16g converted to td05 20g

[NycDSM11]

so after taking a break from the dsm world im back at it. the other day i picked up a blown big 16g, a rebuild kit and a 20g compressor wheel with the housing. now my question is can i just put everything together no problem without balancing it? to my understanding mitsubishi turbos are all component balanced, so does that mean i could put the lager compressor wheel with out problems, also do i use the original shaved nut or the new one?

 

[-red97rum-]

so after taking a break from the dsm world im back at it. the other day i picked up a blown big 16g, a rebuild kit and a 20g compressor wheel with the housing. now my question is can i just put everything together no problem without balancing it? to my understanding mitsubishi turbos are all component balanced, so does that mean i could put the lager compressor wheel with out problems, also do i use the original shaved nut or the new one?

I can answer your question. That is the exact same setup I've been running for the past 3-4 months.

Couple things first, the 20g compressor wheel isn't going to fit into the 16 compressor housing if that's what you're trying to do. I would scribe a mark on the shaft/nut and line it up the same when you reassemble. Make sure to use red, high strength loctite on the nut.

In my situation my EVO III 16g's thrust bearing died and the compressor wheel contacted the housing. I had a blown tdo6h 20g in the garage that died when a piece of a valve went through the turbine. Also, the 20g's journal bearings were in pretty bad shape.

So I took the thrust bearing, oil rings/seals (looked to be in better shape), compressor wheel and compressor housing from the 20g. I used the journal bearings, tubine shaft, center section and turbine housing from the 16g. I just cleaned everything really really good and put it all together, unbalanced.

I've been beating the crap outta the thing for the past few months. Ran an 11.8 @ 120 and an 11.9 @ 122 on 7-17-10 at 25ish psi of boost. I was spiking to 30psi and leveling off at 28-27psi the last couple weeks. I usually didn't even turbo time the thing because I didn't expect it to live long. I pulled the 20g off this past Tuesday 8-31-10 to put on my rebuilt hx35 and that 20g still doesn't have a hint of shaft play. I swear Mitsubishi turbos tough as nails.

 

[manny correa]

wanna sell that 20g red97rum?

 

[JusMX141]

Here's the deal with balancing.

When you buy a new turbine, it comes balanced. When you buy a new compressor wheel, it comes balanced. What Mitsubishi and many turbo companies will do with the assembled turbos they're selling is put the entire turbo together and high-speed balance the entire assembled turbo. This is where you get the balance grinds on the compressor locknut....obviously you cannot get to the rear of the compressor wheel to make balance corrections with the turbo assembled.

Many turbo shops cannot afford this $100K+ VSR balancing machine that literally has it's own oil supply, so they use a low-speed balancing machine to balance the rotating assembly, like a TurboPac. These machines are also quite reliable, and can balance the rotating assembly to a finer specification than just the individual parts because you're also balancing the thrust collar and compressor seal collar, too.

Balancing is less-crucial on turbos with larger rotating assemblies because such a turbo cannot reach a speed where damaging vibration becomes an issue. For example, a T25 rotates almost twice as fast as a HX40, so obviously the balance will be more crucial on the T25.

I've already had small-frame turbos come to my shop with the compressor wheel completely fuct with totally mismatched breakage on the compressor wheel fins, and these turbos had no shaft play nor did they show any sign of being unbalanced. So just how crucial is perfect balance?

 

[-red97rum-]

wanna sell that 20g red97rum?

Nah, not just yet. It's nice knowing I have a good spare turbo sitting in the garage.

So just how crucial is perfect balance?

Well I'm convinced that assembling a turbo with just the static, individually balanced parts, is sufficient probably 95% of the time. There's no way the td05h shaft in my 20g would have survived the last few months at 25+ psi of boost if there was a problem with the balance.

This was the TDO6H 20g you rebuilt for me last year, was going strong until my stock motor let loose and killed it.

 

[JusMX141]

The thing is, most of these people who are bitching that balance killed their turbo either didn't clean it properly upon assembly, didn't give it enough oil or possibly gave it too much oil, and when it failed the reason was "balance"....much like any 2G 7-bolt owner who suffers an engine failure has crankwalk. Even if the oil pump locks up and turns the rods blue....crankwalk.

Some key things to remember- if you have a turbo that was balanced as a rotating assembly (has balance grinds on the locknut), then that nut belongs to the compressor wheel that is behind it...and their alignment MUST be the same. If you move the compressor wheel to another turbine or if you're swapping the turbine, the nut stays with the compressor wheel and the marks you scribe must align when it's reassembled or you risk too much balance offset.