Road Racing a Modified Corvair

[Nashfan]

Moving the turbo out of the engine compartment, while "obvious" sounding, wouldnt seem to do much of anything based on experiments that I've done, except for hot soak. I put a temperature sensor on top of the throttle body in the engine bay and watched what it read during various conditions... basically there was only a 3-6 degree temperature rise relative to ambient when the turbo was good and hot when running down the road, but when parked after driving... the temp sensor would quickly exceed the 130 max for that sensor... it wouldnt have suprised me if the actual temp was 150 or higher when parked.
Back on the road again after that, the sensor went right back down to 3-6 degrees above ambient. Other experiments on water pumper turbo cars that I've seen (more tightly packed engine bays!!) with more temp sensors report the same sort of "slight" temperature changes, into boost or not. The big reason why this doesnt help as much as "common sense" would suggest has every thing to do with how the heat flows in the engine bay from the turbo, which is basically straight up, and heats what is directly above that, which is usually the hood, which then dissipates. This is why the paint on hoods of really high boosted engines can blister/burn the paint directly above it, but doesnt do much of anything to the rest. The easy simple and effective cure for this paint burning problem is to put a heat blanket over the turbo, and be done with it!!
As for thermal barriers on the piston tops and combustion chambers (and exhaust ports, like I have done)... go for it, it works, but be aware that by trapping the heat, this effectively raises the compression ratio and therefore changes the tune quite a bit, and is not the same as correcting the timing for a compression ratio rise without thermal barriers. There is a lot of reasons why Corvair Turbos tend to run way hotter than they should, and crappy ignition timing is a lot of the problem, followed by poor exhaust flow and a really inefficient fan.... really inefficient fan!!
One guy that has boosted racer reported over 500 degrees with the stock fan running without lower shrouds. With the Nashfan in the same race and lower shrouds on he reported less than 400. Gives you an idea as to how bad the stock fan is when presented with a lot of heat load!! In my own limited testing, full tilt full load 18psi in 3rd going up a long hill with the stock fan was enough to change the head temps from 300 to 320 for the short time I was in it, to actually dropping from 300 to 280 with my prototype Nashfan under the same approximate load and duration.

[61SuperMonza]

That's why I want one of your fans. Thank you for all the RD you have done on this fan. I would say this is the biggest development in many years for our cars.