Ducting cool air to engine bay

[JakeL]

Hey all -

I've seen on various cars that there are different solutions for getting some cold air into the engine bay. I was curious to get a sampling on what approaches folks have taken, that seem to have had good results?

On the Stohr there is a large overhead duct that funnels air down into the header area, but I am tempted to do away with that large piece, and take cooling air from somewhere else, such as some 2" hoses run from the sidepods, or a NACA duct, or, or.

Anyway, if you're willing to share, I'd be interested to see some pictures of what you folks have done that seems to do the job of keeping the motors from cooking themselves.

Cheers!

-Jake

[S Lathrop]

The Citations allow a large portion of the radiator air to exit through the engine compartment. The Swifts DB1/6 is the best example of this approach.

The bike engines do the same thing in the bike.

The point here is that you need a lot of air and you have already paid a drag price to run the air through the radiators. Use it again to cool the engine compartment.

The trick is to get the exits right but that is not that hard because the back of the car is mostly low pressure.

[JakeL]

Steve -

Thanks for the reply back.

In the Stohr, there is already a pair of ducts that are taken from just under the engine intake:

http://www.stohr.com/

My thought is to remove that duct under the rollbar, relocate the engine intake to under the rollbar, and thereby reduce the car's frontal area somewhat.

So, even though air has gone through the coolers, your experience is that it's still cool enough to do the job?

It's an interesting question in the Stohr, since our coolers are up high. I'll have to noodle on how I'd redirect or duct the air into the engine bay from the coolers.

Cheers,

-Jake

[S Lathrop]

Steve -

So, even though air has gone through the coolers, your experience is that it's still cool enough to do the job?


-Jake

When the DB1 arrived on the sceen, the trend to fully enclosed cars was well under way. The central radiator was not particularly low drag but the engine environment was improved enough that I think the cars gained more power than the increased drag cost them. The VD that came out shortly after the DB1, and was some what a copy, chose the side radiators because in testing that was a lower drag arrangement. But the engine environment suffered. And the VD did not match the DB1 speed. My opinion only.

In my cars, I do duct air to the intake manifold and to the upper portion of the exhaust. A DB1/6 acomplishes the same thing with radiator exhaust air.

Managing the heat of the exhaust in an FB is a real challenge. I try to emulate what I see done on turbo charged indy cars. They pass cooling air through the exhaust enclosures. Ducting radiator exhaust air over the exhaust will help a ton.

Think more about engine inlet ducting.

[Wren]

Brandon's FB also had the entire exhaust surrounded by the fancy inconel-ceramic-inconel sheets. They "cocooned" the exhaust from the head until the exhaust was clear of the engine. This kept the exhaust heat out of the engine, oil filter, and fuel cell. It also meant that in the case of a big blow up, that oil would spray on the inconel instead of on the header and prevent a fire.

I see people try to find other, cheaper solutions to manage exhaust heat, but it is a false economy. Nothing works as well as the inconel insulation.

[JakeL]

Steve -

Appreciate the concepts, I'll see what falls out when I look at the car closely next. A uniqueness of the Stohr is that a fair portion of the air from the coolers exits through the 'chimneys' on the top side of the bodywork. I'll be interesting to see what way would be useful to try and redirect or capture what does exit out the back.

Think more about engine inlet ducting.

err...perhaps I don't have the knowledge base to give sufficient thought! The intake duct/snorkel already seems pretty good, and I imagine the lower one would also work fairly well, as it does on the WF-1 DSR. I would like for the rollbar area to be faired in instead, and try to clean up that space if possible.

Wren -

I'm not familiar with the inconel sheet you mention - I don't suppose you've got a picture of the installation you're willing to share? The links I found on Google didn't seem to be the right kind of thing.

Cheers,

-Jake

[Wren]

I don't have any pictures, but here is a link:

http://www.koolmat.com/heatmast.shtml

Basically he took three pieces of it and wrapped it around the exhaust header until it was completely covered. Held together with safety wire through the grommets. There was not really any overlap, it just took three pieces because the stuff does not bend great.

[DonArm]

Unfortunately KoolMat has stopped using Inconel because of the cost, they now use aluminum.

[glenn cooper]

Cool Mat Pat is good people...

[DonArm]

Correction. They don't use aluminum, they use .003 stainless. Sorry for the misinformation.
Yes they are good and very easy to work with getting whatever you need.