Where to pull fresh air for engine funtions & heat?

I'm talking about either blast tubes to cool alternators & ignition or fresh air headed to the heat muff.

It seems there are only two general areas where we can draw fresh air, either on the bottom of an intake ramp or on the aft face of the baffle.

Isn't this just a matter of keeping the scat tube runs as short and simple as possible? For heat, I'm looking to draw fresh air up front, run it back through the muff and then to the cabin heat box.

I'm planning to draw cooling air for aft mounted components like ignition from the back side of the baffle. I read reports of less than adaquate air flow for heat from some tube routings, and the advantage of longer routings that will "pre-heat" the air by letting it linger in scat tubing longer, but I have my doubts.

Does anyone make a sort of airflow divider so I can put in one 2" hole in the baffle, and then split that flow into two smaller tubes, one for each ignition? Or a single hole in an intake ramp that leads to both a heat muff and an alternator blast tube?

Plenum air flow, versus Plenum air pressure?

At what point as air enters the cooling ducts up front does that air change from ram effect at the intakes to a pressure vessel at the baffles?
I'm asking because I need to locate a second outlet from the pressurized baffle for heat, beyond the outlet I already have for cooling ignitions. The outlet for ignition cooling is a 2" opening on the aft face of the baffle, so there is no air flow there and I assume I'll be tapping into a pressurized plenum there. I also need to tap for fresh air to send to the heat muff, and I'm looking at the ramp inside the right cowl intake. That intake will be barely inside the entrance for the cooling air, and it will be almost 90 degrees to the airflow passing. It would be perfect to bring air down to a heat muff on the exhaust coming off cylinder #1, if there will be flow through such a tube.

Will there? Anyone else used this location for fresh air for heating?

Clay,

A small tube on the inlet ramp should work for alternator cooling.
Two small openings on the aft face of the baffle should suffice for ignition cooling.
Unless you have a four pipe exhaust, putting the heat muff on a pipe that carries the exhaust from more than one cylinder should get you more heat. You're going to need it in Heber. A 2" hole in the aft baffle could feed the heat muff.

So, that's 4 holes?
One on the intake ramp for Alternator.
Two smaller ones for ignition on the rear face of the baffle.
One larger, 2" one, also on the rear face for heat.

Is there anyway to divide airflow from one hole to a couple of endpoints?
Also, running the heating fresh air from the rear baffle forward to a pipe, and then all the way back to the firewall seems convoluted. As to whether I'll need an additional muff, I'll wait and see, but if I do, can that second muff's worth of heat still be piped into the same single heat box/valve on the firewall, or would I need a second box?

claycookiemonster said:

Is there anyway to divide airflow from one hole to a couple of endpoints?

Click to expand...

Yes, but it will be heavier and the cooling air tubing will be longer after leaving the divider that if it was run from the aft baffle straight down to each ignition.

The majority of heat muffs get installed on an exhaust pipe about where it passes below the aft baffle. This makes for short runs of scat tubing.

claycookiemonster said:

As to whether I'll need an additional muff, I'll wait and see, but if I do, can that second muff's worth of heat still be piped into the same single heat box/valve on the firewall, or would I need a second box?

Click to expand...

Most people who need an additional muff put it in series with the first muff. The air goes: baffle, muff, muff. heat box/valve.

Do you have a four pipe exhaust? If not, putting the muff on a collector pipe for two or more cylinders should work fine.