Ceramic coating supercharger impeller

[Michael]

Hi everyone,

I dropped off the exhaust system from my car today with a reputable performance coatings shop to have the system ceramic coated, and I had a very interesting discussion with the shop owner about ceramic coatings for superchargers.

He said that while he had ceramic coated the rotors of roots-type blowers, and had ceramic coated discharge tubes of various other superchargers, he had never attempted to ceramic coat the impeller of a centrifugal type of supercharger. I found this a bit surprising.

It would serve to reason that ceramic coating an impeller would help keep the discharge air temperature lower. Additionally, the coating would smoothen the surface of the impeller, aiding in overall airflow. The coating is only 0.0015" - 0.0030" thick, so it's well within the impeller-to-housing clearance of any centrifugal supercharger (that I know of). And the cost to ceramic coat an impeller isn't very high either (less than $100). So it seems like a win-win scenario to me.

So this got me to thinking: has anyone tried to ceramic coat the impeller of their centrifugal supercharger before? If so, what was the result (good or bad)?

[Michael]

Well, I went ahead and ceramic coated the impeller for my SN89. I'm in the middle of a full rebuild of the unit, so I figured "what the heck?". Besides, it didn't cost much since the shop that did it was ceramic coating a bunch of other parts for me at the same time.

I really do hope the effect of the ceramic coating really does keep the discharge air temperature lower. If nothing else, it certainly does make the impeller look nicer... LOL!!!

Here's some photos:

[64wagon]

I spoke with my local coater he thinks coating could speed up the air flow in the charger, but dose have conserns about if something would go wrong with the coating coming off. and no benifits fro heat disbursement because of direct metal fit. He does a lot of work for the helicopter ind.

[Michael]

I think the whole heat disbursement question is still up for debate. My guess is that, if anything, the impeller itself may operate at a slightly lower temperature, but I don't know if it will make any difference with respect to the charge's temperature.

As for the coating coming off, the only way I can see that happening is if the impeller makes contact with the housing, either along the back surface or at the vanes themselves. And if that happened, I think the ceramic coating coming off will be the least of my problems... LOL!!!

[Sulaco1976]

Looks good man, shame you never get to see it unless apart :(, but it is sharp looking =)

[FSTFBDY]

Looks good . You would have been better off using a TBC like a piston coat. that dissipates/reflects heat better then a ceramic for a header.
I own a Co. and do ceramic and thermal coatings, etc.. (headers,pistons,valves,turbos,etc....)

Heres A GOOD read on all the diff. coatings
http://www.hotrod.com/techarticles/e...s/viewall.html

[Michael]

Thanks for posting the link to that article. Interesting read, and very informative.

That impeller posted above is still not installed in my SN89 (my move to the U.S. has put a lot of projects on the back burner, but I'll get around to finish the SN's rebuild soon) so I still have the opportunity to have that coating removed and some other coating applied.

You say that I would have been better off using a TBC (Thermal Barrier Coating) that better reflects and dissipates heat than the ceramic coating that was used (which I agree with). The intention of coating this impeller was to try and dissipate some of the heat produced during the compression process. The shop I went to had suggested this ceramic coating, so I trusted their judgement; they had never coated an impeller before and had no idea what the results - if any - would be. So with that said, what coating would you have recommended for this sort of application?

[vinces427bb]

Thanks for posting the link to that article. Interesting read, and very informative.

That impeller posted above is still not installed in my SN89 (my move to the U.S. has put a lot of projects on the back burner, but I'll get around to finish the SN's rebuild soon) so I still have the opportunity to have that coating removed and some other coating applied.

You say that I would have been better off using a TBC (Thermal Barrier Coating) that better reflects and dissipates heat than the ceramic coating that was used (which I agree with). The intention of coating this impeller was to try and dissipate some of the heat produced during the compression process. The shop I went to had suggested this ceramic coating, so I trusted their judgement; they had never coated an impeller before and had no idea what the results - if any - would be. So with that said, what coating would you have recommended for this sort of application?

i don't think it is going to affect the charge heat much either way (+/-) temp.
i think it may help the air flow thru smoother,
i would not think that the air going thru the blower would be heated up much from heat transfer from the impeller/scroll???
is this an issue accelerated by going thru the blower or by the compressing of the air??

[FSTFBDY]

I agree with Vinces427bb,

The impeller really wont get that HOT. I mean yes its gonna get warm but not HOT like a header that ceramic is made for.
Id use something like http://www.nicindustries.com/heat_dissipation.php To help dissipate the heat OFF/out of the parts.
Flow flow its an aluminum part, polish it to smooth it out some. Not a ton to throw off the balance.

Ceramic like used is more of a header coating INSIDE and OUT. what it does since the INSIDE is coated is Keeps the HEAT in the pipes and flows out the exhaust. Similar effect but beeing the Inside of the pipe is coated it doesnt let the metal absorb the heat as quick.

My thought is on a Supercharger you want to dissipate all the heat you can before going into the fmic , a2w , etc..
My pistons ,chambers and valves are coated. My bearings are coated. My Novi2000 is done black tbc now. If I ever have to tear it apart. The shafts and gears will get a dry film lubracant coating. The impeller will get polished. and the complete case will get done in black tbc.