Subject: Re: Primary tube math by anesthes on 2008/8/6 23:10:28
Quote:
tequilaboy wrote: I know there are some ceramic coated impellers intended to improve efficiency mostly used for turbos. I don't know how effective they really are for centrifugal superchargers, though. Less friction with the air maybe, I think the Raptor uses one.
Coating the volute/diffuser may keep the components themselves cooler, but I think that would just tend to increase the charge air temperature.
I'd really like to see somebody do a fully shrouded impeller like the old DVL design. That's supposed to be the most efficient impeller style. Basically an impeller with a cover on top of the vanes which avoids any leakage between the vanes and the case. Would be expensive.
With the Powerdyne I'm more concerned about overheating the bearings than I am the outlet temp. Outlet temp can be cured with alky injection or an intercooler, but I was thinking if the volute was ceramic coated inside it would keep the head unit from getting head soaked.
Now, would the aluminum volute warp in the 550f oven while the ceramic is baking on? that is another question.
Another thing, the ceramic would decrease the clearance between the impeller and the volute by a very small percentage which should aid efficiency. In theory it should keep the volute from expanding when it gets hot, so you would always have the same clearance rather than more when cold, less when hot.
But I guess this is off topic.
I think I'm going to run the 1 3/4" long tubes and have 'em coated in + out locally. maybe if the coating is good it will help with some of the high inlet temps based on where our air cleaners are located. Jethot told me 400f reduction in underhood temps. I've yet to find someone with an IR that has published before + after results.
