Quick turbo question

[93blklightning]

Ok, some of y'all are familiar with what I'm doing, so too make it short and sweet.

I spoke with a reputable diesel shop in my...well general area a few days ago, regarding balancing my turbo after i rebuild it.
I'm running a TP38, this dude says that Garrett classes the GTP38 and the TP38 as ----"neural balance turbos".
Meaning, as long as you use a reputable impeller manufacturer, and stay within torque spec, rebalancing is not mandatory, as long as there is no excessive wear on the shaft, or exhaust side.

Anybody of y'all can verify this ?

 

[BDCarrillo]

Sounds correct. That's the premise behind the owner installed upgraded compressor wheels for many diesels.

 

[icanfixall]

Are you interested in taking chances with your turbo after working on it??? These things spin in excess of 120,000 rpm. Thats 2000 rpm per second. Balancing in done to well less than a gram. Post what you tried out and the results.

 

[93blklightning]

Will do icanfixall, i do understand the extreme high speeds these turbos spin, and the necessity of them being balanced to ensure their longevity.

Although i have 20 years experience in turning wrenches, most of the fine dynamics of turbos are new to me.

That was the way i was explained, I'm just....well, like everything else, getting a second opinion.
Which is pretty much What i do with everything that I'm not 100% on, or haven't done before

 

[icanfixall]

I'm not doubting what was said about the zero balance from the factory for the fans. My concern is in not at least having the balance checked can lead to some horrible damage. I too ask questions more than once and to many others before I choose to change.

 

[93blklightning]

I was concerned about the balance myself, but what that other guy said, he made it sound like it wasn't an absolute have to thing.
The other thing, I'd have to ship mine, because there's no-one close that has the tooling that can balance these things.

He also said that they do quite a few impeller replacements, and alot of people opt out of having the Garretts (GTP38, TP38)balanced due to the cost, and they've not ever had one come back with damage, or excessive wear due to being out of balance , but on the other hand...they recommend balancing the Holset......so...dunno...

I dunno though.....120,??? rpms is awful fast to be out of balance, even if it's only a few grams

 

[icanfixall]

If a turbo was out of balance by a few grams.. Lets say 3 grams it would not last long. 3 grams spinning at that rpm is going to be several lbs out of balance when it spins up there. I recall something about 1 gram at the 8000 rpm for a piston and rod being something like 8 or nine lbs difference weight. Its the same phsycis as spinning in a circle with a 10 lbs sledge on your hands. It gets so heavy you can't hang on to it.

 

[93blklightning]

That's pretty serious

 

[BDCarrillo]

I would like to point out the high quantity of "drop in" wheels across the many auto communities... if there was an absolute requirement to get it balanced, they wouldn't exist as popular DIY modifications.

On the other hand, I do agree that a very tiny imbalance can be very destructive. If your turbo is out of the truck, it would be an ideal time to have a shop run through it completely and install the wheel.

 

[93blklightning]

It's out now,and I've disassembled it.
Surprisingly, it's in really good shape, other than the factory impeller.
There was no play in the shaft prior to disassembly. But this balance thing has me second guessing.
Guess I'll call Mel tomorrow and see how much it will cost balance just the impeller and shaft

 

[93blklightning]

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[BDCarrillo]

Usually the giveaway that it's not a neutral balance turbo would be material removed from the impeller nut. Now would be a good time to replace the bearings... it's only a few more bucks.

 

[93blklightning]

I'm doing a complete rebuild.
Deleting the EBPV, upgrading to the 360° bearing, fabbing a new pedistal for my application

 

[93blklightning]

There's no material missing from the impeller as far as grinding marks that would be associated with balancing, or score marks for alignment

 

[BDCarrillo]

It would be taken off the impeller nut on a non-neutral balance turbo. IE, if material was removed from the impeller nut, it absolutely must be balanced after any mods.

I suppose the jury is still out on neutral balance assemblies. My opinion differs from icanfixall, but my turbo background stems from SRT-4s and 6.4 PSDs.