Flow through ventilation

[dhansen]

Interesting idea. From the TLM website.

[Guest ratchethack]

Hm. Every time I see someone do this, I have to ask, "Why?"

 

Seems to me the benefit of cooling the exhaust side of the heads of an air cooled motor by putting the hottest parts of the motor directly in the airstream (per the conventional wisdom of 100+ years) gets hammered pretty substantially by turning it around backwards.

 

Now hiding the hottest part of the heads and exhaust plumbing in the quieter air behind the motor, whilst putting the intakes up front does wot -- provides some kinda marginal (at best) "ram air" effect?

 

I don't get it.

 

But that's just me.

[Skeeve]

Hm. Every time I see someone do this, I have to ask, "Why?"

 

Seems to me the benefit of cooling the exhaust side of the heads of an air cooled motor by putting the hottest parts of the motor directly in the airstream (per the conventional wisdom of 100+ years) gets hammered pretty substantially by turning it around backwards.

 

Now hiding the hottest part of the heads and exhaust plumbing in the quieter air behind the motor, whilst putting the intakes up front does wot -- provides some kinda marginal (at best) "ram air" effect?

 

I don't get it.

 

But that's just me.

 

Well, theoretically, the amount of cooling depends upon the differential between the temp of the air and the temp of the convecting surface, so the cooler intake side of the head supposedly doesn't heat up the passing air sufficiently to make a difference on cooling the hotter exhaust side of things, while getting direct cool air into the intake & making the exhaust plumbing as easy as possible has decided benefits.

 

All of which is fine for other designs; on a Guzzi, this just means your knees are gonna need asbestos liners!

 

And the theory really only seems to work well for liquid-cooled bikes; seems like the a/c 2-smokes they used to try this on always seized!

 

So I am in ageement with your thinking the time & energy spent doing this would be better utilized in other activities.