raise hood with washer; does it help engine bay cooling?

Discussion in 'Other Technical' started by moon*, Jun 10, 2008.

  1. moon*

    moon* New Member

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    hey guys.. i previously done tis mod, but i change back to normal.

    jst want to know, if i was to raise my hood with washer/nuts. does it affect my engine bay in anyway? cooling? negative positive??

    thanks.

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  2. EK9turbo

    EK9turbo its a rush!

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    Water Wetter by redline lubricants will give you a great inprovement in cooling. I dont like the raising th ebonnet idea.

    If youre having temperature issues then Id suggest try bleeding the cooling system. :nice:
     
  3. moon*

    moon* New Member

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    oh nono ek9turbo..

    so far i m not having any trouble with the cooling system.

    i recently jst did a radiator flush n got new coolant. its working great now.

    cos in a month + time, i'll be going to sepang international circuit to zoom around.

    so.. with stock cooling i kinda jst got worried u see.. so.. i thought raising the hood might help jst like vented hood? so hot air can go out faster?? or so i thought.

    any more ideas? :)
     
  4. blinx9900

    blinx9900 Super Moderator Donator

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    it works but the question is what are you doing that your having cooling problems?

    edit: oops i took too long to post, if your not having cooling problems dont worry about it, the EK9 can handle road racing with stock cooling system no problem, even with cams and higher compression the factory cooling system should be adequate up to 200bhp in my opinion.
     
    Last edited: Jun 10, 2008
  5. Bon87

    Bon87 DC2 ITR Owner

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    Apparently it doesn't work!
    It makes it worse if anything!

    I can only see it working at low speeds or idle.
     
  6. moon*

    moon* New Member

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    ehm.. so far i no problem with teh cooling. cos normal drive daily.

    but the thing is.. malaysia in the noon its freaking HOT HOT HOT. i m jst worried about the temp rising. i havnt enter tracks b4.

    n for those who have enter tracks here in ek9.org.

    wats the climate there like??

    i tink in kl , afternoon temp can go 40c or more??
     
  7. EK4_SIR

    EK4_SIR New Member

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    This is the JDM style of extra cooling, it allows the underbonnet air to escape faster. This is done in turbo cars which did not have enough lourves.
    For a NA car, it looks ricey and people ask whether the bonnet is on properly. Secondly for safety reasons in a crash the bonnet might break off and hit the windscreen and probably hitting you in the face.
    For the lower heat generated than a turbo car, i think it's not worth it. I done that mod before and the angle at which the bonnet meets the holding arms is not at the correct angle placing stress in the bolts.
    ________
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    Last edited: Aug 22, 2011
  8. RagingAngel

    RagingAngel 本田 Gearing Authority

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    on a budget, sure it can work. It's principle is directing air into the engine bay since the base of the windshield is a high pressure area. The air is forced to flow in from the base of the hood/bonnet more than there is flowing out apparently.

    moon, do you have a water temp gauge to monitor just how hot your water temp is getting? Do you have a full width dual core radiator? Is it properly sealed off on the top and the sides?

    A proper bonnet vent should appear right above the header, where the majority of the heat is produced and where air can rapidly escape after it's been forced through the radiator.

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  9. EK4_SIR

    EK4_SIR New Member

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    Last edited: Aug 22, 2011
  10. EK9turbo

    EK9turbo its a rush!

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    WOW! That looks such a good fitment!... What make is that?? where can I get one!? how much??

    When my ek9 was standard, I sat it at redline in 5th flat-out for 1hour ten mins! no overheating issues at all, although that was early in the morning last september time as I recall.

    Its turbo now, fully built, with a fluidyne radiator. I dont have any overheating issues with stock bonnet, but underhood temperatures are higher than standard.
     
  11. moon*

    moon* New Member

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    ic.. thanks for the info.. ehm.. my car is running on stock, no temp gauge reader installed currently. jst a stock ek9 cluster. but i do have a dual core radiator n here's the size.

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    n i browse thru quite alot of website; they introduce something called the radiator cooling plate, n its quite hard to get any here.. so i decided to make my own to cover the gaps inbetween the radiator.

    so here it is..
    [​IMG]


     
  12. Vtec6000

    Vtec6000 Super Moderator Staff Member Donator

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    I dont see how it could make it worse?? I would think that it would give better room for ventilation
     
  13. moon*

    moon* New Member

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    i m quite worried about the hood flying to my face with the hood raise :p

    but yea.. jst going thru all the ideas i can come up with :)
     
  14. EK4_SIR

    EK4_SIR New Member

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    Well, thats if you crash, which i doubt you want to do.
    This is especially true in HK where carbon bonnets are banned as an after market because in a crash the shrapnels will hurt people. The metal bonnets though heavier does not break up.
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    Last edited: Aug 22, 2011
  15. wildcat

    wildcat EK3 Converted to EK9

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    Bonnet Spacers

    In an attempt to reduce the the Underhood Temperature Readings, I thought that I would try raising the back of the bonnet to let some of the hot air escape. Quite a few cars at the drags employ this little trick so I thought I would try it out and use the Cable Free Indoor/Outdoor Thermometer to see what temperature difference it would actually make.

    Fabrication - Installation - Results

    Fabrication
    Installing bonnets spacers is a pretty simple thing to do. You just need to make up some spacers to fit underneath the hinges for the bonnet and put them in place. I have seem some people simply use a handful of washers, but a full mounting plate spacer distributes the load more evenly. Below are some pictures of the mounting plate spacers that were made.

    The mounting plate spacers are made out of 10mm aluminum plate cut to size to fit underneath the existing bonnet mounting plates. You will also need some longer mounting bolts. From memory I think the ones I used were M6 by 25mm. You will also need some washers since the stock mounting bolts have the washers physically attached to them. That little round bit of tube in the photos is to raise the existing alarm bonnet sensor.

    Installation
    Installation is trivial, but you do need two people.

    Open the bonnet and hold it up with the normal bonnet holder.
    Remove the mounting bracket on the side that is not physically held up.
    Insert the new mounting plate spacer and do up the mounting bolts finger tight.
    Remove the mounting bracket on the side that is physically help up. Note that someone will need to hold the bonnet up for this.
    Insert the new mounting plate spacer and do up the mounting bolts finger tight.
    Close the bonnet and see which way it needs to be moved (if at all) to line it up correctly.
    Move the bonnet around as necessary (although the stock mounting positions don't really allow very much movement).
    Tighten both mounting points.
    With the mounting plate spacers installed there is about a 5-6mm gap between the sealing rubber at the back of the engine bay and the bonnet. This is just enough to allow some of the hot underhood air out of the engine bay. The negative pressure behind the lip of the bonnet should also help suck air out. Note that this assumes the space behind the bonnet is actually under negative pressure. Without a manometer to measure the pressure, this is just an educated guess. Turbulence and eddies from the bonnet lip may mean this is not actually the case...

    Results
    Well, the results were really quite interesting. I have a thermometer placed on the tower strut brace as shown in the picture below. I also have some previous readings of the temperature in that location before the bonnet was raised, which can be found on the Underhood Temperature Readings web page.

    From the results I have now obtained with the rear of the bonnet raised it appears that the modification has actually made things worse, much worse! Previously the underhood temperature reading only ever got as high as ~45°C. Now with the spacers in place it is not unusual to see the underhood temperature breaking into the 60°C range. Also after a long drive the left hand side of the tower strut (looking into the engine bay) gets so hot you would burn yourself if you held onto it.

    These results seemed counter-intuitive until I popped the hood and thought about it for a few minutes...

    I suspect that raising the bonnet allows for hot air to not only escape out through the bottom of the engine bay, but also out the top (as was the plan). It would seems that the hot air takes the path of least resistance out the engine bay, and now that the rear of the bonnet is raised, that particular path of resistance is quite small. As the hot air off the headers (actually very hot since they aren't wrapped) passes by the intake manifold and anything else in its path, some of that heat gets absorbed by those components. Those components includes the intake, throttle body and intake manifold. With the bonnet securely shut, the very hot air doesn't get much chance to get anywhere near them.

    In particular the left hand side of the engine bay gets a lot hotter because there is a nice path for the hot air off the Custom B16A Headers to travel around the side of the block, over the transmission, and out the top. On some days I could actually see the heat haze coming out the left hand side when driving forward very slowing (like in peak hour traffic here in Auckland).

    So, with my particularly configuration it appears that raising the bonnet does exactly the opposite of what I intended! It actually increased the temperature of the components I wanted to keep cool. So, the mounting place spacers were prmptly removed. For other configurations, perhaps where the headers have been wrapped, raising the bonnet may actually be beneficial though. Unfortunately, not in my case though.


    see link for pics
    teirney.NET / Honda Civic SiR / Bonnet Spacers
     
  16. EK4_SIR

    EK4_SIR New Member

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    :nice:
    Great experiment, saves us the time and trouble.
    ________
    Live ***
     
    Last edited: Aug 22, 2011
  17. Bon87

    Bon87 DC2 ITR Owner

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    I'm surprised no one has quoted me yet...

    Apparently this only works on 'idle' and at 'LOW speeds'.

    When your driving at 70mph. There is much more pressure between the top of the hood and the lower windscreen. Therefore blocking the flow of heat comming out of the raised hood, causing vacuum or something like that.
    Is that right??? Thats what I was led to believe....
     
  18. RagingAngel

    RagingAngel 本田 Gearing Authority

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    correct...that is what the main discussion was about. Since the base of the windshield is a high pressure area, it's in constant conflict with the air that is supposed to be pushed out.

    Hence why a properly vented hood like the one I posted up is the most desirable. My friends had this on their EG/EKs respectively or EH/EJs in this case since I'm in North America (blah..wutever :p)

    It's made by Buddy Club. Nice 1x1 carbon weave so it's not that ugly cheap looking 2x2 crap that makes it resemble more like a checker board than pretty looking wet CF. I can only wish for dry carbon though....
     
  19. RagingAngel

    RagingAngel 本田 Gearing Authority

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    Just make sure the sides of the radiator are also appropriately sealed off as well.

    I'm guessing you still drive the car on the road which is why you kept the air conditioning? If it's a track car only, I would ditch it entirely and increase the cooling capacity by another 50% with a full width core.
     
  20. moon*

    moon* New Member

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    :D thanks so much for tat article :)

    yea.. i aint a full track guy, tis car also used to daily drive around.
     

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