Engine bay cooling

[Sptwoman]

I'll try and be as brief as possible.
I've read several threads discussing the issues surrounding engine bay temp. and the affects on engine performance - the results of hot fuel and air etc. Also several over heating threads.
While talking to Chris Smith re the delivery of the ali rads the other week. He mentioned he routed his front mounted oil cooler pipes outside the car and under the floor due to lack of room in the central spine. He included skid plates for protection.
Here's the question; Has anyone every thought of fitting low profile ducting, slung under the floor in the same manner to supply cool air from the front to the rear? I though of profiled ali, rivetted to the underside of the floor with suitable front and rear profiles!

[chris.richard]

You'd have to keep clear of speed humps!
With ride heights of 5 1/2 inches, there's not much room under there.

[pimms]

Chris also used some air ducts under his car, just in front of the rear wheels, see picture.

[John]

I would have thought that a properley installed NACA duct in the rear of the floor pan would be a better idea.

[SUSIT]

Good looking water scoop

[strat6v]

From past conversations with somebody 'in the know', underneath, the car has negative pressure so not really a good idea for any cooling purposes. :confused:

[Sptwoman]

MMmmmmmm... I'm sure I asked Colin Artus a similar question re under floor ducting and got a similar response - no good!. My idea was to run a skid protected low profile (Speed bump friendly) but wide duct all the way to the front of the car where the pressure is positive.

[strat6v]

What do you want to achieve Allen?

[mogul_x]

Where is the area of lowest pressure - under the car, or someplace else (like behind the rear window louvers)? You may still be able to draw air from underneath, provided that the engine bay is open to a lower air pressure somewhere else. Granted, it won't be as efficient as drawing air from a high pressure area...

[Sptwoman]

What do you want to achieve Allen?

John,
As you're aware I'm building from new and spend time in the forum reading build issues, solution and asking stupid questions :rolleyes: I've been toying with ideas on cool air ducting for the engine bay for some time. I'm aware it is an issues in hot climates and when pushing the engines on track etc so why not fix it during my build!
A cooler rear end means better overall performance and longevity :D I'm also looking to improve air flow through the rad as mentioned. Is it all worth it??

[tryphon]

There's always the cold airbox solution adopted on originals completely isolating the air intake from the engine compartment...

[Sptwoman]

Pardon my ignorance Tryphon but can you elaborate please?

[chris.richard]

This car is/was a turbo engine, and has intakes under the roof spoiler to get cool air.
Anybody know what happened to it? - I spoke to the chap that was selling it before I got mine.

[chris.richard]

Pardon my ignorance Tryphon but can you elaborate please?

He means this:-

[tryphon]

He means this:-

Yes along with the "ears" that fit the engine cover air intakes ang direct all air to the airbox holes.

[strat6v]

Chopping out the rear deck would help quite a bit, thats what i've done. The two side vents would then channel air straight across the engine top and out through the louvre, probably dragging hot air along too. The castrol car used an underwing duct to scoop air for its intercooler. I think Chris Smith also has a manually switched big fan sat over the engine but i can't confirm.

[PANOS]

I too have a manually switched fan on a hole on the rear deck, which I copied from Chris Smith and when switched on with the engine running, you can feel the hot air comming out if you stand behind the car...
Upto now I never had any overheating problems, even in traffic in the scorching Cyprus summer heat, 45C+...!!!
Ofcourse it will be a different story when I finally fit the turbo engine and I will probably have to rethink the whole cooling thing again...!!!
I will probably have to rely on you guys' wisdom then...!!!

CIAO PANOS

[pimms]

Here's an example of a car with ducts in the undertray at the engine bay, don't know if they are meant for cooling or cold air intake :confused:

By the way a strange way to clean the underside of youre car :D
It looks like the back has been damaged by this way of lifting the car.

[strat6v]

Guess it fell off the lift then. Hope that aint kittenwhiskers lotus? Maybe Mick has had hold of it AGAIN for an oil change and forgot the engine was in the back? :D :D

Look like naca ducts in the floor pan. A couple of big naca ducts in the leading edge of the rear arches on the strat would certainly gather some air.

I'm surprised nobody has made a big hole in the front steel bulkhead section and ducted air down the grp tunnels in their strat, Would work ok if sealed properly?



John.

[Martin K]

I'm surprised nobody has made a big hole in the front steel bulkhead section and ducted air down the grp tunnels in their strat, Would work ok if sealed properly?John.

Thats what is designed to happen in the (road going) Lancia Montecarlo I think

[chris.richard]

Bet the yopper got the fright of his life when he took the wheel off and the C of G shifted!

[Martin K]

A couple of big naca ducts in the leading edge of the rear arches on the strat would certainly gather some air.John.

NACA ducts are not so effective at the rear or a car - something to do with the boundary layer thickening as you get towards the rear of the car. Scoops are much more effective in that location.

[Chris J]

I was just reminded of that photo of, was it Tim and Marcus' Castrol painted turbo car? on PistonHeads.

Anyhow it's the one partly out of shot in the foreground. You can see the twin intakes between the roof wing and rear panel. A similar Idea to the intake on John Whalley's 8 valve turbo car:

http://www.pistonheads.com/clubmans/stoneleigh/21.jpg

[Chris J]

We've been there before with Elise naca ducts:

http://www.stratossupersite.com/forum/showthread.php?t=2791&highlight=naca+elise

I'm guessing Martin is saying the same as Chris R. here?

[Andrew Taylor]

On my Allora the heater supply and return pipes run in the nearside sill, should be possible to get a good supply of air down the other? I fitted a water oil cooler so I have not investigated further.For the heater/demist the cold air scoop under rad (from Graham Bates) works well, unfortunately valve to shut off hot water only seems to work in the winter!
I should be out in the garage now finishing the cold air feed from above engine bay!

Andrew