Turbo rebuilding

[prove_it]

So I've inherited a Big 16G center section with a China EVO III GT cover. The cover will fit a 20G wheel, so I'm looking to build it into a bastard. I'd like to see what everyone has heard and experienced with the different vendors on EBAY. I'm working Justin on tuners, but I'm sure I can just do it myself, at least like to for the cheap. The non MHI parts make me nervous especially the bearings. Does anyone know where to get genuine MHI turbo parts? Also I'd like to just get a new turbine wheel and have it clipped.

Read a lot over on tuners, but some info is too far out of date to be relevant.

 

[transparentdsm]

im going to use this kit once i pull my turbo off click i have click this one to be exact and i have been running it at 24 psi for the last 8 months and put roughly 12k miles on it and it doesn't blow oil, there is no shaft play what so ever and i hit full boost around 3400rpm's.

 

[GSTwithPSI]

G posted this link a while ago, and it looked pretty legit to me. All MHI parts click

Edit: Lol, I just looked and Shane posted the same link...

Check out this thread: click

 

[bmxr152]

I got my 20g wheel off ebay. Spent 90$ threw it on and ran at 28psi for 2 years. Never had a problem

 

[prove_it]

So you literally just swapped the wheel and that's all? How much boost did you push?

 

[GSTwithPSI]

Quoting transparentdsm:
im going to use this kit once i pull my turbo off click i have click this one to be exact and i have been running it at 24 psi for the last 8 months and put roughly 12k miles on it and it doesn't blow oil, there is no shaft play what so ever and i hit full boost around 3400rpm's.



I wouldnt take any of the "facts" that website has posted up as gospel. This first link is that guy saying how proud he is to offer DSMers such a great turbo, and how great they are: click . And the second link is him telling people not to by them because they are junk about 2 years later: click

Just keep an eye on that thing, Shane. I wouldn't want it to fly apart and sh*t metal into your intake tract while you are driving to work or something. I know it is working for you fine now, but there have been a lot of issues associated with that turbo.

 

[prove_it]

Oh the info is so hit and miss out there. Been reading volumes of posts on tuners and one day they rock, the next they dont.

Some blow up wheels, others don't.

Well turns out I inherited a knock off center section, so I'll probably be waiting for a well priced Green to pop up. I'd still like to discuss these bastards though. I got a few 14bs around so upgrading them seems pretty interesting.

 

[transparentdsm]

thanks Brett, i will keep my eye on it. thankfully before i bought this from Shane(brunoboy) it had just been rebuilt with all MHi parts.

well looks like ill be rebuild my GT30 sooner then i thought.

 

[GSTwithPSI]

</font><blockquote><font class="small">Quoting prove_it:</font><hr />
Oh the info is so hit and miss out there. Been reading volumes of posts on tuners and one day they rock, the next they dont.

Some blow up wheels, others don't.

Well turns out I inherited a knock off center section, so I'll probably be waiting for a well priced Green to pop up. I'd still like to discuss these bastards though. I got a few 14bs around so upgrading them seems pretty interesting.

<hr /></blockquote><font class="post">

I totally agree that the info is conflicting. In many cases, there have been guys running Evo III GT turbos and such for long periods of time successfully. But that's the thing; tales like those are sporadic at best. Every part has a service life. Whether it be a true MHI turbo, or an eBay knockoff. Failure is inevitable, but when and how that failure occurs is what matters. When you are using a turbo built with sub-par materials, the risk of a compressor wheel flying apart and taking out your whole engine is much greater than if you were using a turbo built with factory tested and proven MHI parts. That’s not to say MHI turbos don’t fly apart, but we’re comparing the odds here. So, it really comes down to the amount of risk you are willing to take. Saving a few bucks on a turbo doesn’t really add up when you are replacing a motor because of it IMO.

I am interested in this topic though, because I myself have a few 14B/B16G CHRAs laying around that need rebuilds. I’m curious as to what options I have for upgrading? I’m also getting conflicting info about balancing. I always thought any turbo rebuild should be balanced, yet some say parts are balanced from the factory and can be reassembled as is. Some suggest marking components and reassembling the same way they were removed. I’ve also heard you only need to balance when replacing major components. So what parts count as “major” components? It seems to me that balancing is more critical than people want to admit, but it’s not something that gets done often because most people lack the equipment and capabilities to do the job.

So, someone break it down and give me the skinny? What parts are you guys buying to upgrade (compressors, turbines, housings), and what upgrades are available (bastard what? 20G 18G?). Lastly, how exactly are you guys doing rebuilds, and what kind of results are you getting? Thanks.

 

[prove_it]

There was an argument on tooners about the wheels coming apart. Someone mentioned the fact that rally cars blow up evo mag wheels and MHI isn't that great. I was reading it and thinking, wait, rally cars have no BOV or vent, and they surge the crap out of the turbos. So I starting thinking, why does no one realize this.

Options for upgrade are fully centered around the 20g bastard builds. I haven't even seen a 18G wheel available. There are several different wheel designs out there. Justin on tuners can get a genuine MHI wheel and parts, but won't sell parts to the public. I heard you can stuff an HX35 comp wheel into a 16G. I think anything over a 20G will cause surge and loss of efficiency due to the Turbine being way too small for that big of a wheel.

I'm on the fence over balancing. Obviously VSR balancing it best, as it balanced the whole rotating assembly together. So many claim the new comp wheel and turbines are balanced and will hold up just fine. I think in the long run, it's fine. The balance is ok at best, and I'm sure it works. However, I'm almost positive that the turbo will spool slower and have a lower efficiency due to a higher imbalance.

 

[BluFalcon]

Component Balancing - The compressor wheel, and turbine wheels can be balanced individually, before being installed in either a rotating assembly, or into a complete cartridge for for a cartridge balance. Just balancing the individual components and slapping them into a cartridge or onto a turbine wheel, is NOT a good idea. The components need to be assembled and balanced dynamically as either a rotating assembly, or in a assembled cartridge.

Rotating Assembly - Generally consists of a assembled Turbine Wheel/Shaft, along with a Compressor Wheel, Locknut, Thrust Collar and Thrust Sleeve.

After the parts are stacked on the Turbine Wheel, the Locknut is torqued down to factory spec, and alignment marks are scribed on the nose of the Compressor Wheel, the Turbine Wheel/Shaft and the Locknut. This is to ensure that after the assembly is balanced and taken back apart for installation into the bearing housing, that all three of these components remain in "phase" with each other when reassembled.

The assembly is placed in a specialized balance machine, and additional material is removed from the bottom of the Compressor Wheel and Turbine Wheel with a hand or bench grinder, until the assembly is balanced to spec.

Once balanced, the components are disassembled, cleaned, and installed into a assembled bearing housing to form a cartridge, or CHRA. This is how most shops used to do things, before cartridge balancers were made available.


Cartridge Balance - The balanced Compressor and Turbine Wheel are installed into a assembled Bearing Housing, and the entire CHRA is placed into the balance machine.

A small belt, or a directed air jet spins the Turbine Wheel on the CHRA and material is removed from the Locknut, Compressor Wheel Nose (in some extreme cases) and from the small "nut" on the back of the Turbine Wheel. This is the most accurate, and cost effective way to balance a CHRA, as all the components are spinning dynamically, and are riding on the actual bearings in the Bearing Housing.

Most of the larger rebuild shops use this method, because it's quick, and most importantly, accurate and allows your turbocharger to enjoy a nice healthy, life.

When it's spinning as fast as some people push their turbos. the smallest imbalance or error made while assembling the turbo can dramatically shorten its operational life.

Assuming you don't cock it up by running it out of oil, dropping pressure while operating or letting bits of your engine contaminate the oil supply.

 

[GSTwithPSI]

Hey Ed, thanks for that post. So, it sounds like a turbo rebuild at home isn't a great idea? I don't know anyone who owns their own balancing equipment. Thoughts?

 

[coyotes]

Rebuild yourself then take the chra to a turbo shop to balance it.

 

[BluFalcon]

What he said, ^

If you're swapping out a component balanced compressor wheel for an upgrade or repair, you can probably get away with sending the assembled CHRA to a rebuild shop for a cartridge balance.

The Turbine Wheel was balanced from the factory, so if you're reusing it, it shouldn't need to be component balanced unless something happened to it. To give me a warm and fuzzy feeling, I'd pull the wheel out, polish the shaft /ubbthreads/images/graemlins/devil.gif and inspect the back face of the wheel for cracks, or signs of rub against the heatshield. If you see cracks, toss the wheel. It's a time bomb waiting to go off

It might also be a good idea to check the steps on the turbine wheel shaft where the rear piston ring is installed, to make sure the steps are still flat and also check the piston ring lip in the bearing housing to make sure it isn't excessively worn. Axial play in the CHRA can cause wear in these areas, and again..shorten the life of the turbo.