Question regarding compressor wheel to compressor housing clearance and MWE info
Thread Starter
Who is Mr Robot?
iTrader: (2)
Joined: Jul 2004
Posts: 21,474
Likes: 10
From: ATL - Where the Pimps and Players dwell
Question regarding compressor wheel to compressor housing clearance and MWE info
So I might have to machine the inlet of one of my compressor housings a slight bit to clear a .15mm larger inducer billet wheel. The housing is already machined for a 52.5mm cast wheel but the custom billet wheel is 52.65mm
This is an evo 4-8 based turbo (9s have a different chra and larger comp. housing. Now I've seen the FIA homologation papers for the 1-3 evos and it listed .5mm clearance between wheel and housing and .8 for turbine side clearances. I can't remember of this was total clearance (.25mm between the wheel and housing inlet on one side of the wheel, adding up to .5mm) or .5mm all the way around.
Maybe Mac and some of the more experienced turbo builders can chime in.
I know clearances vary based on wheel material and construction.. cast vs billet and aluminum vs titanium, things of that nature but I'm looking for a correct number when I take the housing to machine it (I do it on my own since I have access to a full capability machine shop for free)
That is most of the work as the radius of the wheel is the same as is the exducer (other than the billet wheel being extended tip. Which is a huge help because I'd have to send the housing and wheel to Mac (which I don't mind doing I just know if I have a clearance number I can toss the housing in the lathe and go to town)
Now the billet wheel has a 5mm taller hub height and 5mm taller blades (but the exducer tip height is unaltered) This housing is ported shroud and the groove is based on the stock height wheel. I'm afraid if I don't relocate the groove 5mm higher to sit directly under the primary blades (like all ported shroud housings) that I'll be bypassing too much air around the wheel, causing spool/pressure issues as well as impacting efficiency and generating excess heat.
It's no big deal to have the existing groove welded over and machined down and then I can remachine the groove in the proper location
Advice, tips, etc?
This is an evo 4-8 based turbo (9s have a different chra and larger comp. housing. Now I've seen the FIA homologation papers for the 1-3 evos and it listed .5mm clearance between wheel and housing and .8 for turbine side clearances. I can't remember of this was total clearance (.25mm between the wheel and housing inlet on one side of the wheel, adding up to .5mm) or .5mm all the way around.
Maybe Mac and some of the more experienced turbo builders can chime in.
I know clearances vary based on wheel material and construction.. cast vs billet and aluminum vs titanium, things of that nature but I'm looking for a correct number when I take the housing to machine it (I do it on my own since I have access to a full capability machine shop for free)
That is most of the work as the radius of the wheel is the same as is the exducer (other than the billet wheel being extended tip. Which is a huge help because I'd have to send the housing and wheel to Mac (which I don't mind doing I just know if I have a clearance number I can toss the housing in the lathe and go to town)
Now the billet wheel has a 5mm taller hub height and 5mm taller blades (but the exducer tip height is unaltered) This housing is ported shroud and the groove is based on the stock height wheel. I'm afraid if I don't relocate the groove 5mm higher to sit directly under the primary blades (like all ported shroud housings) that I'll be bypassing too much air around the wheel, causing spool/pressure issues as well as impacting efficiency and generating excess heat.
It's no big deal to have the existing groove welded over and machined down and then I can remachine the groove in the proper location
Advice, tips, etc?
Thread
Thread Starter
Forum
Replies
Last Post