Cross counter flow is a more effective heat exchanger.

Here is the sequence for welding the rads to make a cross counter
flow heat exchangers.

Butt tig weld the in and out tanks first by cutting off all tabs on
the rads.

Don't weld the in and out tubes on yet.

They will be marked for position on the tanks while on the aircraft.

Then the large holes for the tubes will be cut and then the tubes
will be welded over the holes. The tank design will vary depending on
cool side mounting or bottom mounting. The TTC is a bottom mount.
Most other aircraft use a cool side mount. The 3 rotor allows longer
rads to be used. Put the diffuser between the rads and the engine.
See my book How to Cool your Wankel for more info.

After the tanks are done (with out the holes and tubes) bolt the
rads together with the wood strips leaving 1/2 to 3/8 of an inch
between in and out tanks.

The idea here they must not touch each other. The wood strips are
heat insulators between the two rads.

Then weld an aluminium strip 1/2" to 3/8" wide at the other end.
Finish by boxing in the other end (the front end).

Weld on them some and let the rads cool some what. They are brazed
together at only 1100 F so it is important to not get them too hot.
Wet rags around the ends of the fins and tubes might help.

Here are a bunch of pictures attached. The JPGs were Dodge Neon rads
and not the truck rads. The TTC rads will be welded soon.

Apparently when Mercedes owned Chrysler they implemented some up to
date heat exchanger technology. IMHO Chrysler rads are now the best
from an efficiency point of view I have found so far. Honda also uses
up to date tech but they are more expensive.


Paul Lamar



What about a dual pass rad already done?
http://www.jegs.com/i/Allstar-Performance/049/ALL30048/10002/-1

-Matt Boiteau


It will probably work but you will be paying a weight and drag penalty.
I don't know how much on the drag. We don't have any comparison data
on the drag yet. The weight of the core with water will ben at least  150% of the cross
counter flow Dodge truck rads.

Paul Lamar

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