Question around engine heat

**Uncle_Ken** · 10-04-2008, 08:27 PM

I was thinking today about heat build up in the engine bay (as you do when you are at work).

Why don't I 'see' engine bay mods about getting heat out the the engine bay? e.g. ducting from te front, fans forcing it out etc.

Just in case this is a real post, I'm am just curious.

UK

used:

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b2tf · 10-04-2008, 08:29 PM

They do need a certain amount of heat as such to operate efficiently but I get what you're saying. Personally I've never found it to be such an issue that I've needed to do something about it, I have toyed with the idea of putting some billet style bonnet vents into the ute but that would be more for aesthetics.

**Uncle_Ken** · 10-04-2008, 08:34 PM

Yeah thats the kind off thing but I haven't 'seen' anything in the forum.

UK

JC · 10-04-2008, 10:38 PM

The shaker on my car lets plenty of cool air in, which keeps temps down. Though a whole new cooling system means the temp never moves off the L anyway (E series is reverse to AUs, so on AU it would sit on N). Zhodaks fully working shaker actually leaves the intake manifold stone cold to the touch, which is the bit you want cold. It only heats up when the car is stopped, as the heat soak from the engine gets into the manifold.

**Mont5.0** · 11-04-2008, 12:14 AM

Hot air rises, so unless your bonnet was air tight- excess air is released through the gaps between bonnet and guards.

JC · 11-04-2008, 12:19 AM

Quote:

Originally Posted by MrXhUteMan

Hot air rises, so unless your bonnet was air tight- excess air is released through the gaps between bonnet and guards.

There is a rubber seal that seals the bonnet, so not much hot air would get out, plus the air rushing over the bonnet would force the hot air back in anyway.

**Mont5.0** · 11-04-2008, 12:44 AM

there is a seal front and back. but i havent seen any side seals.

RG · 11-04-2008, 02:05 AM

If anyone figures out a way that actually both works and doesn't look shite I'll do it. My intake temps get pretty silly and I get a noticeable drop in power when under bonnet temps go up.

5.0 ED · 11-04-2008, 02:20 AM

We used to move the bonnets so that the rear of them was up and left a gap on earlier XD V8 clevo's to help with cooling them, being that the particular cars i am talking about had over heating problems i can say that it definetly helped with coolant temperature. although if something goes wrong underbonnet it can be very quick to get a oil covered windscreen as we had happen.

**Uncle_Ken** · 12-04-2008, 09:19 AM

So as I see it you can

A. Air from on top then pushed out via bottom (say induction type tube)

B. Air from on top then pushed out via top back (say removing the back rubber trim all or in sections)
or
Fan

C. Air from top and sucked out by fan (either wind driven or electric)
Yes ??
UK

HLC · 12-04-2008, 06:38 PM

Quote:

Originally Posted by 5.0whiteaughia

We used to move the bonnets so that the rear of them was up and left a gap on earlier XD V8 clevo's to help with cooling them, being that the particular cars i am talking about had over heating problems i can say that it definetly helped with coolant temperature. although if something goes wrong underbonnet it can be very quick to get a oil covered windscreen as we had happen.

my ex's sisters (you get that) pulsar GTi-R had the bonnet raised at the rear. looked retarded but was really effective. that thing was a missile.

5.0 ED · 12-04-2008, 08:15 PM

Yeah definetly works but yeah it does look retarded lol.

naughtyfalcon · 13-04-2008, 09:13 AM

i've been thinking about this aswell,,the only solution i can find is bonnet vents colour coded.

but where on the bonnet is the optimal location?

**Mont5.0** · 13-04-2008, 11:01 AM

Quote:

Originally Posted by naughtyfalcon

i've been thinking about this aswell,,the only solution i can find is bonnet vents colour coded.

but where on the bonnet is the optimal location?

Well one would be above the exhaust manifold, i would say the other would be on the opposite side??

naughtyfalcon · 13-04-2008, 12:07 PM

thats logical,lol.

i might think about it for a while and make up my mind.

blackers10 · 13-04-2008, 07:35 PM

well i would think the air would be forced to the BACK of the engine bay so having vents at the back up the top would be the go

primarily on the exhaust side but both looks nicer and more effective

and you want vents not scoops..

bodes-sh · 13-04-2008, 07:47 PM

Quote:

Originally Posted by blackers10

well i would think the air would be forced to the BACK of the engine bay so having vents at the back up the top would be the go

primarily on the exhaust side but both looks nicer and more effective

and you want vents not scoops..

there are probably a couple of issues with that though, i know in some states it's illegal to have rear facing vents incase as said above, something goes wrong under the bonnet and the windscreen gets covered in coolant, oil, etc, and also in winter it can cause the outside of the window to fog up because of the hot air coming up out of the engine bay, it would be better to have something set up to force the air out through the bottom of the engine bay

blackers10 · 13-04-2008, 07:49 PM

go take a look under the bonnet of a WRX STI or a lancer evo or anything with bonnet vents

they typically have a metal plate underneath that fixes that issue ..except i cant remember how it looks but it seems to work ok for them..

JC · 13-04-2008, 07:56 PM

Quote:

Originally Posted by bodes-sh

....it would be better to have something set up to force the air out through the bottom of the engine bay

Like a bonnet, LOL!

**Falcon Coupe** · 13-04-2008, 08:04 PM

Quote:

Originally Posted by Russell

If anyone figures out a way that actually both works and doesn't look shite I'll do it. My intake temps get pretty silly and I get a noticeable drop in power when under bonnet temps go up.

Water wetter may help with this problem, use distilled water in the entire cooling system plus a bottle of this, they claim up to 30 degrees F total temp reduction.

I'm going to try it in a few weeks.

RG · 13-04-2008, 08:08 PM

Quote:

Originally Posted by Falcon Coupe

Water wetter may help with this problem, use distilled water in the entire cooling system plus a bottle of this, they claim up to 30 degrees F total temp reduction.

I'm going to try it in a few weeks.

Cooling system works a treat, it's just the heat from the headers that is heating up the intake. I need to find a way to get rid of that heat.

JC · 13-04-2008, 08:12 PM

Quote:

Originally Posted by Russell

Cooling system works a treat, it's just the heat from the headers that is heating up the intake. I need to find a way to get rid of that heat.

If you are getting excessive heat in your exhaust, it's the first sign that your cats and/or mufflers may be blocked.

RG · 13-04-2008, 09:10 PM

Quote:

Originally Posted by JC

If you are getting excessive heat in your exhaust, it's the first sign that your cats and/or mufflers may be blocked.

Not excessive and I know that all my exhaust system is in top condition, but it can always be better :evil3:

These AU engine bays are pretty cramped with a windsor in there as you'd know.

**Falcon Coupe** · 13-04-2008, 09:28 PM

Quote:

Originally Posted by Russell

Cooling system works a treat, it's just the heat from the headers that is heating up the intake. I need to find a way to get rid of that heat.

I had my headers ceramic coated to take out 30% of the heat, that combined with a lower running temp (water wetter) means less heat in the bay to affect the intake, it's a start and does not require bonnet modification.

v8falconsrule · 13-04-2008, 09:42 PM

just a side note- i have noticed of late that less cars are factory fitted with bonnet vents (as oppososed to scoops). i think back to sierras, ef xrs & el gts, pulsar gtis. they all have vents, but now it seems that vents are becoming a thing of the past.

in the meantime scoops are popping up all over the place- anything diesel, wrx, turbo terry.

sorry, just a random thing i was thinking about at work the other day while detailing an ef xr6.

**Mont5.0** · 13-04-2008, 09:46 PM

Have you thought of manipulating the factory heat shield (S) to fit over your headers?

tufLTD · 13-04-2008, 09:51 PM

Your problem is not getting the hot air out, it's getting the cold air in. As your car travels along, air passes over and under your car, creating a slightly negative pressure in the engine bay which literally sucks the hot air out from underneath. Modern cars are designed with very little frontal area to reduce drag which aids fuel economy, acceleration, etc but also reduces the volume of air being forced into the engine bay. What little area is open (your grill area), is blocked by your radiator, A/C condenser, auto trans cooler. You need to get more cold air in but the fix is very difficult. Apart from removing your headlights there's very little you can do. Ducting from your spoiler is an option but can be difficult and looks messy.