more then that. it has always worked well on hondas in the past how ever hondas have a problem burning oil and it to would smell if the recirculate on the blower was not turned on.

just my input

 

I've read this entire thread and suffered through the arguments. It seems to have worked so I went ahead and did it just like the thread starter using the white rubber bumper and an extra flat rubber washer. Much of the arguments seem to have been not about whether it worked but how it was working. Some argued that air would exit the back of the hood, others argued that as a high pressure area it would not exit the back of the hood.

I put some yarn on the hood afterward and these are the results. The pictures were taken at a standstill with the engine on but (you will have to trust me on this) they were in the same position at a variety of speeds up to 85 mph with the interior vent open and closed and the interior fan on and off. At about 50 mph the strings on the outside edge of the hood on either side would sometimes go inwards, and sometimes flutter out, suggesting that at the edges of the hood its a wash with the direction of airflow. The rest of the strings were vigorously flowing inward at all times. I even stopped and pulled them out to make sure they weren't stuck and they immediately sucked back in.

My view on this is that is doesn't matter whether hot air is going out or cold air in going in, either way its an increase in ventilation and the net result is more air through the radiator and a cooler engine. Also because the air is going in it has no effect on the air conditioning system or windshield fogging.

 

Nice job. Thanks for posting your data!

 

Slightly off topic, but do you need to keep your engine cover on?..
Is there any reason WHY you have to always have it installed...

Thanks
Ash

 

Try removing your battery box/OE intake box to allow the radiator fans/air to flow through and out the rear of the bay.









How can people claim that it will not fog up the windows? Every morning at 7:30 AM my front window is nice and clear. Once I start up my car and begin to drive, fog appears, on the outside. The windshield wipers take care of this and once high speeds are reached/wind factor is added in the fogging stops. Also, I know for a fact that after any drive, spirited or not, I can place my hand on the black plastic where the windshield wipers lie and it is indeed warmer than normal. I stick with my previous statement of needing to remove the intake box and/or battery box to have the best effect of this mod - it prevents the cowl induction via high pressure system...

 

The cover is not necessary whatsoever, other Mazdas have it as well. Aftermarket engine bay parts prevent the ability to use it and many claim substantial gains in cooling simply by removing the cover however I tend to disagree.

Yes, you may remove it safely

 

Based on JustJim's findings I have put the weatherstrip back in on my car. The reasons are I want maximum radiator flow when I track the car and highway drive and Jim's data shows that at high speeds you pull in air from the cowl which will reduce the amount of air being pulled in through the radiator.

I have noticed my in town and traffic temps are ~10 degrees higher and my high speed coolant temps are ~5-10 degrees less. So my conclusion:

-This is an effective mod to reduce coolant temps in city driving and low speed traffic.
-I would not recommend this for track driving or high speed driving.