Thread: Garrett GT series turbocharger nomenclature

TurboByGarrett.com - GT Basics / Nomenclature

GT Basics / Nomenclature

Today, Garrett has a wider selection of GT-series turbos available than ever before. As a result of this, please note that we have made a subtle modification to the GT nomenclature.

In our product catalog, all offerings are grouped according to their turbine wheel frame size. The frame size of a turbo or CHRA is dictated by its turbine wheel inducer diameter . The larger the turbine inducer, the bigger the frame size-- so any turbo in the GT42 family has a larger turbine wheel inducer than those in the GT35 family, and so on.

In the model name of each turbo or CHRA, you'll also notice two digits after the frame size. These two digits refer to the compressor exducer diameter, as measured in millimeters.

Let's use the GT4294 as an example. This unit has a GT42 frame size turbine coupled to a 94mm (exducer diameter) compressor wheel.

If there's an "R" on the end of a model name, this means the unit is ball bearing. So, a GT4294 is not ball bearing; whereas a GT4294R is ball bearing.

The biggest change related to the nomenclature is this: units which utilize a 53mm turbine wheel (as measured at the inducer) are now referred to as "GT25" frame size, while units employing the slightly larger 53.85mm turbine wheel are now referred to as "GT28" frame size.

For those familiar with our product range, this means that the unit formerly known as "the GT28R" (part number 466541-1) is now in the GT25R family. More specifically, it is now a GT2560R model.

A Guide To Garrett’s "GT" Model Numbers

GTxxyyzz:

• Positions "xx" refers to the frame size of the turbine wheel inducer.
  
  • For example the "GT28" in "GT2860RS" refers to its turbine wheel frame size family. All GT28 units use a turbine wheel with 53.85mm inducer diameter
    
  • As a rule of thumb, the larger the number, the larger the turbine wheel.
• Positions "yy" designate the compressor wheel exducer (major) diameter in millimeters
  
  • The "60" in the GT2860RS example above has a 60mm compressor wheel exducer diameter.
    
  • Note: Wheel sizes 100mm and over omit the "1" (hundreds digit)
    
  • Example: the 02 in a GT4202 refers to its 102mm compressor wheel exducer diameter
• Positions "zz" may be used to designate special features of a particular turbocharger where applicable
  
  • Example: GT2860RS
    
  • "R" = this is a Ball Bearing unit
    
  • "S" = used for units which require some differentiation from units in the same family
    Compare a GT2860R to a GT2860RS. While both are ball bearing and externally similar, the GT2860RS is better suited for higher-flow applications than the GT2860R. In this case, the S reflects the higher-flowing nature of the GT2860RS

It would seem also that in Garrett's world the following holds true:

Tx - Denotes exhaust inlet flange size where x can be 1, 2, 3, 4, or 6

That being said, I've seen other companies take the CHRA and wheels from a GT28xxR turbo and slap a custom T3 flanged exhaust housing on it to make a T3 flanged GT28 turbo (and they don't re-name it accordingly).

I've also seen companies take the CHRA and wheels from a GT30xxR turbo and slap a custom T2 flanged exhaust housing on it to make a T2 flanged GT30 turbo (and they don't re-name it accordingly).

Strange combinations are being made now-a-days to accommodate weird packaging issues and power needs of enthusiasts.

http://www.turbobygarrett.com/turbobygarrett/news/race_updates/Garrett_GTXflyer.pdf

I thought garret was bashing all the new billet turbos ?? now they are on the bandwagon ?

It would seem they feel there is no benefit to billet wheels other than quick turn-around for production (cast wheels take more time to bring to market). They were probably lauding billet wheels as nothing special, and trying to combat BW using it as a selling point when there is no performance gain with them.

nice info ben.

nice info ben.

Heres a good link to their product catalog
TurboByGarrett.com - Catalog
Ben, would this be one of the situations that they are using a diffrent compressor wheels and turbines and not re-naming the turbos? It seems like these are custom turbos someone other than garrett is putting together:
GT3076R-WG-TURBO : atpturbo.com

Although the Turbo that I am using in my car is a GT2860RS (and the one I am planning to install as an upgrade is a GT2871) the GT3071R (PN700382-20) uses the same mount or base (T2 size) as the T25 and T28 Turbos, and it is supposed to fit using the same exhaust manifold. It is basically a GT2871 compressor with a bigger 56.5mm (T3 size) Turbine.

Guess I'm not cool enough for Ben to respond to my post...