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Thread: Escort under bonnet temperatures

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    Tyre Kicker larrythelabrador's Avatar

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    Escort under bonnet temperatures

    I'd like to A, improve cold air to induction & B, remove heat from under bonnet. Car is a Mk2 Escort rally car used for hillclimbs & is running a 250bhp XE on throttle bodies. Any thoughts please?

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    Re: Escort under bonnet temperatures

    I don't know what you are allowed in hillclimbing but vents in the bonnet would help lower the engine bay temp, you can buy bonnets with WRC vents in which are huge.Alternatively raising the rear with washers under the hinges helps a little. The exhaust is worth either wrapping or getting ceramic coated which is expensive but would make a big difference. Cutting a couple of circular holes in the inner front panel would allow more airflow through the engine bay too.
    For cold air induction then I would suggest some ducting from the inner front panel or I think you can buy a bespoke carbon airbox which includes ducting

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    Re: Escort under bonnet temperatures

    I don't know what you are allowed in hillclimbing but vents in the bonnet would help lower the engine bay temp, you can buy bonnets with WRC vents in which are huge.Alternatively raising the rear with washers under the hinges helps a little. The exhaust is worth either wrapping or getting ceramic coated which is expensive but would make a big difference. Cutting a couple of circular holes in the inner front panel would allow more airflow through the engine bay too.
    For cold air induction then I would suggest some ducting from the inner front panel or I think you can buy a bespoke carbon airbox which includes ducting

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    Tyre Kicker larrythelabrador's Avatar

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    Re: Escort under bonnet temperatures

    Thanks, I've gone for vents over the exhaust manifold & a scoop to direct air to induction, already done the extra holes in inner front panel. Found a nice carbon intake from GP4 motorsport, needed to match the carbon fibre bonnet!

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    Re: Escort under bonnet temperatures

    I've never done the washers between the bonnet and the hinges but I can imagine it would be very effective.

    I did, however, wrap my manifold with heat wrap, that made a massive difference, along with wrapping my clutch cable it a made the difference between a usable clutch cable or a clutch cable that melting in literally 15 minutes flat an then seized itself up solid.

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    Tyre Kicker larrythelabrador's Avatar

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    Re: Escort under bonnet temperatures

    Quote Originally Posted by rallyrob View Post
    I've never done the washers between the bonnet and the hinges but I can imagine it would be very effective.

    I did, however, wrap my manifold with heat wrap, that made a massive difference, along with wrapping my clutch cable it a made the difference between a usable clutch cable or a clutch cable that melting in literally 15 minutes flat an then seized itself up solid.
    Had that problem once with a cable! Wrapping did indeed cure it. Think you'll find that the area at back of the bonnet on an Escort is a low pressure area & air doesn't get sucked out as you would expect, that's why the heater draws it from that area. Remember seeing a visual from an air tunnel.

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    Re: Escort under bonnet temperatures

    Agreed the area at the bonnet / windscreen should be low pressure and should suck air out if the bonnet edge is raised sufficiently to provide a gap. When the bonnet is fully closed, the under bonnet area exhibits high pressure due to lack of air movement, this is why the heater takes its supply air from here. Physics hates things being unbalanced - high pressure will always flow toward low to try and equalise.

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    Spanner Monkey Ianbavs's Avatar

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    Escort under bonnet temperatures

    Not sure about being low pressure
    You tube has many examples of it being high pressure zone


    Sent from my iPhone using Tapatalk

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    Re: Escort under bonnet temperatures

    Quote Originally Posted by larrythelabrador View Post
    Thanks, I've gone for vents over the exhaust manifold & a scoop to direct air to induction, already done the extra holes in inner front panel. Found a nice carbon intake from GP4 motorsport, needed to match the carbon fibre bonnet!
    Back in 1990 we had a NA Cosworth Engine with a massive up and over Tony Law Exhaust manifold. We fitted a Fiat Strada bonnet vent which incorperated its own scoop. I think we paid couple of quid for it from a scrap yard. I don't think there were any fancy carbon scoops about then and if there was they would be to expensive as we were tight arses.

    I have never been a big lover of exhaust wrap as the manifold gets too hot underneath and cracks.

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    Racer

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    Re: Escort under bonnet temperatures

    Quote Originally Posted by Ianbavs View Post
    Not sure about being low pressure
    You tube has many examples of it being high pressure zone
    Hmmm - Internet physics! If you increase the speed of air, it's pressure drops - that's the rule! Its how an airplane wing / aerofoils work - air speed increases over the upper surface = lower pressure = lift.

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    Re: Escort under bonnet temperatures

    I’ve found the same with exhaust wrap that it can cause the manifold to get to hot and crack in several places, I’ve even seen a classic mini LCB melt out of shape

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    Racer

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    Re: Escort under bonnet temperatures

    Quote Originally Posted by notenoughtime View Post
    I’ve found the same with exhaust wrap that it can cause the manifold to get to hot and crack in several places, I’ve even seen a classic mini LCB melt out of shape
    I've heard of this and generally its mild steel pipes that suffer and usually when connected to a restricted exhaust system. Also if used in a 'wet environment' a MS manifold will rust out double quick - can't see it as would require unwrapping!

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