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Old 10-18-2009, 04:56 PM   #1 (permalink)
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Question Duct radiator into exhaust --- Possible?

Merge them before the catalytic converter, so you can seal the engine compartment completely (well, after the radiator grill) and have no aerodynamic losses from the air going everywhere and around the engine compartment... ?

This would also boost radiator efficiency since the air would be "ducted" and given an airway path- not just a "go find somewhere" around the engine compartment.

What do you think? Possible?

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Old 10-18-2009, 05:08 PM   #2 (permalink)
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...exhaust volume is determined by engine RPM, while radiator air is determined by MPH (assuming all else constant)...so you're gonna encounter one heck of a "merging" problem.

...it's possible, but IMHO going to entail LOTs of duct work.
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Old 10-18-2009, 05:13 PM   #3 (permalink)
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on formula cars as well as sports racers (Formula car with a full body)
The ducting of the air through the radiator has huge effects on speed.

The EVO/Touring Cars all duct their air up through a tuned hole in the hood so as to take the firewall air out of play aerodynamically.

But you have to rethink engine insulation, there is a lot of stuff under the hood that needs some air flow to stay healthy. (Alternator, electronics etc)

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Old 10-18-2009, 05:16 PM   #4 (permalink)
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Well I was thinking of a simple y-pipe with a one way valve on the radiator side so the exhaust doesn't go backwards into the radiator...
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Old 10-18-2009, 05:34 PM   #5 (permalink)
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I think your attacking too deep, what if you just duct the radiator to its own pipe,
It would need to be about 1/4 the size of the radiator... Your radiator needs about 2000 to 4000 CFM depending on the setup. No restrictions allowed. Of course your fan choice would be key, with the right fan the pipe could be smaller...

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Old 10-19-2009, 01:59 AM   #6 (permalink)
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I think ducting radiator air to the wheelwells would be better, and easier. This would reduce snow buildup and maybe improve airflow in the wheelwells, which usually have lower pressure than the engine bay.
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Old 10-19-2009, 03:33 AM   #7 (permalink)
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You'd need a "path of least resistance" setup for the exhuast, so that it could not come back through the vent under low pressure situations.

As was said, yes, it could be done. Special care would need to be taken, though.

When I first read this, I read it as (duct radiator through exhaust) meaning: (run coolant through a radiator fitted to the exhaust pipe to cool the engine). I was all prepared to tell you why it just wouldn't work.

The added benefit of running your heated radiator airflow to the exhaust is that:
At low radiator velocity, high exhaust velocity, the exhaust will act like a siphon flow, pulling more air through the radiator via negative pressure at the back of the radiator's surface.

At high vehicle speed/low engine speed - the excess flow from the radiator, ducted smoothly into the exhaust pipe, would work to increase scavenging due to a siphon flow effect creating negative pressure on the back of the valves, increasing the pressure differential across the face of the valve as it opens.

At a high enough speed with low enough engine speed (not even extremes, here), one could experience lowered pumping losses due to the piston no longer having to apply nominal pressure to the exhaust gasses to force them out.
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Old 10-19-2009, 04:10 AM   #8 (permalink)
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I'm reading it as having an air duct with the exhaust pipe running within it- I mean, if you want something that has a shot at working.
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Old 10-19-2009, 04:27 AM   #9 (permalink)
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Quote:
Originally Posted by basslover911 View Post
Well I was thinking of a simple y-pipe with a one way valve on the radiator side so the exhaust doesn't go backwards into the radiator...
Remember the air flow through the radiator is dependent on zero back pressure behind the radiator, and the air coming into the engine compartment is to cool stuff besides the radiator..

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Old 10-19-2009, 10:46 AM   #10 (permalink)
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Quote:
Originally Posted by Christ View Post
The added benefit of running your heated radiator airflow to the exhaust is that:
At low radiator velocity, high exhaust velocity, the exhaust will act like a siphon flow, pulling more air through the radiator via negative pressure at the back of the radiator's surface.
EXACTLY what I was thinking! And that is 99% the case anyway... unless the fans are on AND you are running above 100mph lol.

I don't know how much restriction a one way valve would give though...

And I also thought about venting them to the wheel wells... but aren't we always trying to remove airflow from them with things like wheel skirts and flat moon discs? Why would we even think about adding more flow there it just contradicts everything I believe...

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