Well Charlie, that cheap one on ebay is now on it's way to me to inspect, cut, experiment, etc. Even that one while it is a paltry $35 with free shipping to ya'll down south of the borderline, it came to $80 canadian pesos after shipping and exchange, but while it always sucks to throw money at something I'm probably not going to be able to use, in the big picture of this project it's not worth worrying about. The new one on ebay, for $116 would actually end up costing $221 by the time I got it. So up here when an Item is available on Amazon's canadian site, it's usually a much better deal than ebay.
Bill, we have one motorsport salvage place here in town and they have far more snowmobile and ATV stuff than motorcycle. Snowmobiles have aluminum heat exchangers in the tunnel above the track, so nothing that would be suitable for our needs, but the newer, large side by side ATV's do have some pretty nice rads that could be made to work if needed, but for now I'm hoping this curved rad will be the ticket.
As far as the amount of heat that the bikes put out; I consider that most of the time these bikes are not putting out max HP for long enough to overload the system. But just for giggles, lets assume that the rad is designed to cool a continuous 120hp (which is not likely) and I'm planning on on putting 2 of them in there for a total of 240hp of heat rejection. Now I doubt I'm pulling anywhere near that much out of my turbo rotary with a mild 6psi of boost, but lets just say I am. I'm only doing that for a limited amount of time on take-off and climb. And further consider that 1/3 of my heat is being rejected by the great new Fluidyne oil cooler (converted to a 2-pass) that all but completely eliminated all my oil pressure and cooling issues. So that leaves me with 160 hp worth of heat to get rid of with these 2 rads. Now consider that at best climb where I'm probably making the most heat, I'll be at ~80mph which is a high cruising speed (not top speed) for these bikes, but with a bit of effort I hope to build an inlet diffuser that can slow this airflow down somewhat. Now to further muddy the waters, the rotary does produce more heat per HP produced than a reciprocating engine so those examples given may mean nothing without a conversion to BTU's (this is where Ed would would step in and provide that sorta data)
Will it work? Well, I just spent $80 to find out if I can fit them in there, with more money to follow if I can....
Todd (what do people without airplanes do with all that time and money?)
C-FSTB