Notices
Series I Do It Yourself Forum Wanna save some coin or time/money in the shop? Read up on Do-It-Yourself custom mods and repairs & post your own here.

DIY: Hood Ventilation Mod

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old 08-02-2007 | 08:59 AM
  #1  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
DIY: Hood Ventilation Mod

This mod is the result of a collaborative thinking of a group of very talented individuals (which is what this site is all about). If you want more info on the original idea behind this, please read this: https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/hood-ventilation-ideas-123434/
But I posted the results here, as I thought that this is a more appropriate place for it.


After a day elaborating on the topic, I settled on an inexpensive, or rather completely expense FREE solution based on the hint from MazdaManiac:

To do this you'll need:

1. 2 blocks of plastic hard rubber or some other hard material sized approximately 1/2"X1/2"X3/4" (Hight may vary slightly depending on how your hood cover is aligned)

2. PVC cement or other glue or adhesive.

Now roll your sleeves and get to work

1. Remove the rubber seal in from the cowl (the back of the engine compartment above the firewall).

2. Install the plastic blocks (I just glued them into the two off center holes on the panel where the rubber seal used to be mounted)

3. Close the hood.

There will be a very slight resistance as you are locking the hood. That is because the rear portion of your hood cover is pushed up to enlarge the opening. If you look at the hood from inside the car you'll see now that there is about a half inch tall opening all across the width of the hood. If you look at it from the outside, you'll see no difference, and no misalignment.

http://picasaweb.google.com/vdarevsk...05087982547106

http://picasaweb.google.com/vdarevsk...05075097645202

http://picasaweb.google.com/vdarevsk...05066507710594

This hefty little mod helps to keep your under-hood temps and running and idling coolant temps lower by an average of 6-10C while driving in a 95-100 F outside temperature, and costs nothing.


Happy modding everyone.

Last edited by rotorocks; 08-03-2007 at 01:37 PM.
Old 08-02-2007 | 09:11 AM
  #2  
DrewMan's Avatar
Culpam Poena Premit Comes
 
Joined: Oct 2006
Posts: 1,230
Likes: 0
From: Sydney, Australia
wont this cause the hood to bend?
Old 08-02-2007 | 09:15 AM
  #3  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Originally Posted by DrewMan
wont this cause the hood to bend?
No, it just pries it up a little, without deforming anything.
Old 08-02-2007 | 09:43 AM
  #4  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
Just wait until a few thousand miles of heat cause that little stretch to stay permenantly. You do know aluminum is pretty malleable, right? especially when warm? and that its a good conductor? So the engine bay heat will wam it up much more than a steel hood.

Last edited by mac11; 08-02-2007 at 09:53 AM.
Old 08-02-2007 | 11:10 AM
  #5  
Red Devil's Avatar
Registered User
 
Joined: Jun 2002
Posts: 3,086
Likes: 1
From: Misinformation Director - Evolv Chicago
Any plans to post pics?
Old 08-02-2007 | 01:05 PM
  #6  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
ohhh.
sometimes a pick is worth a 1000 words as they say, but this mod is so simple it just feels like posting pics is not worth the effort.

But ok
I didn't have the time to take pics of it, but maybe today I will.
Old 08-02-2007 | 10:12 PM
  #7  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Updated the original post with pics
Old 08-03-2007 | 12:55 PM
  #8  
shaunv74's Avatar
Power!!
 
Joined: Feb 2004
Posts: 4,412
Likes: 3
From: Sunny See attle
Nice. Very nice and simple. Any coolant temp or oil temp differences to speak of?
Old 08-03-2007 | 01:18 PM
  #9  
lepichichi's Avatar
I LuV mY Rotary....
iTrader: (10)
 
Joined: May 2007
Posts: 3,408
Likes: 0
From: killADelPhia
pics please
Old 08-03-2007 | 01:19 PM
  #10  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Originally Posted by shaunv74
Nice. Very nice and simple. Any coolant temp or oil temp differences to speak of?
Mine runs around 6-10C cooler.
Old 08-03-2007 | 01:25 PM
  #11  
StealthTL's Avatar
Metatron
iTrader: (1)
 
Joined: Mar 2003
Posts: 7,284
Likes: 175
From: A Pacific Island.
Gonna hafta call bullshit on that one.

Coolant runs 10*C cooler?....just not possible.
Oil?....even less likely, sorry.

S
Old 08-03-2007 | 01:33 PM
  #12  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
I have a very large Intercooler sitting in front of the radiator, and it blocks quite a bit of the airflow. Causes the car run hotter. As i posted in the other tread. It run in the figures of a 98-100C degrees. After this, the cooling temps are holing up in the area of 90-94C on a highway going around 80-85 mph.
Same thing when idling.

Call it what you will.
I have no interest in this to bullshit.

P.S
I bet if it was Racing Beat or some other company offering these things for like a $50 and claiming the same numbers, people would be all over it like flies around the droppings...

Last edited by rotorocks; 08-03-2007 at 01:45 PM.
Old 08-03-2007 | 01:35 PM
  #13  
shaunv74's Avatar
Power!!
 
Joined: Feb 2004
Posts: 4,412
Likes: 3
From: Sunny See attle
Actually I would believe it at highway speeds. According to Racing Beat's observations the biggest problem with the cooling system is airflow evacuation from the engine compartment.
Old 08-03-2007 | 01:41 PM
  #14  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Over a 100F here today, i just got back from lunch, and had to go like 7 miles in city traffic to get the visual inspection for the insurance company, and back. Drove nice and cool, never even got over 94C. You can actually see the waves of hot air pouring out through the opening as the car sat at a traffic light.
Old 08-03-2007 | 02:10 PM
  #15  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
Originally Posted by shaunv74
Actually I would believe it at highway speeds. According to Racing Beat's observations the biggest problem with the cooling system is airflow evacuation from the engine compartment.
The air does not evacuate the engine bay through this opening when traveling. only when moving very slowly or not at all.
Old 08-03-2007 | 02:16 PM
  #16  
XDEEDUBBX's Avatar
RX8 HA HA
 
Joined: Aug 2003
Posts: 11,772
Likes: 5
From: Gardena Cali 310
not sure if it was mentioned in the previous thread but why not just buy some metal washers and bolt them under the hood to where the arma attach to it. The honda guys do it all the time. That way the hood wont "bend". Probably as cheap if not cheaper than those pvc blocks you mention.
Old 08-03-2007 | 02:18 PM
  #17  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
It was mentioned. No one cared. The hyundai guys do the same.
Old 08-03-2007 | 02:23 PM
  #18  
Trekk's Avatar
Goat rider
 
Joined: Feb 2006
Posts: 587
Likes: 0
Originally Posted by mac11
The air does not evacuate the engine bay through this opening when traveling. only when moving very slowly or not at all.
Dude... I mean really. Have you proven it doesn't work on a RX-8? Or are you guessing and stating it as a fact?

We have a few people here that have done the mod and claim it works for them. Then we have a few that haven't done it and KNOW (some how) it doesn't work. I will try it soon and see what happens, before I go as far as just saying it will or will not work (N/A set up).
Old 08-03-2007 | 02:28 PM
  #19  
MazdaManiac's Avatar
Banned
iTrader: (3)
 
Joined: Oct 2003
Posts: 16,386
Likes: 26
From: Under my car
Originally Posted by mac11
The air does not evacuate the engine bay through this opening when traveling. only when moving very slowly or not at all.
Why do you continue to repeat this? This is your theory only. The facts, despite running contrary to the supposed science, indicate that air does leave this gap in a reasonable volume at all vehicle speeds.
Don't bother trying to save face on this one or beat your chest. You just got it wrong, so let it go.

As for pics, I think rotorocks went a little overboard with the plastic chocks - I just used adhesive, medium density insulating foam from Home Depot.
Just pull the strip off and put 4 or so 1" long strips of foam along the cowl at a regular interval.

I got another good, real-world test that this works yesterday:
Normally, if the ambient air temp is over 107°F or so, I cannot maintain a highway speed over whatever 4kRPM is (I don't look at my speedometer much, so I don't remember what that RPM correlates to speed in 6th, so you do the math) for more than a minute or two with the A/C on before the car starts to overheat. By overheat, I mean add 2° or 3° past 220°F every 5 seconds until I take a countermeasure. I've easily seen 240° a few times, but I've always caught it and arrested it by letting off a bit and turning off the A/C compressor for a minute or two until it stabilizes under 215°F and then I start the cycle all over again.
On Thursday, I traveled the 130 miles or so across the desert from Blythe, CA to Phoenix in 110°F ambient with an average engine RPM of 5100 RPM (again, you do the math) and never saw the coolant temp go over 217°F!. I never turned the A/C off even once and these temps stayed stable for the 2 hours of the trip in the middle of the afternoon in moderate traffic.
YMMV.
Attached Thumbnails DIY: Hood Ventilation Mod-1.jpg   DIY: Hood Ventilation Mod-2.jpg   DIY: Hood Ventilation Mod-3.jpg  

Last edited by MazdaManiac; 08-03-2007 at 02:36 PM.
Old 08-03-2007 | 02:29 PM
  #20  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
Originally Posted by Trekk
Dude... I mean really. Have you proven it doesn't work on a RX-8? Or are you guessing and stating it as a fact?

We have a few people here that have done the mod and claim it works for them. Then we have a few that haven't done it and KNOW (some how) it doesn't work. I will try it soon and see what happens, before I go as far as just saying it will or will not work (N/A set up).
I didn't say it doesn't work. go back and read the posts i have had on exactly what i did and what is going on.

Yes, heat rises, therefore at a stop or slow speed hot air will pour out.

when you are moving there is a low pressure zone in the engine bay and a high pressure zone at the cowl that actually draws ambient air in from the base of the windshield down into the engine bay. What it does after that is anyones guess as I haven't mounted a camera in my engine bay to date.
Old 08-03-2007 | 02:29 PM
  #21  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Originally Posted by XDEEDUBBX
not sure if it was mentioned in the previous thread but why not just buy some metal washers and bolt them under the hood to where the arma attach to it. The honda guys do it all the time. That way the hood wont "bend". Probably as cheap if not cheaper than those pvc blocks you mention.
Because by doing that you misalign the hood cover and the fender.
Just stop to think how ugly it is going to look if the corners of your hood stuck out 1/2"? It was one of the things i listed when starting the other tread.

Originally Posted by mac11
The air does not evacuate the engine bay through this opening when traveling. only when moving very slowly or not at all.
You are like an old record player.
Old 08-03-2007 | 02:32 PM
  #22  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
Originally Posted by MazdaManiac
Why do you continue to repeat this? This is your theory only. The facts, despite running contrary to the supposed science, indicate that air does leave this gap in a reasonable volume at all vehicle speeds.
Don't bother trying to save face on this one or beat your chest. You just got it wrong, so let it go.
.
I forgot, what you post is fact regardless, what someone else posts are just theory. How silly of me.
Old 08-03-2007 | 02:34 PM
  #23  
mac11's Avatar
Rotary , eh?
iTrader: (1)
 
Joined: Jun 2006
Posts: 1,850
Likes: 1
From: Elkhart, IN
Originally Posted by rotorocks
Because by doing that you misalign the hood cover and the fender.
Just stop to think how ugly it is going to look if the corners of your hood stuck out 1/2"? It was one of the things i listed when starting the other tread.

WTF are you talking about, its been done on thousands of cars w/o misaligning anything.
Old 08-03-2007 | 02:37 PM
  #24  
rotorocks's Avatar
Thread Starter
RotoRocks Powered
 
Joined: May 2006
Posts: 1,236
Likes: 6
From: Delray Beach, FL
Originally Posted by mac11
WTF are you talking about, its been done on thousands of cars w/o misaligning anything.
Then perhaps you would like to implement this on your car and post the pictures?


Originally Posted by MazdaManiac
Why do you continue to repeat this?
Dude, take a look at the second portion of his signature, and after that just ignore him.

Last edited by rotorocks; 08-03-2007 at 02:39 PM.
Old 08-03-2007 | 02:38 PM
  #25  
MazdaManiac's Avatar
Banned
iTrader: (3)
 
Joined: Oct 2003
Posts: 16,386
Likes: 26
From: Under my car
Originally Posted by mac11
I forgot, what you post is fact regardless, what someone else posts are just theory. How silly of me.
Actually, that is true. I test what I say. You just flap your gums (fingers).

Originally Posted by mac11
when you are moving there is a low pressure zone in the engine bay and a high pressure zone at the cowl that actually draws ambient air in from the base of the windshield down into the engine bay. What it does after that is anyones guess as I haven't mounted a camera in my engine bay to date.
Nope. The air continues to leave through the gap at the cowl I have the laser thermometer measurements to prove it.
Go get some fresh air.


You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: DIY: Hood Ventilation Mod



All times are GMT -5. The time now is 06:25 AM.