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Very high under bonnet temps

Discussion in 'VT - VX Holden Commodore (1997 - 2002)' started by 01SS, Dec 20, 2018.

  1. 01SS

    01SS Member

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    I have a vx ss with a vortech v2 crammed under the bonnet. Live in Brisbane and in the summer time I dare not get stuck in traffic or my temperature creeps up until I get moving again. I don't have and any bonnet scoops as I am not a fan and I am keeping the car looking as mild as possible. I have removed the rubber seal at the rear of the engine bay and that has dropped my temperature by a few degrees when driving. I don't really want to go the route of a fiberglass bonnet or reverse cowl. Has anyone with a turbo or supercharged engine just put rear facing vents in to get heat out of the engine bay or have any other ways to extract heat from under the bonnet?
     
  2. NeddyBear

    NeddyBear Veteran Mountain Biker

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    Hows the condition of radiator, hoses, water pump and fans.
     
  3. 01SS

    01SS Member

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    All was renewed with the new motor 10k ago. Ithe temp doesn't go too high, it sits around 98 degrees, but when stuck in traffic the floor gets so hot I have to have thongs on to touch the foot rest. I have difillipo 4 into 1 extractors, so they are very close to the floor. Since removing the rubber strip at the rear of the engine bay the temp actually drops to about 95 when the thermostat opens. Most ppl I talk to seem to just say to put a reverse cowl on, but I don't really like them.
     
  4. accentstencil

    accentstencil Well-Known Member

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    Maybe some sort of heat shield where the heat is affecting you.
     
  5. 01SS

    01SS Member

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    Well I got stuck in traffic the other week and the heat couldn't escape the engine bay, whilst sitting at the lights the temp to to 110C. When I moved it dropped a bit, but next set of lights, 110C again. I guess what I'm asking is about rear facing bonnet vents, anyone had similar problems they just didn't fix with a 2000 dollar savage bonnet or a reverse cowl?
     
  6. vc commodore

    vc commodore Well-Known Member

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    That helps cool things under the bonnet.o_O

    To the OP....Any sort of bonnet venting will help the heat escape quicker, which seems to be the issue.....What you do about adding vents is your choice....You could try and get the same coloured bonnet through a wrecker and add vents in to see how it goes
     
  7. Lex

    Lex Well-Known Member

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    I'm thinking, mounting a thermo fan underneath the engine bay, thermostatically controlled, & suck out the hot air underneath the car when a certain temperature is reached (ex 98).
    Only a thought. Would save cutting holes in the bonnet.
     
  8. 01SS

    01SS Member

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    Yeah, hadn't thought of that. I know some people argue about bonnet vents because of low pressure areas caused by air rushing over the top. Thermo underneath will help when stuck in traffic. Thank you for the responses, coz not driving the ss due to heat factors is annoying.
    Is exhaust wrapping OK for street cars?
     
  9. BlackVXGTS

    BlackVXGTS Well-Known Member

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    You need to make sure your radiator fans are working properly. The VX cooling system is very efficient, and unless someone has fiddled around with the engine (grout filled?) or the engine is running too lean, there should not be excessive under bonnet temperatures in normal driving.
     
  10. accentstencil

    accentstencil Well-Known Member

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    He was also saying that his feet get unbearably hot due to his extractors, hence the heat shield suggestion!
     
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  11. 01SS

    01SS Member

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    The engine and bay his highly modified . By the sound of it I'm just going to have to bite the bullet and chop up a bonnet. I'm just truing to slide under the radar. The current combo makes 410rwkw, I'm still running factory mags, had my intercooler and piping powder coated black to avoid un wanted attention. Attention I don't want, it's very Suttle that's why I wanted to avoid reverse cowl and bonnet vents. it's very street able, uses alot of fuel, hence more fuel more heat, just suffering heat soak. Thanks again for some ideas.
     
  12. vc commodore

    vc commodore Well-Known Member

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    Good idea, but hot air rises......So it mightn't be too effective.....You can only try
     
  13. Sabbath'

    Sabbath' Redblock Jesus

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    You have a static heat removal problem in the cooling system.

    The excessive heat being caused by the exhaust system, whether this is due to a tune/blocked cat/whatever issue is separate.

    You need to look at the cooling capacity of the radiator that is in there. If it's a stock item, Is it big enough for the current purpose?
     
  14. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    Where is the intake filter located?
     
  15. BlackVXGTS

    BlackVXGTS Well-Known Member

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    Hmmm. Intercooler and airconditioning condenser both heating up the air before it even gets to the radiator. As other members have suggested, probably needs an upgraded radiator.
     
  16. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    My bet is that with all that extra stuff in front the low speed thermofan just can't draw enough air through, if I'm not mistaken 110°C is the high speed thermofan on temp.

    The question is what thermostat does it have and what are the thermofan on/off settings? Also, the location of the air intake filter is critical, if it is under the bonnet and not shielded then when stationary it will be sucking hot air and with a lack of airflow through the front of the car you will end up with thermal runaway...
     
  17. EYY

    EYY Well-Known Member

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    Yeah agree that the vx cooling system is very adequate. Drove my ss the other day for 40 min in 40-50kmph traffic in 34 degrees without the fans connected (by accident) and it was fine until I came to a complete stop.

    Where are you measuring the temperature? If that’s coolant temp I wouldn’t worry too much about it.
     
  18. 01SS

    01SS Member

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    Removed the rubber strip at the rear and spaced the bonnet up a few mm at the back. It made a bit of difference. It looks definitely like I'm going to have to bite the bullet and vent the bonnet.
    Thanks for the replies.
     
  19. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    If it was me I'd be working out why it's getting so hot. Talk to your tuner and ask what the thermofan temps are, a simple change of settings he could probably do at no or little cost (considering what has already been spent on tuning it) and may very well fix your problem without going to drastic steps like cutting the bonnet.
     
  20. 01SS

    01SS Member

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    Yeah looks like another option to try, it does use a lot of fuel, even driving around off boost. The difilipo are hpc coated, would there be an advantage to pulling the extractors off and wrapping them?
     

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