So I was doing some research on clipped turbine wheels and came across this picture of a compressor that was polished on the INside.

Check it out:





Does polishing the inside of the compressor housing serve any benefit? I mean, it's on the inside, so it can't be for bling factor.

Here's the thread:
http://www.duramaxforum.com/forum/sc...ker-turbo.html

 

i dont get it....

maybe the turbo was ker-sploded?
he was polishing it for a table decoration?

i read the thread.... i still dont get it...

 

Smoother airflow? Quicker spool? Never heard of that before...

 

I didn't read the thread, but its basically the same concept as this;
http://www.turblown.net/store/index.php?productID=124

Probably same price, but no where near the results..

 

And what exactly are the results? Any back to back comparisons between coated and non coated housings?

 

ExtrudeHone has been doing that to compressors and turbine housings for yrs now. I don't see how polishing that would hurt anything as long as you don't mess with the tolerances.

 

**** ton of work<negliable hp gain

 

I have received some from customers, but I haven't personally done it. I don't know how well the testing was controlled so I won't post the results. It appears promising. I sell it as one of those things to do if you are near maxed out with your current compressor, or in a racing to gain that extra edge.

 

I think the coating option isn't bad if proven, it's not expensive or labor intensive. Extrude hone has said as much as a 10% improvement years ago but I haven't seen solid numbers on it. I would bet it depends on how much material they removed out of the cover is my guess. Polishing the diffuser is marginal at best since you never polished the inside of the volute. As already mentioned, all of this though is likely only going to benefit you once you've already dialed the car in a much as possible.

~S~

 

now his polished surface is nice and uneven.

 

Its hard for me to believe that polishing the well machined areas shown will provide measurable gains (note the visible machining lines on billet compressor wheels) even if you could do it without enlarging the tolerances.

It is possible the work shown could decrease performance by enlarging the tolerances- note the use of abradable compressor housings to measurably increase performance by decreasing the tolerances in a safe manner.

However, polishing the rough cast interior of the compressor volute might have larger gains. This is where the Extrude Hone process would be useful.