Bonnet Scoop - Air Vents for Cooling

[Rotary]

Ambient and Radiant heat (via headers) under the bonnet will transfer a percentage of heat to the intake tube, but become more negligable as the total volume of air through the tube increases, meaning that the intake air from outside will act to a degree to cool the intake tube thus overcoming some of the heat transfer, materials used also have an affect on this heat transfer.
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That is exactly my line of thinking, the massive volumes of air should easilly counteract this heatsoak and therefore i did not bother with covering my pipework. but my experimentation proved there is some heatsoak somewhere. my testing on the gtech showed quite subtantial drops in outputs and mph for 1/4 testing. and when i last went to WSID, i had the perfect opurtunity to check this when they let me go on consecutive runs and my kph was 3 down on my results all night.
I do agree with the theory, understanding the flows and volumes within every engine i tune, and it is a massive volume of air, but there is something measurable going on, wether it is occuring more in the intake runners and plenum, or in my tubing after the TB i can't say with 100% certainty, but it is a very interesting topic.

I would surmise that most of it would actually occur within the Intake body, due to the large amount of Al(high thermal conductivity) used and large surface area of exposure through the runners. and may be negligible where that heat is not replenished ie, intake attached to Head. (would you say this where it is happening?)
either way starting of with cold air will make a big difference

[Okibi]

So what you need to do is use your aircon knowledge to find an efficient way to cool the incoming air.

[grump]

If a person was to make a composite tube from the TB to the intake,( assuming that the intake point is external from the engine bay).this would eliminate heat transfer as much as possible. By composite I mean a tube that is insulated ,wether it be in fibreglass with a layer of foam in the laminate, or a tube with insulation on the outside. am I on the right track?

[Tedsmx5]

Why would you want a cold air intake with a intercooler????
The intercooler will remove the heat and feed air into the intake at near ambient temperatures.
All air under the hood is around 70degC as it's feed thru the radiator (I've done extensive measurements under the hood (it was cramped under there )) CAI will help on na engine but is pointless when you have an intercooler.
Ted

[Benny]

If you want cold air to get into the engine, why don't you just run the intake air through the A/C condensor, or wherever the cold air comes from?

You could also get a bottle of compressed CO2 with a valve you can open and close from the driver's seat, and use it when you need a cool charge.
There is a gadget I've seen, which is basically a SS tube with little holes in it, and is usually mounted on the front of an intercooler, and when switched on, either by a switch at WOT, or an internal manual switch, and it blasts the cold CO2 over the intercooler to cool the charge.

Re ram air intakes, from what I've heard, they don't work.
In fact, the air gets so turbulent that it can actually lower the hp.

When you look at say a F3 car, with the big blob sticking out the side of the car, you would think it is a ram air intake, but in fact, it leads to a plenum chamber so the air can settle down before being sucked into the engine.
This is to stop turbulence, as tubulent air can effect the intake mixtures and hence, lower the power produced.

[randymx5]

if its cold air uyou want how about getting a Cryo2 and cryo2 intake kit??

http://www.designengineering.com/products.asp?m=sp&pid=72&gclid=CPOewcnd_ZYCFQJNagodUgzVZA

[Rotary]

If a person was to make a composite tube from the TB to the intake,( assuming that the intake point is external from the engine bay).this would eliminate heat transfer as much as possible. By composite I mean a tube that is insulated ,wether it be in fibreglass with a layer of foam in the laminate, or a tube with insulation on the outside. am I on the right track?

I Think Most of the heating is occurring after the Throttle Body, and what’s happening before is much less significant.

So what we need is plastic intake runners and plenum, like many new cars are using, these days.
I have searched around Oz for a plastics manufacturer that may do it, and found a few good manufacturers, that say the make Auto parts, but nothing by way of induction manifolds. so unless they have the appropriate tooling(dies etc) it would be ridiculously expensive.

I did find a specific manufacturer to OEM in the UK, but i would like to approach a company in person, to see what they could make and how i could adapt it.
Overall for the gains achievable, it wouldn't be worth over $1000 for most as the money is better spent elsewhere,(except those looking for every gain possible.) so it would be difficult to achieve this.
I am still keeping an eye out if anyone knows of a company in that area.
(Redesigning an Intake Manifold is a good way of making gains and specific RPM tuning your power output, without even looking at any heat reduction)

The alternative is to design an intermediate insulating piece between the head and manifold, which would act as a barrier to the constant heat from the Head, I have seen these made for some cars, but not sure of there effectiveness in cars they have been made for.
IMO if coupled to a redesigned Intake Manifold, then they would be very effective

Anyway theyre just a few tricks to get extra power, every bit does add up, but should only really be done after other more gainful power mods are applied.

[bruce]

In a nutshell, all this rooting around may only gain literally a handful of horsepower. You can only get so much out of a 1.6/1.8, even if you stuck frigid air directly into the motor.

[MX5CHIC]

It's becoming a rather complex topic .. you are correct when you mention turbulence, hence the need for high pressure entry points for the air intake, for example Mania are selling a cabin air cooling device which scoops air from over the windscreen and pushes it down towards the occupents, it works very well because it locates at a point of very high wind velocity (pressure).
Placement of forced air systems are very critical as certain areas fluctuate between high and low pressure, if you have your window down with the top up you notice the "buffeting" effect of the passing wind, this buffeting is actually alternating high and low pressure, if applied to your intake it would cause the air to alternate constantly and have a very negative impact.
As for the heat ingress to the motor, well that is always going to be affected by what you put in at the entry point, air velocity has an enormous effect, if you begin with an entry temp of 70 Deg C and pick up 15 Deg C along the ducting then you have induction temp of 85 Deg C. It stands to reason then if your entry temp is 20 Deg C + 15 Deg C you have induction temp of 35 Deg C.
The induction temp is affected also by the velocity of the air, if the inlet velocity is much higher then a far larger volume of air passes through (this occurs with more throttle opening) the increased velocity then picks up less latent heat from the inlet tract - simply put, the faster you travel the cooler your final induction temp will be.

It works like a funnel by having as large an intake area as possible placed in a position of (constant) High Pressure, as the area that the air enters is reduced the pressure increases, this increase in pressure counteracts the obstructions within the path of flow - the air filter, air flow meter etc
What it all means is that no matter what heat you pick up from components under the bonnet, you will counteract this to a smaller degree at idle and to a larger degree whilst moving forward - more speed = lower induction temperatures => lower induction temps = denser air which equals higher efficiency.
Then add : more speed = higher air pressure, which equates to less induction restriction, again providing higher efficiency ...... your motor is not trying to suck air through a straw.

As said, there are many methods to assist your car in breathing, headers, high flow cat and muffler, port and polish etc but a low restriction, high air pressure inlet system works in exactly the same manner as a supercharger - just on a "much" smaller scale.

Don't get me wrong on this, I'm not trying to get blood out of a stone, if you want sheer horsepower and lots of it then of course you have to do the big mods with the big spend - what I'm trying to achieve is efficiency which I hope will equate to lower fuel consumption and increased responsiveness ..... I'll get back to you when I get it all finished, but don't hold your breath, it's gonna take some time

[grump]

In my humble opinion , (and let me tell you I have been called an idiot on more occasions than i care to remember)the whole purpose of a turbo and supercharger is to make the most gains out of the breathing side of an engine. Either pushing more air in or pulling more air out.( this time don't just hit me with the idiot stick ,use the whole branch). the whole purpose of this debate is to see if there is a way to simply use the system that we have and make it more efficient. Its through discussion that we all hopefully understand how things work. MX5CHIC has simply asked is there an efficient CAI that gives you a good gain. We could run our intake through the air conditioning, but our fuel consumption would be through the roof. Of course the ECU would just feed in more fuel because of the lack of heat. There must be an optimum temperature for the air coming into the engine.
The whole idea of a forum is to discuss topics and glean at least some information from it. I think that the fiasco that happened with jakob was out of control and I for one felt a little bit ashamed of myself for stooping to the depths of sarcasm and ridicule just to make myself seem more knowlegeable. Now here is my thinking out side of the square. How about a sock made of wetsuit rubber that slips over the intake tubing, acting as insulation to at least keep the temperature at a reasonable level. What do you think?

[Okibi]

Many moons ago Matty did similar testing on the NA6 intake to look at it's efficiency, that same article is like the NA CAI bible and keeps appearing on MX-5 forums around the world.

If one of you engineers would be keen to do some testing i'd love to build it into the tech achieves.

We have a few engineers in our club, I wonder if any have access to the right equipment.

[MX5CHIC]

All this tech discussion for nothing ...... now why didn't I think of that. BTW - do you have any of that wetsuit left?

Okibi, I'll certainly be documenting everything from start to finish and be happy to post up results.

[SuperMazdaKart]

the stuff thats in oven mittens could probably work well too

[Hammer]

Ok, love the ideas - here is the AutoExec System at around $400 UK Pounds

I like the concept of this. It's discreet. I could use this to lower the under bonnet temperature of my SP. But not for 400 pounds?!!!! I'd rather buy a 2nd hand NB8B bonnet and cut some slits to form the duct, or put a NACA style duct.

[Benny]

if its cold air uyou want how about getting a Cryo2 and cryo2 intake kit??

http://www.designengineering.com/products.asp?m=sp&pid=72&gclid=CPOewcnd_ZYCFQJNagodUgzVZA

That's the kit I was talking about.